title: Metal-on-metal hip resurfacing: correlation between clinical and radiological assessment, metal ions and ultrasound findings.
abstract: OBJECTIVE
  We report the clinical, radiological and wear analysis of 52 consecutive MoM hip resurfacings (performed on 49 younger patients) to a mean follow-up of 9.2 years.
  
  
  METHODS
  Every patient underwent X-ray and clinical evaluation (HHS). Ultrasonography of the hip was performed in all patients in order to identify possible cystic or solid mass in periprosthetic tissue. In case of mass >20 mm, further MRI was performed to better analyse the characteristics of lesion.
  
  
  RESULTS
  Five patients (five hips) had a revision. The overall survival rate was 90.38 %. The average HHS at follow-up examination was 95.5 points. No progressive radiolucent areas and no sclerosis or osteolysis around the implants were found. The US and RMI imaging showed a pseudotumour formation in two patients (correlated with high metal ion levels in blood and urine), both asymptomatic.
  
  
  CONCLUSIONS
  A significant positive correlation between inclination of the acetabular component and serum metal ion levels was found (r = 0.64 and r = 0.62 for cobalt and chromium, respectively).
authors.affiliation: Department of Orthopedics, University of Pisa, Via Paradisa 2, Ed 3, 56100, Pisa, Italy, m.scaglione@ao-pisa.toscana.it.
authors.forename: M
authors.initials: M
authors.lastname: Scaglione
authors.forename: L
authors.initials: L
authors.lastname: Fabbri
authors.forename: N
authors.initials: N
authors.lastname: Bianchi
authors.forename: D
authors.initials: D
authors.lastname: Dell'Omo
authors.forename: G
authors.initials: G
authors.lastname: Guido
mesh_terms: D000077:Acetabulum / Q000737:chemistry / Q000000981:diagnostic imaging*; D000328:Adult; D019644:Arthroplasty, Replacement, Hip / Q000379:methods / Q000401:mortality; D002516:Ceramics; D002857:Chromium / Q000097:blood / Q000652:urine; D002858:Chromium Alloys; D003035:Cobalt / Q000097:blood / Q000652:urine; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis / Q000706:statistics & numerical data; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging* / Q000401:mortality / Q000601:surgery; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014463:Ultrasonography
chemical_list: D002858:Chromium Alloys; D002857:Chromium; D003035:Cobalt