Patient injuries in primary total hip replacement Nationwide analysis in Finland

Background and purpose — Although the results of primary total hip replacements (THRs) are generally excellent, sometimes seri- ous complications arise. Some of these severe complications are considered to be patient injuries. We analyzed primary THR- related patient injuries in a nationwide setting. Patients and methods — We evaluated all the primary THR- related patient injury claims in Finland between 2008 and 2010. We used the original medical records and 2 nationwide registries, the Care Register for Social Welfare and Health Care and the Patient Injury Claim Register. Results — We identifi ed 563 claims, 44% of which were com- pensated (n = 250). Of these 250 compensated claims, 79% were considered to be avoidable (treatment injuries) and 21% were severe unexpected infections (with a preoperative infection risk of less than 2%). The most common type of technical error was cup malposition (31%). High-volume hospitals (with an annual primary THR volume ≥ 400) had a lower patient injury rate. In lower-volume hospitals (with an annual primary THR volume of < 400), the relative risks (RRs) of patient injury for any reason, due to technical errors, or because of cup malposition were 2-fold (95% CI: 1.6–3.1), 4-fold (95% CI: 2.3–6.2), and 9-fold (95% CI: 3–28), respectively, compared to high-volume hospitals. Interpretation — Our study provides the fi rst comprehensive nationwide data on THR-related patient injury types. Hospital volume was associated with the quality and quantity of errors detected. An annual hospital volume of ≥ 400 primary THRs was established as a protective factor against patient injuries.