Stoyan Ivanov1,2, Aleksandar Stefanov3,4, Ivan Zderic3, Christian Rodemund5, Tim Schepers6, Dominic Gehweiler3, Jan Dauwe7, Torsten Pastor3,8, Biser Makelov9,10, Dimitur Raykov9, Geoff Richards3, Boyko Gueorguiev3. 1. AO Research Institute Davos, Davos, Switzerland. dr.ton.ivanov@gmail.com. 2. Medical University Varna, Varna, Bulgaria. dr.ton.ivanov@gmail.com. 3. AO Research Institute Davos, Davos, Switzerland. 4. University Multiprofile Hospital for Active Treatment and Emergency Medicine 'N. I. Pirogov', Sofia, Bulgaria. 5. AUVA Trauma Center Linz, Linz, Austria. 6. Trauma Unit, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands. 7. University Hospitals Leuven, Leuven, Belgium. 8. Lucerne Cantonal Hospital, Lucerne, Switzerland. 9. Medical University Varna, Varna, Bulgaria. 10. University Multiprofile Hospital for Active Treatment 'S. Kirkovitch', Stara Zagora, Bulgaria.
Abstract
PURPOSE: The aim of this study was to assess the biomechanical performance of different screw configurations for fixation of Sanders type II B joint-depression calcaneal fractures. METHODS: Fifteen human cadaveric lower limbs were amputated and Sanders II B fractures were simulated. The specimens were randomized to three groups for fixation with different screw configurations. The calcanei in Group 1 were treated with two parallel longitudinal screws, entering superiorly the Achilles tendon insertion, and two screws fixing the intraarticular posterior facet fracture line. In Group 2 two screws entered the tuberosity inferiorly to the Achilles tendon insertion and two transverse screws fixed the posterior facet. In Group 3 two screws were inserted along the bone axis, one transverse screw fixed the posterior facet and one oblique screw was inserted from the posteroplantar part of the tuberosity supporting the posterolateral part of the posterior facet. All specimens were biomechanically tested to failure under progressively increasing cyclic loading. RESULTS: Initial stiffness did not differ significantly between the groups, P = 0.152. Cycles to 2 mm plantar movement were significantly higher in both Group 1 (15,847 ± 5250) and Group 3 (13,323 ± 4363) compared with Group 2 (4875 ± 3480), P ≤ 0.048. No intraarticular displacement was observed in any group during testing. CONCLUSIONS: From a biomechanical perspective, posterior facet support by means of buttress or superiorly inserted longitudinal screws results in less plantar movement between the calcaneal tuberosity and the anterior fragments. Inferiorly inserted longitudinal screws are associated with bigger interfragmentary movements.
PURPOSE: The aim of this study was to assess the biomechanical performance of different screw configurations for fixation of Sanders type II B joint-depression calcaneal fractures. METHODS: Fifteen human cadaveric lower limbs were amputated and Sanders II B fractures were simulated. The specimens were randomized to three groups for fixation with different screw configurations. The calcanei in Group 1 were treated with two parallel longitudinal screws, entering superiorly the Achilles tendon insertion, and two screws fixing the intraarticular posterior facet fracture line. In Group 2 two screws entered the tuberosity inferiorly to the Achilles tendon insertion and two transverse screws fixed the posterior facet. In Group 3 two screws were inserted along the bone axis, one transverse screw fixed the posterior facet and one oblique screw was inserted from the posteroplantar part of the tuberosity supporting the posterolateral part of the posterior facet. All specimens were biomechanically tested to failure under progressively increasing cyclic loading. RESULTS: Initial stiffness did not differ significantly between the groups, P = 0.152. Cycles to 2 mm plantar movement were significantly higher in both Group 1 (15,847 ± 5250) and Group 3 (13,323 ± 4363) compared with Group 2 (4875 ± 3480), P ≤ 0.048. No intraarticular displacement was observed in any group during testing. CONCLUSIONS: From a biomechanical perspective, posterior facet support by means of buttress or superiorly inserted longitudinal screws results in less plantar movement between the calcaneal tuberosity and the anterior fragments. Inferiorly inserted longitudinal screws are associated with bigger interfragmentary movements.
Authors: Richard Buckley; Suzanne Tough; Robert McCormack; Graham Pate; Ross Leighton; Dave Petrie; Robert Galpin Journal: J Bone Joint Surg Am Date: 2002-10 Impact factor: 5.284
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