title: What causes unexplained pain in patients with metal-on metal hip devices? A retrieval, histologic, and imaging analysis.
abstract: BACKGROUND
  Adverse tissue reactions associated with metal-on-metal (MOM) hips are common in resurfacing and total hip arthroplasty (THA) designs. The etiology of these reactions in painful, well-positioned arthroplasties is inconsistently described.
  
  
  OBJECTIVE
  The purposes of this study were to compare the (1) articular wear rates; (2) histologic findings; (3) synovial response on MRI; and (4) graded intraoperative tissue damage between well-positioned, MOM hips revised for unexplained pain and MOM hips revised for other reasons and to (5) determine whether the presence of a taper junction on a MOM articulation affects these four parameters in unexplained pain.
  
  
  METHODS
  We retrospectively studied 88 patients (94 hips) who had undergone revision of either a hip resurfacing or a large-head (> 36 mm) THA. Thirty-five hips revised for unexplained pain were compared with a control group of 59 hips revised for other causes. Articular wear was measured using three-dimensional contactless metrology and histologic analysis was performed using the aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL) score. Preoperative MRI was performed on 57 patients to determine synovial volumes and thicknesses. Tissue damage was graded from intraoperative reports.
  
  
  RESULTS
  Articular wear rates in the unexplained pain group were lower than in the control group (median 2.6 μm/year versus 12.8 μm/year, p < 0.001). Sixty-six percent of patients in the unexplained pain group had histologic confirmation of ALVAL compared with 19% in the control group (p < 0.001). The synovial thickness on MRI was higher in the unexplained pain group (p = 0.04) and was highly predictive of ALVAL. Severe intraoperative tissue damage was noted in more cases in the unexplained pain group (p = 0.01). There were no differences in articular wear, histology, MRI, and tissue damage between resurfacings and THAs revised for unexplained pain.
  
