Altered Lower Extremity Joint Energetic Patterns in Patients with Chronic Ankle Instability during Walking

Abstract

A lateral ankle sprain is among the most common sports-related injuries often leading to chronic ankle instability (CAI). Identification of energetic patterns in patients with CAI may clarify underlying injury pathomechanics of CAI. PURPOSE: To examine the effect of CAI on energetic patterns of the lower extremity joints during walking. METHODS: 100 CAI patients (M=49, F=51; 22±2 yrs, 174±10 cm, 71±14 kg, 82±9% FAAM ADL, 62±13% FAAM Sports, 4.5±2.6 ankle sprains) and 100 controls (M=56, F=44; 22±3 yrs, 172±13 cm, 72±18 kg, 100% FAAM ADL & Sports, no previous sprains) performed five walking trials, while ankle, knee and hip joint powers (W/kg) were measured during the stance phase of walking tasks. Functional analyses (α=.05) were used to evaluate difference in joint power between groups. If functions and associated 95% confidence intervals did not cross zero, group differences existed. RESULTS: Figure 1. CAI subjects had less ankle eccentric power and concentric power during early to mid and late stance phase respectively. CAI demonstrated decreased eccentric knee joint power during the initial phase and increased eccentric knee joint power during pre-swing phase. Both concentric and eccentric hip joint power were increased throughout the entire stance phase in patients with CAI. CONCLUSIONS: The CAI group increased proximal joint energy absorption and generation to compensate for decreased distal joint power during walking compared to a control group. More data are needed to determine if joint power redistribution in CAI patients is a risk factor for further ankle injury.Figure