M. Alexander Otto

SAN DIEGO – Male gender, obesity, pain level, and baseline radiographic severity independently predict the progression of knee osteoarthritis, while race and baseline multiple joint involvement, knee misalignment, and physical inactivity do not, according to the results of a large cohort study.

The findings could help drug developers figure out whom to include in trials of drugs aimed at slowing progression. Also, the blood, DNA, and other samples collected in the study, upon further analysis, may suggest new drug targets in people at risk for progression, said lead investigator Dr. Charles Eaton, professor of family medicine at Brown University, Providence, R.I.

"It may be some of the metabolic factors related to obesity," such as inflammation, "make you progress," and could be targeted in drug development, he said.

Meanwhile, it’s a good idea to encourage obese patients who have knee osteoarthritis (OA) to lose weight. Also, "if you have a male coming in complaining of a lot of knee pain, they might be at high risk for progression. Get an x-ray and see if they actually have arthritis, and see how severe it is," Dr. Eaton said at the World Congress on Osteoarthritis.

He and his colleagues used publicly available data from the Osteoarthritis Initiative, a multicenter longitudinal cohort study looking for biomarkers of incidence and progression, to track 1,842 knees in 1,247 knee OA patients. For each knee, the investigators analyzed x-rays taken at baseline and at 4 years of follow-up to see who had medial joint-space narrowing of 0.5 mm or more. The researchers then looked to see what baseline characteristics predicted progression. Subjects were 45-79 years old. Almost 60% of the knees in the study belonged to women.

Compared with women, the adjusted odds ratio for progression among men was 1.27 (95% confidence interval 1.02-1.59).

Patients who entered the study with Kellgren-Lawrence grade 3 disease, instead of grade 2 disease, had twice the risk of progression (OR 2.09, 95% CI 1.72-2.54). Those who enrolled with a body mass index of 30 kg/m² or higher were about 1.5 times more likely to progress than those who entered with a BMI below 25 kg/m² (OR 1.41, 95% CI 1.02-1.96).

Patients with the worst pain at baseline – WOMAC (Western Ontario and McMaster Universities index) pain scores in the fourth quartile – were twice as likely to progress as those who entered with first quartile pain (OR 2.18, 95% CI 1.69-2.82).

Time itself was a factor, too; 4 years into the trial, patients were nine times as likely as in the first year to have progressed (OR 9.14, 95% CI 7.45-11.22).

"Previously, it was thought that females were more likely to progress. Initial studies suggested that African Americans were more likely to progress. But when we adjusted for everything, that was no longer true," Dr. Eaton said. Baseline income, smoking, depression, and Knee Injury and Osteoarthritis Outcome Score (KOOS) functionality were among the other potential risk-factors that did not pan out on multivariate analysis.

"We are trying to understand" the increased risk for men. Men may have entered the trial with a greater burden of meniscal damage than women, and a greater likelihood of past knee surgery; there was a trend in the data toward increased progression risk for previous knee operations, but it dropped out on multivariate analysis.

The meeting was sponsored by the Osteoarthritis Research Society International.

The Osteoarthritis Initiative is funded by the National Institutes of Health, Merck, GlaxoSmithKline, Novartis Pharmaceuticals, and Pfizer. Dr. Eaton said he had no disclosures.

SAN DIEGO – Male gender, obesity, pain level, and baseline radiographic severity independently predict the progression of knee osteoarthritis, while race and baseline multiple joint involvement, knee misalignment, and physical inactivity do not, according to the results of a large cohort study.

The findings could help drug developers figure out whom to include in trials of drugs aimed at slowing progression. Also, the blood, DNA, and other samples collected in the study, upon further analysis, may suggest new drug targets in people at risk for progression, said lead investigator Dr. Charles Eaton, professor of family medicine at Brown University, Providence, R.I.

"It may be some of the metabolic factors related to obesity," such as inflammation, "make you progress," and could be targeted in drug development, he said.

Meanwhile, it’s a good idea to encourage obese patients who have knee osteoarthritis (OA) to lose weight. Also, "if you have a male coming in complaining of a lot of knee pain, they might be at high risk for progression. Get an x-ray and see if they actually have arthritis, and see how severe it is," Dr. Eaton said at the World Congress on Osteoarthritis.

He and his colleagues used publicly available data from the Osteoarthritis Initiative, a multicenter longitudinal cohort study looking for biomarkers of incidence and progression, to track 1,842 knees in 1,247 knee OA patients. For each knee, the investigators analyzed x-rays taken at baseline and at 4 years of follow-up to see who had medial joint-space narrowing of 0.5 mm or more. The researchers then looked to see what baseline characteristics predicted progression. Subjects were 45-79 years old. Almost 60% of the knees in the study belonged to women.

Compared with women, the adjusted odds ratio for progression among men was 1.27 (95% confidence interval 1.02-1.59).

Patients who entered the study with Kellgren-Lawrence grade 3 disease, instead of grade 2 disease, had twice the risk of progression (OR 2.09, 95% CI 1.72-2.54). Those who enrolled with a body mass index of 30 kg/m² or higher were about 1.5 times more likely to progress than those who entered with a BMI below 25 kg/m² (OR 1.41, 95% CI 1.02-1.96).

Patients with the worst pain at baseline – WOMAC (Western Ontario and McMaster Universities index) pain scores in the fourth quartile – were twice as likely to progress as those who entered with first quartile pain (OR 2.18, 95% CI 1.69-2.82).

Time itself was a factor, too; 4 years into the trial, patients were nine times as likely as in the first year to have progressed (OR 9.14, 95% CI 7.45-11.22).

"Previously, it was thought that females were more likely to progress. Initial studies suggested that African Americans were more likely to progress. But when we adjusted for everything, that was no longer true," Dr. Eaton said. Baseline income, smoking, depression, and Knee Injury and Osteoarthritis Outcome Score (KOOS) functionality were among the other potential risk-factors that did not pan out on multivariate analysis.

"We are trying to understand" the increased risk for men. Men may have entered the trial with a greater burden of meniscal damage than women, and a greater likelihood of past knee surgery; there was a trend in the data toward increased progression risk for previous knee operations, but it dropped out on multivariate analysis.

The meeting was sponsored by the Osteoarthritis Research Society International.

The Osteoarthritis Initiative is funded by the National Institutes of Health, Merck, GlaxoSmithKline, Novartis Pharmaceuticals, and Pfizer. Dr. Eaton said he had no disclosures.

SAN DIEGO – Male gender, obesity, pain level, and baseline radiographic severity independently predict the progression of knee osteoarthritis, while race and baseline multiple joint involvement, knee misalignment, and physical inactivity do not, according to the results of a large cohort study.

The findings could help drug developers figure out whom to include in trials of drugs aimed at slowing progression. Also, the blood, DNA, and other samples collected in the study, upon further analysis, may suggest new drug targets in people at risk for progression, said lead investigator Dr. Charles Eaton, professor of family medicine at Brown University, Providence, R.I.

"It may be some of the metabolic factors related to obesity," such as inflammation, "make you progress," and could be targeted in drug development, he said.

Meanwhile, it’s a good idea to encourage obese patients who have knee osteoarthritis (OA) to lose weight. Also, "if you have a male coming in complaining of a lot of knee pain, they might be at high risk for progression. Get an x-ray and see if they actually have arthritis, and see how severe it is," Dr. Eaton said at the World Congress on Osteoarthritis.

He and his colleagues used publicly available data from the Osteoarthritis Initiative, a multicenter longitudinal cohort study looking for biomarkers of incidence and progression, to track 1,842 knees in 1,247 knee OA patients. For each knee, the investigators analyzed x-rays taken at baseline and at 4 years of follow-up to see who had medial joint-space narrowing of 0.5 mm or more. The researchers then looked to see what baseline characteristics predicted progression. Subjects were 45-79 years old. Almost 60% of the knees in the study belonged to women.

Compared with women, the adjusted odds ratio for progression among men was 1.27 (95% confidence interval 1.02-1.59).

Patients who entered the study with Kellgren-Lawrence grade 3 disease, instead of grade 2 disease, had twice the risk of progression (OR 2.09, 95% CI 1.72-2.54). Those who enrolled with a body mass index of 30 kg/m² or higher were about 1.5 times more likely to progress than those who entered with a BMI below 25 kg/m² (OR 1.41, 95% CI 1.02-1.96).

Patients with the worst pain at baseline – WOMAC (Western Ontario and McMaster Universities index) pain scores in the fourth quartile – were twice as likely to progress as those who entered with first quartile pain (OR 2.18, 95% CI 1.69-2.82).

Time itself was a factor, too; 4 years into the trial, patients were nine times as likely as in the first year to have progressed (OR 9.14, 95% CI 7.45-11.22).

"Previously, it was thought that females were more likely to progress. Initial studies suggested that African Americans were more likely to progress. But when we adjusted for everything, that was no longer true," Dr. Eaton said. Baseline income, smoking, depression, and Knee Injury and Osteoarthritis Outcome Score (KOOS) functionality were among the other potential risk-factors that did not pan out on multivariate analysis.

"We are trying to understand" the increased risk for men. Men may have entered the trial with a greater burden of meniscal damage than women, and a greater likelihood of past knee surgery; there was a trend in the data toward increased progression risk for previous knee operations, but it dropped out on multivariate analysis.

The meeting was sponsored by the Osteoarthritis Research Society International.

The Osteoarthritis Initiative is funded by the National Institutes of Health, Merck, GlaxoSmithKline, Novartis Pharmaceuticals, and Pfizer. Dr. Eaton said he had no disclosures.

SAN DIEGO – It’s not unusual for total knee replacement patients to have arthritis in other joints, and it negatively impacts surgery outcomes, Toronto researchers have found.

In their study, 420 of 494 knee replacement patients (85%) reported problems in at least one other joint. Those with foot or ankle arthritis had a significantly reduced chance of achieving an MCID (Minimally Clinically Important Difference) on postoperative WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) pain and function scores (odds ratio pain 0.32, 95% confidence interval 0.185-0.544; OR function 0.53, 95% CI 0.303, 0.940).

Patients who reported neck problems also had reduced odds of achieving an MCID on physical function WOMAC scores (OR 0.37, 95% CI 0.183, 0.726).

"It’s not surprising that ankles and feet [were] significant. [They] impact activities for which lower-extremity joints are involved. How the upper extremities are associated here, in particular the neck, is unclear," said lead investigator Anthony Perruccio, Ph.D., an epidemiologist and research scientist at the Toronto Western Research Institute.

Because patients with neck problems also saw less improvement in fatigue, anxiety, depression, and pain, there may also be a mental health component, he said.

Whatever the case, the lesson is to treat the whole patient, not just the knee. Referrals to other types of providers are appropriate, including physiotherapists and mental health counselors as needed, said Dr. Perruccio.

"There’s more than just the one joint that’s involved here. Outcomes could be improved if a more holistic approach to osteoarthritis management were considered," he said.

