title: MR imaging of soft tissue alterations after total hip arthroplasty: comparison of classic surgical approaches.
abstract: OBJECTIVE
  To compare soft-tissue changes after total hip arthroplasty with posterior, direct-lateral, anterolateral, or anterior surgical approaches.
  
  
  METHODS
  MRI of 120 patients after primary total hip arthroplasty (30 per approach) were included. Each MRI was assessed by two readers regarding identification of surgical access, fatty muscle atrophy (Goutallier classification), tendon quality (0 = normal, 1 = tendinopathy, 2 = partial tear, 3 = avulsion), and fluid collections. Readers were blinded to the surgical approach.
  
  
  RESULTS
  Surgical access was correctly identified in all cases. The direct lateral approach showed highest Goutallier grades and tendon damage for gluteus minimus muscle (2.07-2.67 and 2.00-2.77; p = 0.017 and p = 0.001 for readers 1 and 2, respectively) and tendon (2.30/1.67; p < 0.0005 for reader 1/2), and the lateral portion of the gluteus medius tendon (2.77/2.20; p < 0.0005 for reader 1/2). The posterior approach showed highest Goutallier grades and tendon damage for external rotator muscles (1.97-2.67 and 1.57-2.40; p < 0.0005-0.006 for reader 1/2) and tendons (1.41-2.45 and 1.93-2.76; p < 0.0005 for reader 1/2). The anterolateral and anterior approach showed less soft tissue damage. Fluid collections showed no differences between the approaches.
  
  
  CONCLUSIONS
  MRI is well suited to identify surgical approaches after THA. The anterior and anterolateral approach showed less soft tissue damage compared to the posterior and direct lateral approach.
  
  
  CONCLUSIONS
  • Identification of the surgical approach is well possible with MR imaging. • Anterolateral/anterior approaches show less soft-tissue damage compared to lateral/posterior approaches. • Posterior approaches show marked damage to external rotator tendons and muscles. • After direct lateral approaches the gluteus minimus tendon/muscle show severe damage.
authors.affiliation: Radiology, Balgrist University Hospital, Forchstrasse 340, CH-8008, Zurich, Switzerland. christoph.agten@balgrist.ch.|Faculty of Medicine, University of Zurich, Zurich, Switzerland. christoph.agten@balgrist.ch.
authors.forename: Christoph A
authors.initials: CA
authors.lastname: Agten
authors.affiliation: Radiology, Balgrist University Hospital, Forchstrasse 340, CH-8008, Zurich, Switzerland.|Faculty of Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Reto
authors.initials: R
authors.lastname: Sutter
authors.affiliation: Orthopedic Surgery, Balgrist University Hospital, Forchstrasse 340, CH-8008, Zurich, Switzerland.|Faculty of Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Claudio
authors.initials: C
authors.lastname: Dora
authors.affiliation: Radiology, Balgrist University Hospital, Forchstrasse 340, CH-8008, Zurich, Switzerland.|Faculty of Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Christian W A
authors.initials: CW
authors.lastname: Pfirrmann
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D005260:Female; D006621:Hip Joint / Q000000981:diagnostic imaging*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging*; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D013710:Tendons / Q000000981:diagnostic imaging*
keywords: Abductor tendons and muscles; Magnetic resonance imaging; Postoperative imaging; Surgical approach; Total hip arthroplasty