title: Rare implant-specific complications of the MoPyC radial head prosthesis.
abstract: BACKGROUND
  According to currently available data, the clinical short-term results of the MoPyC radial head prosthesis (Bioprofile, Tornier, Montbonnot-Saint-Martin, France) seem favorable. However, we have encountered several implant-specific complications in recent years. Hence, this case series reports rare complications after radial head arthroplasty with the MoPyC prosthesis to make surgeons aware of their existence and to provide information about the underlying cause and possible salvage strategies.
  
  
  METHODS
  A retrospective chart review from 2011 to 2016 was conducted to identify all adult patients with a minimum 2-year follow-up who underwent or were referred after radial head arthroplasty with the MoPyC radial head prosthesis and experienced implant-related complications.
  
  
  RESULTS
  Five patients with 7 implant-related complications were found. One patient experienced breakage of the pyrocarbon head. In another patient, breakage of the stem and-after revision surgery-partial breakage were observed. Disassembly of the prosthesis was seen in 1 case. Extensive periprosthetic stress shielding was seen in 3 patients resulting in symptomatic loosening (1), periprosthetic radial neck fracture (1), and stem migration (1).
  
  
  CONCLUSIONS
  Whereas clinical short-term results of the MoPyC radial head prosthesis are satisfactory, rare implant-related complications can occur. Surgeons should be aware of these complications as they may lead to a poor outcome.
authors.affiliation: Center for Orthopedic and Trauma Surgery, Uniklinik Köln, Köln, Germany; Köln Center for Musculoskeletal Biomechanics, Medical Faculty, University of Köln, Köln, Germany. Electronic address: michaelhackl@live.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Hackl
authors.affiliation: Center for Orthopedic and Trauma Surgery, Uniklinik Köln, Köln, Germany; Köln Center for Musculoskeletal Biomechanics, Medical Faculty, University of Köln, Köln, Germany.
authors.forename: Kilian
authors.initials: K
authors.lastname: Wegmann
authors.affiliation: Chirurgische Klinik, St. Elisabeth Krankenhaus, Köln, Germany.
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Koslowsky
authors.affiliation: Center for Orthopedic and Trauma Surgery, University Medical Center, Heidelberg, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Zeifang
authors.affiliation: Center for Orthopedic and Trauma Surgery, University Medical Center, Heidelberg, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Schoierer
authors.affiliation: Center for Orthopedic and Trauma Surgery, Uniklinik Köln, Köln, Germany; Köln Center for Musculoskeletal Biomechanics, Medical Faculty, University of Köln, Köln, Germany.
authors.forename: Lars P
authors.initials: LP
authors.lastname: Müller
mesh_terms: D000328:Adult; D000368:Aged; D057929:Arthroplasty, Replacement, Elbow; D002244:Carbon; D004551:Elbow Joint / Q000601:surgery; D058569:Elbow Prosthesis / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010014:Osteolysis / Q000209:etiology; D057068:Periprosthetic Fractures / Q000209:etiology; D011474:Prosthesis Design; D012189:Retrospective Studies
chemical_list: C009139:pyrolytic carbon; D002244:Carbon
keywords: MoPyC; complications; implant related; radial head arthroplasty; radial head fracture; radial head replacement