All 494 patients had primary, unilateral knee replacements secondary to osteoarthritis. Their mean age was 65, 65% were women, and almost half were obese.

The patients filled out several surveys before their operations, including WOMAC and other pain and function scales plus the Profile of Mood States (POMS) fatigue scale, the Knee injury and Osteoarthritis Outcome Score (KOOS) sports and recreation scale, and the Hospital Anxiety and Depression Scale (HADS). They also pointed out on a homunculus diagram which joints were causing trouble.

Almost half (46%) reported pain on most days in four or more joints in addition to their operative knee. The nonoperative knee was a problem for 57%, elbows/wrists/hands were problematic for 49%, ankles/feet for 36%, the back for 31%, shoulders for 29%, hips for 25%, and neck for 22%. Just 15% said only their operative knee was symptomatic.

A year after their operation, patients took the surveys again. Those with back problems tended to see less improvement in fatigue at 1 year. Those with ankle or foot arthritis – in addition to diminished returns on pain and function – also saw less improvement than others in depression and sports and recreation scores.

The congress was sponsored by the Osteoarthritis Research Society International. Dr. Perruccio said he had no relevant financial disclosures. The work was funded by the Canadian Institutes of Health Research.

* Correction, 10/21/11: The original headline of this story, "Knee Replacement Worsens Arthritis in Other Joints," misrepresented the findings of this study. The headline has been revised.

SAN DIEGO – It’s not unusual for total knee replacement patients to have arthritis in other joints, and it negatively impacts surgery outcomes, Toronto researchers have found.

In their study, 420 of 494 knee replacement patients (85%) reported problems in at least one other joint. Those with foot or ankle arthritis had a significantly reduced chance of achieving an MCID (Minimally Clinically Important Difference) on postoperative WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) pain and function scores (odds ratio pain 0.32, 95% confidence interval 0.185-0.544; OR function 0.53, 95% CI 0.303, 0.940).

Patients who reported neck problems also had reduced odds of achieving an MCID on physical function WOMAC scores (OR 0.37, 95% CI 0.183, 0.726).

"It’s not surprising that ankles and feet [were] significant. [They] impact activities for which lower-extremity joints are involved. How the upper extremities are associated here, in particular the neck, is unclear," said lead investigator Anthony Perruccio, Ph.D., an epidemiologist and research scientist at the Toronto Western Research Institute.

Because patients with neck problems also saw less improvement in fatigue, anxiety, depression, and pain, there may also be a mental health component, he said.

Whatever the case, the lesson is to treat the whole patient, not just the knee. Referrals to other types of providers are appropriate, including physiotherapists and mental health counselors as needed, said Dr. Perruccio.

"There’s more than just the one joint that’s involved here. Outcomes could be improved if a more holistic approach to osteoarthritis management were considered," he said.

All 494 patients had primary, unilateral knee replacements secondary to osteoarthritis. Their mean age was 65, 65% were women, and almost half were obese.

The patients filled out several surveys before their operations, including WOMAC and other pain and function scales plus the Profile of Mood States (POMS) fatigue scale, the Knee injury and Osteoarthritis Outcome Score (KOOS) sports and recreation scale, and the Hospital Anxiety and Depression Scale (HADS). They also pointed out on a homunculus diagram which joints were causing trouble.

Almost half (46%) reported pain on most days in four or more joints in addition to their operative knee. The nonoperative knee was a problem for 57%, elbows/wrists/hands were problematic for 49%, ankles/feet for 36%, the back for 31%, shoulders for 29%, hips for 25%, and neck for 22%. Just 15% said only their operative knee was symptomatic.

A year after their operation, patients took the surveys again. Those with back problems tended to see less improvement in fatigue at 1 year. Those with ankle or foot arthritis – in addition to diminished returns on pain and function – also saw less improvement than others in depression and sports and recreation scores.

The congress was sponsored by the Osteoarthritis Research Society International. Dr. Perruccio said he had no relevant financial disclosures. The work was funded by the Canadian Institutes of Health Research.

* Correction, 10/21/11: The original headline of this story, "Knee Replacement Worsens Arthritis in Other Joints," misrepresented the findings of this study. The headline has been revised.

SAN DIEGO – It’s not unusual for total knee replacement patients to have arthritis in other joints, and it negatively impacts surgery outcomes, Toronto researchers have found.

In their study, 420 of 494 knee replacement patients (85%) reported problems in at least one other joint. Those with foot or ankle arthritis had a significantly reduced chance of achieving an MCID (Minimally Clinically Important Difference) on postoperative WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) pain and function scores (odds ratio pain 0.32, 95% confidence interval 0.185-0.544; OR function 0.53, 95% CI 0.303, 0.940).

Patients who reported neck problems also had reduced odds of achieving an MCID on physical function WOMAC scores (OR 0.37, 95% CI 0.183, 0.726).

"It’s not surprising that ankles and feet [were] significant. [They] impact activities for which lower-extremity joints are involved. How the upper extremities are associated here, in particular the neck, is unclear," said lead investigator Anthony Perruccio, Ph.D., an epidemiologist and research scientist at the Toronto Western Research Institute.

Because patients with neck problems also saw less improvement in fatigue, anxiety, depression, and pain, there may also be a mental health component, he said.

Whatever the case, the lesson is to treat the whole patient, not just the knee. Referrals to other types of providers are appropriate, including physiotherapists and mental health counselors as needed, said Dr. Perruccio.

"There’s more than just the one joint that’s involved here. Outcomes could be improved if a more holistic approach to osteoarthritis management were considered," he said.

All 494 patients had primary, unilateral knee replacements secondary to osteoarthritis. Their mean age was 65, 65% were women, and almost half were obese.

The patients filled out several surveys before their operations, including WOMAC and other pain and function scales plus the Profile of Mood States (POMS) fatigue scale, the Knee injury and Osteoarthritis Outcome Score (KOOS) sports and recreation scale, and the Hospital Anxiety and Depression Scale (HADS). They also pointed out on a homunculus diagram which joints were causing trouble.

Almost half (46%) reported pain on most days in four or more joints in addition to their operative knee. The nonoperative knee was a problem for 57%, elbows/wrists/hands were problematic for 49%, ankles/feet for 36%, the back for 31%, shoulders for 29%, hips for 25%, and neck for 22%. Just 15% said only their operative knee was symptomatic.

A year after their operation, patients took the surveys again. Those with back problems tended to see less improvement in fatigue at 1 year. Those with ankle or foot arthritis – in addition to diminished returns on pain and function – also saw less improvement than others in depression and sports and recreation scores.

The congress was sponsored by the Osteoarthritis Research Society International. Dr. Perruccio said he had no relevant financial disclosures. The work was funded by the Canadian Institutes of Health Research.

* Correction, 10/21/11: The original headline of this story, "Knee Replacement Worsens Arthritis in Other Joints," misrepresented the findings of this study. The headline has been revised.

SAN DIEGO – Patients with severe pain in the first 3 months after total knee replacement have worse pain and function outcomes at 1 and 2 years, and are less satisfied with the procedure, Boston researchers have found.

Because of that, severe pain after the operation "is something that we ought to be intervening on," said lead investigator Dr. Jeffrey N. Katz, professor of medicine and orthopedic surgery at Harvard Medical School, Boston.

Depressed, catastrophizing patients and those in severe pain before the operation are all at risk for severe pain afterward. Using cognitive-behavioral therapy and optimizing antidepressant dosages and pain control can help, both before and after the operation, Dr. Katz said at the World Congress on Osteoarthritis.

Also, "people might consider operating sooner," before pain becomes severe, he said.

Of the approximately 600,000 total knee replacements in the United States every year, about 15% of patients have severe pain after the operation, but until now, it wasn’t known "whether that portends poor outcomes over time," Dr. Katz said.

His team found that it did, at least in the 622 unilateral, primary, total knee replacement patients in their study. Overall, 62% were aged older than 65 years, 58% were women, 35% had a body mass index greater than 30 kg/m²; and about half had two or more comorbidities.

Their mean preoperative function score on the WOMAC (Western Ontario and McMaster Universities) osteoarthritis index was 47, and their mean preoperative WOMAC pain score was 41 (with 100 being the best score on the WOMAC index and 0 the worst possible).

Following the surgery, 15% of the patients had WOMAC pain scores lower than 50 at 3 months, which indicated severe pain. Dr. Katz and his team compared these patients with the other 85%.

The patients with severe pain at 3 months had mean WOMAC function scores of about 60 at both the 1- and 2-year follow-up. The 85% of patients without severe pain had function scores in the mid-70s at both points.

Similarly, the severe pain group had WOMAC pain scores in the mid-60s at both 1 and 2 years. The other patients had mean WOMAC scores in the mid-80s at both points.

About 60% in the severe pain group said they couldn’t walk five blocks at both 1 and 2 years. Among those without severe pain, about 40% said that couldn’t walk five blocks at both points.

Finally, about a quarter of patients in the severe pain group were dissatisfied with their surgery at both 1 and 2 years afterward. About 5% of patients without severe postsurgical pain were dissatisfied with their operation at 1 year and about 3% were dissatisfied at 2 years. All the results were statistically significant (P less than .001).

The patients came from 12 referral centers in the United States, the United Kingdom, and Australia. The study did not capture the reasons for the pain, the problems with implants (if any), or the patients’ psychiatric histories.

Dr. Katz said that the 5-year findings appear to be similar to the 1- and 2-year results, but there weren’t enough data to include them in the analysis.

The congress was sponsored by the Osteoarthritis Research Society International. The study was funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases. The data used in the analysis came from a multicenter, prospective cohort study sponsored by implant maker Stryker Corp. about a decade ago. Dr. Katz said he has no disclosures.

SAN DIEGO – Patients with severe pain in the first 3 months after total knee replacement have worse pain and function outcomes at 1 and 2 years, and are less satisfied with the procedure, Boston researchers have found.

Because of that, severe pain after the operation "is something that we ought to be intervening on," said lead investigator Dr. Jeffrey N. Katz, professor of medicine and orthopedic surgery at Harvard Medical School, Boston.

Depressed, catastrophizing patients and those in severe pain before the operation are all at risk for severe pain afterward. Using cognitive-behavioral therapy and optimizing antidepressant dosages and pain control can help, both before and after the operation, Dr. Katz said at the World Congress on Osteoarthritis.

Also, "people might consider operating sooner," before pain becomes severe, he said.

Of the approximately 600,000 total knee replacements in the United States every year, about 15% of patients have severe pain after the operation, but until now, it wasn’t known "whether that portends poor outcomes over time," Dr. Katz said.

His team found that it did, at least in the 622 unilateral, primary, total knee replacement patients in their study. Overall, 62% were aged older than 65 years, 58% were women, 35% had a body mass index greater than 30 kg/m²; and about half had two or more comorbidities.

Their mean preoperative function score on the WOMAC (Western Ontario and McMaster Universities) osteoarthritis index was 47, and their mean preoperative WOMAC pain score was 41 (with 100 being the best score on the WOMAC index and 0 the worst possible).

