Patients with Type 2 diabetes mellitus have a worse functional outcome post knee arthroplasty: a matched cohort study

Knee arthroplasty provides not only pain relief but also an improvement in function and range of movement. Limited joint mobility is a common complication of diabetes mellitus. We therefore examined functional outcome post total knee arthroplasty in a cohort of subjects with (n=367) and a cohort matched for age, sex, BMI and functional movement at baseline, without diabetes mellitus (n=367). Participants were examined at baseline (pre-operatively), 1, 5 and 10 years post TKA. There was no significant difference in fixed flexion, maximal flexion or total range of movement between the two groups at baseline. By 1 year the group with diabetes had a significantly lower maximal flexion (p<0.001), total range of movement (p<0.001) and Knee Society Score (p=0.034). Similar results were observed at years 5 (except for the KSS) and 10 post procedure. At 5 years post arthroplasty a significant increase was observed in fixed flexion (p=0.026) in the diabetic group. Ten years post arthroplasty yielded similar results. This study demonstrates that the pre-operative presence of diabetes mellitus leads to a worse outcome post knee arthroplasty, although no significant difference was demonstrable in KSS at 5 years (p=0.35) suggesting patient satisfaction remains high during this period.