Treatment with posterior capsular release, botulinum toxin injection, hamstring tenotomy, and peroneal nerve decompression improves flexion contracture after total knee arthroplasty: minimum 2-year follow-up.

[PURPOSE] No definite treatment option with reasonable outcome has been presented for old and refractory flexion contracture after total knee arthroplasty (TKA). We describe a surgical technique for 21 refractory cases of knee flexion contracture, including 12 patients with history of failed manipulation under anesthesia (MUA).

[METHODS] Retrospective review was conducted for procedures performed by a single surgeon between 2005 and 2016. Twenty-one knees (19 patients) with knee flexion contracture after primary TKA were treated with all the following procedures: posterior capsular release, hamstring tenotomy, prophylactic peroneal nerve decompression, and botulinum toxin type A injections. Twelve of the 21 knees had at least 1 prior unsuccessful MUA before this soft-tissue release procedure. Mean age at intervention was 60 years (range 46-78 years). Mean preoperative knee range of motion (ROM) was - 27° extension (range - 20° to - 40°) to 100° flexion (range 90°-115°). All radiographs were evaluated for proper component sizing and signs of loosening.

[RESULTS] Full extension was achieved immediately after surgery in all patients. Only one knee required repeat botulinum toxin type A injection. All patients had full extension at mean follow-up of 31 months (range 24-49 months). No significant change was observed in knee flexion after the procedure (n.s.). Significant improvement was noted in the postoperative Knee Society Score (KSS) (mean 80, range 70-90) when compared with preoperative KSS (mean 45, range 25-65) (p = 0.008).

[CONCLUSION] The proposed surgical technique is efficacious in treating patients with refractory knee flexion contracture following TKA to gain and maintain full extension at minimum 2-year follow-up.

[LEVEL OF EVIDENCE] IV, retrospective case series.