Following the surgery, 15% of the patients had WOMAC pain scores lower than 50 at 3 months, which indicated severe pain. Dr. Katz and his team compared these patients with the other 85%.

The patients with severe pain at 3 months had mean WOMAC function scores of about 60 at both the 1- and 2-year follow-up. The 85% of patients without severe pain had function scores in the mid-70s at both points.

Similarly, the severe pain group had WOMAC pain scores in the mid-60s at both 1 and 2 years. The other patients had mean WOMAC scores in the mid-80s at both points.

About 60% in the severe pain group said they couldn’t walk five blocks at both 1 and 2 years. Among those without severe pain, about 40% said that couldn’t walk five blocks at both points.

Finally, about a quarter of patients in the severe pain group were dissatisfied with their surgery at both 1 and 2 years afterward. About 5% of patients without severe postsurgical pain were dissatisfied with their operation at 1 year and about 3% were dissatisfied at 2 years. All the results were statistically significant (P less than .001).

The patients came from 12 referral centers in the United States, the United Kingdom, and Australia. The study did not capture the reasons for the pain, the problems with implants (if any), or the patients’ psychiatric histories.

Dr. Katz said that the 5-year findings appear to be similar to the 1- and 2-year results, but there weren’t enough data to include them in the analysis.

The congress was sponsored by the Osteoarthritis Research Society International. The study was funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases. The data used in the analysis came from a multicenter, prospective cohort study sponsored by implant maker Stryker Corp. about a decade ago. Dr. Katz said he has no disclosures.

SAN DIEGO – Patients with severe pain in the first 3 months after total knee replacement have worse pain and function outcomes at 1 and 2 years, and are less satisfied with the procedure, Boston researchers have found.

Because of that, severe pain after the operation "is something that we ought to be intervening on," said lead investigator Dr. Jeffrey N. Katz, professor of medicine and orthopedic surgery at Harvard Medical School, Boston.

Depressed, catastrophizing patients and those in severe pain before the operation are all at risk for severe pain afterward. Using cognitive-behavioral therapy and optimizing antidepressant dosages and pain control can help, both before and after the operation, Dr. Katz said at the World Congress on Osteoarthritis.

Also, "people might consider operating sooner," before pain becomes severe, he said.

Of the approximately 600,000 total knee replacements in the United States every year, about 15% of patients have severe pain after the operation, but until now, it wasn’t known "whether that portends poor outcomes over time," Dr. Katz said.

His team found that it did, at least in the 622 unilateral, primary, total knee replacement patients in their study. Overall, 62% were aged older than 65 years, 58% were women, 35% had a body mass index greater than 30 kg/m²; and about half had two or more comorbidities.

Their mean preoperative function score on the WOMAC (Western Ontario and McMaster Universities) osteoarthritis index was 47, and their mean preoperative WOMAC pain score was 41 (with 100 being the best score on the WOMAC index and 0 the worst possible).

Following the surgery, 15% of the patients had WOMAC pain scores lower than 50 at 3 months, which indicated severe pain. Dr. Katz and his team compared these patients with the other 85%.

The patients with severe pain at 3 months had mean WOMAC function scores of about 60 at both the 1- and 2-year follow-up. The 85% of patients without severe pain had function scores in the mid-70s at both points.

Similarly, the severe pain group had WOMAC pain scores in the mid-60s at both 1 and 2 years. The other patients had mean WOMAC scores in the mid-80s at both points.

About 60% in the severe pain group said they couldn’t walk five blocks at both 1 and 2 years. Among those without severe pain, about 40% said that couldn’t walk five blocks at both points.

Finally, about a quarter of patients in the severe pain group were dissatisfied with their surgery at both 1 and 2 years afterward. About 5% of patients without severe postsurgical pain were dissatisfied with their operation at 1 year and about 3% were dissatisfied at 2 years. All the results were statistically significant (P less than .001).

The patients came from 12 referral centers in the United States, the United Kingdom, and Australia. The study did not capture the reasons for the pain, the problems with implants (if any), or the patients’ psychiatric histories.

Dr. Katz said that the 5-year findings appear to be similar to the 1- and 2-year results, but there weren’t enough data to include them in the analysis.

The congress was sponsored by the Osteoarthritis Research Society International. The study was funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases. The data used in the analysis came from a multicenter, prospective cohort study sponsored by implant maker Stryker Corp. about a decade ago. Dr. Katz said he has no disclosures.

Major Finding: Following training on a birth simulator, the percentage of clinicians pulling with more than 150 N during simulated shoulder dystocia deliveries fell from 75% to 43%.

Data Source: A nonrandomized educational intervention involving 40 clinicians.

Disclosures: Dr. Guise said she had no relevant financial disclosures. The project was funded by the Agency for Healthcare Research and Quality (AHRQ).

SEATTLE – Use of a birth force simulator taught clinicians better how to modulate how much force they use when handling a case of shoulder dystocia to avoid brachial plexus and other injuries.

The pull should be no more than 100 newtons (N), a gentle but firm traction, according to Dr. Jeanne-Marie Guise, an obstetrician and gynecologist at Oregon Health and Science University, Portland. It's hard to know, however, exactly how much that is. Shoulder dystocia occurs in only 0.2%-3.0% of births, so training opportunities are rare, and shoulder dystocia emergencies are not very teachable moments. Dr. Guise and her colleagues wanted to see if training on a birth simulator would help clinicians get a feel for how much force to use.

Twenty-eight obstetricians, six family physicians, and six certified midwives, with experience ranging from 6 months to 34 years, were trained on a PROMPT birthing simulator with force monitoring, made by Limbs & Things Ltd. (Bristol, England). Initially, they were blinded to the force-monitoring screen; 38 (95%) pulled with more than 100 N, 30 (75%) with more than 150 N, and 21 (53%) with more than 200 N. Greater force was used as time wore on.

Then, while watching the screen and then from memory, participants pulled with 50 N and then 100 N several times, to get a feel for what those levels of force felt like. At 100 N, Dr. Guise told them, “this is the most you should ever feel, so pay attention” to what it feels like: “If you're starting to shake, how your facial muscles feel,” and so on.

To see if the training took, participants went through surprise simulations. During their shifts, a nurse came running up saying, “I need a doctor, I need a doctor!” Trainees were pulled into a triage room, “but didn't exactly know why,” Dr. Guise said. In the room, they faced the PROMPT simulator again, but this time with an actress playing the part of a frantic mother during a shoulder dystocia delivery. Participants couldn't see the force-monitoring screen. “We plummeted the heart rate and tried to get everything as realistic as it could be. The actress was really acting it up,” she said.

Even under pressure, training made a significant difference. Although 33 (82%) of the participants used more than 100 N, only 17 (43%) used more than 150 N, and 11 (28%) used more than 200 N. “There was a reduction in overall forces applied after simulation training. Participants were able to gauge forces applied after training,” Dr. Guise and her colleagues concluded in the study abstract.

“It's nice to find a way to teach providers to modulate the amount of force in a moment that's not as critical,” she said.

Major Finding: Following training on a birth simulator, the percentage of clinicians pulling with more than 150 N during simulated shoulder dystocia deliveries fell from 75% to 43%.

Data Source: A nonrandomized educational intervention involving 40 clinicians.

Disclosures: Dr. Guise said she had no relevant financial disclosures. The project was funded by the Agency for Healthcare Research and Quality (AHRQ).

SEATTLE – Use of a birth force simulator taught clinicians better how to modulate how much force they use when handling a case of shoulder dystocia to avoid brachial plexus and other injuries.

The pull should be no more than 100 newtons (N), a gentle but firm traction, according to Dr. Jeanne-Marie Guise, an obstetrician and gynecologist at Oregon Health and Science University, Portland. It's hard to know, however, exactly how much that is. Shoulder dystocia occurs in only 0.2%-3.0% of births, so training opportunities are rare, and shoulder dystocia emergencies are not very teachable moments. Dr. Guise and her colleagues wanted to see if training on a birth simulator would help clinicians get a feel for how much force to use.

Twenty-eight obstetricians, six family physicians, and six certified midwives, with experience ranging from 6 months to 34 years, were trained on a PROMPT birthing simulator with force monitoring, made by Limbs & Things Ltd. (Bristol, England). Initially, they were blinded to the force-monitoring screen; 38 (95%) pulled with more than 100 N, 30 (75%) with more than 150 N, and 21 (53%) with more than 200 N. Greater force was used as time wore on.

Then, while watching the screen and then from memory, participants pulled with 50 N and then 100 N several times, to get a feel for what those levels of force felt like. At 100 N, Dr. Guise told them, “this is the most you should ever feel, so pay attention” to what it feels like: “If you're starting to shake, how your facial muscles feel,” and so on.

To see if the training took, participants went through surprise simulations. During their shifts, a nurse came running up saying, “I need a doctor, I need a doctor!” Trainees were pulled into a triage room, “but didn't exactly know why,” Dr. Guise said. In the room, they faced the PROMPT simulator again, but this time with an actress playing the part of a frantic mother during a shoulder dystocia delivery. Participants couldn't see the force-monitoring screen. “We plummeted the heart rate and tried to get everything as realistic as it could be. The actress was really acting it up,” she said.

Even under pressure, training made a significant difference. Although 33 (82%) of the participants used more than 100 N, only 17 (43%) used more than 150 N, and 11 (28%) used more than 200 N. “There was a reduction in overall forces applied after simulation training. Participants were able to gauge forces applied after training,” Dr. Guise and her colleagues concluded in the study abstract.

“It's nice to find a way to teach providers to modulate the amount of force in a moment that's not as critical,” she said.

Major Finding: Following training on a birth simulator, the percentage of clinicians pulling with more than 150 N during simulated shoulder dystocia deliveries fell from 75% to 43%.

Data Source: A nonrandomized educational intervention involving 40 clinicians.

Disclosures: Dr. Guise said she had no relevant financial disclosures. The project was funded by the Agency for Healthcare Research and Quality (AHRQ).

SEATTLE – Use of a birth force simulator taught clinicians better how to modulate how much force they use when handling a case of shoulder dystocia to avoid brachial plexus and other injuries.

The pull should be no more than 100 newtons (N), a gentle but firm traction, according to Dr. Jeanne-Marie Guise, an obstetrician and gynecologist at Oregon Health and Science University, Portland. It's hard to know, however, exactly how much that is. Shoulder dystocia occurs in only 0.2%-3.0% of births, so training opportunities are rare, and shoulder dystocia emergencies are not very teachable moments. Dr. Guise and her colleagues wanted to see if training on a birth simulator would help clinicians get a feel for how much force to use.

Twenty-eight obstetricians, six family physicians, and six certified midwives, with experience ranging from 6 months to 34 years, were trained on a PROMPT birthing simulator with force monitoring, made by Limbs & Things Ltd. (Bristol, England). Initially, they were blinded to the force-monitoring screen; 38 (95%) pulled with more than 100 N, 30 (75%) with more than 150 N, and 21 (53%) with more than 200 N. Greater force was used as time wore on.

