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Editorial Commentary: Hip Arthroscopy for Patients With Decreased Center-Edge Angle and Bipolar Cartilage Lesions Is Associated With Early Conversion to Total Hip Arthroplasty

      Abstract

      The utilization of hip arthroscopy to treat femoroacetabular impingement has continued to grow year after year. Clinical studies and cost-effectiveness analyses have repeatedly shown the benefits of hip arthroscopy in improving quality of life, offering much promise to this patient population. Through years of research, a more comprehensive understanding of impingement pathologies has brought improving surgical techniques. However, predictors of poor outcomes are still not entirely understood. Although many patients attain significant relief, some patients do not attain meaningful improvement. Meaningful improvement can be found even years after hip arthroscopy, but this is a long road for patients who do not find sustained relief. Thus, as with defining appropriate indications for hip arthroscopy, it is equally important to identify factors that may instead suggest alternative treatment regimens for patients with hip pathology who may not benefit from arthroscopic intervention. However, rather than exclude large groups entirely based on the presence of certain factors such as increased age or arthritis, the goal should be to understand the nuances among patients in these higher-risk groups to identify those who may still find success with hip arthroscopy.
      The utilization of hip arthroscopy to treat femoroacetabular impingement continues to grow, as does our understanding of the appropriate indications (and contraindications) to achieve positive outcomes for our patients. In their article “Lower Center Edge Angle and Bipolar Cartilage Lesions Are Associated With Conversion to Hip Arthroplasty Within 2 Years Following Hip Arthroscopy: A Matched Cohort Analysis,” Ruzbarsky, Seiter, Soares, Pierpoint, Briggs, and Philippon
      • Ruzbarsky J.J.
      • Seiter M.N.
      • Soares R.
      • Pierpoint L.
      • Briggs K.
      • Philippon M.J.
      Lower center edge angle and bipolar cartilage lesions are associated with conversion to hip arthroplasty within 2 years following hip arthroscopy: A matched cohort analysis.
      perform a unique analysis with a population selected to include only patients who underwent conversion to total hip arthroplasty (THA) after hip arthroscopy. The study matched 49 patients who underwent early conversion to THA (<2 years) to a cohort that underwent late conversion to THA (>2 years) based on age and sex. They concluded that patients with a decreased center-edge angle (<25°) and those with bipolar chondral lesions at the time of arthroscopy were associated with early conversion to THA rather than late conversion.
      The choice of how to define early versus late conversion to THA is important. Setting the mark at 1 year would include too many early failures in the “late” failure group; similarly, moving the bar to 3 or 4 years would include some patients who may have fared arguably well in the “early” failure group. This study incorporated data from a systematic review that showed that half of conversions occurred before 2 years and half occurred after 2 years—thus creating a well-thought-out cutoff based on multiple studies to define a cutoff of early and late failures at the 50% mark. Additionally, this seems to be in line with data from cost-effectiveness studies—although cost-effectiveness analyses rely heavily on the input data and assumptions, most studies have identified hip arthroscopy to treat femoroacetabular impingement as a highly cost-effective intervention. In a particularly detailed evaluation, Mather et al.
      • Mather III, R.C.
      • Nho S.J.
      • Federer A.
      • et al.
      Effects of arthroscopy for femoroacetabular impingement syndrome on quality of life and economic outcomes.
      included indirect cost data and found the threshold for cost to be 1.87 years—approximately 22 months.
      As would be expected in a study population undergoing THA conversion after hip arthroscopy, the average age is older than that of the general population that may undergo hip arthroscopy (51 years of age in this study
      • Ruzbarsky J.J.
      • Seiter M.N.
      • Soares R.
      • Pierpoint L.
      • Briggs K.
      • Philippon M.J.
      Lower center edge angle and bipolar cartilage lesions are associated with conversion to hip arthroplasty within 2 years following hip arthroscopy: A matched cohort analysis.
      ). Although hip arthroscopy may be considered somewhat controversial for this older age group given many studies showing higher rates of failure with increased age and the presence of arthritis,
      • McCormick F.
      • Nwachukwu B.U.
      • Alpaugh K.
      • Martin S.D.
      Predictors of hip arthroscopy outcomes for labral tears at minimum 2-year follow-up: The influence of age and arthritis.
      this is exactly why we commend the authors on their analysis. Large-population studies have shown increased rates of THA conversion in older groups, such as 20% in patients aged 50 to 69 years and 30% in patients aged 70 years or older at 2 years.
      • Schairer W.W.
      • Nwachukwu B.U.
      • McCormick F.
      • Lyman S.
      • Mayman D.
      Use of hip arthroscopy and risk of conversion to total hip arthroplasty: A population-based analysis.
      Although these rates are quite high, 70% to 80% of patients older than 50 years did not undergo conversion to THA—and the important next question is to determine which patients did well.
      This is why the current study by Ruzbarsky et al.
      • Ruzbarsky J.J.
      • Seiter M.N.
      • Soares R.
      • Pierpoint L.
      • Briggs K.
      • Philippon M.J.
      Lower center edge angle and bipolar cartilage lesions are associated with conversion to hip arthroplasty within 2 years following hip arthroscopy: A matched cohort analysis.
      addresses such an important clinical question. Although the lack of conversion to THA is not by any means a marker of clinical success, this is the major limitation of population studies: They are unable to identify specific clinical and radiographic factors that may help identify patients in these higher-risk populations who may indeed do well with hip arthroscopy. The findings of a decreased center-edge angle and bipolar cartilage lesions being associated with early THA conversion provide additional caution in patient selection. Ideally, future studies will continue to find preoperative factors that can push the survival curve of hip arthroscopy in older patients to prolong the need for THA.
      Although there remains much to be learned to continue improving patient selection, there are much cost-effectiveness data to support the improved outcomes from hip arthroscopy, even if it is delaying THA and not preventing it.
      • Go C.C.
      • Kyin C.
      • Chen J.W.
      • Domb B.G.
      • Maldonado D.R.
      Cost-effectiveness of hip arthroscopy for treatment of femoroacetabular impingement syndrome and labral tears: A systematic review.
      Studying the more challenging patient populations will help improve the overall effectiveness of hip arthroscopy through more nuanced patient indications.

