Osteoarthritic changes rather than age predict outcome following arthroscopic treatment of femoroacetabular impingement in middle-aged patients

Simon Jakob Herrmann, Manuel Bernauer, Benjamin Erdle, Norbert Paul Südkamp, Peter Helwig, Oliver Hauschild

Our purpose was to evaluate outcome following arthroscopic treatment of femoroacetabular impingement (FAI) in middle-aged patients and to define risk factors for conversion to total hip arthroplasty (THA). This was a retrospective case series of 79 consecutive patients (40 to 65 years) undergoing arthroscopic treatment of FAI (follow-up ≥12 months). Outcome at follow-up was assessed using Hip outcome score (HOS). Alpha angle, Kellgren Lawrence grade (K-L grade), joint space width (JS), lateral center edge (LCE) angle, caput-collum-diaphysis (CCD) angle and acetabular index (AI) were analysed retrospectively. THA group and Non-THA group were compared. Seventy-nine patients (mean age 48.6 years, mean follow-up 32 months) were included. 18 patients (22.8 %) were converted to THA. Mean HOS score in the Non-THA group at time point of follow-up was 80.2. Non-THA group and THA group showed no significant differences for mean age (48.2 years vs. 49.9 years, p = 0.278), alpha angel (p = 0.541), LCE (p = 0.294), CCD (p = 0.101) and AI (p = 0.661) in contrast to differences for JS (p = <0.001) and K-L grade (p = <0.001). Risk of conversion to THA was higher for patients with K-L grade 3 (p = 0.003) or joint space less or equal 2 mm (p = 0.001). One fifth of the middle-aged patients required early conversion to THA. Advanced JS narrowing and K-L grade rather than age alone can be considered as risk factor for conversion to THA.