1. Department of Orthopaedic Surgery, Kobe University School of Medicine, Kobe, Japan
2. Division of Orthopaedic Surgery, Case Western Reserve University, Cleveland, Ohio
3. Division of Orthopaedic Surgery, Case Western Reserve University, Cleveland, Ohio; Department of Biomechanics, The Hospital for Special Surgery, Affiliated with New York Hospital-Cornell University Medical College, New York, N.Y. 10021