Is there a difference in physical activity levels in patients before and up to one year after unilateral total hip replacement? A systematic review and meta-analysis.

The included evidence was generally poor to moderate in quality, and no study fully addressed all appraisal criteria. Most studies were observational longitudinal studies, with only one randomised control trial, so the review cannot show that hip replacement caused any change. Sample sizes were small and uneven, ranging from one to 88 participants, and one included study did not clearly state its number of participants. Postoperative measurements were taken at different times, from six weeks to up to one year, so pooled results mix early and later recovery. The 6-minute walk pooled analysis had high heterogeneity (I2 84%), and the positive subgroup result depended on excluding one study of 15 participants. No included study identified confounding factors that may have influenced physical activity, such as pain, medical conditions, age, gender or surgical technique. Only one study examined characteristics of excluded participants, so representativeness is unclear.

The authors declared no potential conflicts of interest. The work was supported by a doctoral studentship funded by the University of East Anglia.

Do not read the 6-minute walk subgroup increase as proof that hip replacement raises physical activity. It was a secondary subgroup analysis, not the primary outcome, and it depended on excluding one older-only study. The overall 6-minute walk analysis also had high heterogeneity.