Preoperative planning for total hip arthroplasty. Quantitating its utility and precision.

This study evaluated the usefulness and accuracy of preoperative planning for cemented and cementless total hip arthroplasty (THA). The authors conducted a prospective study of 110 consecutive primary cases in which surgeons recorded the preoperative plan and what occurred in each case. Measured variables included estimated magnification, acetabular cup and femoral stem size, planned lengthening, and anticipated problems. Preoperative estimates of magnification frequently differed from actual magnification, and in 17% of cases it affected choice of implant size. Preoperative bone morphology did not correlate with type of femoral stem fixation. Implant sizing was predicted from the preoperative plan for 62% of acetabular cups, 78% of cemented stems, and 42% of the cementless stems. Leg-length equalization was a goal in only 70% of cases. Anticipated problems focused on anatomic variations, but intraoperative problems involved technique and equipment. The authors conclude that surgeons need better methods to estimate magnification and bone morphology from preoperative radiographs. Preoperative planning may not reduce intraoperative complications, which can arise from unanticipated technique and equipment mishaps.