Beyond arthroplasty conversion: Rethinking failure after hip arthroscopy for femoroacetabular impingement syndrome.

Hip arthroscopy is increasingly used in the management of femoroacetabular impingement syndrome (FAIS), yet the definition of treatment failure remains unsettled. In response to the recent study by Mygind-Klavsen et al., we argue that conversion to total hip arthroplasty (THA), although clinically important, is a late and highly selective endpoint that does not capture the broader spectrum of unsuccessful hip preservation. Patients who remain symptomatic, fail to achieve clinically meaningful improvement, or undergo revision without THA are not represented by arthroplasty conversion alone. We further question whether conventional radiographic variables such as alpha angle, lateral joint-space width, and Tönnis grade are sufficient to explain failure in a condition as structurally and biologically heterogeneous as femoroacetabular impingement syndrome. Recent evidence suggests that cartilage status, composite risk stratification, and technique-related factors may be more informative for long-term survivorship than conventional morphology alone. Finally, the long registry period analysed in the target article spans different technical eras, raising the possibility that treatment-era effects were conflated with patient-related risk. In our view, the study provides a useful registry-based estimate of THA conversion after hip arthroscopy, but its findings should not be interpreted as establishing the dominant determinants of failure in contemporary hip-preservation practice.