An in vitro study was performed on 11 cadaver legs to study the effects of tarsal tunnel release, distraction calcaneocuboid arthrodesis, and triple arthrodesis on tibial nerve tension in surgically created pes planus feet. Baseline tibial nerve tension was measured during maximal dorsiflexion, eversion, combined dorsiflexion-eversion, and cyclical load with varying degrees of internal rotation. These measurements were repeated on the same leg after each surgical procedure.
This study demonstrated that a tarsal tunnel release significantly increased nerve tension during eversion, dorsiflexion-eversion, and cyclical load compared with the pes planus foot. Both triple arthrodesis and distraction calcaneocuboid arthrodesis were effective at decreasing tibial nerve tension; the former was more effective than the latter.
Procedures producing skeletal instability, such as ligament release producing a pes planus deformity and a tarsal tunnel release, increased tibial nerve tension. Procedures that corrected deformity and increased stability decreased tibial nerve tension. If increased tibial nerve tension plays a role in the pathophysiology of tarsal tunnel syndrome, then this needs to be considered for treatment of patients with this syndrome.