Acetabular Chondral Lesions Associated With Femoroacetabular Impingement Treated by Autologous Matrix-Induced Chondrogenesis or Microfracture: A Comparative Study at 8-Year Follow-Up.

Abstract

The aim of this retrospective study was to investigate, at 8 years, the clinical follow-up and failure rate (revision rate/conversion to arthroplasty) of patients with hip chondral lesions associated with femoroacetabular impingement and to compare over time the treatment by microfracture (MFx) and autologous matrix-induced chondrogenesis (AMIC). Patients aged between 18 and 55 years, with acetabular grade III and IV chondral lesions (Outerbridge), measuring 2 to 8 cm² operated on at least 8 years before enrollment. Exclusion criteria were rheumatoid arthritis, dysplasia, or axial deviation of the femoral head. There were no arthritic lesions, Tonnis < 2, or joint space of at least 2 mm. MFx was performed with an awl, and the Chondro-Gide membrane used for the AMIC procedure was placed without glue. Outcomes used modified Harris hip score (mHHS) at 6 months and yearly for 8 years and patient acceptable symptomatic state. Among 130 patients, 109 fulfilled inclusion criteria. Fifty were treated by MFx and 59 by AMIC. The mHHS significantly improved in both groups from 46 ± 6.0 to 78 ± 8.8 for mHHS at 6-12 months, even for lesions > 4 cm². From 2 to 8 years, mHHS in the AMIC group was better than in the MFx group (P < .005). This mHHS improvement in the AMIC group was maintained through the 8-year follow-up period, whereas it deteriorated after 1 year in the MFx group (P < .005). Eleven patients (22%) in the MFx group required total hip arthroplasty (THA); none in the AMIC group did. Patient acceptable symptomatic state analysis confirmed similar short-term improvement, but a significant (P < .007) degradation after 2-8 years in MFx patients. MFx and AMIC techniques led to marked clinical short-term improvement in patients with chondral defects resulting from femoroacetabular impingement in the first 2 years. However, AMIC gave significantly better results as measured by mHHS, which were maintained after 8 years, the results of MFx in the hip deteriorated over time with 22% of patients undergoing conversion to THA. No patient in the AMIC group was converted to THA; the results of AMIC appeared stable over time and independent of lesion size. III, retrospective patient group study.