Functional Orthosis Versus Cast Immobilization for Partially Unstable Weber B Ankle Fractures

Inclusion Criteria: * Patients: * With isolated Weber type B fractures that are deemed stable on weightbearing radiographs (MCS injured ankle - MCS uninjured ankle \< 1 mm). * With concomitant gravity stress test evaluated as unstable (MCS injured ankle - MCS uninjured ankle \< 1 mm) * Presenting to one of the participating hospitals, and that are available for stability evaluation within 14 days after injury. * 18-80 years of age * With pre-injury walking ability without aids. Exclusion Criteria: * Patients: * with fracture of the medial malleolus, pre-hospital closed fracture reduction, open fracture, fracture resulting from high-energy trauma or multi-trauma or pathologic fracture. * with fracture of the posterior malleolus involving 25% or more of the joint surface or with a step of the intraarticular surface. (non-displaced fractures smaller than 25% can be included) * with neuropathies and generalized joint disease such as Rheumatoid Arthritis. * that are assumed not compliant (drug use, cognitive- and/or psychiatric disorders). * with previous history of ipsilateral ankle fracture. * with previous history of ipsilateral major ankle-/foot surgery. * who live outside one of the participating hospitals catchment areas (not available for follow-up).