The value of intra-articular corticosteroid injection in predicting pain relief following periacetabular osteotomy.

Determining which patients with acetabular dysplasia will benefit most from periacetabular osteotomy (PAO) can be challenging. Intra-articular corticosteroid injection (CSI) is often used for therapeutic and diagnostic purposes in various hip pathologies. This study aims to assess the relationship between self-reported preoperative CSI pain relief and postoperative pain relief after PAO. The case log of a single hip-preservation surgeon was queried from 2013 onward for patients who underwent PAO with preoperative intra-articular CSI. Patients were asked, 'overall, what percent improved are your symptoms from 0-100%?' following preoperative CSI and again at each postoperative visit. A successful postoperative pain outcome was defined as pain relief ≥75% compared to preoperative symptoms at the approximate 6 month postoperative visit. A total of 76 hips met inclusion criteria. Average self-reported relief from preoperative intra-articular CSI was 70 ± 35%. Mean postoperative pain relief was 88 ± 18%. Analysis showed a positive but weak correlation between preoperative CSI response and postoperative relief (0.278, P = .016). Receiver operator characteristic curve analysis found CSI pain relief ≥60% to be the optimal threshold for predicting a successful postoperative pain outcome. Positive predictive value remained high and negative predictive value (NPV) remained low over a range of CSI relief thresholds. Most patients had significant pain relief following PAO, with only 10 patients failing to achieve at least 75% improvement. As a result, the NPV associated with any CSI pain relief threshold remained low. As our patients generally experienced significant postoperative pain relief regardless of preoperative CSI response, further work is warranted to identify those less likely to benefit from surgery.