title: Effect of elbow and forearm position on contact pressure between the extensor origin and the lateral side of the capitellum.
abstract: OBJECTIVE
  Bone-to-tendon contact in the origin of the common extensor tendons is considered to be one of the causes of lateral epicondylitis. Some factors, including elbow and forearm position, varus stress to the elbow, or contraction of the wrist extensor tendons, are considered to affect this bone-to-tendon contact. However, no studies have evaluated the effect of the elbow and forearm position on bone-tendon interface. The purpose of this study is to evaluate the effect of the position of the elbow and forearm on the contact pressure of the tendinous origin of the common wrist and finger extensors.
  
  
  METHODS
  We used 8 fresh cadaveric upper extremities. Contact pressure between the origin of the common extensor tendons and the lateral side of the capitellum was measured with a pressure sensor and was compared among various conditions, including elbow flexion angle (0°, 30°, 60°, and 90°), forearm rotation position (neutral and 81.5° pronation position), and varus stress load of the elbow (none, gravity on the forearm, and gravity on the forearm +1.96 Nm). Contact pressure was also measured during tension force of the extensor carpi radialis longus, extensor carpi radialis brevis, and extensor digitorum communis by 0, 9.8, and 19.6 N.
  
  
  RESULTS
  Contact pressure was significantly increased with the elbow extension position, forearm pronation position, and varus stress to the elbow under tension of the extensor carpi radialis longus or extensor carpi radialis brevis.
  
  
  CONCLUSIONS
  This study provides data about the amount of contact pressure between bone and tendon at the origin of the common extensor tendons in the elbow. This information may lead to a better understanding of, and better treatment for, lateral epicondylitis.
authors.affiliation: Department of Orthopaedic Surgery, Japan Self Defense Force, Sapporo General Hospital, Sapporo, Japan. yoshi1869@paw.hi-ho.ne.jp
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Aoki
authors.forename: Tomoki
authors.initials: T
authors.lastname: Izumi
authors.forename: Takuro
authors.initials: T
authors.lastname: Wada
authors.forename: Mineko
authors.initials: M
authors.lastname: Fujimiya
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Yamashita
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D004551:Elbow Joint / Q000502:physiology*; D005542:Forearm / Q000502:physiology*; D006801:Humans; D011312:Pressure; D013536:Suture Techniques; D013716:Tennis Elbow / Q000503:physiopathology