Background and purpose: Injuries after primary total hip arthroplasty (THA) can be compensated through the National Swedish Patient Insurance Company (Löf). This study examined injury incidence, types, consequences, and subgroup differences in compensated claims following primary THA for osteoarthritis (OA) in Sweden over 10 years.
Methods: Data from Löf and the Swedish Arthroplasty Register were used for compensated claims following primary THA between 2012 and 2021. Injury incidence and subgroup differences by sex, age, OA diagnosis, and surgical volume were analyzed. Injury types, severity, reoperation rate, and surgical approach were evaluated. Absolute risk differences (ARD) and incidence rate ratios (IRR) were calculated.
Results: 1,343 injuries were followed up. The injury incidence was 1.3%. Injury rates were higher in patients < 65 years than ≥ 65 years (ARD 0.2%, 95% confidence interval [CI] 0.1-0.3), in OA due to hip dysplasia compared with primary OA (IRR 1.78, CI 1.31-2.35), and at low- and medium-volume compared with high-volume hospitals (IRR 1.35, CI 1.11-1.64; IRR 1.27, CI 1.14-1.42). In surgery-related injuries (n = 1,251), infection (38%, CI 35-41) and nerve injury (22%, CI 20-25) were the most common injury types, and direct lateral incisions were more frequent than national reference proportions of all THAs during the study period (ARD 9%, CI 6-12). Permanent disability occurred in 74% (CI 72-77) of the claims, and the 2-year reoperation rate was 51% (CI 48-54) (0.4% of the total population).
Conclusion: The injury incidence after primary THA was 1.3% and frequently resulted in permanent disability and reoperation. Infection and nerve injury were the most common injury types. Higher injury rates in younger patients, hip dysplasia, and lower-volume hospitals highlight potential areas for prevention and increased awareness.