Background: The biomechanical abnormalities in patients with posterior tibial tendon dysfunction (PTTD) have been described, but few studies have investigated biomechanical chains of adjacent joints. Therefore, we examined the gait pattern of the lower extremity in subjects with PTTD, focusing on the hip and knee joints.
Methods: We compared 19 PTTD patients (average age: 67.1) with 30 age-matched control subjects (average age: 65.1). Gait analysis was performed with a nine-camera motion-capture system and four force plates, using the Vicon Plug-In-Gait and Vicon Nexus software. Temporal-spatial parameters were compared between PTTD and control subjects, and motion and ground reaction force data were compared between the affected limb, the contralateral limb, and the right limb in control subjects.
Results: Subjects with PTTD had increased stance phase ratio and decreased stride length, cadence, and gait speed. The limbs of subjects with PTTD showed increased knee internal rotation at lording response, which was biased to abduction in the knee joint during the gait cycle, and irregular hip flexion and knee extension moment in the terminal stance, even under control of gait speed.
Significance: We believe that the subjects with PTTD have an increased risk of knee osteoarthritis in both the affected and contralateral limbs.
Keywords: Acquired; Foot deformities; Gait; Kinematics; Kinetics; Posterior tibial tendon dysfunction.
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