title: How Should We Follow-Up Asymptomatic Metal-on-Metal Hip Resurfacing Patients? A Prospective Longitudinal Cohort Study.
abstract: Current surveillance for metal-on-metal hip resurfacing (MoMHR) patients is not evidence based. This study established changes that occurred in 152 asymptomatic MoMHRs using repeat ultrasound and patient-reported outcomes. Factors associated with (1) ultrasound progression and (2) developing new pseudotumors were analyzed. Patients underwent repeat assessments 4.3 years later. Ultrasound progression was observed in 19% (n = 29), with 10% (n = 15) developing new pseudotumors. Key predictors of ultrasound progression included high blood cobalt (P = .00013) and chromium (P = .00065), and high initial ultrasound grade (P = .003) and volume (P = .036). No asymptomatic MoMHRs with initially normal metal ions (<2 μg/L) and normal ultrasounds (33% of cohort) developed new pseudotumors. This patient subgroup does not require repeat follow-up within 5 years.
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Nuffield Orthopaedic Centre, Oxford, United Kingdom, OX3 7LD.
authors.forename: Adrian K
authors.initials: AK
authors.lastname: Low
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Nuffield Orthopaedic Centre, Oxford, United Kingdom, OX3 7LD.
authors.forename: Gulraj S
authors.initials: GS
authors.lastname: Matharu
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Nuffield Orthopaedic Centre, Oxford, United Kingdom, OX3 7LD.
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Ostlere
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Nuffield Orthopaedic Centre, Oxford, United Kingdom, OX3 7LD.
authors.forename: David W
authors.initials: DW
authors.lastname: Murray
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Nuffield Orthopaedic Centre, Oxford, United Kingdom, OX3 7LD.
authors.forename: Hemant G
authors.initials: HG
authors.lastname: Pandit
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D002857:Chromium / Q000097:blood / Q000737:chemistry; D003035:Cobalt / Q000097:blood / Q000737:chemistry; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006104:Granuloma, Plasma Cell / Q000175:diagnosis / Q000000981:diagnostic imaging*; D006622:Hip Prosthesis; D006801:Humans; D007477:Ions / Q000097:blood; D008137:Longitudinal Studies; D008297:Male; D008670:Metals / Q000097:blood; D008875:Middle Aged; D011446:Prospective Studies; D011474:Prosthesis Design; D014463:Ultrasonography
chemical_list: D007477:Ions; D008670:Metals; D002857:Chromium; D003035:Cobalt
keywords: asymptomatic; blood metal ions; follow-up; hip resurfacing; metal-on-metal; ultrasound