Then, while watching the screen and then from memory, participants pulled with 50 N and then 100 N several times, to get a feel for what those levels of force felt like. At 100 N, Dr. Guise told them, “this is the most you should ever feel, so pay attention” to what it feels like: “If you're starting to shake, how your facial muscles feel,” and so on.

To see if the training took, participants went through surprise simulations. During their shifts, a nurse came running up saying, “I need a doctor, I need a doctor!” Trainees were pulled into a triage room, “but didn't exactly know why,” Dr. Guise said. In the room, they faced the PROMPT simulator again, but this time with an actress playing the part of a frantic mother during a shoulder dystocia delivery. Participants couldn't see the force-monitoring screen. “We plummeted the heart rate and tried to get everything as realistic as it could be. The actress was really acting it up,” she said.

Even under pressure, training made a significant difference. Although 33 (82%) of the participants used more than 100 N, only 17 (43%) used more than 150 N, and 11 (28%) used more than 200 N. “There was a reduction in overall forces applied after simulation training. Participants were able to gauge forces applied after training,” Dr. Guise and her colleagues concluded in the study abstract.

“It's nice to find a way to teach providers to modulate the amount of force in a moment that's not as critical,” she said.

SAN DIEGO – Separating an osteoarthritic knee joint for 2 months – that is, stretching the top of the tibia away from the base of the femur and holding the bones in place with pins set into an external fixation frame – stimulates the joint to produce new cartilage, thereby reducing pain and improving function for at least 2 years, according to findings from a small European pilot study.

The 20 patients in the trial were all facing knee replacement due to osteoarthritis (OA); the technique, known as knee joint distraction, has postponed surgery for 2 years and counting in the subjects. The hope is the patients will never need an artificial knee, according to senior investigator Dr. Floris Lafeber, a professor of experimental rheumatology at the University Medical Center Utrecht (the Netherlands).

Their minimum joint space width increased from a baseline mean of 1.0 mm to 1.8 mm at 2 years. Patients started the trial with, on average, about 22% of their subchondral bone denuded; that dropped to about 8% at 2 years.

In short, there was an “astonishing increase in cartilage volume,” Dr. Lafeber said at the congress, which was sponsored by the Osteoarthritis Research Society International.

Meanwhile, total WOMAC (Western Ontario and McMaster Universities) osteoarthritis index scores increased from about 45% at baseline to about 78% at 2 years, with improvements in WOMAC pain, function, and stiffness subscales. Visual Analog Scale pain scores improved from 73 at baseline to 28 at 2 years. The results were statistically significant.

The technique, which had been used in the past for ankle OAs, “looks very promising” for osteoarthritic knees, Dr. Lafeber said. The 1 year results have been previously published (Ann. Rheum. Dis. 2011;70:1441-6;; Rheumatology News, August 2011, p. 28)

His team will next pit knee distraction against total knee replacement and osteotomy in two randomized trials. The researchers will keep tracking the original 20 patients as well. “We are now having follow-up of the first patients for more than 4 years, and no prostheses are placed yet,” Dr. Lafeber said.

The researchers plan “more sophisticated MRIs to look at the quality of the cartilage,” although the increased joint space on weight-bearing x-rays suggests mechanical competence. Biomarker analysis also suggests “the quality of the cartilage has a hyaline aspect,” according to Dr. Lafeber.

The 20 patients' average age was 49 years; 11 were women. All had end-stage, unilateral knee OA with severe pain and cartilage damage. Patients with major problems in both knees were excluded from the study. In a variation of the Ilizarov procedure, a tube with internal coil springs was placed on each side of the patients' osteoarthritic knees, bridging the joints. Joints were then distracted to 5 mm over a few days. Full weight bearing was allowed. The tubes and pins were removed after 2 months.

The theory is that temporarily unloading the knee prevents additional wear and tear and allows cartilage to start repairing itself. Pin sites became infected in 17 of the 20 patients, and were treated with local and oral antibiotics. Dr. Lafeber said he and his colleagues hope that technique refinements will reduce the infection rate.

“On the MRI, it looked [as if] the cartilage was regenerated, but it's unlikely to be truly hyaline articular cartilage.

“It's much more likely to be fibrocartilage, repair-type cartilage. It's difficult to know how long [patients] maintain that fibrocartilage” before it's worn away, said Dr. David Hunter, a rheumatologist, epidemiologist, and professor of medicine at the University of Sydney. “In terms of the clinical applicability of that intervention, I'm not sure it has much utility,”he said, noting that, pending randomized trial results, doubt about the clinical utility of the technique must be maintained.

Dr. Lafeber and Dr. Hunter each reported having no disclosures. The work was supported by the Dutch Arthritis Association.

Three years after a 2-month joint distraction, joint space is larger.

Source Images courtesy Dr. Floris Lafeber

SAN DIEGO – Separating an osteoarthritic knee joint for 2 months – that is, stretching the top of the tibia away from the base of the femur and holding the bones in place with pins set into an external fixation frame – stimulates the joint to produce new cartilage, thereby reducing pain and improving function for at least 2 years, according to findings from a small European pilot study.

The 20 patients in the trial were all facing knee replacement due to osteoarthritis (OA); the technique, known as knee joint distraction, has postponed surgery for 2 years and counting in the subjects. The hope is the patients will never need an artificial knee, according to senior investigator Dr. Floris Lafeber, a professor of experimental rheumatology at the University Medical Center Utrecht (the Netherlands).

Their minimum joint space width increased from a baseline mean of 1.0 mm to 1.8 mm at 2 years. Patients started the trial with, on average, about 22% of their subchondral bone denuded; that dropped to about 8% at 2 years.

In short, there was an “astonishing increase in cartilage volume,” Dr. Lafeber said at the congress, which was sponsored by the Osteoarthritis Research Society International.

Meanwhile, total WOMAC (Western Ontario and McMaster Universities) osteoarthritis index scores increased from about 45% at baseline to about 78% at 2 years, with improvements in WOMAC pain, function, and stiffness subscales. Visual Analog Scale pain scores improved from 73 at baseline to 28 at 2 years. The results were statistically significant.

The technique, which had been used in the past for ankle OAs, “looks very promising” for osteoarthritic knees, Dr. Lafeber said. The 1 year results have been previously published (Ann. Rheum. Dis. 2011;70:1441-6;; Rheumatology News, August 2011, p. 28)

His team will next pit knee distraction against total knee replacement and osteotomy in two randomized trials. The researchers will keep tracking the original 20 patients as well. “We are now having follow-up of the first patients for more than 4 years, and no prostheses are placed yet,” Dr. Lafeber said.

The researchers plan “more sophisticated MRIs to look at the quality of the cartilage,” although the increased joint space on weight-bearing x-rays suggests mechanical competence. Biomarker analysis also suggests “the quality of the cartilage has a hyaline aspect,” according to Dr. Lafeber.

The 20 patients' average age was 49 years; 11 were women. All had end-stage, unilateral knee OA with severe pain and cartilage damage. Patients with major problems in both knees were excluded from the study. In a variation of the Ilizarov procedure, a tube with internal coil springs was placed on each side of the patients' osteoarthritic knees, bridging the joints. Joints were then distracted to 5 mm over a few days. Full weight bearing was allowed. The tubes and pins were removed after 2 months.

The theory is that temporarily unloading the knee prevents additional wear and tear and allows cartilage to start repairing itself. Pin sites became infected in 17 of the 20 patients, and were treated with local and oral antibiotics. Dr. Lafeber said he and his colleagues hope that technique refinements will reduce the infection rate.

“On the MRI, it looked [as if] the cartilage was regenerated, but it's unlikely to be truly hyaline articular cartilage.

“It's much more likely to be fibrocartilage, repair-type cartilage. It's difficult to know how long [patients] maintain that fibrocartilage” before it's worn away, said Dr. David Hunter, a rheumatologist, epidemiologist, and professor of medicine at the University of Sydney. “In terms of the clinical applicability of that intervention, I'm not sure it has much utility,”he said, noting that, pending randomized trial results, doubt about the clinical utility of the technique must be maintained.

Dr. Lafeber and Dr. Hunter each reported having no disclosures. The work was supported by the Dutch Arthritis Association.

Three years after a 2-month joint distraction, joint space is larger.

Source Images courtesy Dr. Floris Lafeber

SAN DIEGO – Separating an osteoarthritic knee joint for 2 months – that is, stretching the top of the tibia away from the base of the femur and holding the bones in place with pins set into an external fixation frame – stimulates the joint to produce new cartilage, thereby reducing pain and improving function for at least 2 years, according to findings from a small European pilot study.

The 20 patients in the trial were all facing knee replacement due to osteoarthritis (OA); the technique, known as knee joint distraction, has postponed surgery for 2 years and counting in the subjects. The hope is the patients will never need an artificial knee, according to senior investigator Dr. Floris Lafeber, a professor of experimental rheumatology at the University Medical Center Utrecht (the Netherlands).

Their minimum joint space width increased from a baseline mean of 1.0 mm to 1.8 mm at 2 years. Patients started the trial with, on average, about 22% of their subchondral bone denuded; that dropped to about 8% at 2 years.

In short, there was an “astonishing increase in cartilage volume,” Dr. Lafeber said at the congress, which was sponsored by the Osteoarthritis Research Society International.

Meanwhile, total WOMAC (Western Ontario and McMaster Universities) osteoarthritis index scores increased from about 45% at baseline to about 78% at 2 years, with improvements in WOMAC pain, function, and stiffness subscales. Visual Analog Scale pain scores improved from 73 at baseline to 28 at 2 years. The results were statistically significant.

The technique, which had been used in the past for ankle OAs, “looks very promising” for osteoarthritic knees, Dr. Lafeber said. The 1 year results have been previously published (Ann. Rheum. Dis. 2011;70:1441-6;; Rheumatology News, August 2011, p. 28)

His team will next pit knee distraction against total knee replacement and osteotomy in two randomized trials. The researchers will keep tracking the original 20 patients as well. “We are now having follow-up of the first patients for more than 4 years, and no prostheses are placed yet,” Dr. Lafeber said.

The researchers plan “more sophisticated MRIs to look at the quality of the cartilage,” although the increased joint space on weight-bearing x-rays suggests mechanical competence. Biomarker analysis also suggests “the quality of the cartilage has a hyaline aspect,” according to Dr. Lafeber.

The 20 patients' average age was 49 years; 11 were women. All had end-stage, unilateral knee OA with severe pain and cartilage damage. Patients with major problems in both knees were excluded from the study. In a variation of the Ilizarov procedure, a tube with internal coil springs was placed on each side of the patients' osteoarthritic knees, bridging the joints. Joints were then distracted to 5 mm over a few days. Full weight bearing was allowed. The tubes and pins were removed after 2 months.

