The effectiveness of an exercise programme on knee loading, muscle co-contraction, and pain in patients with medial knee osteoarthritis : A pilot study

Background: Knee loading, muscle co-contraction, and pain are increased in knee osteoarthritis (OA). Exercisesdecreased pain in knee OA, yet OA is a mechanical disease and biomechanical changes need to be explored aswell. Therefore, this study aims to investigate the effectiveness of an exercise programme on these outcomesin people with medial knee osteoarthritis.Methods: Cohort pilot study design. Nineteen participants with knee OA attended group exercise sessions,integrated with self-management education, once a week for six weeks, with additional home exercises.Outcomes assessed pre- and post-exercise programme were: External Knee Adduction Moment (EKAM), KneeAdduction Angular Impulse (KAAI), knee antagonist muscle co-contraction during gait, and the pain-subscaleof the Knee injury and Osteoarthritis Outcome Score (KOOS).Results: Fourteen participants completed the study. Post-exercise intervention, the EKAM and KAAI did notchange significantly (p= 0.21–0.7, p = 0.56, respectively). Muscle co-contraction between the vastus-lateralisand biceps-femoris muscles decreased in early-stance (64.78 (44.35) compared to 38.10 (23.10), p = 0.01)andmid-stance (27.62 (32.12) compared to 14.94 (17.40), p=0.04). A corresponding significant pain reductionwas seen (p = 0.00) with a median and range of 51.50 (47.00–62.50) at week six compared to 34.50 (29.25–41.25) at baseline.Conclusion: This is the first knownstudy to explore the effect of an exercise programmeon knee loading andmuscleco-contraction in knee OA. Although EKAMdid not change, the findings suggest a reduction in vastus-lateralisand biceps-femoris co-contraction might be a mechanism by which pain is reduced in knee OA