The first case involves a 58-year-old woman with Müller-Weiss syndrome (adult-onset idiopathic progressive navicular bone degeneration) s/p multiple midfoot fusions. Following re-bone grafting for a right foot medial geniculate flap and talonavicular fusion performed under thigh tourniquet, the patient developed chronic paresthesias and numbness in the posterolateral foot extending proximally to the mid-shin with intermittent radicular pain. Despite persistent symptoms, the diagnosis was delayed for seven years until electrodiagnostic testing (EDX) identified a right sciatic (tibial-division) mononeuropathy at or proximal to the takeoff to the biceps femoris-long head. This diagnostic delay underscores the inertia of confirmation bias (in this case, toward S1 radiculopathy), whereby iatrogenic nerve constriction was overlooked.
The second case involves a 31-year-old woman s/p motor vehicle accident presented with right tibial pilon fracture and burst fracture of the L5 vertebral body with retropulsion causing cauda equina syndrome. She underwent open reduction and internal fixation with external fixation and L3–S1 fusion (with subsequent resolution of neural compression), respectively. Postoperatively, she reported intractable pain over the dorsum of the right foot and great toe. After six months of symptoms, EDX revealed a right superficial peroneal axonal neuropathy, which ultrasound localized to the ankle just proximal to the lateral malleolus in proximity to a hyperechoic structure compatible with orthopedic hardware. This case illustrates how anchoring bias—attributing postoperative symptoms to known spinal pathology or surgical site pain—obfuscated the diagnosis of distal focal mononeuropathy.