Investigation performed at the Department of Orthopaedic Surgery, University of Iow Hospitals and Clinics, Iowa City.*No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. No funds were received in support of this study.** Department of Orthopaedic Surgery, University of Iowa Hospitals and Clinics. 200 Hawkins Drive, Iowa City, Iowa 52242. Please address requests for reprints to Dr. Blair.