The effect of flexion balance on functional outcomes in cruciate-retaining total knee arthroplasty

Abstract

Purpose: We investigated the relations between flexion balances and functional outcomes after total knee arthroplasty (TKA).

Methods: Sixty-one knees that underwent a TKA were included in this study. Clinical assessments were performed and flexion balances of the knee were assessed on varus and valgus stress radiographs at 90° of knee flexion. Total laxity was defined as the sum of medial and lateral laxities. Knees were divided into balanced (≤3°, n = 51) and unbalanced (>3°, n = 10) groups based on the only difference of mediolateral laxity regardless of total laxity. And the balanced group was divided into Grade I (<6°), Grade II (≥6° but ≤10°) or Grade III (>10°) groups based on the amount of total laxity.

Results: Although no statistically significant differences were observed between the balanced and unbalanced groups in terms of range of motion (ROM) and KS pain scores, the balanced group achieved better results in terms of KS function and WOMAC scores than the unbalanced group. Total laxity was significantly less in the balanced group. In addition, Grade II knees in the balanced group had significantly better KS pain and function scores, and WOMAC scores than Grade Ior Grade III knees.

Conclusions: These results suggest that total knees with good balanced flexion stability can provide good functional outcomes after TKA.