title: The natural history of inflammatory pseudotumors in asymptomatic patients after metal-on-metal hip arthroplasty.
abstract: BACKGROUND
  Although pseudotumors have been reported in 32% of asymptomatic metal-on-metal hips, the natural history of asymptomatic pseudotumors is unknown.
  
  
  OBJECTIVE
  The purpose of this study was to assess changes over time in asymptomatic pseudotumors and the effect of revision on pseudotumor mass.
  
  
  METHODS
  Followup ultrasound was performed a mean of 25.8 months (range, 21-31 months) after the detection of 15 pseudotumors and five isolated fluid collections in a cohort of 20 asymptomatic patients (13 metal-on-metal, three metal-on-polyethylene, and four hip resurfacings) [42]. Changes in pseudotumors and fluid collections size and nature, and serum ion levels were determined.
  
  
  RESULTS
  Among the 15 nonrevised patients, pseudotumors increased in size in six (four solid and two cystic) of 10 patients, three of which had clinically important increases (13-148 cm(3); 28-74 cm(3); 47-104 cm(3)). Three pseudotumors (one solid and two cystic) disappeared completely (the largest measured 31 cm(3)). One solid pseudotumor decreased in size (24 to 18 cm(3)). In five revised patients, pseudotumors completely disappeared in four patients. The fifth patient had two masses that decreased from 437 cm(3) to 262 cm(3) and 43 cm(3) to 25 cm(3). All revision patients had a reduction of chromium (40.42 μ/L to 2.69 μ/L) and cobalt ions (54.19 μ/L to 0.64 μ/L). Of five isolated fluid collections, four completely disappeared (two metal-on-metal and two metal-on-polyethylene) and one (metal-on-metal) increased from 26 cm(3) to 136 cm(3).
  
  
  CONCLUSIONS
  Our observations suggest pseudotumors frequently increase in size in asymptomatic patients with occasional remission of small masses. Revision resulted in remission of pseudotumors.
authors.affiliation: Department of Orthopaedics, University of British Columbia, Room 3114, 910 West 10th Avenue, Vancouver, British Columbia, V5Z 4E3, Canada.
authors.forename: Sulaiman A
authors.initials: SA
authors.lastname: Almousa
authors.forename: Nelson V
authors.initials: NV
authors.lastname: Greidanus
authors.forename: Bassam A
authors.initials: BA
authors.lastname: Masri
authors.forename: Clive P
authors.initials: CP
authors.lastname: Duncan
authors.forename: Donald S
authors.initials: DS
authors.lastname: Garbuz
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000295:instrumentation; D005260:Female; D006104:Granuloma, Plasma Cell / Q000000981:diagnostic imaging / Q000209:etiology*; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D007592:Joint Diseases / Q000000981:diagnostic imaging / Q000209:etiology*; D008297:Male; D008670:Metals; D008875:Middle Aged; D011474:Prosthesis Design; D014463:Ultrasonography
chemical_list: D008670:Metals
references.citation: Orthop Clin North Am. 2011 Apr;42(2):251-7, ix
references.pmid: 21435499
references.citation: J Rheumatol. 1988 Dec;15(12):1833-40
references.pmid: 3068365
references.citation: J Bone Joint Surg Am. 2008 Mar;90(3):517-22
references.pmid: 18310701
references.citation: J Bone Joint Surg Br. 2010 Feb;92(2):202-8
references.pmid: 20130309
references.citation: J Bone Joint Surg Br. 2004 Mar;86(2):177-84
references.pmid: 15046429
references.citation: J Bone Joint Surg Am. 2005 Jan;87(1):18-27
references.pmid: 15634811
references.citation: J Arthroplasty. 2011 Feb;26(2):282-8
references.pmid: 20206466
references.citation: Clin Biomech (Bristol, Avon). 2011 Mar;26(3):267-73
references.pmid: 21122957
references.citation: Med Care. 1992 Jun;30(6):473-83
references.pmid: 1593914
references.citation: Clin Orthop Relat Res. 2010 Sep;468(9):2321-7
references.pmid: 20458645
references.citation: Orthop Clin North Am. 2005 Apr;36(2):223-30, x
references.pmid: 15833460
references.citation: J Bone Joint Surg Am. 2012 Feb 15;94(4):317-25
references.pmid: 22336970
references.citation: Clin Orthop Relat Res. 2010 Feb;468(2):318-25
references.pmid: 19697090
references.citation: J Bone Joint Surg Br. 2008 Jun;90(6):715-23
references.pmid: 18539663
references.citation: Med J Aust. 2011 Jun 20;194(12):649-51
references.pmid: 21692725
references.citation: J Arthroplasty. 2007 Sep;22(6 Suppl 2):140-4
references.pmid: 17823033
references.citation: J Bone Joint Surg Am. 2008 Aug;90 Suppl 3:52-6
references.pmid: 18676937
references.citation: J Bone Joint Surg Am. 2011 Dec 7;93(23):2180-8
references.pmid: 22159853
references.citation: J Arthroplasty. 2011 Jun;26(4):511-8
references.pmid: 20591612
references.citation: J Bone Joint Surg Br. 2006 Mar;88(3):402-4
references.pmid: 16498023
references.citation: Acta Orthop Belg. 2008 Dec;74(6):870-4
references.pmid: 19205339
references.citation: J Arthroplasty. 2004 Dec;19(8 Suppl 3):124-30
references.pmid: 15578566
references.citation: J Arthroplasty. 2004 Dec;19(8 Suppl 3):41-4
references.pmid: 15578551
references.citation: J Bone Joint Surg Br. 2009 Aug;91(8):1019-24
references.pmid: 19651827
references.citation: J Bone Joint Surg Am. 2011 May;93 Suppl 2:118-21
references.pmid: 21543700
references.citation: J Bone Joint Surg Am. 2008 Sep;90(9):1988-93
references.pmid: 18762660
references.citation: J Bone Joint Surg Am. 1984 Feb;66(2):228-41
references.pmid: 6693450
references.citation: Acta Orthop Belg. 2011 Dec;77(6):777-81
references.pmid: 22308623
references.citation: Clin Orthop Relat Res. 2003 Jan;(406):282-96
references.pmid: 12579029
references.citation: Hip Int. 2011 May-Jun;21(3):279-83
references.pmid: 21698574
references.citation: Virchows Arch. 2008 Nov;453(5):529-34
references.pmid: 18769936
references.citation: J Bone Joint Surg Am. 2010 Dec 1;92(17):2847-51
references.pmid: 21037026
references.citation: J Bone Joint Surg Br. 2008 Jul;90(7):847-51
references.pmid: 18591590
references.citation: Hip Int. 2013 May-Jun;23(3):243-9
references.pmid: 23233174
references.citation: J Arthroplasty. 2007 Sep;22(6):923-7
references.pmid: 17826287
references.citation: J Bone Joint Surg Am. 2011 May;93 Suppl 2:107-17
references.pmid: 21543699
references.citation: J Bone Joint Surg Am. 2011 Dec 7;93(23):2164-71
references.pmid: 22159851
references.citation: J Bone Joint Surg Br. 2008 Sep;90(9):1137-42
references.pmid: 18757951