Aims. The purpose of this exploratory study was to investigate if the 24-hour activity profile (i.e. waking activities and sleep) objectively measured using wrist-worn accelerometry of patients scheduled for total hip arthroplasty (THA) improves postoperatively. Patients and Methods. A total of 51 THA patients with a mean age of 64 years (24 to 87) were recruited from a single public hospital. All patients underwent THA using the same surgical approach with the same prosthesis type. The 24-hour activity profiles were captured using wrist-worn accelerometers preoperatively and at 2, 6, 12, and 26 weeks postoperatively. Patient-reported outcomes (Hip Disability and Osteoarthritis Outcome Score (HOOS)) were collected at all timepoints except two weeks postoperatively. Accelerometry data were used to quantify the intensity (sedentary, light, moderate, and vigorous activities) and frequency (bouts) of activity during the day and sleep efficiency. The analysis investigated changes with time and differences between Charnley class. Results. Patients slept or were sedentary for a mean of 19.5 hours/day preoperatively and the 24-hour activity pattern did not improve significantly postoperatively. Outside of sleep, the patients spent their time in sedentary activities for a mean of 620 minutes/day (. sd. 143) preoperatively and 641 minutes/day (. sd. 133) six months postoperatively. No significant improvements were observed for light, moderate, and vigorous intensity activities (p = 0.140, p = 0.531, and p = 0.407, respectively). Sleep efficiency was poor (< 85%) at all timepoints. There was no postoperative improvement in sleep efficiency when adjusted for medications (p > 0.05). Patient-reported outcome measures showed a significant improvement with time in all domains when compared with preoperative levels. There were no differences with Charnley class at six months postoperatively. However, Charnley class C patients were more sedentary at two weeks postoperatively when compared with Charnley class A patients (p < 0.05). There were no further differences between Charnley classifications. Conclusion. This study describes the 24-hour activity profile of THA patients for the first time. Prior to THA, patients in this cohort were inactive and slept poorly. This cohort shows no improvement in 24-hour activity profiles at six months postoperative. Cite this article: Bone Joint J 2019;101-B:415–425

We compared the dynamic instability of 25 dysplastic hips in 25 patients using triaxial accelerometry before and one year after periacetabular osteotomy. We also evaluated the hips clinically using the Harris hip score and assessed acetabular orientation by radiography before surgery and after one year. The mean overall magnitude of acceleration was significantly reduced from 2.30 m/s. 2. (. sd. 0.57) before operation to 1.55 m/s. 2. (. sd. 0.31) afterwards. The mean Harris hip score improved from 78.08 (47 to 96) to 95.36 points (88 to 100). The radiographic parameters all showed significant improvements. This study suggests that periacetabular osteotomy provides pain relief, improves acetabular cover and reduces the dynamic instability in patients with dysplastic hips