title: Determination of optimal screw positioning in flexor hallucis longus tendon transfer for chronic tendoachilles rupture.
abstract: BACKGROUND
  Neglected ruptures of the tendoachilles pose a difficult surgical problem. There are no data to determine the optimal positioning of the FHL tendon to the calcaneus.
  
  
  METHODS
  Two computer programmes (MSC.visualNastran Desktop 2002™ and Solid Edge(®) V19) were used to generate a human ankle joint model. Different attachment points of FHL tendon transfer to the calcaneus were investigated.
  
  
  RESULTS
  The lowest muscle force to produce plantarflexion (single stance heel rise) was 1355 N. Plantarflexion increased for a more anterior attachment point. The maximum range of plantarflexion was 33.4° for anterior attachment and 24.4° for posterior attachment. There was no significant difference in range of movement when the attachment point was moved to either a medial or lateral position.
  
  
  CONCLUSIONS
  A more posterior attachment point is advantageous in terms of power and the arc of motion (24.4°) is physiological. We recommend that FHL is transferred to the calcaneus in a posterior position.
authors.affiliation: South West Thames Region, UK. marastu@hotmail.com
authors.forename: M H
authors.initials: MH
authors.lastname: Arastu
authors.forename: R
authors.initials: R
authors.lastname: Partridge
authors.forename: A
authors.initials: A
authors.lastname: Crocombe
authors.forename: M
authors.initials: M
authors.lastname: Solan
mesh_terms: D000125:Achilles Tendon / Q000293:injuries / Q000601:surgery*; D000843:Ankle Joint / Q000502:physiology; D001696:Biomechanical Phenomena; D001863:Bone Screws; D002908:Chronic Disease; D003198:Computer Simulation; D006801:Humans; D021621:Imaging, Three-Dimensional; D008023:Ligaments, Articular / Q000502:physiology; D008954:Models, Biological; D019919:Prosthesis Implantation / Q000379:methods*; D016059:Range of Motion, Articular / Q000502:physiology; D012421:Rupture / Q000601:surgery; D013709:Tendon Transfer / Q000379:methods*