Abstract
Background: Total hip arthroplasty (THA) is a widely performed procedure that effectively alleviates pain and restores mobility in patients with hip joint disease. However, postoperative leg length discrepancy (LLD) remains a common concern, particularly when limb lengthening occurs, potentially leading to functional limitations and patient dissatisfaction. Aim: This study aimed to evaluate the accuracy of a novel intraoperative technique that uses pelvic soft tissue structures as reference points to predict limb length discrepancy following primary THA. Patients and Methods: A prospective observational study was conducted at the Medical City Complex in Baghdad from February to November 2023, involving 35 patients (13 males, 22 females; aged 19–57 years) undergoing primary cementless THA. The main indication was avascular necrosis (n=31), followed by osteoarthritis (n=4). Preoperative and postoperative limb lengths were measured clinically and radiologically. Intraoperatively, a fixed pelvic reference point was created using a stay suture in the short external rotators. Limb position was standardized, and reference points were marked on the proximal femur before dislocation and after prosthesis placement to estimate intraoperative limb length changes. Results: With a measurement error of 1.94 ± 0.93 mm, the mean observed intraoperative limb lengthening was 14.5 ± 5.3 mm, somewhat similar to the mean postoperative net lengthening of 14.97 ± 5.3 mm. Conclusion: Without adding operating time or complexity, this straightforward and repeatable intraoperative procedure provides a consistent means of forecasting LLD during THA.

Key words: Total hip arthroplasty, leg length discrepancy, intraoperative technique