T he patient was a 61-year-old woman who was referred to a phys- ical therapist with a diagnosis of right common fibular neuropathy at the fibular head involving both the deep and superficial nerve branches, as determined through electrophysiologic examination. The patient described a 4-month history of progressive right lateral knee pain, right lateral lower-leg paresthesia, and weakness of her right ankle dorsiflexors. Visual gait inspection revealed exces- sive hip and knee flexion during right lower extremity swing phase to clear the right ankle and toes. A decrease in light touch sensation over the anterior and lateral aspects of the right lower leg and marked weakness of her right ankle dorsiflexors and evertors were noted. Although examination of her right knee was generally unremarkable, the patient’s right lateral knee pain was reproduced with palpation of the right proximal tib- iofibular joint. Physical therapist intervention in- cluded fitting the patient with a right an- kle-foot orthosis to aid ambulation. The patient was also referred to her physician due to concern for a potential compres- sive lesion at the right proximal tibiofibu- lar joint, which might have explained the patient’s clinical symptoms. Subsequent magnetic resonance imaging identified a lobulated, fluid-filled mass, likely rep- [ MUSCULOSKELETAL IMAGING ] EDWARD P. MULLIGAN, PT, DPT, OCS, SCS, ATC, Assistant Professor, Department of Physical Therapy, School of Health Professions, University of Texas Southwestern Medical Center, Dallas, TX. KAREN MCCAIN, PT, DPT, NCS, Assistant Professor, Department of Physical Therapy, School of Health Professions, University of Texas Southwestern Medical Center, Dallas, TX. Common Fibular (Peroneal) Neuropathy as the Result of a Ganglion Cyst resenting a ganglion cyst, around the fibular head at the level of the proximal tibiofibular joint, which compressed the adjacent neurovascular bundle, includ- ing the common fibular nerve (FIGURES 1 and 2). Following surgical excision of the mass, 1 which histopathological investiga- tion revealed as a ganglion cyst, the pa- tient no longer complained of pain and paresthesia in the right lateral lower-leg region, her right ankle dorsiflexor and evertor strength improved, and she no longer needed the ankle-foot orthosis for ambulation. t J Orthop Sports Phys Ther 2012;42(12):1051. doi:10.2519/ jospt.2012.0421 FIGURE 1. Proton density–weighted fat-saturated axial magnetic resonance image demon- strating a ganglion cyst anterior and lateral to the proximal tibiofibular joint (arrows). FIGURE 2. Proton density–weighted fat-saturated sagittal magnetic resonance image demon- strating a ganglion cyst just posterior to the fibular head (arrow). journal of orthopaedic & sports physical therapy | volume 42 | number 12 | december 2012 | 1051 Reference 1. Hersekli MA, Akpinar S, Demirors H, et al. Synovial cysts of proximal tibiofibular joint causing peroneal nerve palsy: report of three cases and review of the literature. Arch Orthop Trauma Surg. 2004;124:711-714. http://dx.doi.org/10.1007/s00402-004-0717-y Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at on May 26, 2020. For personal use only. No other uses without permission. Copyright © 2012 Journal of Orthopaedic & Sports Physical Therapy®. All rights reserved.