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Chapple C1, Nur Amirulhusni Alshukor A1, Abbott H2
1University of Otago, School of Physiotherapy, Dunedin, New Zealand, 2University of Otago, Surgical Sciences, Dunedin, New Zealand
Background: Pain, stiffness and muscle weakness are well-recognised symptoms of knee osteoarthritis (OA). Less familiar, but important, is knee instability with a reported prevalence of 60-80%. Knee instability is a sensation of knee buckling or giving way. It can lead to a notable loss of confidence, fear of falling, reduced physical function and quality of life. Biomechanical factors, pain and muscle weakness are thought to contribute to instability, and are potentially modifiable with exercise. Reduction of instability is therefore a viable therapeutic target in people with knee OA. Research has shown the beneficial effects of muscle strengthening programmes. The extent to which a multi-modal exercise programme impacts on self-reported instability in patients with knee OA remains uncertain.
Purpose: The purpose of this study was to evaluate the likelihood that a multi-modal exercise programme reduced self-reported knee joint instability in people with knee OA.
Methods: We performed a secondary analysis of data from the MOA randomized controlled trial (RCT) conducted in New Zealand with people with hip or knee OA. Knee OA data were extracted and analysed separately. This was a 2X2 factorial trial where two groups received exercise therapy (ExT) and were compared to two groups who did not receive ExT. Eligibility for the MOA trial included meeting the ACR clinical classification for knee OA, and not having any conditions that precluded safe participation in exercise. Of the 113 participants with knee OA in the RCT, 84 (74%) reported knee instability at baseline assessment and formed the sub-group for this secondary analysis.
The exercise intervention was a multi-modal exercise programme incorporating aerobic, strengthening, stretching and neuromuscular co-ordination exercises. Participants received a tailored exercise programme, supervised and progressed by a physiotherapist. Seven treatment sessions were delivered in nine weeks and reinforced with a home exercise programme.
The dependent outcome was self-reported knee instability using a question adapted from the Knee Outcome Survey - Activities of Daily Living scale dichotomized into a yes/no response.
Data analysis. Data collected by blinded assessors at baseline and 9-week follow-up were used for analysis. Backwards stepwise logistic regression was performed, with 9-week instability as the dependent variable and group allocation as the independent variable. Analysis was then adjusted for age, sex and BMI. Results are reported as Odds Ratios (OR) with 95% CI.
Results: Of the 84 participants reporting instability, 40 were randomized to receive ExT, and 44 no ExT. At 9-weeks 20 participants reported instability in the ExT group, and 34 in the no ExT group. The OR was 3.4 (95%CI 1.33, 8.69), meaning the ExT group was 3.4 times more likely to have no instability at 9 weeks compared to the no ExT group. This finding was significant (p 0.05) and remained similar in the adjusted analysis.
Conclusion(s): Multi-modal exercise therapy, including strengthening exercises, was successful in reducing self-reported instability in people with knee OA. Further research should examine benefits to outcomes such as knee confidence, frequency of falls and physical function.
Implications: Knee instability is an important therapeutic target for people with knee OA, and improves with exercise
Keywords: Knee osteoarthritis, Instability, Exercise
Funding acknowledgements: Health Research Council of New Zealand
University of Otago
Lottery Health Board of New Zealand
Purpose: The purpose of this study was to evaluate the likelihood that a multi-modal exercise programme reduced self-reported knee joint instability in people with knee OA.
Methods: We performed a secondary analysis of data from the MOA randomized controlled trial (RCT) conducted in New Zealand with people with hip or knee OA. Knee OA data were extracted and analysed separately. This was a 2X2 factorial trial where two groups received exercise therapy (ExT) and were compared to two groups who did not receive ExT. Eligibility for the MOA trial included meeting the ACR clinical classification for knee OA, and not having any conditions that precluded safe participation in exercise. Of the 113 participants with knee OA in the RCT, 84 (74%) reported knee instability at baseline assessment and formed the sub-group for this secondary analysis.
The exercise intervention was a multi-modal exercise programme incorporating aerobic, strengthening, stretching and neuromuscular co-ordination exercises. Participants received a tailored exercise programme, supervised and progressed by a physiotherapist. Seven treatment sessions were delivered in nine weeks and reinforced with a home exercise programme.
The dependent outcome was self-reported knee instability using a question adapted from the Knee Outcome Survey - Activities of Daily Living scale dichotomized into a yes/no response.
Data analysis. Data collected by blinded assessors at baseline and 9-week follow-up were used for analysis. Backwards stepwise logistic regression was performed, with 9-week instability as the dependent variable and group allocation as the independent variable. Analysis was then adjusted for age, sex and BMI. Results are reported as Odds Ratios (OR) with 95% CI.
Results: Of the 84 participants reporting instability, 40 were randomized to receive ExT, and 44 no ExT. At 9-weeks 20 participants reported instability in the ExT group, and 34 in the no ExT group. The OR was 3.4 (95%CI 1.33, 8.69), meaning the ExT group was 3.4 times more likely to have no instability at 9 weeks compared to the no ExT group. This finding was significant (p 0.05) and remained similar in the adjusted analysis.
Conclusion(s): Multi-modal exercise therapy, including strengthening exercises, was successful in reducing self-reported instability in people with knee OA. Further research should examine benefits to outcomes such as knee confidence, frequency of falls and physical function.
Implications: Knee instability is an important therapeutic target for people with knee OA, and improves with exercise
Keywords: Knee osteoarthritis, Instability, Exercise
Funding acknowledgements: Health Research Council of New Zealand
University of Otago
Lottery Health Board of New Zealand
Topic: Musculoskeletal: lower limb; Musculoskeletal; Rheumatology
Ethics approval required: Yes
Institution: New Zealand Ministry of Health
Ethics committee: Lower South Regional Ethics Committee of New Zealand
Ethics number: LRS/07/11/044
All authors, affiliations and abstracts have been published as submitted.
