Stefan Werlen MD, Presenter: Nothing to Disclose

Martin Beck, Abstract Co-Author: Nothing to Disclose

Inge Kress MD, Abstract Co-Author: Nothing to Disclose

Tallal Charles Mamisch MD, Abstract Co-Author: Research Consultant, Siemens AG, Erlangen, Germany

Aim of the study was to investigate the MRA image findings of patients after treatment of Femuro-acetabular impingement by surgical dislocation, which underwent MRA evaluation due to complications and indication for re-surgery by arthroscopy.

21 patients with consisting pain after treatment for FAI and indication for Arthroscopy underwent standardized MR-Arthrography at 1.5T of the hip for further evaluation prior to re-surgery. All these patients had the same MRA assessment prior to their first treatment by surgical dislocation. All the MRA included an axial 3D GRE sequence and a radial PD-TSE for assessment of FAI findings. The MRA images were analysed for morphology of the acetabular labrum, cartilage and the bony anatomy, including acetabular version, acetabular depth and alpha angle by two different observers and compared within the two scans. In addition capsular and scarf morphology was assessed and all findings were compared to the intraoperative diagnosis by hip arthroscopy.

In all the patients a significant decrease of the alpha angle and the acetabular depth could be observed. The acetabular version changed significantly in all the patients. These findings could not be correlated to the clinical findings in theses patients. A significant increase of the capsular depth could be observed and adhesion in 13 of the patients. These findings could be correlated to arthroscopy findings. 8 patients showed re-tear of the acetabular labrum, no changes in the cartilage assessment could be observed. Especially precise cartilage diagnosis was limited due to metal artefacts.

The post operative MRA could diagnose the effects of surgical dislocation therapy in terms of changes in bony anatomy of the acetabular rim and femoral head-neck junction. Adhesion and capsular changes as predictor for post-operative pain could be assessed and correlated to intra-operative findings. The cartilage showed no changes and should be goal of further long term assessment.

Based on the increasing importance of FAI and therapy standardized post-operative evaluation could improve monitoring of therapy

Werlen, S, Beck, M, Kress, I, Mamisch, T, Postoperative MR Arthrography in Patients with FAI Prior to Re-surgery: Comparison to Preoperative MRA and Intraoperative Findings.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5015696.html