Patient-Reported Outcomes Following Periacetabular Osteotomy versus Hip Arthroscopy for Borderline Acetabular Dysplasia Are Comparable: A Systematic Review

Purpose: The purpose of this systematic review was to compare patient populations and outcomes in studies treating borderline hip dysplasia (BHD) with either hip arthroscopy or periacetabular osteotomy (PAO). We hypothesized that studies would show significant postoperative improvement following both PAO and arthroscopy for BHD, and that subjects undergoing arthroscopy would have a higher rate of Cam morphology.

Methods: A literature review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was conducted to identify studies published after 2014 that reported patient-reported outcome measures (PROMs) following hip arthroscopy or PAO for BHD. Preoperative demographics, radiographic variables, operative findings, procedures, postoperative outcomes, and complications were recorded. Forest plots were constructed of disaggregated data to identify study heterogeneity using the I² statistic.

Results: 26 studies (8 PAO; 18 Arthroscopy) were included. Acetabular morphology was comparable between the PAO and arthroscopy studies while the arthroscopy studies reported higher alpha angles (range 48.3-75.3°) compared to the PAO studies (range 47.6-55°). No PAO studies reported an average alpha angle greater than 60° while this was reported in 71% of arthroscopy studies. The most common PROMs were the modified Harris Hip Score (mHHS), with average improvement ranging from 20-29 for PAO and 17.9-34.4 for arthroscopy, and the International Hip Outcome Tool-12 (iHOT-12), with mean postoperative scores ranging from 73.3-74.3 for PAO and 67.5-85.4 for arthroscopy. Postoperative PROM improvement was significant for all studies with significant heterogeneity for the mHHS (I²=0.90) and iHOT-12 (I²=0.98).

Conclusions: There was significant postoperative improvement following both PAO and modern hip arthroscopy for the surgical management of BHD with high levels of heterogeneity limiting comparability between study groups. Hip arthroscopy studies recorded higher alpha angles suggesting that cam deformities in the setting of BHD can be managed arthroscopically, however further study on optimizing indications between procedures is required.