Total knee arthroplasty for treatment of osteoarthritis associated with extra-articular deformity

Objective

Our purpose was to review senior author results of TKA in patients with extra-articular angular deformities (correction of mechanical axis was performed without an additional procedure for osteotomy).

Methods

Results of TKA in nine knees with osteoarthritis and associated extra-articular angular deformity of femur were reviewed retrospectively. This group was compare with a with a control group of 20 patients diagnosed with osteoarthritis that underwent TKA without extra-articular deformity. Angulation of deformity in patients was 19° in coronal plane (range 15°–25°) and 12° in sagittal plane (range 8°–5°). Knee Score (KS) and Functional Score (FS) were measured pre and post-surgery, likewise arc flexion was reported. Results in KS and FS were correlationed with extra-articular angulation.

Results

Duration of follow-up averaged 55 months (range, 48–63 months). KS Average and FS increased from 50.5 and 38.4 points, preoperatively, to 96.5 and 84.4 points, respectively, at time of following-up. No statistically significant differences in any postoperative parameters were found between the postoperative group of extra-articular deformities and the control group were found. Positive correlation was obtained between deformity degrees and KS. Arc of motion averaged 86° preoperatively and 118° at time of following-up. No total knee arthroplasty was revised.

Conclusion

In our opinion, best management for extra-articular deformities associated to osteoarthritis is to carry out a knee replacement without corrective osteotomy on condition that planification allow to us avoid ligaments insertions, using an extensive soft-tissue balancing in conjunction with a minimally constrained TKA.