LAUSR

Background and purpose Little is known about the outcome after receiving total hip arthroplasty (THA), specifically in young patients. We identified different recovery trajectories in young patients using data from the Dutch Arthroplasty Register (LROI). We also explored whether risk factors commonly associated with functional outcome were associated with recovery trajectory. Patients and methods We used HOOS-PS score data up to 1 year postoperatively from the LROI from all patients younger than 55 years who received a primary THA between 2014 and 2019. To investigate whether different recovery trajectories could be distinguished, we performed latent class growth analysis (LCGA). Subsequently, we used multinomial logistic regression analyses to explore factors associated with class membership. Results 3,207 patients were included. LCGA identified 3 groups of patients: optimal responders (75%), good responders (21%), and poor responders (4.7%). Female sex (RR 1.1; 95% CI 1.1–1.1), ASA II (RR 1.1; CI 1.0–1.1), ASA III–IV (RR 1.1; CI 1.0–1.2), smoking (RR 1.1; CI 1.0–1.1), cemented fixation (RR 1.2; CI 1.1–1.2), and a 22–28 mm head diameter (RR 1.1; CI 1.0–1.2) were associated with “good responder” class membership. ASA II (RR 1.1; 1.0–1.2), ASA III–IV (RR 1.2; 1.1–1.3), smoking (RR 1.2; CI 1.1–1.2), and hybrid fixation (RR 1.2; CI 1.0–1.2) were associated with “poor responder” class membership. Interpretation 3 recovery trajectories could be identified. Female sex, higher ASA classifications, smoking, cemented or hybrid fixation, and small head diameter were associated with a suboptimal result after primary THA in young patients. These findings can aid in the process to determine which patients are at risk of a suboptimal outcome.