The incidence and clinical outcomes of peroneal nerve injuries associated with posterolateral corner injuries of the knee

The purpose of the study was to investigate the incidence of complete and partial peroneal nerve injuries in patients with posterolateral corner (PLC) knee injuries; additionally, to compare patient-reported outcomes among patients with and without peroneal nerve injury and to examine the factors that predict the recovery of nerve function. A retrospective chart review was performed to identify patients who underwent PLC reconstruction or repair from 2000 to 2012 with a minimum 6-month clinical follow-up. Peroneal nerve injuries were identified, and treatments and outcomes were analyzed. IKDC and KOOS outcome scores at the final follow-up were reported. There were 61 PLC injuries in 60 patients. Sixteen of the 61 knees (26.2%) had a peroneal nerve injury at initial presentation; there were 13 complete and 3 partial nerve injuries. The median age was 31 years (15 men and 1 woman) and 31 years (33 men and 12 women) in the nerve and non-nerve injury cohorts, respectively. The median follow-up in the nerve injury group was 26 months (interquartile range (IQR): 12-48), and in the non-nerve injury cohort (n.s.) 61 months (IQR 22-85). All 13 complete injuries were treated with neurolysis: 3 were complete transections and 10 were stretch injuries. Of the ten stretch injuries, five (50%) spontaneously recovered full nerve function at the final follow-up. The remaining six patients chose definitive treatment with ankle-foot orthoses. Two of the three transected nerve patients underwent successful posterior tibialis transfer, and one chose ankle-foot orthoses. All three partial nerve injuries underwent neurolysis and had complete nerve recovery at the final follow-up. The median IKDC scores in the nerve injury group and the non-nerve injury group were 64.4 (IQR 47.8-73.3) and 72.8 (IQR 59.3-87.9) (n.s.), respectively, and the median Lysholm scores were 85 (IQR 83-92) and 86.5 (IQR 79-90) (n.s.), respectively. There were no significant differences in the rates of complications, secondary surgeries, mechanism of injury, KDIII injuries, or other injuries. This study demonstrated comparable rates of peroneal nerve injuries in PLC injuries (26.2%) to that in the literature. The rates of nerve recovery for complete disrupted injury, complete stretched injury, and partial injury were 0, 50, and 100% with an overall rate of recovery of 50%. The outcome scores were similar between patients with and without nerve injuries; however, a small cohort size led to limitations in statistical analysis. Thus, a prolonged trial of non-operative treatment is recommended for peroneal nerve injuries to allow for assessment of nerve recovery and patient outcome before entertaining surgical treatments. Level IV.