  
  CONCLUSIONS
  Unexplained pain in patients with well-positioned MOM hips warrants further investigation with MRI to look for features predictive of ALVAL. Tissue destruction in these cases does not appear to be related to high bearing wear or the presence of a taper.
authors.affiliation: Adult Reconstruction and Joint Replacement Service, Department of Orthopaedic Surgery, Hospital for Special Surgery, 535 East 70th Street, New York, NY, 10021, USA, nawabid@hss.edu.
authors.forename: Danyal H
authors.initials: DH
authors.lastname: Nawabi
authors.forename: Nader A
authors.initials: NA
authors.lastname: Nassif
authors.forename: Huong T
authors.initials: HT
authors.lastname: Do
authors.forename: Kirsten
authors.initials: K
authors.lastname: Stoner
authors.forename: Marcella
authors.initials: M
authors.lastname: Elpers
authors.forename: Edwin P
authors.initials: EP
authors.lastname: Su
authors.forename: Timothy
authors.initials: T
authors.lastname: Wright
authors.forename: Hollis G
authors.initials: HG
authors.lastname: Potter
authors.forename: Douglas E
authors.initials: DE
authors.lastname: Padgett
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018771:Arthralgia / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000295:instrumentation*; D001696:Biomechanical Phenomena; D020878:Device Removal; D005260:Female; D005549:Foreign-Body Reaction / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D006621:Hip Joint / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D008206:Lymphatic Diseases / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D061825:Metal-on-Metal Joint Prostheses; D008875:Middle Aged; D010147:Pain Measurement; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012086:Reoperation; D012189:Retrospective Studies; D012307:Risk Factors; D013314:Stress, Mechanical; D000074402:Synovectomy; D013583:Synovial Membrane / Q000473:pathology; D016896:Treatment Outcome; D014657:Vasculitis / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D055815:Young Adult
references.citation: Orthop Clin North Am. 2011 Apr;42(2):207-30, viii
references.pmid: 21435496
references.citation: J Bone Joint Surg Br. 2011 Aug;93(8):1011-6
references.pmid: 21768621
references.citation: J Bone Joint Surg Am. 2004 Sep;86(9):1947-54
references.pmid: 15342757
references.citation: J Bone Joint Surg Br. 2012 Feb;94(2):281-6
references.pmid: 22323701
references.citation: Clin Orthop Relat Res. 2012 Jul;470(7):1895-906
references.pmid: 22179978
references.citation: J Bone Joint Surg Am. 2013 Jun 19;95(12):e81
references.pmid: 23783212
references.citation: J Bone Joint Surg Br. 2008 Sep;90(9):1158-63
references.pmid: 18757954
references.citation: J Clin Pathol. 2012 May;65(5):409-18
references.pmid: 22422805
references.citation: J Bone Joint Surg Am. 1978 Mar;60(2):217-20
references.pmid: 641088
references.citation: J Bone Joint Surg Br. 2011 Oct;93(10):1308-13
references.pmid: 21969427
references.citation: J Arthroplasty. 2010 Jun;25(4):607-13
references.pmid: 20022454
references.citation: Clin Orthop Relat Res. 2010 Sep;468(9):2321-7
references.pmid: 20458645
references.citation: J Bone Joint Surg Br. 2011 Feb;93(2):164-71
references.pmid: 21282753
references.citation: J Bone Joint Surg Am. 2009 Jul;91(7):1614-20
references.pmid: 19571083
references.citation: J Bone Joint Surg Am. 2012 Feb 15;94(4):317-25
references.pmid: 22336970
references.citation: J Bone Joint Surg Am. 2011 Dec 7;93(23):2180-8
references.pmid: 22159853
references.citation: J Bone Joint Surg Am. 2005 Jan;87(1):28-36
references.pmid: 15637030
references.citation: J Bone Joint Surg Br. 2011 Mar;93(3):307-14
references.pmid: 21357950
references.citation: J Bone Joint Surg Am. 2013 May 15;95(10):895-902
references.pmid: 23677356
references.citation: J Bone Joint Surg Am. 2011 Dec 21;93(24):2287-93
references.pmid: 22258775
references.citation: J Arthroplasty. 2013 Apr;28(4):650-3
references.pmid: 23140992
references.citation: Biomed Mater. 2009 Apr;4(2):025018
references.pmid: 19349653
references.citation: Clin Orthop Relat Res. 2012 Nov;470(11):3101-8
references.pmid: 22864616
references.citation: Clin Orthop Relat Res. 2011 Sep;469(9):2590-7
references.pmid: 21656317
references.citation: J Bone Joint Surg Br. 2010 Mar;92(3):356-61
references.pmid: 20190305
references.citation: Clin Orthop Relat Res. 2012 Oct;470(10):2810-8
references.pmid: 22395871
references.citation: Clin Orthop Relat Res. 2002 Aug;(401):149-61
references.pmid: 12151892
references.citation: J Bone Joint Surg Br. 2009 Oct;91(10):1287-95
references.pmid: 19794161
references.citation: J Bone Joint Surg Am. 2012 Sep 19;94(18):1655-61
references.pmid: 23289127
references.citation: J Bone Joint Surg Br. 2010 Jan;92(1):38-46
references.pmid: 20044676
references.citation: Acta Biomater. 2009 Jan;5(1):172-80
references.pmid: 18725188
references.citation: Orthop Clin North Am. 2011 Apr;42(2):241-50, ix
references.pmid: 21435498
references.citation: J Bone Joint Surg Br. 2010 Nov;92(11):1501-8
references.pmid: 21037343
references.citation: J Bone Joint Surg Br. 2009 Jun;91(6):738-44
references.pmid: 19483225
references.citation: J Bone Joint Surg Br. 2008 Jul;90(7):847-51
references.pmid: 18591590
references.citation: Clin Orthop Relat Res. 2014 Feb;472(2):471-81
references.pmid: 23354460
references.citation: J Bone Joint Surg Br. 2012 Aug;94(8):1045-50
references.pmid: 22844044
references.citation: J Bone Joint Surg Br. 2011 Mar;93(3):315-20
references.pmid: 21357951
references.citation: Clin Orthop Relat Res. 2012 Nov;470(11):3127-33
references.pmid: 22528380
references.citation: Clin Orthop Relat Res. 2010 Feb;468(2):318-25
references.pmid: 19697090
references.citation: Orthop Clin North Am. 2006 Jul;37(3):361-73, vi-vii
references.pmid: 16846767
references.citation: J Bone Joint Surg Am. 2012 Feb 15;94(4):e22
references.pmid: 22336981
references.citation: J Bone Joint Surg Am. 2008 Aug;90 Suppl 3:125-33
references.pmid: 18676947
references.citation: J Bone Joint Surg Am. 2011 Dec 7;93(23):2164-71
references.pmid: 22159851