Harris Orthopaedic Laboratory, Massachusetts General Hospital, Boston, Massachusetts; Department of Orthopedics, Clinical Orthopedic Research Hvidovre, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark. Harris Orthopaedic Laboratory, Massachusetts General Hospital, Boston, Massachusetts. Department of Orthopaedics, Aalborg University Hospital, Aalborg, Denmark. Department of Orthopedics, Clinical Orthopedic Research Hvidovre, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.