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. Tibial nerve tension was measured during dorsiflexion, eversion, combined dorsiflexion-eversion, and cyclical load with 0°, 15°, and 25° of internal rotation, and repeated on the same leg following each surgical procedure

A pes planus deformity significantly increased tibial nerve tension compared to baseline for all foot positions and cyclical load. A tarsal tunnel release significantly increased nerve tension during eversion, dorsiflexion-eversion, and cyclical load compared to the pes planus foot. A triple arthrodesis more effectively decreased nerve tension than a distraction calcaneocuboid arthrodesis.

Procedures producing skeletal instability (pes planus deformity and a tarsal tunnel release) increased tibial nerve tension. Procedures which corrected deformity and increased stability, decreased tibial nerve tension. In pes planus feet, if increased tibial nerve tension contributes to tarsal tunnel syndrome, then treatment with orthotics should be exhausted before considering surgery, which can further increase nerve tension.