A Novel Measurement Using Digital Radiography to Minimize Fluoroscopy in Total Hip Arthroplasty

Abstract

Preoperative templating for total hip arthroplasty (THA) is fraught with uncertainty. Specifically, the conventional measurement of the lesser trochanter to the center (LTC) of the femoral head used in preoperative planning is easily measured on a template but not measurable intraoperatively. The purpose of this study was to examine the utility of a novel measurement that is reproducible both on templating and in surgery as a more accurate and practical guide. We retrospectively reviewed 201 patients with a history of osteoarthritis who underwent primary THA. For preoperative templating, the distance from the top of the lesser trochanter to the equator (LeTE) of the femoral head was measured on a calibrated digital radiograph with a neutral pelvis. This measurement was used intraoperatively to guide the choice of the trial neck and head. As with any templating technique, the goal was to construct a stable, impingement-free THA with equivalent leg lengths and hip offset. In evaluating this novel templating technique, the primary outcomes measured were the number of trial reductions and the amount of fluoroscopic time, exposures, and radiation required to obtain a balanced THA reconstruction. Using the LeTE measurement, the mean number of trial reductions was 1.21, the mean number of intraoperative fluoroscopy images taken was 2.63, the mean dose of radiation exposure from fluoroscopy was 0.02 mGy, and the mean fluoroscopy time per procedure was 0.6 seconds. In hips templated with the conventional LTC prior to the LeTE, the mean fluoroscopy time was 0.9 seconds. There was a statistically significant difference in fluoroscopy time (p < 0.001). The LeTE is a reproducible measurement that transfers reliably from digital templating to surgery. This novel preoperative templating metric reduces the fluoroscopy time and consequent radiation exposure to the surgical team and may minimize the number of trial reductions.