Biomechanics and Motion Analysis

Effects of Medial Displacement Calcaneal Osteotomy on Ankle Joint Contact Characteristics

Principal Investigator: Harold B. Kitaoka, M.D.
Project Coordinator: Lawrence J. Berglund, B.S. — berglund.lawrence@mayo.edu
Funding Source: Walter Bohne, M.D. and Hospital for Special Surgery

Figure 1: Preliminary results for the central (top) and lateral (bottom) ankle joints. While trends are similar, foot position has a clear impact on contact area.

Medial calcaneal osteotomy (MDO) is often performed in patients with painful flatfoot resulting from posterior tibial tendon dysfunction (PTTD). However the affects of this procedure on the biomechanics of the foot is yet to be understood. The purpose of this study was to compare the dynamic contact characteristics of tibiotalar and fibrotalar joints during simulated midstance phase of the gait cycle in the normal foot, a simulated flatfoot, and a simulated flatfoot treated with MDO. It was hypothesized that contact characteristics of these two joints are significantly altered due to the flatfoot condition, but improved with an MDO procedure. These characteristics include contact area, contact pressure, and peak contact pressure.

Testing setup included a cadaveric lower leg specimen. Tendon loads were incorporated using pneumatic actuators. The foot plate moves in three planes creating repeatable moments about the ankle. Pressure sensors measure contact characteristics within the ankle.

Initial findings report a broad range of contact behaviors. These results imply that the MDO procedure does in fact impact tibiotalar and fibrotalar contact characteristics. However this relationship is complicated by the influence of foot position.

Presentations:

• Hirano T, et al., Effects of Medial Displacement Calcaneal Osteotomy on Ankle Joint Contact Characteristics Poster Presentation AAOS Annual Meeting 2009, Short Talk Presentation ORS Annual Meeting 2009