Disclosures: Daniel C. Oh, MD, MS: Nothing to disclose

Case Description: The patient presented with right medial ankle pain 7 years after arthroscopy. About 4-5 years prior to presentation, patient had increased the intensity, duration, and frequency of running and noticed medial arch and posterior medial malleolar paresthesias and pain. Symptoms were minimal at rest but excruciating during exertion. Previous evaluation by an outside provider did not reveal a tibial nerve (TN) entrapment, and a subsequent series of 3 corticosteroid injections around the nerve provided only temporary relief. As such, he was referred for high frequency diagnostic ultrasound for further evaluation. Physical exam was notable for mild discomfort with resisted inversion and positive Tinel’s sign at the tarsal tunnel (TT). Ultrasound evaluation was performed at rest and following 10 minutes of treadmill running. Initial evaluation revealed insertional posterior tibial (PT) and flexor hallucis longus (FHL) tendinopathies, compression of the TN in the TT, and subtalar joint (STJ) arthropathy. After exertion, an effusion was visualized in the subtalar joint, which caused compression of the medial plantar nerve (MPN) between the FHL tendon and tibial artery (TA).

Setting: Outpatient center.

Patient: A 58-year-old man with a remote history of right talar dome injury status post arthroscopic debridement 4 years later.

Assessment/Results: This patient had remote pathology of the talar dome, predisposing him to dynamic effusions. He also had subclinical tarsal tunnel syndrome. However, the majority of his symptomatology was due to a dynamic subtalar effusion compressing the MPN on the FHL tendon and TA, causing severe exertional pain. The patient was subsequently referred for surgical decompression of MPN.

Discussion: This is the first reported case, to our knowledge, of dynamic, symptomatic compression of the MPN due to a STJ effusion.

Conclusion: In patients that have pathology predisposing them to dynamic effusions, transient compression of nearby nerves may be considered as a possible pain generator.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/medial-plantar-neuropathy-secondary-to-dynamic-compression-in-a-runner-a-case-report/