Atypical Cause Of Lateral Knee Pain In A High School Football Athlete

HISTORY: A 17-year-old male high school football offensive and defensive lineman presented to primary care sports medicine clinic with complaint of right knee pain. Patient injured his knee during a game the week prior when another player collided with his knee during a pile-up. He did not recall feeling a pop or any twisting mechanism at the time but reported swelling and pain immediately after the injury. The next morning, he experienced stiffness and was unable to bend his knee. On presentation, the patient reported lateral knee pain and a sensation of instability but denied locking or catching. He had not been practicing due to his symptoms. PHYSICAL EXAM: Physical examination revealed a large effusion of his right knee. Range of motion was limited to 120 degrees and pain was elicited with maximal flexion. He was tender to palpation along lateral femoral condyle, lateral joint line, and distal ITB insertion site. Special testing was remarkable for pain laterally with McMurray testing and pain with varus stress but no laxity. DIFFERENTIAL DIAGNOSIS: 1.Lateral meniscus tear 2.Lateral collateral ligament sprain 3.ITB injury TESTING AND RESULTS: XR of R knee: •No acute fracture or dislocation. MRI R knee: •ACL intact with increased signal representing low grade sprain •PCL, MCL, LCL intact •Medial and lateral menisci intact •Patellar and quadriceps tendons intact •Soft tissue edema surrounding proximal tibiofibular joint with tearing of the anterior superior tibiofibular ligament Final Diagnosis: Anterior superior tibiofibular ligament tear Treatment and Outcomes: •Hinged knee brace for support during activity for 6 weeks •Naproxen twice daily for pain control •Rehabilitation exercises •Cleared to play as tolerated that week but with limited snaps (played only defensive line) •Returned to high level impact play the following two weeks, tolerating full game participation with some mild pain and swelling •8 weeks out began playing basketball without symptoms