Abstract
Introduction
Magnetic resonance imaging with intraarticular contrast (arthro-MRI) and radial cuts is the gold standard to quantify labral and chondral lesions in the setting of femoroacetabular impingement. To date, no study exists that has evaluated these findings as potential predictors of outcome for the long term follow-up after surgical treatment of FAI.
Objectives
The purpose of this study was to detect potential predictors for failure after surgical hip dislocation for FAI based on specific preoperative arthro-MRI of the hip at a minimum follow-up of 10 years.
Methods
Retrospective case series of 97 hips (75 patients) undergoing surgical hip dislocation for FAI between July 2001 and March 2003. Minimum follow-up was 10 years. Twelve radiographic factors were preoperatively evaluated on specific arthro-MRIs with radial cuts of the hips. Patients were then evaluated clinically and radiographically at latest follow-up (mean followup of 11 years, range 10–13 years). The following endpoints were chosen: conversion to total hip arthroplasty (THA), radiographic evidence of progression of osteoarthritis (OA), and/or a Merle d'Aubigné-Postel score of less than 15 indicating a poor clinical result. Univariate and multivariate Cox-regression analysis were performed with these endpoints as failures.
Results
Hips with failure at 10-year follow up after surgical hip dislocation where more likely to show typical signs like decentration of the femoral head (52.9% compared to 17% in hips with good long term outcome; p = 0.007) in preoperative arthro-MRI evaluation. The strongest arthro-MRI based predictors of failure at the 10 year follow-up were a ‘double fond’ (hazard ratio with 95% confidence interval, 3.4 [3.2–3.7], p = 0.001), decentration of the femoral head (3.0 [2.8–3.3], p = 0.004) and posterior-inferior femoral osteophytes (3.3 [3.1–3.6], p = 0.002).
Conclusions
Factors like double fond, decentration of the femoral head and postero-inferior femoral osteophytes in preoperative arthro-MRI predict inferior long term outcome after surgical hip dislocation for FAI. Therefore we recommend preoperative evaluation with arthro-MRI in addition to conventional radiography.
