Axonotmesis On The Basketball Court: Not-so Common Common Peroneal Neuropathy

HISTORY: A 23-year-old male collegiate basketball player sustained a right lower extremity injury after landing awkwardly after making a pass during a basketball game. He denied a fall or contact with other players. Despite pain, he finished the rest of the game. After the game, he complained of pain, foot numbness, and paresthesia with associated significant swelling. He was evaluated in the ER where a fracture and acute compartment syndrome were ruled out. He was discharged with a steroid taper and a CAM boot, and recommended outpatient follow-up. PHYSICAL EXAMINATION: On examination, patient was noted to have right foot drop. There was no tenderness at around the fibular head, but sensation to light touch was reduced over the superficial and deep peroneal nerve distribution. He had significant weakness with dorsiflexion (0/5) and eversion (3/5), but otherwise had a full strength. DIFFERENTIAL DIAGNOSIS: 1. Common peroneal neuropathy 2. Complete tear of tibialis anterior and/or peroneus muscles 3. Sciatic neuropathy TEST AND RESULTS:EMG/NCS:- Common peroneal neuropathy likely around the fibular head- No activity, with denervation potentials in the tibialis anterior and peroneus longus muscles- No evidence of tibial or sural neuropathy, or lumbar radiculopathy MRI of the knee and tibia/fibula: - Thickening and increased signal in the common peroneal nerve extending into the superficial and deep peroneal nerve branches at the level of the fibular neck- Near complete chronic tear and hematoma of the proximal peroneus longus muscle. - Feathery intramuscular edema throughout the tibialis anterior and extensor digitorum longus. FINAL/WORKING DIAGNOSIS: Common peroneal neuropathy consistent with Sunderland grade II-III with concomitant peroneus longus tear TREATMENT AND OUTCOMES:He saw an Orthopedic Surgeon who felt he had a good prognosis given his mild improvements at 8 weeks post injury and recommended to continue conservative treatment. Patient was placed in a posterior leaf spring AFO and continued physical therapy throughout the off season to work on strengthening and to maintain range of motion to prevent equinus contracture. At 10-month post injury, he had almost full recovery of strength, no longer requiring the AFO, and was advised to continue therapy to regain full strength before returning to sport.