Knee osteoarthritis is a bilateral disease

Abstract

Knee osteoarthritis (OA) is a common cause of pain and disability. Patients often complain that they overload the other limb when they walk, resulting in disease in the unaffected knee. However, it is unknown whether this happens or the mechanism by which it occurs. Data was analysed from an established longitudinal cohort study to examine the development of bilateral knee OA. One hundred and forty-three subjects were examined over a 12 year period with bilateral radiographs. Bilateral knee osteoarthritis was found to be very common over time, and the majority of individuals with unilateral knee OA eventually developed bilateral disease. A gait analysis study was performed on 20 subjects with unilateral knee OA awaiting arthroplasty surgery and 20 healthy age equivalent controls. Abnormal moments and muscle co-contractions were observed in the other knee and hips when they walked due a characteristic slow, cautious, stiff-legged gait pattern. Fifteen subjects re-attended 12 months following their surgery. Whilst moments returned to normal in most of the replaced knees, they remained elevated at the contra-lateral side and co-contraction failed to recover in either knee. A novel study design is presented to examine the effect of gait-derived loading waveforms on fresh human osteochondral plugs. By applying mechano-biology techniques and Finite Element Modelling to fresh human tissue, new observations vi can be made about the relationship between in-vivo loading and cartilage mechano-biology. A characteristic gait pattern was observed in knee OA which is not simply antalgic but tends towards symmetry, with an increase in joint loading bilaterally. The observed gait behaviour does not resolve, despite arthroplasty of the affected joint. This would be expected to contribute to the development of disease in an inherently vulnerable joint. Additional training may have a role to play in restoring normal biomechanics and protecting the other knee from disease