Disclosures: Anton Matveev, MD: No financial relationships or conflicts of interest

Case Diagnosis: Acquired tibial and fibular neuropathy

Case Description: A 49-year-old male with bilateral knee osteoarthritis developed left foot drop after genicular nerve radiofrequency ablation (GNRFA). He noted left dorsiflexion (DF) weakness and paresthesias in the anterolateral ankle, dorsal and plantar foot within 24 hours of the procedure. He presented to the emergency department for evaluation after 3 days, where his DF strength was 4/5 with hypoesthesia in the dorsum of the foot and web space. A month later his strength was 0/5 DF, 0/5 big toe extension, 1/5 ankle eversion, and 1/5 plantarflexion (PF). Sensation was decreased in the distribution of the tibial and common fibular nerves.

Setting: OutpatientAssessment/

Results: Electrodiagnostic (EDX) evaluation demonstrated axonal injury of the left common fibular nerve proximal to the short head of biceps femoris with active denervation of the tibialis anterior and fibularis longus. There was also tibial nerve involvement without active denervation. Ultrasonography of the popliteal fossa was negative for residual hematoma or sciatic, tibial, or common fibular nerve pathology. At 3 weeks follow-up from EDX evaluation, the patient’s PF improved to 3/5 with no improvement in DF or big toe extension.

Discussion: GNRFA is a treatment option for patients with knee osteoarthritis who have failed conservative management or are poor surgical candidates. Although considered safe, complications may still be unmasked due to the novelty of GNRFA. Cases of septic arthritis, pes anserine tendon injury, and hematoma have been reported. Here we identify tibial and fibular neuropathy as a previously unreported complication of GNRFA. The procedure targets the superior lateral, superior medial, and inferior medial genicular nerves, which provide sensory innervation to the knee joint. The inferior lateral genicular nerve is avoided due to the risk of fibular neuropathy.

Conclusion: Tibial and fibular neuropathy are possible complications of GNRFA. Serial electrodiagnostic evaluation is useful in establishing a diagnosis and prognosticating recovery.

Level of Evidence: Level IV

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/acute-foot-drop-following-genicular-nerve-radiofrequency-ablation-a-case-report/