title: Proper placement of the distal biceps tendon during repair improves supination strength--a biomechanical analysis.
abstract: BACKGROUND
  Anatomic repair of the distal biceps tendon can be difficult to achieve. This study was designed to compare the effect of anatomic and nonanatomic repairs on forearm supination torque. A nonanatomic repair re-establishes the footprint radial and more anterior to the tuberosity apex, whereas an anatomic repair re-establishes the footprint ulnar and more posterior to the tuberosity apex.
  
  
  METHODS
  Eight fresh frozen cadaver arms were surgically prepared and mounted on an elbow simulator. Controlled loads were applied to the long head and short head in positions of pronation, neutral, and supination. This was done with intact tendons and then repeated with repaired tendons that were repaired either anatomically (ulnar position) or nonanatomically (radial position).
  
  
  RESULTS
  All anatomic repairs showed no difference compared with intact tendon measurements. In comparing anatomic and nonanatomic repairs, we found no differences in the supination torque when the forearm was in 45° of pronation. However, when the arm was in neutral rotation, we found that 15% less supination torque was generated by the nonanatomic repair. When the arm was tested in 45° of supination, we found that 40% less supination torque was generated in the nonanatomic repair (P = .01).
  
  
  CONCLUSIONS
  This study supports the idea that an anatomic repair of the biceps tendon onto the ulnar side of the radial tuberosity is important. If the tendon is repaired too radially, the biceps will lose the cam effect and may not be able to generate full supination torque when the forearm is in neutral rotation or in supination.
authors.affiliation: Division of Orthopaedics, University of Ottawa, Ottawa, ON, Canada. Electronic address: mprud102@uOttawa.ca.
authors.forename: Marc
authors.initials: M
authors.lastname: Prud'homme-Foster
authors.affiliation: Division of Orthopaedics, University of Ottawa, Ottawa, ON, Canada.
authors.forename: Hakim
authors.initials: H
authors.lastname: Louati
authors.affiliation: Division of Orthopaedics, University of Ottawa, Ottawa, ON, Canada.
authors.forename: J Whitcomb
authors.initials: JW
authors.lastname: Pollock
authors.affiliation: Division of Orthopaedics, University of Ottawa, Ottawa, ON, Canada.
authors.forename: Steven
authors.initials: S
authors.lastname: Papp
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D002102:Cadaver; D005542:Forearm; D006801:Humans; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000379:methods*; D011403:Pronation; D011884:Radius / Q000601:surgery; D012399:Rotation; D012421:Rupture / Q000601:surgery; D013484:Supination; D013708:Tendon Injuries / Q000601:surgery*; D019415:Torque
keywords: Distal biceps tendon; biceps rupture; biceps tendon repair; supination moment arm; supination torque; tendon attachment location