The objective of this study was to compare foot kinematics, using 3-dimensional tracking methods, during a bilateral heel rise between participants with posterior tibial tendon dysfunction (PTTD) and participants with a normal medial longitudinal arch (MLA). Forty-five individuals volunteered to participate, including 30 patients diagnosed with unilateral stage II PTTD and 15 controls. Foot kinematic data were collected during a bilateral heel rise task from the calcaneus (hindfoot), first metatarsal, and hallux, using an Optotrak motion analysis system and Motion Monitor software. A 2-way mixed-effects analysis of variance model, with normalized heel height as a covariate, was used to test for significant differences between the normal MLA and PTTD groups. The patients in the PTTD group exhibited significantly greater ankle plantar flexion, greater first metatarsal dorsiflexion, and less hallux dorsiflexion compared to controls. At peak heel rise, hindfoot inversion was similar between the PTTD and control groups.
Except for hindfoot eversion/inversion, the differences in foot kinematics in participants with stage II PTTD, when compared to the control group, mainly occur as an offset, not an alteration in shape, of the kinematic patterns.