BACKGROUND: In 1976, Ramsey and Hamilton published a classic experiment investigating the biomechanical effects of talar shift in a simple ankle fracture model. Their finding was that 1 mm of talar shift resulted in a 42% decrease in tibiotalar contact surface area. Based on this conclusion, 1 mm of talar shift became the recognized indication for operative fixation. METHODS: Twelve cadaver ankles were dissected and the distal tibia coated with carbon powder. A 70-kg load was applied to the distal tibia that resulted in transference of the carbon onto the talus. The contact surface area was determined at 0, 1, 2, 4 and 6 mm of talar shift using spacers fixed in the medial gutter. Tracing paper was used to mark the outline of the contact area and measured using graph paper. RESULTS: Our results were similar to Ramsey and Hamilton's original experiment. One millimeter of lateral talar shift resulted in 40% loss of contact surface area compared with 42% in the original experiment. A large variance was seen in talar contact surface area depending on the morphology of the ankle joint. CONCLUSION: Ramsey and Hamilton's original experiment was valid.
BACKGROUND: In 1976, Ramsey and Hamilton published a classic experiment investigating the biomechanical effects of talar shift in a simple ankle fracture model. Their finding was that 1 mm of talar shift resulted in a 42% decrease in tibiotalar contact surface area. Based on this conclusion, 1 mm of talar shift became the recognized indication for operative fixation. METHODS: Twelve cadaver ankles were dissected and the distal tibia coated with carbon powder. A 70-kg load was applied to the distal tibia that resulted in transference of the carbon onto the talus. The contact surface area was determined at 0, 1, 2, 4 and 6 mm of talar shift using spacers fixed in the medial gutter. Tracing paper was used to mark the outline of the contact area and measured using graph paper. RESULTS: Our results were similar to Ramsey and Hamilton's original experiment. One millimeter of lateral talar shift resulted in 40% loss of contact surface area compared with 42% in the original experiment. A large variance was seen in talar contact surface area depending on the morphology of the ankle joint. CONCLUSION: Ramsey and Hamilton's original experiment was valid.
Authors: John M Marzo; Melissa A Kluczynski; Corey Clyde; Mark J Anders; Christopher E Mutty; Christopher A Ritter Journal: Quant Imaging Med Surg Date: 2017-12
Authors: C Niek van Dijk; Mikel L Reilingh; Maartje Zengerink; Christiaan J A van Bergen Journal: Knee Surg Sports Traumatol Arthrosc Date: 2010-02-12 Impact factor: 4.342
Authors: Christiaan J A van Bergen; Maartje Zengerink; Leendert Blankevoort; Maayke N van Sterkenburg; Jakob van Oldenrijk; C Niek van Dijk Journal: Acta Orthop Date: 2010-08 Impact factor: 3.717