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Final Program


Final Program

686 - Peroneal nerve injury after traumatic knee injury​: A Case Report

Thursday, February 27, 2025
5:00 PM - 6:30 PM MST

    Presenting Author(s)

  • MB

    Margaret D. Becker, MD

    Resident Physician
    IUSM Department of Physical Medicine and Rehabilitation
    Indianapolis, Indiana, United States

    • Corresponding Author(s)

  • JR

    Jacob Ramsey-Morrow, MD

    Assistant Clinical Professor of PM&R
    Indiana University
    Indianapolis, Indiana, United States

Case Diagnosis: Peroneal nerve injury

Case Description:












A 21-year-old female with no significant past medical history presented to outpatient PM&R clinic. Patient fell 2 months prior while running in sandals and immediately felt heaviness and weakness of the left lower extremity with concurrent knee pain. Initial orthopedic evaluation led to imaging, a course of PT, and PM&R referral. X-rays were negative for fractures. Subsequent MRI showed complete ACL tear, partial PCL and LCL tear, MCL sprain, complete popliteus tendon tear, and possible avulsion fracture of the lateral femoral condyle. Upon physiatry evaluation, she was found to have weak dorsiflexion and eversion of left ankle with sensory deficits of lateral leg and dorsum of foot. Gait evaluation revealed left foot drop. Patient endorsed neuropathic pain in left lateral leg and foot.


























Discussions:












This patient was referred for EMG/NCS, clinically treated with physical therapy and AFO fitting, and started on gabapentin for neuropathic pain. Electrodiagnostics demonstrated severe left sensorimotor common peroneal neuropathy with acute denervation. There was also reinnervation of both peroneus longus and tibialis anterior, more significant in the former than in the latter. At the time of patient's presentation for EMG (4 months after injury), she was using AFO and experiencing pain and sensory changes in the previous distribution, although some of her symptoms had improved and strength in ankle dorsiflexion had improved from a 1/5 to 2/5. She was referred to plastic surgery for consideration of tendon/nerve transfer to restore strength and function in distal left lower extremity. 


























Conclusions:











The presentation of this patient serves as a reminder that isolated peroneal nerve injury may result from trauma to the knee. In patients with a constellation of bony or ligamentous knee injuries, especially those demonstrating posterolateral knee involvement as well as distal neurological deficits in ipsilateral leg, this mononeuropathy should be considered as a potential diagnosis.