Biomechanics and Motion Analysis

Gliding Resistance of the Posterior Tibial Tendon During Passive Motion in an Intact And Simulated Flatfoot

Principal Investigator: Harold B. Kitaoka, M.D.
Project Coordinator: Lawrence J. Berglund — berglund.lawrence@mayo.edu

Figure 1: Gliding resistance of PTT with 2 kg load applied to PTT, while moving hindfoot/ankle in coronal, sagittal, and transverse planes.

Patients who are not effectively treated for early stages of posterior tibial tendon dysfunction (PTTD) risk progression to a severely deformed rigid hindfoot, advanced hindfoot arthritis, calcaneofibular impingement, and ankle instability. Most studies of the posterior tibial tendon focus on conservative and surgical treatment of PTTD, while only a few studies have examined the biomechanics and etiology of PTTD. Studying the change in gliding resistance in the tendon during physiological passive motions with an intact and simulated flatfoot may improve the understanding of the biomechanics of PTTD. Using cadaveric foot specimens, gliding resistance of the PTT was measured and found to be higher in the flatfoot than the intact condition. Flatfoot deformity increased the gliding resistance in the coronal plane by 43%, in the transverse plane by 26% and in the sagittal plane by 17% (Fig. 1). This suggested the importance of aggressive treatment of early stages of PTTD with bracing designed to limit coronal and transverse motions to decrease the potential of progressive deformity, while permitting sagittal motion to allow for more normal ambulation. It also suggested the importance of restoring anatomic alignment during operative treatment of PTTD.