Age is predictive of higher rate of conversion to total hip arthroplasty after core decompression for osteonecrosis of the hip.

Background: Core decompression may be performed for early osteonecrosis with a goal of improving symptoms and potentially delaying the need for total hip arthroplasty. The effectiveness and complication rate of this procedure is not well understood given the relatively rare nature of hip osteonecrosis. Purpose: The purpose of this study is to determine time to total hip arthroplasty (THA) after core compression, assess predictors of early conversion to THA, and to examine complications after hip core decompressions. Methods: Using Current Procedural Terminology (CPT) codes, we queried the Mariner PearlDiver dataset for patients who underwent hip core decompression. Patient demographics were recorded and subsequent THA conversion within 2 years after surgery were tracked. Patient demographic factors, including age, sex, obesity, diabetes, prior fractures, steroid use, tobacco use, or alcohol use, were evaluated as possible predictors of early conversion to THA. International Classification of Diseases (ICD) codes were used to identify complications at 90 days after core decompression. Multiple linear regression was used to test if the patient demographics significantly predicted conversion to THA and complications after core decompression. Results: Between 2010 and 2020, 555 patients underwent hip core decompression. Within 2 years of core decompression, 226 patients converted to THA (40.7%). Age was the only significant risk factor for conversion to THA. The highest proportion of patients (61.1%, 138/226) who converted to THA were between age 40-59. The 90-day complication rate was 2.9% (16/555). The most common complication was femoral neck fracture (11/16 of all complications). Discussion: There is a high failure rate following core decompression for hip osteonecrosis with over one third of patients converting to THA within 2 years. Age was the only variable predictive of conversion to THA. The overall complication rate after core decompression is low at 90 days. Conclusion: Patients should be counseled regarding the risk of early conversion to THA if over 40 and the potential risk of femoral neck fracture.