1. From the Department of Orthopedics, the Section of Biostatistics, and the Department of Diagnostic Radiology, Mayo Clinic and Mayo Foundation, Rochester, Minnesota.
2. Senior Resident in Orthopedics, Mayo Graduate School of Medicine, Rochester, Minnesota.
3. Instructor in Orthopedics, Mayo Medical School, Rochester, Minnesota. To whom requests for reprints should be addressed at the Department of Orthopedics, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905.
4. Assistant Professor of Biostatistics, Mayo Medical School, Rochester, Minnesota.
5. Professor of Radiology, Mayo Medical School, Rochester, Minnesota.
6. Orthopedic Physicians' Assistant, Mayo Clinic and Mayo Foundation, Rochester, Minnesota.