title: The calcar screw in angular stable plate fixation of proximal humeral fractures--a case study.
abstract: BACKGROUND
  With new minimally-invasive approaches for angular stable plate fixation of proximal humeral fractures, the need for the placement of oblique inferomedial screws ('calcar screw') has increasingly been discussed. The purpose of this study was to investigate the influence of calcar screws on secondary loss of reduction and on the occurrence of complications.
  
  
  METHODS
  Patients with a proximal humeral fracture who underwent angular stable plate fixation between 01/2007 and 07/2009 were included. On AP views of the shoulder, the difference in height between humeral head and the proximal end of the plate were determined postoperatively and at follow-up. Additionally, the occurrence of complications was documented. Patients with calcar screws were assigned to group C+, patients without to group C-.
  
  
  RESULTS
  Follow-up was possible in 60 patients (C+ 6.7 ± 5.6 M/C- 5.0 ± 2.8 M). Humeral head necrosis occurred in 6 (C+, 15.4%) and 3 (C-, 14.3%) cases. Cut-out of the proximal screws was observed in 3 (C+, 7.7%) and 1 (C-, 4.8%) cases. In each group, 1 patient showed delayed union. Implant failure or lesions of the axillary nerve were not observed. In 44 patients, true AP and Neer views were available to measure the head-plate distance. There was a significant loss of reduction in group C- (2.56 ± 2.65 mm) compared to C+ (0.77 ± 1.44 mm; p = 0.01).
  
  
  CONCLUSIONS
  The placement of calcar screws in the angular stable plate fixation of proximal humeral fractures is associated with less secondary loss of reduction by providing inferomedial support. An increased risk for complications could not be shown.
authors.affiliation: Division of Trauma Surgery, University Hospital Zurich, Rämistrasse 100, 8091 Zurich, Switzerland.
authors.forename: Georg
authors.initials: G
authors.lastname: Osterhoff
authors.forename: Christian
authors.initials: C
authors.lastname: Ossendorf
authors.forename: Guido A
authors.initials: GA
authors.lastname: Wanner
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Simmen
authors.forename: Clément M
authors.initials: CM
authors.lastname: Werner
mesh_terms: D000328:Adult; D000368:Aged; D001860:Bone Plates; D001863:Bone Screws; D005500:Follow-Up Studies; D005592:Fracture Fixation / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology; D011859:Radiography; D012189:Retrospective Studies; D012307:Risk Factors; D012784:Shoulder Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D012785:Shoulder Joint / Q000000981:diagnostic imaging / Q000601:surgery; D016896:Treatment Outcome