The theory is that temporarily unloading the knee prevents additional wear and tear and allows cartilage to start repairing itself. Pin sites became infected in 17 of the 20 patients, and were treated with local and oral antibiotics. Dr. Lafeber said he and his colleagues hope that technique refinements will reduce the infection rate.

“On the MRI, it looked [as if] the cartilage was regenerated, but it's unlikely to be truly hyaline articular cartilage.

“It's much more likely to be fibrocartilage, repair-type cartilage. It's difficult to know how long [patients] maintain that fibrocartilage” before it's worn away, said Dr. David Hunter, a rheumatologist, epidemiologist, and professor of medicine at the University of Sydney. “In terms of the clinical applicability of that intervention, I'm not sure it has much utility,”he said, noting that, pending randomized trial results, doubt about the clinical utility of the technique must be maintained.

Dr. Lafeber and Dr. Hunter each reported having no disclosures. The work was supported by the Dutch Arthritis Association.

Three years after a 2-month joint distraction, joint space is larger.

Source Images courtesy Dr. Floris Lafeber

Major Finding: After 8 weeks of strength training, subjects whose knees had been injected with a painful saline solution before each workout had quadriceps that were 22% stronger; the quadriceps of peers who didn't get painful injections were 7% stronger.

Data Source: Randomized, controlled trial involving 27 people.

Disclosures: Ms. Sorensen said she has no disclosures. The work was supported by the Association of Danish Physiotherapists.

SAN DIEGO – Induced knee pain appears to have improved strength training in a small, Danish randomized trial.

Researchers injected the right knee infrapatellar fat pads of 13 healthy subjects in their mid-20s with painful, hypertonic saline. Immediately afterward, participants did three sets of leg presses and knee extensions. After three sessions per week for 8 weeks, their right quadriceps were 22% stronger than at baseline. Fourteen controls, injected with nonpainful isotonic saline, increased quadricep strength by 7% (P less than .0001).

Common wisdom holds that pain diminishes muscle function, inhibits strength training, and may prevent rehabilitation in patients with knee problems, including osteoarthritis, but “no one has ever proven that is actually the case,” said lead study author Tina Sorensen, a doctoral candidate at the Institute of Sports Science and Clinical Biomechanics at the University of Southern Denmark in Odense.

The results suggest “maybe it's not that bad to exercise with pain, at least if it's not caused by inflammation”; perhaps they also hint at a role for induced pain in some settings, said Ms. Sorensen, who is a physiotherapist. The researchers said they are interested in seeing if their early results hold up in patients with actual knee problems.

Loads used in training were 80% of a given subject's maximum repetition strength, assessed weekly and without pain. Participants worked each set to the point of muscle fatigue, usually 8-12 repetitions, and rested a minute between sets. The groups were evenly matched, with no significant differences in height, body mass index, or baseline strength. There were 10 men in the pain group and 6 in the control group, but as with other factors, the difference was not statistically significant.

The injections (1 mL of saline under ultrasound guidance) came after a 10-minute warm-up on a stationary bicycle. The pain from the hypertonic shots diminished as subjects worked through their sets, starting on average at about 25 mm on the 100-mm visual analog pain scale and ending at about 10 mm. Strength was assessed weekly 30 minutes after training.

After 8 weeks, the right legs of subjects in the pain group were 24.6% stronger at 60 degrees of knee extension, 21.6% stronger at 120 degrees, and 19.6% at 180 degrees. Subjects in the control group were 7.5% stronger at 60 degrees of knee extension, 5.0% at 120 degrees, and 8.2% at 180 degrees.

“It could be that when you have pain, your type 1 muscle fibers [the endurance fibers,] are inhibited, and your type 2 [power and speed] fibers are easily recruited, which could explain why the pain group had the larger increase in muscle strength,” Ms. Sorensen said at the meeting, which was sponsored by the Osteoarthritis Research Society International.

Major Finding: After 8 weeks of strength training, subjects whose knees had been injected with a painful saline solution before each workout had quadriceps that were 22% stronger; the quadriceps of peers who didn't get painful injections were 7% stronger.

Data Source: Randomized, controlled trial involving 27 people.

Disclosures: Ms. Sorensen said she has no disclosures. The work was supported by the Association of Danish Physiotherapists.

SAN DIEGO – Induced knee pain appears to have improved strength training in a small, Danish randomized trial.

Researchers injected the right knee infrapatellar fat pads of 13 healthy subjects in their mid-20s with painful, hypertonic saline. Immediately afterward, participants did three sets of leg presses and knee extensions. After three sessions per week for 8 weeks, their right quadriceps were 22% stronger than at baseline. Fourteen controls, injected with nonpainful isotonic saline, increased quadricep strength by 7% (P less than .0001).

Common wisdom holds that pain diminishes muscle function, inhibits strength training, and may prevent rehabilitation in patients with knee problems, including osteoarthritis, but “no one has ever proven that is actually the case,” said lead study author Tina Sorensen, a doctoral candidate at the Institute of Sports Science and Clinical Biomechanics at the University of Southern Denmark in Odense.

The results suggest “maybe it's not that bad to exercise with pain, at least if it's not caused by inflammation”; perhaps they also hint at a role for induced pain in some settings, said Ms. Sorensen, who is a physiotherapist. The researchers said they are interested in seeing if their early results hold up in patients with actual knee problems.

Loads used in training were 80% of a given subject's maximum repetition strength, assessed weekly and without pain. Participants worked each set to the point of muscle fatigue, usually 8-12 repetitions, and rested a minute between sets. The groups were evenly matched, with no significant differences in height, body mass index, or baseline strength. There were 10 men in the pain group and 6 in the control group, but as with other factors, the difference was not statistically significant.

The injections (1 mL of saline under ultrasound guidance) came after a 10-minute warm-up on a stationary bicycle. The pain from the hypertonic shots diminished as subjects worked through their sets, starting on average at about 25 mm on the 100-mm visual analog pain scale and ending at about 10 mm. Strength was assessed weekly 30 minutes after training.

After 8 weeks, the right legs of subjects in the pain group were 24.6% stronger at 60 degrees of knee extension, 21.6% stronger at 120 degrees, and 19.6% at 180 degrees. Subjects in the control group were 7.5% stronger at 60 degrees of knee extension, 5.0% at 120 degrees, and 8.2% at 180 degrees.

“It could be that when you have pain, your type 1 muscle fibers [the endurance fibers,] are inhibited, and your type 2 [power and speed] fibers are easily recruited, which could explain why the pain group had the larger increase in muscle strength,” Ms. Sorensen said at the meeting, which was sponsored by the Osteoarthritis Research Society International.

Major Finding: After 8 weeks of strength training, subjects whose knees had been injected with a painful saline solution before each workout had quadriceps that were 22% stronger; the quadriceps of peers who didn't get painful injections were 7% stronger.

Data Source: Randomized, controlled trial involving 27 people.

Disclosures: Ms. Sorensen said she has no disclosures. The work was supported by the Association of Danish Physiotherapists.

SAN DIEGO – Induced knee pain appears to have improved strength training in a small, Danish randomized trial.

Researchers injected the right knee infrapatellar fat pads of 13 healthy subjects in their mid-20s with painful, hypertonic saline. Immediately afterward, participants did three sets of leg presses and knee extensions. After three sessions per week for 8 weeks, their right quadriceps were 22% stronger than at baseline. Fourteen controls, injected with nonpainful isotonic saline, increased quadricep strength by 7% (P less than .0001).

Common wisdom holds that pain diminishes muscle function, inhibits strength training, and may prevent rehabilitation in patients with knee problems, including osteoarthritis, but “no one has ever proven that is actually the case,” said lead study author Tina Sorensen, a doctoral candidate at the Institute of Sports Science and Clinical Biomechanics at the University of Southern Denmark in Odense.

The results suggest “maybe it's not that bad to exercise with pain, at least if it's not caused by inflammation”; perhaps they also hint at a role for induced pain in some settings, said Ms. Sorensen, who is a physiotherapist. The researchers said they are interested in seeing if their early results hold up in patients with actual knee problems.

Loads used in training were 80% of a given subject's maximum repetition strength, assessed weekly and without pain. Participants worked each set to the point of muscle fatigue, usually 8-12 repetitions, and rested a minute between sets. The groups were evenly matched, with no significant differences in height, body mass index, or baseline strength. There were 10 men in the pain group and 6 in the control group, but as with other factors, the difference was not statistically significant.

The injections (1 mL of saline under ultrasound guidance) came after a 10-minute warm-up on a stationary bicycle. The pain from the hypertonic shots diminished as subjects worked through their sets, starting on average at about 25 mm on the 100-mm visual analog pain scale and ending at about 10 mm. Strength was assessed weekly 30 minutes after training.

After 8 weeks, the right legs of subjects in the pain group were 24.6% stronger at 60 degrees of knee extension, 21.6% stronger at 120 degrees, and 19.6% at 180 degrees. Subjects in the control group were 7.5% stronger at 60 degrees of knee extension, 5.0% at 120 degrees, and 8.2% at 180 degrees.

“It could be that when you have pain, your type 1 muscle fibers [the endurance fibers,] are inhibited, and your type 2 [power and speed] fibers are easily recruited, which could explain why the pain group had the larger increase in muscle strength,” Ms. Sorensen said at the meeting, which was sponsored by the Osteoarthritis Research Society International.

Major Finding: After going through a rigorous 3-month exercise program, 40% of patients with hip osteoarthritis (22) got a hip replacement within 3.5-6 years; 57% of their control group peers who did not go through the exercise program (31) got an artificial hip during the same period.

Data Source: Randomized controlled trial involving 109 patients.

Disclosures: The study was funded by the Norwegian Foundation for Health and Rehabilitation, the Norwegian Rheumatism Association, and the South-Eastern Norway Regional Health Authority. The researchers said they have no relevant financial disclosures.

SAN DIEGO – A 3-month exercise program appears to have significantly delayed, and perhaps even prevented, hip replacements in a Norwegian randomized controlled trial.

Within the first 6 years after participating in the exercise program, 40% of patients (22) had gotten a hip replacement; in the control group, 57% (31) had gotten an artificial hip during the follow-up period.

The 109 patients who started the trial had mild to moderate hip pain and were not yet eligible for surgery. They went through three 90-minute education sessions where they were told to stay active, even if it hurts a bit.

The message was “don't be afraid of your pain. It won't damage your cartilage” and might improve symptoms, said researcher Linda Fernandes, Ph.D., a physiotherapist at Diakonhjemmet Hospital in Oslo.

Immediately after the education part of the trial, 55 patients were randomized to a 3-month, supervised strength and flexibility exercise program.

“We pushed them quite hard,” Dr. Fernandes said at the congress sponsored by the Osteoarthritis Research Society International.

They “had to exercise at 70%-80% of [their] maximum” for over 1 hour. Patients attended, on average, about twice a week; 80% completed 20 sessions.

In spring 2011 − 3.5-6 years after the exercise program, Dr. Fernandes and her associates telephoned patients in both arms of the trial to learn if they had a subsequent hip replacement.

