Survivorship of Primary Hip Arthroscopy in New York State - A Population-Based Study

Abstract

Objectives:Hip arthroscopy utilization has significantly increased over the past decade, with annual rates increasing as much as 300-600% in that time period. While large sample data demonstrates significant improvement in clinical outcomes out to two years post-operatively, with low rates of associated post-operative complications, there is little information on the long-term survival of primary hip arthroscopy procedures. The purpose of this study is to report on the rates of revision hip arthroscopy and conversion to resurfacing or total hip arthroplasty (THA) following hip arthroscopy in the State of New York. We will also report on prognostic variables that may contribute to the need for repeat surgery.Methods:The Statewide Planning and Research Cooperative System (SPARCS) database, a census of all hospital admissions and ambulatory surgery in New York State, was used to identify cases of outpatient primary hip arthroscopy. Demographic information was collected for these patients. After case identification, unique identifiers were utilized to identify those patients that underwent revision hip arthroscopy or subsequent ipsilateral hip resurfacing or THA. The risks of each of these outcomes were modeled with use of age, sex, socio-economic status, hospital and surgeon volume as potential risk factors. Patients were also tracked for 30-day and 90-day complications requiring re-admission.Results:We identified 8,267 hip arthroscopy cases from 1998-2012 performed by 295 surgeons in 137 different surgical centers. Demographics revealed that 46.1% of patients were male, with 80.2% carrying private insurance. Annual hip arthroscopy rates increased 88-fold over the observation period, with a 750% increase over the last 10 years. Revision surgery (scope or arthroplasty) was required in 1,087 cases (13.1%) at a mean of 622 ± 603 days. More specifically, revision hip arthroscopy was required in 310 cases (3.8%) at a mean of 649 ± 586 days after the index procedure, while conversion to either resurfacing or THA was required in 796 (9.7%) cases at an average of 616 ± 616 days. The 30-day complication rate, excluding revision surgery, was 0.2%, while the 90-day complication rate was 0.3%. Thirty-day all-cause re-admission rate was 0.7%. Regression analysis revealed that age > 50 y.o. was associated with increased risk of re-operation (Hazard Ratio[HR] 2.30; CI 2.02-2.62), while males carried a slightly lower risk of re-operation (HR 0.88, CI 0.78 -1.0). Additionally, increased surgical volume, for both surgeon and center (≥75th percentile of annual cases), resulted in a lower risk of re-operation (HR 0.64; CI 0.53-0.77; HR 0.61; CI 0.51-0.73).Conclusion:Hip arthroscopy represents a viable treatment option for femoroacetabular impingement, with low rates of revision surgery and conversion to hip arthroplasty. Age less than 50 and higher surgeon and center surgical volume were associated with lower risk of re-operation.