1. Division of Orthopaedics and Rehabilitation; Department of Surgery; Southern Illinois University School of Medicine; Springfield Illinois 62794-9679
2. Campbell Clinic Department of Orthopaedic Surgery & Biomedical Engineering; University of Tennessee; 956 Court Ave, Suite E226 Memphis Tennessee 38163
3. Clinic for Orthopaedic Surgery, Campus Grosshadern; Ludwig Maximilians University; Munich; Germany Aesculap AG, Research & Development Tuttlingen Germany