Effects of restoration of hip-related parameters following primary total hip arthroplasty on patient-reported outcome measures

Total hip arthroplasty (THA) is a safe and cost-effective surgical intervention for relieving pain and restoring functionality in various hip joint disorders. The present study aimed to analyze the relationship between restoration of the hip parameters like center of rotation (COR), limb length discrepancy (LLD), and femoral offset (FO) following primary THA and patient-reported outcomes using the Oxford Hip Score (OHS) in an Indian population.

In this combined retrospective and prospective study, patients undergoing unilateral THA at Manipal hospital, Bangalore, during January 2016 to September 2019 were included. Pre- and postoperative assessment of COR, LLD and FO of the normal and operated hip was performed and patient-reported outcomes were evaluated using OHS at 12 months after THA.

A total of 110 patients were included with mean age of 47.1 (15.2) years. The mean horizontal COR was significantly reduced (3.3 cm vs 3.1 cm; P = 0.015) and the vertical COR was significantly increased (1.6 cm vs1.7 cm; P = 0.006) postoperatively. The mean postoperative limb length and FO were increased compared to respective preoperative values (6.4 cm vs 5.9 cm; P < 0.001 and 4.8 cm vs 4.7 cm; P = 0.046, respectively). Around three-fourths of patients had restored limb length (75.5%), and 69.1% had restored FO. Based on postoperative OHS assessment, 63.6% of patients achieved excellent scores. Postoperative complications were observed in three patients.

In most patients THA effectively restored key hip parameters including COR, LLD, and FO and a higher OHS score among those with restored biomechanics indicates better functional outcomes.