Gait Characteristics and Intersegmental Foot and Ankle Motion in Patients With Neglected Achilles Tendon Rupture.

Neglected Achilles tendon rupture is associated with persistent weakness and altered gait; however, the detailed intersegmental foot and ankle biomechanics have not been fully characterized. This study quantitatively evaluated temporospatial, kinematic, and kinetic gait alterations in patients with neglected Achilles tendon rupture using a multi-segment foot model. Thirteen patients were compared with 26 healthy participants selected by propensity score matching based on age, sex, and body mass index. Intersegmental foot and ankle kinematics were calculated using the DuPont foot model, and ankle kinetics, including plantarflexion moment and ankle power, were evaluated along with temporospatial parameters. Patients with neglected Achilles tendon rupture walked more slowly with shorter strides, a wider step width, and a larger stance phase proportion than matched controls. During the terminal stance phase, the hallux dorsiflexion and hindfoot plantarflexion were reduced. Hallux sagittal range of motion decreased, whereas hindfoot sagittal range of motion did not differ significantly. In the coronal plane, the forefoot and hindfoot range of motion were reduced, with a more everted forefoot and a more inverted hindfoot position. The neglected Achilles tendon rupture group demonstrated significantly lower ankle power during the terminal stance phase and reduced ankle plantarflexion moment during the late stance phase compared with the control group. Collectively, these gait-based findings demonstrate measurable functional deficits in patients with neglected Achilles tendon rupture and highlight the clinical importance of recognizing and appropriately treating this condition.