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

PURPOSE: 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).

METHODS: 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.

RESULTS: 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.

CONCLUSIONS: 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.

LEVEL OF EVIDENCE: III, retrospective patient group study.