There Is a Significant Discrepancy Between “Big Data” Database and Original Research Publications on Hip Arthroscopy Outcomes: A Systematic Review

Purpose: The purpose of this study was to compare (1) major complication, (2) revision, and (3) conversion to arthroplasty rates following hip arthroscopy between database studies and original research peer-reviewed publications. Methods: A systematic review was performed using PRISMA guidelines. PubMed, SCOPUS, SportDiscus, and Cochrane Central Register of Controlled Trials were searched for studies that investigated major complication (dislocation, femoral neck fracture, avascular necrosis, fluid extravasation, septic arthritis, death), revision, and hip arthroplasty conversion rates following hip arthroscopy. Major complication, revision, and conversion to hip arthroplasty rates were compared between original research (single- or multicenter therapeutic studies) and database (insurance database using ICD-9/10 and/or current procedural terminology coding terminology) publishing studies. Results: Two hundred seven studies (201 original research publications [15,780 subjects; 54% female] and 6 database studies [20,825 subjects; 60% female]) were analyzed (mean age, 38.2 ± 11.6 years old; mean follow-up, 2.7 ± 2.9 years). The database studies had a significantly higher age (40.6 + 2.8 vs 35.4 ± 11.6), body mass index (27.4 ± 5.6 vs 24.9 ± 3.1), percentage of females (60.1% vs 53.8%), and longer follow-up (3.1 ± 1.6 vs 2.7 ± 3.0) compared with original research (P <.0001 for all). Ninety-seven (0.6%) major complications occurred in the individual studies, and 95 (0.8%) major complications occurred in the database studies (P =.029; relative risk [RR], 1.3). There was a significantly higher rate of femoral neck fracture (0.24% vs 0.03%; P <.0001; RR, 8.0), and hip dislocation (0.17% vs 0.06%; P =.023; RR, 2.2) in the database studies. Reoperations occurred at a significantly higher rate in the database studies (11.1% vs 7.3%; P <.001; RR, 1.5). There was a significantly higher rate of conversion to arthroplasty in the database studies (8.0% vs 3.7%; P <.001; RR, 2.2). Conclusions: Database studies report significantly increased major complication, revision, and conversion to hip arthroplasty rates compared with original research investigations of hip arthroscopy outcomes. Level of Evidence: Level IV, systematic review of Level I-IV studies.