Medial and Lateral Column Load Distribution After In Situ Subtalar/Talonavicular Fusion With and Without...

Area of Science:

• Orthopedic Surgery
• Biomechanics
• Podiatric Medicine

Background:

• Triple arthrodesis aims to fuse three joints in the hindfoot to treat complex foot deformities.
• Concerns exist that stiffening the lateral column during arthrodesis may increase lateral plantar pressures, potentially causing pain.
• The comparative effect of sparing the calcaneocuboid joint versus including it in triple arthrodesis on lateral forefoot pressures is not well understood.

Purpose of the Study:

• To compare the effects of calcaneocuboid (CC)-sparing hindfoot arthrodesis versus traditional triple arthrodesis on lateral forefoot plantar pressures.
• To investigate whether preserving the CC joint reduces lateral column overload compared to a complete triple arthrodesis.

Main Methods:

• Nine cadaveric legs were subjected to tendon loading and axial pressure in a neutral foot position.
• Plantar pressures under the medial and lateral forefoot were measured using a pressure-sensitive plate in the native state, after subtalar and talonavicular fixation (CC-sparing), and after additional CC fixation (triple arthrodesis).
• Testing was conducted on both a neutral sensor plate and a plate with a 10-degree lateral slope.

Main Results:

• Both CC-sparing fusion and triple arthrodesis significantly increased pressure under the fifth metatarsal compared to the native state in the neutral position (P=.018 and P=.023, respectively).
• In the everted position, neither CC-sparing fusion nor triple arthrodesis showed a significant difference in pressure under the fifth metatarsal compared to the native state (P=.134 and P=.111, respectively).
• No statistically significant difference in lateral forefoot pressure was observed between the CC-sparing and triple arthrodesis groups on either the neutral or sloped surface (P=.687 and P=.393, respectively).

Conclusions:

• In this cadaveric model, both triple arthrodesis and CC-sparing hindfoot fusion significantly increased lateral forefoot plantar pressures compared to the native state.
• There was no significant difference in lateral forefoot pressure between the two arthrodesis techniques when tested on flat or laterally inclined surfaces.
• Preserving the calcaneocuboid joint during hindfoot fusion did not reduce lateral column overload in this experimental setup, although other clinical factors might still favor this approach.