The results were “kind of surprising to us,” said senior author and physiotherapist May Arna Risberg, Ph.D., professor in the sport medicine department at the Norwegian School of Sport Sciences in Oslo.

Among patients who had gotten an artificial hip, the median time to surgery in the exercise group was 5.4 years; it was 3.5 years in the control group. Exercise patients also had significantly less pain and better function, not only in the spring of 2011 but also at earlier follow-up points.

The two groups were evenly balanced, with no significant baseline differences in age, sex, joint space, Harris Hip Score, and self-reported pain and function.

The progression of radiographic osteoarthritis was also significantly worse in the patients who did not get supervised exercise. “The mechanism for how this works we don't know,” Dr. Risberg said.

Patients worked on 26 exercises, including squats, crunches, cycling, and stepping. If they learned how to balance on one foot, patients were put on a balance pad to make it harder. If they got to the point where they could do eight leg curls, “we increased the load,” Dr. Fernandes said. If pain got to be too much, they backed off the exercise until it diminished (Phys. Ther. 2010;90:592-601).

The team collected data on cardiovascular and other physiologic parameters in the two groups but has not analyzed them yet. They also surveyed how active patients were at various follow-up points, but lost confidence in their assessment scale – the Physical Activity Scale for the Elderly (PASE) – after one of the researchers determined it was not valid for their setting.

To date, there have been few randomized controlled trials to see if exercise helps hip osteoarthritis, though exercise is known to help knee osteoarthritis, Dr. Risberg said.

Patients in the study were 40-80 years old and had hip pain for more than 3 months, radiographically confirmed hip osteoarthritis, Harris Hip Scores of 60-95, and no previous joint replacements.

The next best step would be a larger randomized trial, Dr. Fernandes said, but in the meantime the team is analyzing patients' biomechanics to see if they correlate with the outcomes.

Major Finding: After going through a rigorous 3-month exercise program, 40% of patients with hip osteoarthritis (22) got a hip replacement within 3.5-6 years; 57% of their control group peers who did not go through the exercise program (31) got an artificial hip during the same period.

Data Source: Randomized controlled trial involving 109 patients.

Disclosures: The study was funded by the Norwegian Foundation for Health and Rehabilitation, the Norwegian Rheumatism Association, and the South-Eastern Norway Regional Health Authority. The researchers said they have no relevant financial disclosures.

SAN DIEGO – A 3-month exercise program appears to have significantly delayed, and perhaps even prevented, hip replacements in a Norwegian randomized controlled trial.

Within the first 6 years after participating in the exercise program, 40% of patients (22) had gotten a hip replacement; in the control group, 57% (31) had gotten an artificial hip during the follow-up period.

The 109 patients who started the trial had mild to moderate hip pain and were not yet eligible for surgery. They went through three 90-minute education sessions where they were told to stay active, even if it hurts a bit.

The message was “don't be afraid of your pain. It won't damage your cartilage” and might improve symptoms, said researcher Linda Fernandes, Ph.D., a physiotherapist at Diakonhjemmet Hospital in Oslo.

Immediately after the education part of the trial, 55 patients were randomized to a 3-month, supervised strength and flexibility exercise program.

“We pushed them quite hard,” Dr. Fernandes said at the congress sponsored by the Osteoarthritis Research Society International.

They “had to exercise at 70%-80% of [their] maximum” for over 1 hour. Patients attended, on average, about twice a week; 80% completed 20 sessions.

In spring 2011 − 3.5-6 years after the exercise program, Dr. Fernandes and her associates telephoned patients in both arms of the trial to learn if they had a subsequent hip replacement.

The results were “kind of surprising to us,” said senior author and physiotherapist May Arna Risberg, Ph.D., professor in the sport medicine department at the Norwegian School of Sport Sciences in Oslo.

Among patients who had gotten an artificial hip, the median time to surgery in the exercise group was 5.4 years; it was 3.5 years in the control group. Exercise patients also had significantly less pain and better function, not only in the spring of 2011 but also at earlier follow-up points.

The two groups were evenly balanced, with no significant baseline differences in age, sex, joint space, Harris Hip Score, and self-reported pain and function.

The progression of radiographic osteoarthritis was also significantly worse in the patients who did not get supervised exercise. “The mechanism for how this works we don't know,” Dr. Risberg said.

Patients worked on 26 exercises, including squats, crunches, cycling, and stepping. If they learned how to balance on one foot, patients were put on a balance pad to make it harder. If they got to the point where they could do eight leg curls, “we increased the load,” Dr. Fernandes said. If pain got to be too much, they backed off the exercise until it diminished (Phys. Ther. 2010;90:592-601).

The team collected data on cardiovascular and other physiologic parameters in the two groups but has not analyzed them yet. They also surveyed how active patients were at various follow-up points, but lost confidence in their assessment scale – the Physical Activity Scale for the Elderly (PASE) – after one of the researchers determined it was not valid for their setting.

To date, there have been few randomized controlled trials to see if exercise helps hip osteoarthritis, though exercise is known to help knee osteoarthritis, Dr. Risberg said.

Patients in the study were 40-80 years old and had hip pain for more than 3 months, radiographically confirmed hip osteoarthritis, Harris Hip Scores of 60-95, and no previous joint replacements.

The next best step would be a larger randomized trial, Dr. Fernandes said, but in the meantime the team is analyzing patients' biomechanics to see if they correlate with the outcomes.

Major Finding: After going through a rigorous 3-month exercise program, 40% of patients with hip osteoarthritis (22) got a hip replacement within 3.5-6 years; 57% of their control group peers who did not go through the exercise program (31) got an artificial hip during the same period.

Data Source: Randomized controlled trial involving 109 patients.

Disclosures: The study was funded by the Norwegian Foundation for Health and Rehabilitation, the Norwegian Rheumatism Association, and the South-Eastern Norway Regional Health Authority. The researchers said they have no relevant financial disclosures.

SAN DIEGO – A 3-month exercise program appears to have significantly delayed, and perhaps even prevented, hip replacements in a Norwegian randomized controlled trial.

Within the first 6 years after participating in the exercise program, 40% of patients (22) had gotten a hip replacement; in the control group, 57% (31) had gotten an artificial hip during the follow-up period.

The 109 patients who started the trial had mild to moderate hip pain and were not yet eligible for surgery. They went through three 90-minute education sessions where they were told to stay active, even if it hurts a bit.

The message was “don't be afraid of your pain. It won't damage your cartilage” and might improve symptoms, said researcher Linda Fernandes, Ph.D., a physiotherapist at Diakonhjemmet Hospital in Oslo.

Immediately after the education part of the trial, 55 patients were randomized to a 3-month, supervised strength and flexibility exercise program.

“We pushed them quite hard,” Dr. Fernandes said at the congress sponsored by the Osteoarthritis Research Society International.

They “had to exercise at 70%-80% of [their] maximum” for over 1 hour. Patients attended, on average, about twice a week; 80% completed 20 sessions.

In spring 2011 − 3.5-6 years after the exercise program, Dr. Fernandes and her associates telephoned patients in both arms of the trial to learn if they had a subsequent hip replacement.

The results were “kind of surprising to us,” said senior author and physiotherapist May Arna Risberg, Ph.D., professor in the sport medicine department at the Norwegian School of Sport Sciences in Oslo.

Among patients who had gotten an artificial hip, the median time to surgery in the exercise group was 5.4 years; it was 3.5 years in the control group. Exercise patients also had significantly less pain and better function, not only in the spring of 2011 but also at earlier follow-up points.

The two groups were evenly balanced, with no significant baseline differences in age, sex, joint space, Harris Hip Score, and self-reported pain and function.

The progression of radiographic osteoarthritis was also significantly worse in the patients who did not get supervised exercise. “The mechanism for how this works we don't know,” Dr. Risberg said.

Patients worked on 26 exercises, including squats, crunches, cycling, and stepping. If they learned how to balance on one foot, patients were put on a balance pad to make it harder. If they got to the point where they could do eight leg curls, “we increased the load,” Dr. Fernandes said. If pain got to be too much, they backed off the exercise until it diminished (Phys. Ther. 2010;90:592-601).

The team collected data on cardiovascular and other physiologic parameters in the two groups but has not analyzed them yet. They also surveyed how active patients were at various follow-up points, but lost confidence in their assessment scale – the Physical Activity Scale for the Elderly (PASE) – after one of the researchers determined it was not valid for their setting.

To date, there have been few randomized controlled trials to see if exercise helps hip osteoarthritis, though exercise is known to help knee osteoarthritis, Dr. Risberg said.

Patients in the study were 40-80 years old and had hip pain for more than 3 months, radiographically confirmed hip osteoarthritis, Harris Hip Scores of 60-95, and no previous joint replacements.

The next best step would be a larger randomized trial, Dr. Fernandes said, but in the meantime the team is analyzing patients' biomechanics to see if they correlate with the outcomes.

Major Finding: Patients had a higher revision risk after a total hip replacement if, at the time of their initial surgery, they had a BMI greater than 30 kg/m

Data Source: Case-control study involving 1,672 patients.

Disclosures: The work was funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases. Dr. Katz said he has no relevant financial disclosures.

SAN DIEGO – People who are overweight or younger than 75 years when they have a total hip replacement face an increased risk for revision within 12 years; the risk is also increased if cement was used to hold the femoral stem of the implant in place, a study has shown.

Based on the findings, “when you talk to somebody who is in their mid- to late 70s about hip replacement, I think you can say revision is not particularly likely. For a younger person, they should recognize that we may have to go back again. At that point, they'll be older and have greater surgical risk,” said the study's lead author, Dr. Jeffrey Katz, professor of medicine and orthopedic surgery at Harvard Medical School, Boston.

Using hospital records and Medicare claims data, Dr. Katz and his associates examined the presurgery characteristics of 836 people who had initial total hip replacements (THRs) from July 1995 to June 1996 and subsequent revisions sometime before 2009. The researchers then compared those patients to 836 matched controls who also had THRs in the mid-1990s but whose prosthetic hip had not been revised by the time their case had a revision.

Patients who had a prior contralateral hip replacement, who had a prior history of other orthopedic surgery, and who lived with others, instead of alone also had a higher revision risk. Odds ratios were modest but statistically significant, ranging from 1.3 to 1.7.

“Age and weight were not surprising. We thought we might see an effect of sex [since] there is a literature of males being at higher risk, but we did not. There is also literature on comorbidity being associated with revision, which we did not see,” Dr. Katz said at the congress.

The cement finding (OR, 1.4) adds “to what is a rather conflicted literature on the durability of cemented versus uncemented designs,” he said.

Cement techniques – including techniques for reaming out the femur and applying the pressure to the cement – have improved since the mid-1990s, so “you have to be careful interpreting the [cement] data. They may not apply to the way cement is used now,” Dr. Katz said.

