Trajectories of Rehabilitation Exercise Adherence after Hip Fracture Surgery in Older Adults: a Prospective Longitudinal Study

Recovery after hip fracture surgery in older adults depends on sustained rehabilitation exercise, yet adherence after discharge is heterogeneous and may change over time. Previous studies have focused on single time points or average changes, which may overlook clinically meaningful heterogeneity. This study aimed to identify trajectories of rehabilitation exercise adherence during the first 6 months after hip fracture surgery and to examine factors associated with trajectory membership. This prospective longitudinal study enrolled 199 older adults undergoing hip fracture surgery at a secondary-level Class A general hospital in Hangzhou, China, June–December 2025. Baseline demographic, clinical, and psychosocial data were collected during hospitalization. Rehabilitation exercise adherence was assessed at 1, 3, and 6 months postoperatively using the Orthopaedic Patient Functional Exercise Compliance Scale. Latent growth mixture modelling identified adherence trajectories. Univariate analyses and multinomial logistic regression were used to examine factors associated with trajectory membership, with binary logistic regression performed as a sensitivity analysis. Follow-up assessments included 196 participants at 1 month, 194 at 3 months, and 191 at 6 months. Mean adherence scores increased steadily, from 30.00 ± 16.49 at 1 month to 38.39 ± 14.95 at 3 months and 48.58 ± 18.85 at 6 months. A 3-class solution was selected as optimal and clinically interpretable, identifying a low-adherence trajectory (11/199, 5.53