title: Stability of Lisfranc joints in ballet pointe position.
abstract: BACKGROUND
  Ballerinas develop stress fractures at the second metatarsal base associated with dancing en pointe. The purpose of this study was to evaluate the relative importance of the pointe shoe and the tarsometatarsal ligaments in Lisfranc joint stability en pointe.
  
  
  METHODS
  Eleven cadaver feet were dressed with pointe shoes, loaded in foot flat with ligaments intact, and loaded en pointe before and after sequential sectioning of the dorsal, interosseous, and plantar ligaments between the first and second metatarsals and cuneiforms. Relative motion between the first and second metatarsals and cuneiforms was determined radiographically.
  
  
  RESULTS
  No significant displacement of the Lisfranc joints occurred when the shod foot with intact ligaments was loaded in the foot flat or en pointe positions. Serial sectioning of the ligaments from dorsal to plantar in the shod foot en pointe demonstrated no change in alignment after the dorsal and interosseous ligaments were cut, but a significant change in alignment between the second metatarsal and second cuneiform was noted after the plantar ligament was cut (p < 0.0001). Removal of the pointe shoe after cutting the ligaments and applying a minimal (1 to 2 kg) load resulted in complete subluxation and diastasis through the first-second intermetatarsal and intercuneiform region. Replacing the shoe improved alignment en pointe with similar loading.
  
  
  CONCLUSIONS
  Both the pointe shoe and Lisfranc ligaments are important for Lisfranc region stability in feet en pointe. The plantar ligaments are major stabilizers of the Lisfranc region in the loaded, shod foot en pointe. Selection of a pointe shoe with adequate support may limit susceptibility to stress fracture of the second metatarsal base in ballerinas.
authors.affiliation: Department of Orthopaedics and Sports Medicine, University of Washington, 1959 NE Pacific Street, Box 356500, Seattle, WA 98195, USA. kadel@u.washington.edu
authors.forename: Nancy
authors.initials: N
authors.lastname: Kadel
authors.forename: Mark
authors.initials: M
authors.lastname: Boenisch
authors.forename: Carol
authors.initials: C
authors.lastname: Teitz
authors.forename: Elly
authors.initials: E
authors.lastname: Trepman
mesh_terms: D002102:Cadaver; D003615:Dancing / Q000502:physiology*; D033023:Foot Joints / Q000502:physiology*; D015775:Fractures, Stress / Q000209:etiology / Q000517:prevention & control; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology*; D008023:Ligaments, Articular / Q000502:physiology*; D012775:Shoes