Passive dorsiflexion flexibility after cast immobilization for ankle fracture.

Ankle fracture is frequently managed with cast immobilization, but immobilization may produce ankle contracture (loss of flexibility). We aimed to quantify recovery of ankle dorsiflexion flexibility in people treated with cast immobilization after ankle fracture, and to determine if initial orthopaedic management was associated with recovery. Ankle flexibility was measured in 150 people with plantarflexion contracture who had been referred for outpatient physical therapy following cast immobilization for ankle fracture. We obtained measurements using an instrumented footplate within 5 days of cast removal and then 4 weeks and 3 months later. Data were compared with published normative data. Both stiffness and the torque corresponding to the peak dorsiflexion angle at baseline decreased during the 3 month recovery period, but recovery was still incomplete 3 months after cast removal. Surgical fixation was associated with higher stiffness, preload and torque values. Passive ankle flexibility does not return to normal values within 3 months of cast removal after ankle fracture. Recovery of normal ankle dorsiflexion flexibility typically takes longer than the initial period of immobilization.