Changes in 24-Hour Physical Activity Patterns and Walking Gait Biomechanics After Primary Total Hip Arthroplasty: A 2-Year Follow-up Study.

BACKGROUND: Despite marked improvements in self-reported pain, perceived functional ability, and gait function following primary total hip arthroplasty (THA), it remains unclear whether these improvements translate into improved physical activity and sleep behaviors. The aim of this study was to determine the change in 24-hour activity profile (waking activities and sleep) and laboratory-based gait function from preoperatively to 2 years following the THA. METHODS: Fifty-one patients undergoing primary THA at a single public hospital were recruited. All THAs were performed using a posterior surgical approach with the same prosthesis type. A wrist-worn accelerometer was used to capture 24-hour activity profiles preoperatively and at 1 and 2 years postoperatively. Three-dimensional gait analysis was performed to determine changes in temporospatial and kinematic parameters of the hip and pelvis. RESULTS: Patients showed improvements in all temporospatial and kinematic parameters with time. Preoperatively, patients were sedentary or asleep for a mean time (and standard deviation) of 19.5 ± 2.2 hours per day. This remained unchanged up to 2 years postoperatively (19.6 ± 1.3 hours per day). Sleep efficiency remained suboptimal (<85%) at all time points and was worse at 2 years (77% ± 10%) compared with preoperatively (84% ± 5%). More than one-quarter of the sample were sedentary for >11 hours per day at 1 year (32%) and 2 years (41%), which was greater than the preoperative percentage (21%). Patients accumulated their activity performing light activities; however, patients performed less light activity at 2 years compared with preoperative levels. No significant differences (p = 0.935) were observed for moderate or vigorous activity across time. CONCLUSIONS: Together with improvements in self-reported pain and perceived physical function, patients had significantly improved gait function postoperatively. However, despite the opportunity for patients to be more physically active postoperatively, patients were more sedentary, slept worse, and performed less physical activity at 2 years compared with preoperative levels. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.