title: Early Lessons From a Worldwide, Multicenter, Followup Study of the Recalled Articular Surface Replacement Hip System.
abstract: BACKGROUND
  Adverse local tissue reactions (ALTRs) around hip arthroplasties are an important reason for failure of metal-on-metal (MoM) hip implants. Little is known about capsular dehiscence patterns as ALTRs decompress from the hip into the surrounding tissue planes; these patterns may also influence the onset and severity of patient symptoms.
  
  
  OBJECTIVE
  Through a multicenter study approach, we asked: (1) Is ALTR location related to the surgical approach used for arthroplasty in patients who underwent hip arthroplasty (resurfacing or THA) with a single, recalled hip arthroplasty system? (2) Do ALTR severity and location affect patient-reported outcomes in these patients? (3) Is ALTR severity different between patients who received the resurfacing version of this component (Articular Surface Replacement [ASR]) and those who received the THA implant in this system (ASR XL)?
  
  
  METHODS
  In a multicenter prospective study of patients who had undergone surgery with use of the ASR and ASR XL hip system (DePuy Orthopaedics, Warsaw, IN, USA), 288 patients (333 hips) from two centers had a metal artifact reduction sequence MRI of the hip performed at a mean time of 6 years postsurgery. Procedures included 166 hips (50%) with ASR resurfacing and 167 hips (50%) with ASR XL THA performed between 2004 and 2010. One hundred twenty-nine hips (39%) had been operated on using a direct lateral approach and 204 using a posterior approach (61%). The EQ-5D, Harris hip score, UCLA activity score, and visual analog scale pain score were obtained for each patient. ALTRs were classified using the Anderson ALTR grading system, and the location, synovial thickness, and diameter of the ATLRs were assessed. The relationship between ALTR location and surgical approach as well as for ALTR severity and patient-reported outcomes were evaluated, and logistic regression was used to identify predictors for moderate-to-severe ALTRs.
  
  
  RESULTS
  Moderate or severe ALTRs were identified in 79 hips (24%); 41 of these hips had been operated on using the direct lateral approach and 38 using the posterior approach. In patients in whom the lateral approach was used, 83% had an anterior ALTR. Similarly, 71% of patients in the posterior approach group had posterior ALTRs. There were no differences in patient-reported outcome measures between patients with moderate-to-severe ALTRs and those with no ALTR findings on MRI (p > 0.09). Use of ASR XL was an independent risk factor for moderate-to-severe ALTRs (odds ratio, 2.8; 95% confidence interval, 1.4-5.5 p = 0.004) and patients with ASR XL also had a thicker synovium (median ASR XL = 3.6 mm [1.2-10.6 mm], median ASR = 2.6 mm [1.2-10.7 mm], p < 0.001) and larger maximal ALTR diameter (median ASR XL = 47.6 mm [14-109.70 mm], median ASR = 38.4 [17.2-118.0 mm], p = 0.02) than patients treated with ASR.
  
  
  CONCLUSIONS
  The location of ALTRs can be predicted based on the previous surgical approach to the hip. Patients with ASR XL are more likely to develop moderate-to-severe ALTRs compared with ASR patients. An extensive range of patient-reported outcome measures may not identify all patients with ALTRs further supporting the use of MRI as a screening measure for ALTRs.
  
  
  METHODS
  Level II, therapeutic study.
authors: Harris Orthopaedic Laboratory, Massachusetts General Hospital, 55 Fruit Street, GRJ 1231, Boston, MA, 02114, USA.
authors: Rami
authors: R
authors: Madanat
authors: Harris Orthopaedic Laboratory, Massachusetts General Hospital, 55 Fruit Street, GRJ 1231, Boston, MA, 02114, USA.
authors: Daniel K
authors: DK
authors: Hussey
authors: Harris Orthopaedic Laboratory, Massachusetts General Hospital, 55 Fruit Street, GRJ 1231, Boston, MA, 02114, USA.
authors: Gabrielle S
authors: GS
authors: Donahue
authors: Department of Radiology and Imaging, Hospital for Special Surgery, New York, NY, USA.
authors: Hollis G
authors: HG
authors: Potter
authors: Sportsmed SA, Stepney, Australia.
authors: Robert
authors: R
authors: Wallace
authors: Harris Orthopaedic Laboratory, Massachusetts General Hospital, 55 Fruit Street, GRJ 1231, Boston, MA, 02114, USA.
authors: Charles
authors: C
authors: Bragdon
authors: Harris Orthopaedic Laboratory, Massachusetts General Hospital, 55 Fruit Street, GRJ 1231, Boston, MA, 02114, USA.
authors: Orhun
authors: O
authors: Muratoglu
authors: Harris Orthopaedic Laboratory, Massachusetts General Hospital, 55 Fruit Street, GRJ 1231, Boston, MA, 02114, USA. hmalchau@partners.org.
authors: Henrik
authors: H
authors: Malchau
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000295:instrumentation*; D001315:Australia; D001696:Biomechanical Phenomena; D004185:Disability Evaluation; D005060:Europe; D005260:Female; D005500:Follow-Up Studies; D005549:Foreign-Body Reaction / Q000175:diagnosis / Q000209:etiology*; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D016015:Logistic Models; D008279:Magnetic Resonance Imaging; D008297:Male; D057052:Medical Device Recalls; D061825:Metal-on-Metal Joint Prostheses / Q000009:adverse effects*; D008875:Middle Aged; D010147:Pain Measurement; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography; D012307:Risk Factors; D012720:Severity of Illness Index; D013019:South Africa; D013499:Surface Properties; D011795:Surveys and Questionnaires; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States