The researchers also found a higher risk of revision if, at the time of their initial surgery, patients had a body mass index (BMI) greater than 30 kg/m

Height, weight, and BMI are likely related to the biomechanical load on the implant, Dr. Katz noted. Regarding the greater risk below age 75 years (OR, 1.5), younger, more active patients may be more likely to have a faulty THR fixed. Increased risk for prior contralateral hip replacements (OR, 1.4) or orthopedic surgery (OR, 1.5) may indicate a willingness and ability to undergo surgery.

The added risk from living with others (OR, 1.3) “may represent having the social support in place to deal with rehab and a temporary dependency,” which facilitates elective surgery, he said at the congress, which was sponsored by the Osteoarthritis Research Society International.

The manufacturer of the implants, the initial surgeon's level of experience with the procedure, and the reasons for the revisions were not captured by the study.

Major Finding: Patients had a higher revision risk after a total hip replacement if, at the time of their initial surgery, they had a BMI greater than 30 kg/m

Data Source: Case-control study involving 1,672 patients.

Disclosures: The work was funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases. Dr. Katz said he has no relevant financial disclosures.

SAN DIEGO – People who are overweight or younger than 75 years when they have a total hip replacement face an increased risk for revision within 12 years; the risk is also increased if cement was used to hold the femoral stem of the implant in place, a study has shown.

Based on the findings, “when you talk to somebody who is in their mid- to late 70s about hip replacement, I think you can say revision is not particularly likely. For a younger person, they should recognize that we may have to go back again. At that point, they'll be older and have greater surgical risk,” said the study's lead author, Dr. Jeffrey Katz, professor of medicine and orthopedic surgery at Harvard Medical School, Boston.

Using hospital records and Medicare claims data, Dr. Katz and his associates examined the presurgery characteristics of 836 people who had initial total hip replacements (THRs) from July 1995 to June 1996 and subsequent revisions sometime before 2009. The researchers then compared those patients to 836 matched controls who also had THRs in the mid-1990s but whose prosthetic hip had not been revised by the time their case had a revision.

Patients who had a prior contralateral hip replacement, who had a prior history of other orthopedic surgery, and who lived with others, instead of alone also had a higher revision risk. Odds ratios were modest but statistically significant, ranging from 1.3 to 1.7.

“Age and weight were not surprising. We thought we might see an effect of sex [since] there is a literature of males being at higher risk, but we did not. There is also literature on comorbidity being associated with revision, which we did not see,” Dr. Katz said at the congress.

The cement finding (OR, 1.4) adds “to what is a rather conflicted literature on the durability of cemented versus uncemented designs,” he said.

Cement techniques – including techniques for reaming out the femur and applying the pressure to the cement – have improved since the mid-1990s, so “you have to be careful interpreting the [cement] data. They may not apply to the way cement is used now,” Dr. Katz said.

The researchers also found a higher risk of revision if, at the time of their initial surgery, patients had a body mass index (BMI) greater than 30 kg/m

Height, weight, and BMI are likely related to the biomechanical load on the implant, Dr. Katz noted. Regarding the greater risk below age 75 years (OR, 1.5), younger, more active patients may be more likely to have a faulty THR fixed. Increased risk for prior contralateral hip replacements (OR, 1.4) or orthopedic surgery (OR, 1.5) may indicate a willingness and ability to undergo surgery.

The added risk from living with others (OR, 1.3) “may represent having the social support in place to deal with rehab and a temporary dependency,” which facilitates elective surgery, he said at the congress, which was sponsored by the Osteoarthritis Research Society International.

The manufacturer of the implants, the initial surgeon's level of experience with the procedure, and the reasons for the revisions were not captured by the study.

Major Finding: Patients had a higher revision risk after a total hip replacement if, at the time of their initial surgery, they had a BMI greater than 30 kg/m

Data Source: Case-control study involving 1,672 patients.

Disclosures: The work was funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases. Dr. Katz said he has no relevant financial disclosures.

SAN DIEGO – People who are overweight or younger than 75 years when they have a total hip replacement face an increased risk for revision within 12 years; the risk is also increased if cement was used to hold the femoral stem of the implant in place, a study has shown.

Based on the findings, “when you talk to somebody who is in their mid- to late 70s about hip replacement, I think you can say revision is not particularly likely. For a younger person, they should recognize that we may have to go back again. At that point, they'll be older and have greater surgical risk,” said the study's lead author, Dr. Jeffrey Katz, professor of medicine and orthopedic surgery at Harvard Medical School, Boston.

Using hospital records and Medicare claims data, Dr. Katz and his associates examined the presurgery characteristics of 836 people who had initial total hip replacements (THRs) from July 1995 to June 1996 and subsequent revisions sometime before 2009. The researchers then compared those patients to 836 matched controls who also had THRs in the mid-1990s but whose prosthetic hip had not been revised by the time their case had a revision.

Patients who had a prior contralateral hip replacement, who had a prior history of other orthopedic surgery, and who lived with others, instead of alone also had a higher revision risk. Odds ratios were modest but statistically significant, ranging from 1.3 to 1.7.

“Age and weight were not surprising. We thought we might see an effect of sex [since] there is a literature of males being at higher risk, but we did not. There is also literature on comorbidity being associated with revision, which we did not see,” Dr. Katz said at the congress.

The cement finding (OR, 1.4) adds “to what is a rather conflicted literature on the durability of cemented versus uncemented designs,” he said.

Cement techniques – including techniques for reaming out the femur and applying the pressure to the cement – have improved since the mid-1990s, so “you have to be careful interpreting the [cement] data. They may not apply to the way cement is used now,” Dr. Katz said.

The researchers also found a higher risk of revision if, at the time of their initial surgery, patients had a body mass index (BMI) greater than 30 kg/m

Height, weight, and BMI are likely related to the biomechanical load on the implant, Dr. Katz noted. Regarding the greater risk below age 75 years (OR, 1.5), younger, more active patients may be more likely to have a faulty THR fixed. Increased risk for prior contralateral hip replacements (OR, 1.4) or orthopedic surgery (OR, 1.5) may indicate a willingness and ability to undergo surgery.

The added risk from living with others (OR, 1.3) “may represent having the social support in place to deal with rehab and a temporary dependency,” which facilitates elective surgery, he said at the congress, which was sponsored by the Osteoarthritis Research Society International.

The manufacturer of the implants, the initial surgeon's level of experience with the procedure, and the reasons for the revisions were not captured by the study.

SAN DIEGO – Lateral wedge shoe insoles reduce the gait load on the inside of the knee but fail to lessen pain long term in patients with medial knee osteoarthritis.

A British research team thinks it may have solved the mystery. It seems the inserts work only in the subset of patients who have flatter feet and who plant their heels more squarely when they walk, rather than rolling their foot to the outside, said lead investigator Graham Chapman, Ph.D., at the World Congress on Osteoarthritis.

Previous studies (BMJ 2011;342:d2912) seem to have "grouped everyone together and assumed they are going to respond to wearing a lateral wedge," said Dr. Chapman, a research fellow in biomechanics at the University of Salford (England).

That was not the case when he and his colleagues analyzed 33 patients who had medial knee osteoarthritis (OA) and a Kellgren-Lawrence grade 2 or 3. Their mean age was 59 years, their mean body mass index was 32.2 kg/m², and 42% (14) were women.

Patients "who walked more on the lateral hindfoot and those with pes cavus [high arch] were unlikely to respond to lateral wedges."

In 13 (39%) of the patients, the inserts did not help. Their use actually increased the load on the inside of the knee, as measured by the external knee adduction moment. In the remaining patients, use of the 5-degree lateral wedge insoles – which look much like any shoe insole except for a "fat bit on outside," Dr. Chapman said – reduced the adduction moment by a mean of 4.1%.

The researchers next looked to see how those who did not benefit from the insoles differed from those who did benefit.

The 13 patients who did not benefit were likely to have more contact on their lateral heel as they walked (about 19 cm² vs. about 17.5 cm²) and higher medial arches (with mean subarch angles of about 104 degrees vs. about 111 degrees in those who benefited from the inserts). The findings were statistically significant.

Patients "who walked more on the lateral hindfoot and those with pes cavus [high arch] were unlikely to respond to lateral wedges. Excluding persons whose foot dynamics make them unlikely to respond to insoles may leave a large group of patients who can experience their potential therapeutic benefits," the researchers concluded in their abstract.

The next step is a randomized trial to see if people who fit the profile of responders truly do have less pain when they wear shoes with lateral wedges rather than control shoes.

The ultimate goal is to help clinicians predict who will benefit from the insoles, Dr. Chapman said at the meeting, which was sponsored by the Osteoarthritis Research Society International.

Dr. Chapman said he has no disclosures. The work was funded by Arthritis Research UK.

SAN DIEGO – Lateral wedge shoe insoles reduce the gait load on the inside of the knee but fail to lessen pain long term in patients with medial knee osteoarthritis.

A British research team thinks it may have solved the mystery. It seems the inserts work only in the subset of patients who have flatter feet and who plant their heels more squarely when they walk, rather than rolling their foot to the outside, said lead investigator Graham Chapman, Ph.D., at the World Congress on Osteoarthritis.

Previous studies (BMJ 2011;342:d2912) seem to have "grouped everyone together and assumed they are going to respond to wearing a lateral wedge," said Dr. Chapman, a research fellow in biomechanics at the University of Salford (England).

That was not the case when he and his colleagues analyzed 33 patients who had medial knee osteoarthritis (OA) and a Kellgren-Lawrence grade 2 or 3. Their mean age was 59 years, their mean body mass index was 32.2 kg/m², and 42% (14) were women.

Patients "who walked more on the lateral hindfoot and those with pes cavus [high arch] were unlikely to respond to lateral wedges."

In 13 (39%) of the patients, the inserts did not help. Their use actually increased the load on the inside of the knee, as measured by the external knee adduction moment. In the remaining patients, use of the 5-degree lateral wedge insoles – which look much like any shoe insole except for a "fat bit on outside," Dr. Chapman said – reduced the adduction moment by a mean of 4.1%.

The researchers next looked to see how those who did not benefit from the insoles differed from those who did benefit.

The 13 patients who did not benefit were likely to have more contact on their lateral heel as they walked (about 19 cm² vs. about 17.5 cm²) and higher medial arches (with mean subarch angles of about 104 degrees vs. about 111 degrees in those who benefited from the inserts). The findings were statistically significant.

Patients "who walked more on the lateral hindfoot and those with pes cavus [high arch] were unlikely to respond to lateral wedges. Excluding persons whose foot dynamics make them unlikely to respond to insoles may leave a large group of patients who can experience their potential therapeutic benefits," the researchers concluded in their abstract.

The next step is a randomized trial to see if people who fit the profile of responders truly do have less pain when they wear shoes with lateral wedges rather than control shoes.

The ultimate goal is to help clinicians predict who will benefit from the insoles, Dr. Chapman said at the meeting, which was sponsored by the Osteoarthritis Research Society International.

Dr. Chapman said he has no disclosures. The work was funded by Arthritis Research UK.

