title: Biomechanical evaluation of 2 techniques for ulnar collateral ligament reconstruction of the elbow.
abstract: BACKGROUND
  Elbow medial ulnar collateral ligament tears often result in pain and instability that may be career threatening in overhead-throwing athletes. Surgical reconstruction is frequently chosen to treat this injury. Ulnar collateral ligament reconstruction as described by Jobe is the most commonly used technique. Testing of this construct has not demonstrated that the biomechanical parameters of the native ligament are restored. A more recent construct, the docking technique, may more reliably reproduce these factors.
  
  
  OBJECTIVE
  Increasing the number of strands of palmaris longus tendon graft used in ulnar collateral ligament reconstruction and tensioning them using the docking technique result in a construct with improved biomechanical parameters as compared with the Jobe technique.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Thirty-three fresh-frozen human cadaveric elbows were randomized into 3 subgroups: Jobe (11), docking (12), and native (10). The Jobe and docking groups underwent reconstruction using their described palmaris tendon graft constructs. The ulnar collateral ligament was left intact in the native group. Elbows were potted and tested using a servohydraulic materials testing machine to apply a valgus moment at 30 degrees of elbow flexion. Maximal moments to failure, stiffness, and strain at maximal moment and with a 3 N.m force applied were determined using a 2-camera motion analysis system to track reflective markers spanning the site.
  
  
  RESULTS
  The docking (14.3 N.m) and native (18.8 N.m) subgroups resulted in higher maximal moment to failure than did the Jobe (8.9 N.m) subgroup (P < .001). There was no significant difference between native and docking groups (P > .05). Native ligaments were stiffer (301.4 N.m) than were Jobe (74.3 N.m) or docking (80.8 N.m; P < .001). Native ligaments demonstrated lower strain at maximal force (0.087 mm/mm) and 3 N.m forces (0.030 mm/mm) than did the Jobe (0.198/0.057 mm/mm) or docking (0.287/0.042 mm/mm) subgroups. There was no difference in stiffness or strain between the Jobe and docking subgroups (P > .05).
  
  
  CONCLUSIONS
  Neither technique reproduced the biomechanical profile of the native ulnar collateral ligament; the findings of this study suggest that the docking construct may offer initial biomechanical advantage over the Jobe construct.
authors.affiliation: Center for the Athlete's Shoulder and Elbow at the Orthopaedic Center of St Louis, Chesterfield, Missouri, USA.
authors.forename: George A
authors.initials: GA
authors.lastname: Paletta
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Klepps
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Difelice
authors.forename: Tracy
authors.initials: T
authors.lastname: Allen
authors.forename: Michael D
authors.initials: MD
authors.lastname: Brodt
authors.forename: Meghan E
authors.initials: ME
authors.lastname: Burns
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Silva
authors.forename: Rick W
authors.initials: RW
authors.lastname: Wright
mesh_terms: D000704:Analysis of Variance; D001178:Arthroplasty / Q000379:methods*; D001484:Baseball / Q000293:injuries*; D001696:Biomechanical Phenomena; D002102:Cadaver; D017885:Collateral Ligaments / Q000293:injuries* / Q000601:surgery; D004551:Elbow Joint / Q000601:surgery; D006801:Humans; D007593:Joint Instability / Q000601:surgery*; D008875:Middle Aged; D012421:Rupture; D018709:Statistics, Nonparametric; D013536:Suture Techniques; D013710:Tendons / Q000637:transplantation*; D014457:Ulna; D000092464:Elbow Injuries