Multi-Ligament Knee Injury with Common Peroneal Nerve Palsy

Robert G. Marx, MD, MSc, FRCSC; Aaron Daluiski, MD


March 15, 2017

Case Report

An 18-year-old high school quarterback playing in his final game prior to starting his collegiate baseball career on a scholarship was tackled in the open field. He had his left foot planted and his knee gave way. Referred for consultation by his local orthopedic surgeon one month after the injury, and generally in excellent health, the patient was 6' 4'' and weighed 225 pounds. There was a large effusion in the left knee with motion from 0 to 130 degrees. The knee was nontender. There was gross AP translation with the Lachman test. The medial side was stable but the lateral side opened grossly in full extension and at 30° of flexion. Motor function in the distribution of the common peroneal nerve was absent. Sensation in the distribution of the deep and superficial peroneal nerves was decreased, but the patient could detect light touch in those distributions. Tibial nerve motor function and sensation were normal. Pedal pulses were normal.

MRI demonstrated obvious bi-cruciate disruption. There was avulsion of the long head of the biceps and iliotibial band. The structures of the posterior lateral corner were torn, including the fibular collateral ligament and popliteus tendon (Figure 1). MRI indicated large areas of bone contusion on the anterior medial femoral condyle and tibial plateau. The patient had an EMG, which demonstrated no peroneal nerve muscle activation.

Figure 1

Coronal MRI demonstrating bi-cruciate and lateral side disruptions.

The patient was taken to the operating room for anterior and posterior cruciate ligament as well as posterolateral corner reconstruction, including biceps tendon repair by one surgeon (RGM). During the same procedure, another surgeon (AD) performed neurolysis of the common peroneal nerve.

Single-bundle Achilles tendon allografts were used for both ACL and PCL reconstructions, with an arthroscopic, trans-tibial PCL technique. PCL tensioning was performed using a tensioning boot as described by Fanelli.[1] Lateral side reconstruction was performed using the anatomic technique described by Schechinger et al. with a single Achilles tendon allograft (Figure 2).[2] The bone plug of the Achilles was inserted in the popliteus origin at the anterior aspect of the popliteus sulcus. The soft tissue portion of the allograft was passed down through the popliteus hiatus and then from posteromedial to anterolateral through a 7-mm drill-hole in the fibular head. The graft was then passed back up under the iliotibial band, and the isometric point just proximal and posterior to the lateral epicondyle was identified by inserting a guide pin. With range of motion from zero to ninety degrees of flexion, the graft length was unchanged when measured to the pin. A 7-mm tunnel was reamed over the pin and the graft was inserted into the tunnel. Lastly, a posterolateral capsular plication was performed with multiple figure-of-eight # 2 ethibond sutures. Graft fixation was performed with metal screws for all grafts (Figure 3).

Figure 2

Lateral side reconstruction using a single Achilles tendon allograft.

Figure 3

 Lateral x-ray left knee after reconstruction

The peroneal nerve was extremely scarred to the surrounding tissue and extensive, meticulous common peroneal neurolysis was performed.

The patient was immobilized in full extension and non-weight bearing for four weeks, followed by physical therapy, range of motion exercises and progressive weight bearing as tolerated. At 6 months, he began to have early return of peroneal motor function, specifically dorsiflexion. One year after surgery, he had normal, symmetrical peroneal eversion strength with slight weakness of dorsiflexion power on the left. Sensation on the dorsal aspect of the foot was improved, but not quite normal. One year after surgery the patient began fielding and batting practice, with excellent left knee stability and function. At 16 months following surgery he returned to baseball competition, playing his usual position, first base, for his college team (Figure 4).

Figure 4

One year after surgery the patient began fielding and batting practice.


Multi-ligament knee injury is a complex and difficult injury to manage, particularly when there are associated nerve or vascular injuries. In this case, despite complete palsy of the common peroneal nerve following the injury, the patient had near full motor recovery. We believe factors that allowed for recovery include meticulous neurolysis as well as the patient's age, which has been shown to be a predictor of peroneal nerve recovery following knee dislocation.[3] While return to high-level athletics is not expected following knee dislocation, with careful surgical technique and a motivated, dedicated patient, it can be achieved.


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