Cast Immobilization Versus Functional Therapy for Acute, Severe Lateral Ankle Sprains

Acute, severe lateral ankle sprains are estimated to comprise between 3-5% of emergency department visits and are the most common musculoskeletal injury in the physically active population. Although the current accepted treatment of ankle sprains is to encourage early mobilization with functional rehabilitation, there is little high-quality evidence directing this clinical practice. This pilot study is to: * provide quantitative data for estimation of mean outcome scores and standard deviations to allow subsequent sample size calculations * evaluate the feasibility of the proposed study design * assess patient enrollment issues specific to randomization into an active rehabilitation program compared to below knee immobilization.