title: Axial load weightbearing radiography in determining lateral malleolus fracture stability: a cadaveric study.
abstract: BACKGROUND
  Ankle fractures are the most common fracture treated by orthopaedic surgeons in the United States. Isolated lateral malleolus fractures are treated nonoperatively, while associated deltoid disruption injuries are unstable and usually treated by fixation of the fracture. Various stress radiographs and MRI have been used to determine deltoid competency and the subsequent need for operative stabilization of lateral malleolus fractures. To date, no standardization of stress radiography has been performed. The aim of this study was to evaluate the ability of weightbearing ankle X-rays to determine stability and their reliability.
  
  
  METHODS
  This study sought to utilize simulated weightbearing radiography as a potential method to determine the need for lateral malleolus fixation. Twelve cadaveric ankle specimens were tested by obtaining ankle mortise radiographs for interpretation of medial clear space. Each ankle was tested with 0, 25, 36, and 50 kg of axially applied weight. The groups of measurements obtained were: intact ankles (Group A), ankles with an isolated oblique fibular osteotomy (Group B), and osteotomized ankles after complete deltoid ligament transaction (Group C). Three authors measured the medial clear space for every ankle using PACSR software. Instability of the ankle mortise was defined as medial clear space widening of greater than 2 mm from the intact ankle.
  
  
  RESULTS
  An isolated lateral malleolus fracture (Group B) and a lateral malleolus fracture with an incompetent deltoid ligament (Group C) showed no statistical medial clear space widening with simulated axial weightbearing radiography when compared to intact ankles (Group A). ANOVA's between Group A and B had p < 0.001, and between Group A and C of p < 0.001.
  
  
  CONCLUSIONS
  Our model did not find instability with an osteotomized fibula and a disrupted deltoid.
  
  
  CONCLUSIONS
  This study suggests a weightbearing radiograph of an isolated lateral malleolus fracture cannot determine deltoid ligament integrity and thus need for fibular operative fixation.
authors: Christopher
authors: C
authors: Stewart
authors: Omar
authors: O
authors: Saleem
authors: Debi P
authors: DP
authors: Mukherjee
authors: Michael
authors: M
authors: Suk
authors: John
authors: J
authors: Marymont
authors: Lucas
authors: L
authors: Anissian
mesh_terms: D000704:Analysis of Variance; D016512:Ankle Injuries / Q000000981:diagnostic imaging* / Q000503:physiopathology; D002102:Cadaver; D005360:Fibula / Q000601:surgery; D050723:Fractures, Bone / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D007593:Joint Instability / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008023:Ligaments, Articular / Q000601:surgery; D010027:Osteotomy; D011859:Radiography; D016474:Weight-Bearing / Q000502:physiology*