Entrapment of the Common Peroneal Nerve in Closed Fracture-Dislocation of the Knee―― A Case Report

閉鎖性膝關節骨折併脫臼導致總腓神經壓迫－個案報告

李京軒(Jing-Syuan Lee) ； 李曜洲(Yao-Chou Lee)

《臺灣整形外科醫學會雜誌》 26卷3期 (2017/09) Pp. 347-355

摘要

Background: Common peroneal nerve is the most common injured nerve in the lower extremity trauma. Its injury leads to the foot drop and the loss of sensation of the anterolateral lower leg and the dorsal foot. For those with open injuries, the treatment is straightforward by direct exploration and repair. For those with closed injuries, conservative treatment for 6 months is recommended. However, the wait-and-see policy is such a suffering not only for the patient but also for the physician. Aim and Objectives: By presenting a case of common peroneal nerve palsy after a closed injury of the knee, the rationales and the results of performing the surgery within 6 months after the injury are discussed. Materials and Methods: A 42-year-old man had a motor vehicle accident and was diagnosed with left knee closed fracture-dislocation. Closed reduction and external skeletal fixation were performed in the following hours. After that, complete common peroneal nerve palsy was firstly noted and was treated conservatively. The external skeletal fixation was shifted to internal plate fixation at 1 week after the injury. The electrodiagnostic study performed at 1 month after the injury revealed that there was no evoked action potential in the common peroneal nerve, only increased spontaneous activity. During the following 4 months, the common peroneal nerve palsy was not improved. Surgical exploration was therefore performed, which revealed that the common peroneal nerve was entrapped by a contracture band nearby the insertion of biceps femoris tendon. Neurolysis revealed a characteristic hourglass deformity with intact continuity. Results: The sensation improved on postoperative day 1 according to the patient’s statement. The dorsiflexion of the foot also greatly improved to normal power at 3-months’ followup. Conclusion: For closed fracture-dislocation injury of the knee, the common peroneal nerve injury should be kept in mind. Conservative treatment for 6 months is recommended because spontaneous recovery is usually expected. For those with complete palsy and absence of functional recovery, prompt surgical intervention within 6 months might be helpful to achieve satisfactory results.

關鍵字

common peroneal nerve ； knee closed fracture-dislocation

並列摘要

背景：總腓神經是下肢外傷中容易受傷的神經，臨床上會導致垂足、下小腿前外側及足背的感覺喪失。針對開放性的受傷，治療上建議直接手術探查神經受損並且修補，針對閉鎖性的受傷，建議先進行保守性治療六個月，然而此等待過程對於醫師及病患都是一種煎熬。目的及目標：藉由報告一閉鎖性膝蓋傷害後導致之總腓神經損傷的個案，討論於傷後六個月內施行手術的理由及結果。材料及方法：一位四十二歲的男性發生交通事故導致左膝閉鎖性骨折併脫臼，在接下來幾個小時內，病患接受了閉鎖性復位及骨外固定手術，在此之後，總腓神經麻痺首次被注意到並且給予保守治療，傷後一周骨外固定轉成內骨板固定，傷後一個月的電生理檢查顯示總腓神經無誘導動作電位，只有增強之自發性活性，接下來的四個月追蹤顯示總腓神經麻痺無改善，於是病患接受手術治療，術中發現總腓神經在靠近股二頭肌腱附著處被一攣縮束帶陷壓，神經減壓後發現神經外觀呈現典型的沙漏型畸形但神經連續 性是完整的。結果：術後第一天，病患自述皮膚感覺改善，在三個月的追蹤，足板背屈的功能也大幅改善趨近完全恢復。結論：在閉鎖性的膝關節骨折併脫位傷害中，須警覺總腓神經受損，通常自發性復原是可被預期的，因此建議先保守性治療六個月，對於那些完全性痲痺且無復原徵象者，六個月內進行手術治療以期達到令人滿意的預後可能是有幫忙的。