Hafizur Rahman, Sidketa Fofana, Gerrard Farrell, Luis Venegas, Javier La Fontaine
Hammertoe deformity was associated with a distal‑to‑proximal redistribution of mechanical work during gait, characterized by diminished distal torque and power generation and compensatory proximal joint mechanics. These findings provide biomechanical insight into gait alterations associated with hammertoe deformity and may inform future interventions targeting propulsion and distal function during walking.
BACKGROUND: Hammertoe deformity disrupts distal foot mechanics by reducing toe purchase and plantar fascia engagement; however, its whole‑limb kinematic and kinetic consequences during gait remain poorly characterized. This study investigated lower‑extremity joint mechanics and ground reaction force (GRF) patterns in adults with hammertoe deformity compared with age‑matched controls to identify gait deviations and compensatory strategies associated with impaired distal function.
METHODS: In this cross‑sectional observational study, 17 adults with clinically diagnosed hammertoe deformity and 30 healthy controls underwent three‑dimensional motion capture and force‑plate analysis during self‑selected walking. Gait analyses were performed on 28 limbs from patients with hammertoe deformity and 30 limbs from healthy controls. Lower-extremity joint kinematics, joint torques, and joint powers were computed using inverse dynamics and analyzed across stance sub‑phases.
RESULTS: Patients with hammertoe deformity exhibited marked distal impairments, including reduced ankle dorsiflexor and plantarflexor torques and a 58.7% reduction in ankle push‑off power. Braking and propulsive anterior-posterior GRF peaks were reduced by 41%. Knee and hip ranges of motion were lower, while hip power generation during weight acceptance was increased, indicating a proximal compensation strategy. Vertical GRFs demonstrated a flattened profile, with reduced early- and late-stance peaks, and an elevated mid‑stance minimum, consistent with impaired rocker function. Medial‑lateral GRF differences indicated altered frontal‑plane loading patterns.
SIGNIFICANCE: Hammertoe deformity was associated with a distal‑to‑proximal redistribution of mechanical work during gait, characterized by diminished distal torque and power generation and compensatory proximal joint mechanics. These findings provide biomechanical insight into gait alterations associated with hammertoe deformity and may inform future interventions targeting propulsion and distal function during walking.