Review Question - QID 3840

The patient presents with tarsal tunnel syndrome (TTS), impingement of the tibial nerve, often associated with adult-acquired flatfoot and plantar fasciitis.

TTS is a compression neuropathy of the tibial nerve as it enters and courses through the tarsal tunnel, composed of the talus and calcaneus deep to the structures, flexor retinaculum superficially, and abductor hallucis inferiorly. Tunnel contents include the posterior tibialis tendon, flexor digitorum longus, posterior tibial artery, tibial nerve, and flexor hallucis longus. Nerve impingment can be caused by multiple etiologies, but in the "heel pain triad" with flatfoot, plantar fasciitis, and tarsal tunnel syndrome, gradual loss of the stabilizers of the plantar arch can contribute to stretch and subsequent compression of the nerve as it courses through the tarsal tunnel, resulting in pain, parasthesias, a sharp burning sensation, a positive Tinel's sign, and possible muscle wasting. Pain is often medial but can also present on the lateral side depending on severity and which branches of tibial nerve involved.

The tibial nerve branches as it passes through the tarsal tunnel into medial and lateral plantar nerves and the calcaneal nerve. In this patient, the lateral plantar nerve fibers seem to be primarily affected given lateral foot burning, but likely with some medial planter nerve involvement as well.

Labib et al. describe and coin the term "heel pain triad" after a review of of 286 patients with chronic heel pain. They identify 14 patients with the combination of posterior tibial tendon deficiency, plantar fasciitis, and tarsal tunnel syndrome. They hypothesize loss of dynamic and static stabilizers of the medial arch leads to traction neuropathy on the tibial nerve and found an 86% improvement rate after operative management.

Ahmad et al. present a literature review of tarsal tunnel syndrome describing presentation, anatomy, and workup. They emphasize that TTS is a clinical diagnosis which can be complemented by ultrasound and nerve conduction studies but caution against false negative results in symptomatic patients with negative conduction studies. They recommend early operative management to prevent fibrosis, with 44%-96% success rates reported. Particularly good results were found in patients with a positive Tinel's sign pre-operatively.

Incorrect Answers:
Answer 2-4: The sural, saphenous, SPN and DPN are not involved in tarsal tunnel syndrome nor part of the heel pain triad.