title: Early reactive synovitis and osteolysis after total hip arthroplasty.
abstract: BACKGROUND
  Little is known about intraarticular pathology following THA prior to the radiographic appearance of osteolysis, primarily due to imaging limitations. MRI has recently been applied to imaging the postarthroplasty hip with the ability to detect periarticular bony and soft tissue pathology; specifically, it is able to detect abnormal synovial patterns and focal bone loss well before the radiographic appearance of osteolysis.
  
  
  OBJECTIVE
  We therefore used MRI to determine the incidence of early reactive synovitis and osteolysis in asymptomatic patients after THA, and whether there is an association between these MRI findings and clinical outcomes or radiographic wear measurements at this early stage.
  
  
  METHODS
  We recruited 31 patients (33 hips) who underwent routine noncemented THA with one of three types of bearing surfaces: metal-on-cross-linked polyethylene (n = 7), ceramic-on-ceramic (n = 12), and ceramic-on-cross-linked polyethylene (n = 14). Patients underwent specialized MRI at a minimum of 12 months (mean, 23 months; range, 12-37 months) after surgery. MR images were analyzed for the presence of synovitis or osteolysis. WOMAC scores, patient assessment questionnaires, and radiographic wear measurements were correlated with MRI findings.
  
  
  RESULTS
  Reactive synovitis was observed in 13 of 33 patients (39%) and focal osteolysis in one of 33 (3%). The presence of synovitis did not correlate with pain, activity level, patient satisfaction or clinical outcome scales, nor did it correlate with radiographic wear measurements at early followup.
  
  
  CONCLUSIONS
  Our observations suggest reactive synovitis is common yet asymptomatic at short-term followup. We do not know either the etiology or the long-term implications of these observations.
authors.affiliation: Department of Orthopaedic Surgery, Lenox Hill Hospital, William Black Hall, 11th Floor, 130 East 77th Street, New York, NY 10075, USA. jcooper02@gmail.com
authors.forename: H John
authors.initials: HJ
authors.lastname: Cooper
authors.forename: Amar S
authors.initials: AS
authors.lastname: Ranawat
authors.forename: Hollis G
authors.initials: HG
authors.lastname: Potter
authors.forename: Li Foong
authors.initials: LF
authors.lastname: Foo
authors.forename: Trevor W
authors.initials: TW
authors.lastname: Koob
authors.forename: Chitranjan S
authors.initials: CS
authors.lastname: Ranawat
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000295:instrumentation; D016009:Chi-Square Distribution; D005260:Female; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009519:New York City; D010014:Osteolysis / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D011474:Prosthesis Design; D011859:Radiography; D020127:Recovery of Function; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D013585:Synovitis / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D013997:Time Factors; D016896:Treatment Outcome