Physical impairments in Adults with Developmental Dysplasia of the Hip (DDH) undergoing Periacetabular osteotomy (PAO): A Systematic Review and Meta-Analysis.

All 24 studies were observational, none was randomised, and many were retrospective, so the review's own authors say the results cannot reach a high level of evidence and rate the certainty as low. Most studies did not describe the patients they lost to follow-up, and only four of the 24 said the outcome measures they used were valid and reliable. Post-operative assessment timepoints and outcome measures varied widely, which stopped the reviewers pooling most of the data; several findings rest on a single study, including running and functional tasks. Only four studies measured strength, and some had fewer than 30 patients, so a real change in strength could have been missed. Some participants are counted more than once because their data were published in more than one paper. The review looked only at people awaiting or recovering from this surgery, so it says nothing about people with dysplasia who are managed without it.

The authors report no conflicts of interest. The review was registered in advance on PROSPERO (CRD42020180571). The paper does not state who funded the work.

Do not read this review as evidence that periacetabular osteotomy restores hip muscle strength or clears a positive impingement test. Pooled results showed hip abduction and flexion strength unchanged one and two years after surgery, and 58% of patients still tested positive one to three years afterwards. The impingement figure only fell to 17% in studies of people five or more years out.