title: Preoperative Risk Factors Associated With Poor Outcomes of Revision Surgery for "Pseudotumors" in Patients With Metal-on-Metal Hip Arthroplasty.
abstract: Revision surgery of failed metal-on-metal (MoM) total hip arthroplasty (THA) for adverse tissue reaction (pseudotumor) can be challenging as a consequence of soft tissue and muscle necrosis. The aims of this study were to (1) report the revision outcomes of patients who underwent revision surgery for failed MoM hip arthroplasty due to symptomatic pseudotumor and (2) identify preoperative risk factors associated with revision outcomes.
  
  
  
  Between January 2011 and January 2013, a total of 102 consecutive large head MoM hip arthroplasties in 97 patients (male: 62, female: 35), who underwent revision surgery were identified from the database of a multidisciplinary referral center.
  
  
  
  At minimum follow-up of 2 years (range: 26-52 months), at least one complication had occurred in 14 of 102 revisions (14%). Prerevision radiographic loosening (P = .01), magnetic resonance imaging (MRI) findings of solid lesions with abductor deficiency on MRI (P < .001), and intraoperative grading of adverse tissue reactions (P = .05) were correlated with post-revision complications. The reoperation rate of revised MoM THA was 7% (7 of 102 hips). Implant survivorship was 88% at 3 years. Metal ion levels declined in most patients after removal of MoM articulation.
  
  
  
  Revision outcomes of revision surgery for failed MoM THA due to symptomatic pseudotumor demonstrated 14% complication rate and 7% re-revision rate at 30-month follow-up. Our study identified prerevision radiographic loosening, solid lesions/abductor deficiency on MRI, and high grade intraoperative tissue damage as risk factors associated with poorer revision outcomes. This provides clinically useful information for preoperative planning and perioperative counseling of MoM THA patients undergoing revision surgery.
authors.affiliation: Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Ming Han Lincoln
authors.initials: MH
authors.lastname: Liow
authors.affiliation: Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Dimitris
authors.initials: D
authors.lastname: Dimitriou
authors.affiliation: Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Tsung-Yuan
authors.initials: TY
authors.lastname: Tsai
authors.affiliation: Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Young-Min
authors.initials: YM
authors.lastname: Kwon
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D002857:Chromium; D003035:Cobalt; D005260:Female; D006615:Hip / Q000601:surgery; D006621:Hip Joint / Q000601:surgery*; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D061825:Metal-on-Metal Joint Prostheses / Q000009:adverse effects*; D008670:Metals / Q000009:adverse effects; D008875:Middle Aged; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012086:Reoperation / Q000379:methods*; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D008670:Metals; D002857:Chromium; D003035:Cobalt
keywords: clinical outcomes; metal ion levels; metal-on-metal; pseudotumors; revision hip arthroplasty