Abstract
Introduction: Chronic hip diseases — hip osteoarthritis, avascular necrosis of the femoral head and the sequelae of osteoporotic femoral-neck fractures — are leading causes of pain and functional disability. Total hip arthroplasty (THA) is established as the principal intervention for these chronic diseases, with improving quality of life as its goal. Iraqi data are limited. Objective: To assess the functional and pain outcomes of primary THA performed for chronic hip diseases in an Iraqi cohort and identify baseline factors associated with improving quality of life. Methods: Prospective observational study (2019–2023) in four hospitals in Al-Najaf, Iraq. Sixty-four consecutive adults aged ≥40 years (ASA I–II) undergoing primary THA were enrolled. The Harris Hip Score (HHS) was recorded preoperatively and at 3 weeks, 3, 6 and 12 months. Predictors of the 12-month HHS were modelled by multivariable linear regression. Sample-size adequacy was confirmed by post-hoc power analysis (G*Power 3.1.9.7; α = 0.05, two-tailed; achieved power ≥ 0.80 for the primary association). STROCSS 2021 reporting was followed. Results: Mean age was 60.9 ± 13.1 years (70.3% ≥60 years); 53.1% women; 82.8% overweight or obese. Indications were avascular necrosis (40.6%), femoral-neck fracture (31.3%), hip osteoarthritis (25.0%) and intertrochanteric fracture (3.1%). The HHS rose from 43.2 ± 8.3 preoperatively to 92.1 ± 6.3 at 12 months (P < 0.001), with 92.2% of patients achieving good or excellent outcome — substantial improving quality of life. Body mass index was the only baseline variable independently associated with the outcome (standardised β = −0.327, P = 0.002). Complications were limited (leg-length discrepancy 7.8%, heterotopic ossification 4.7%, dislocation 4.7%, one superficial infection); no revision or mortality occurred. Conclusions: Primary THA is highly effective for chronic hip diseases in Iraqi patients, producing durable, clinically important improving quality of life. Body mass index emerges as a modifiable nutrological target whose optimisation may further enhance outcomes.