SAN DIEGO – Lateral wedge shoe insoles reduce the gait load on the inside of the knee but fail to lessen pain long term in patients with medial knee osteoarthritis.

A British research team thinks it may have solved the mystery. It seems the inserts work only in the subset of patients who have flatter feet and who plant their heels more squarely when they walk, rather than rolling their foot to the outside, said lead investigator Graham Chapman, Ph.D., at the World Congress on Osteoarthritis.

Previous studies (BMJ 2011;342:d2912) seem to have "grouped everyone together and assumed they are going to respond to wearing a lateral wedge," said Dr. Chapman, a research fellow in biomechanics at the University of Salford (England).

That was not the case when he and his colleagues analyzed 33 patients who had medial knee osteoarthritis (OA) and a Kellgren-Lawrence grade 2 or 3. Their mean age was 59 years, their mean body mass index was 32.2 kg/m², and 42% (14) were women.

Patients "who walked more on the lateral hindfoot and those with pes cavus [high arch] were unlikely to respond to lateral wedges."

In 13 (39%) of the patients, the inserts did not help. Their use actually increased the load on the inside of the knee, as measured by the external knee adduction moment. In the remaining patients, use of the 5-degree lateral wedge insoles – which look much like any shoe insole except for a "fat bit on outside," Dr. Chapman said – reduced the adduction moment by a mean of 4.1%.

The researchers next looked to see how those who did not benefit from the insoles differed from those who did benefit.

The 13 patients who did not benefit were likely to have more contact on their lateral heel as they walked (about 19 cm² vs. about 17.5 cm²) and higher medial arches (with mean subarch angles of about 104 degrees vs. about 111 degrees in those who benefited from the inserts). The findings were statistically significant.

Patients "who walked more on the lateral hindfoot and those with pes cavus [high arch] were unlikely to respond to lateral wedges. Excluding persons whose foot dynamics make them unlikely to respond to insoles may leave a large group of patients who can experience their potential therapeutic benefits," the researchers concluded in their abstract.

The next step is a randomized trial to see if people who fit the profile of responders truly do have less pain when they wear shoes with lateral wedges rather than control shoes.

The ultimate goal is to help clinicians predict who will benefit from the insoles, Dr. Chapman said at the meeting, which was sponsored by the Osteoarthritis Research Society International.

Dr. Chapman said he has no disclosures. The work was funded by Arthritis Research UK.

SAN DIEGO – Separating an osteoarthritic knee joint for 2 months – that is, stretching the top of the tibia away from the base of the femur and holding the bones in place with pins set into an external fixation frame – stimulates the joint to produce new cartilage, thereby reducing pain and improving function for at least 2 years, according to findings from a small European pilot study.

The 20 patients in the trial were all facing knee replacement due to osteoarthritis (OA); the technique, known as knee joint distraction, has postponed surgery for 2 years and counting in the subjects. The hope is the patients will never need an artificial knee, according to senior investigator Dr. Floris Lafeber, a professor of experimental rheumatology at the University Medical Center Utrecht (the Netherlands).

Their minimum joint space width increased from a baseline mean of 1.0 mm to 1.8 mm at 2 years. Patients started the trial with, on average, about 22% of their subchondral bone denuded; that dropped to about 8% at 2 years.

In short, there was an "astonishing increase in cartilage volume," Dr. Lafeber said at the World Congress on Osteoarthritis, which was sponsored by the Osteoarthritis Research Society International.

Meanwhile, total WOMAC (Western Ontario and McMaster Universities) osteoarthritis index scores increased from about 45% at baseline to about 78% at 2 years, with improvements in WOMAC pain, function, and stiffness subscales. Visual Analog Scale pain scores improved from 73 at baseline to 28 at 2 years. The results were statistically significant.

The technique, which had been used in the past for ankle OAs, "looks very promising" for osteoarthritic knees, Dr. Lafeber said. The 1 year results have been previously published (Ann. Rheum. Dis. 2011;70:1441-6; Internal Medicine News, August 2011, p. 22).

His team will next pit knee distraction against total knee replacement and osteotomy in two randomized trials. The researchers will keep tracking the original 20 patients as well. "We are now having follow-up of the first patients for more than 4 years, and no prostheses are placed yet," Dr. Lafeber said.

The researchers plan "more sophisticated MRIs to look at the quality of the cartilage," although the increased joint space on weight-bearing x-rays suggests mechanical competence. Biomarker analysis also suggests "the quality of the cartilage has a hyaline aspect," according to Dr. Lafeber.

The 20 patients’ average age was 49 years; 11 were women. All had end-stage, unilateral knee OA with severe pain and cartilage damage. Patients with major problems in both knees were excluded from the study.

In a variation of the Ilizarov procedure, a tube with internal coil springs was placed on each side of the patients’ osteoarthritic knees, bridging the joints. Joints were then distracted to 5 mm over a few days. Full weight bearing was allowed. The tubes and pins were removed after 2 months.

The theory is that temporarily unloading the knee prevents additional wear and tear and allows cartilage to start repairing itself.

Pin sites became infected in 17 of the 20 patients, and were treated with local and oral antibiotics. Dr. Lafeber said he and his colleagues hope that technique refinements will reduce the infection rate.

Dr. Lafeber said he had no disclosures. The work was supported by the Dutch Arthritis Association.

SAN DIEGO – Separating an osteoarthritic knee joint for 2 months – that is, stretching the top of the tibia away from the base of the femur and holding the bones in place with pins set into an external fixation frame – stimulates the joint to produce new cartilage, thereby reducing pain and improving function for at least 2 years, according to findings from a small European pilot study.

The 20 patients in the trial were all facing knee replacement due to osteoarthritis (OA); the technique, known as knee joint distraction, has postponed surgery for 2 years and counting in the subjects. The hope is the patients will never need an artificial knee, according to senior investigator Dr. Floris Lafeber, a professor of experimental rheumatology at the University Medical Center Utrecht (the Netherlands).

Their minimum joint space width increased from a baseline mean of 1.0 mm to 1.8 mm at 2 years. Patients started the trial with, on average, about 22% of their subchondral bone denuded; that dropped to about 8% at 2 years.

In short, there was an "astonishing increase in cartilage volume," Dr. Lafeber said at the World Congress on Osteoarthritis, which was sponsored by the Osteoarthritis Research Society International.

Meanwhile, total WOMAC (Western Ontario and McMaster Universities) osteoarthritis index scores increased from about 45% at baseline to about 78% at 2 years, with improvements in WOMAC pain, function, and stiffness subscales. Visual Analog Scale pain scores improved from 73 at baseline to 28 at 2 years. The results were statistically significant.

The technique, which had been used in the past for ankle OAs, "looks very promising" for osteoarthritic knees, Dr. Lafeber said. The 1 year results have been previously published (Ann. Rheum. Dis. 2011;70:1441-6; Internal Medicine News, August 2011, p. 22).

His team will next pit knee distraction against total knee replacement and osteotomy in two randomized trials. The researchers will keep tracking the original 20 patients as well. "We are now having follow-up of the first patients for more than 4 years, and no prostheses are placed yet," Dr. Lafeber said.

The researchers plan "more sophisticated MRIs to look at the quality of the cartilage," although the increased joint space on weight-bearing x-rays suggests mechanical competence. Biomarker analysis also suggests "the quality of the cartilage has a hyaline aspect," according to Dr. Lafeber.

The 20 patients’ average age was 49 years; 11 were women. All had end-stage, unilateral knee OA with severe pain and cartilage damage. Patients with major problems in both knees were excluded from the study.

In a variation of the Ilizarov procedure, a tube with internal coil springs was placed on each side of the patients’ osteoarthritic knees, bridging the joints. Joints were then distracted to 5 mm over a few days. Full weight bearing was allowed. The tubes and pins were removed after 2 months.

The theory is that temporarily unloading the knee prevents additional wear and tear and allows cartilage to start repairing itself.

Pin sites became infected in 17 of the 20 patients, and were treated with local and oral antibiotics. Dr. Lafeber said he and his colleagues hope that technique refinements will reduce the infection rate.

Dr. Lafeber said he had no disclosures. The work was supported by the Dutch Arthritis Association.

SAN DIEGO – Separating an osteoarthritic knee joint for 2 months – that is, stretching the top of the tibia away from the base of the femur and holding the bones in place with pins set into an external fixation frame – stimulates the joint to produce new cartilage, thereby reducing pain and improving function for at least 2 years, according to findings from a small European pilot study.

The 20 patients in the trial were all facing knee replacement due to osteoarthritis (OA); the technique, known as knee joint distraction, has postponed surgery for 2 years and counting in the subjects. The hope is the patients will never need an artificial knee, according to senior investigator Dr. Floris Lafeber, a professor of experimental rheumatology at the University Medical Center Utrecht (the Netherlands).

Their minimum joint space width increased from a baseline mean of 1.0 mm to 1.8 mm at 2 years. Patients started the trial with, on average, about 22% of their subchondral bone denuded; that dropped to about 8% at 2 years.

In short, there was an "astonishing increase in cartilage volume," Dr. Lafeber said at the World Congress on Osteoarthritis, which was sponsored by the Osteoarthritis Research Society International.

Meanwhile, total WOMAC (Western Ontario and McMaster Universities) osteoarthritis index scores increased from about 45% at baseline to about 78% at 2 years, with improvements in WOMAC pain, function, and stiffness subscales. Visual Analog Scale pain scores improved from 73 at baseline to 28 at 2 years. The results were statistically significant.

The technique, which had been used in the past for ankle OAs, "looks very promising" for osteoarthritic knees, Dr. Lafeber said. The 1 year results have been previously published (Ann. Rheum. Dis. 2011;70:1441-6; Internal Medicine News, August 2011, p. 22).

His team will next pit knee distraction against total knee replacement and osteotomy in two randomized trials. The researchers will keep tracking the original 20 patients as well. "We are now having follow-up of the first patients for more than 4 years, and no prostheses are placed yet," Dr. Lafeber said.

The researchers plan "more sophisticated MRIs to look at the quality of the cartilage," although the increased joint space on weight-bearing x-rays suggests mechanical competence. Biomarker analysis also suggests "the quality of the cartilage has a hyaline aspect," according to Dr. Lafeber.

The 20 patients’ average age was 49 years; 11 were women. All had end-stage, unilateral knee OA with severe pain and cartilage damage. Patients with major problems in both knees were excluded from the study.

In a variation of the Ilizarov procedure, a tube with internal coil springs was placed on each side of the patients’ osteoarthritic knees, bridging the joints. Joints were then distracted to 5 mm over a few days. Full weight bearing was allowed. The tubes and pins were removed after 2 months.

The theory is that temporarily unloading the knee prevents additional wear and tear and allows cartilage to start repairing itself.

Pin sites became infected in 17 of the 20 patients, and were treated with local and oral antibiotics. Dr. Lafeber said he and his colleagues hope that technique refinements will reduce the infection rate.

Dr. Lafeber said he had no disclosures. The work was supported by the Dutch Arthritis Association.