Prophylactic Common Peroneal Nerve Release for Total Arthroplasty of the Valgus Knee: Surgical Technique and Early Outcomes

Background: Common peroneal nerve (CPN) palsy after primary total knee arthroplasty represents a relatively rare but serious complication. Recently, there has been a growing interest in prophylactic CPN decompression in high-risk patients with significant combined valgus and flexion deformity. This study aimed to examine outcomes at our institution in those undergoing prophylactic CPN decompression at the time of total knee arthroplasty. Methods: A retrospective evaluation of a single-institution experience with selected patients at high risk for CPN palsy who underwent prophylactic nerve decompression through a separate incision at the time total knee arthroplasty was performed between July 1, 2018 and December 31, 2022. Patient demographics as well as perioperative and intraoperative clinical and radiographic measurements were collected and analyzed. Results: A total of 14 patients (15 knees) met our inclusion criteria. The mean preoperative femorotibial angle was 18.6° of valgus (range 13°-22°). The mean preoperative flexion contracture was 4.3° (range 0°-25°). The patients with flexion contractures preoperatively had a mean combined valgus/flexion contracture deformity of 28.8° (range 23°-38°) . There was preservation of nerve function in all knees. No knees required subsequent operative intervention within 90 days of surgery. Conclusions: Early experience with prophylactic CPN release in our high-risk population demonstrates preservation of nerve function in all patients and is reasonable to consider in patients with a large preoperative combined valgus/flexion deformity. Further studies with larger sample sizes would be beneficial in verification of the results with this technique, as well as determining an angular deformity threshold for which CPN release should be considered.