A new method for intraoperative assessment of leg length, sizing and placement of the components in total hip replacement

Abstract

Background: Intraoperative radiograph of the pelvis is a well-established way to avoid misplacement/undersizing of the components and leg length discrepancy (LLD) in total hip replacement (THR). We describe a method for the obtainment and the evaluation of intraoperative radiographs with a sophisticated wireless radiographic system and a computerized digital tool originally used for preoperative templating.

Methods: In this retrospective case-control study, 60 patients with unilateral hip osteoarthritis who underwent THR with intraoperative radiographic check with the conventional method (n = 30, control group) or the new method (AGFA flat panel DR14eG™/Orthosize™, n = 30, case group) were evaluated and compared for operation time, intraoperative changes in size/placement of the components and final radiological outcome (LLD, acetabular inclination and femoral offset) based on postoperative radiographs of the pelvis.

Results: Mean operation time was lower in case group (85.3 min vs. 103.3 min, p value < 0.005), as well as mean absolute LLD (1.93 mm vs. 2.94 mm, p value = 0.242). There was a higher percentage of intraoperative changes in the offset of the prostheses' head (70% vs. 40%, p value = 0.018) and a significantly lower percentage of patients with LLD > 5 mm in the case group (0% vs. 27%, p value = 0.002).

Conclusions: This new method for the obtainment and assessment of intraoperative radiographs proved to be fast and assuring for keeping LLD below 5 mm in all patients.

Keywords: Intraoperative digital imaging; Intraoperative radiograph; Leg length discrepancy; Total hip replacement; Wireless flat panel.