      Supplementary Data

      References

        • Ruzbarsky J.J.
        • Seiter M.N.
        • Soares R.
        • Pierpoint L.
        • Briggs K.
        • Philippon M.J.
        Lower center edge angle and bipolar cartilage lesions are associated with conversion to hip arthroplasty within 2 years following hip arthroscopy: A matched cohort analysis.
        Arthroscopy. 2022; 38: 1480-1485
        • Mather III, R.C.
        • Nho S.J.
        • Federer A.
        • et al.
        Effects of arthroscopy for femoroacetabular impingement syndrome on quality of life and economic outcomes.
        Am J Sports Med. 2018; 46: 1205-1213
        • McCormick F.
        • Nwachukwu B.U.
        • Alpaugh K.
        • Martin S.D.
        Predictors of hip arthroscopy outcomes for labral tears at minimum 2-year follow-up: The influence of age and arthritis.
        Arthroscopy. 2012; 28: 1359-1364
        • Schairer W.W.
        • Nwachukwu B.U.
        • McCormick F.
        • Lyman S.
        • Mayman D.
        Use of hip arthroscopy and risk of conversion to total hip arthroplasty: A population-based analysis.
        Arthroscopy. 2016; 32: 587-593
        • Go C.C.
        • Kyin C.
        • Chen J.W.
        • Domb B.G.
        • Maldonado D.R.
        Cost-effectiveness of hip arthroscopy for treatment of femoroacetabular impingement syndrome and labral tears: A systematic review.
        Orthop J Sports Med. 2021; 9 (2325967120987538)