I Mehling1, P Hoehle2, W Sternstein3, J Blum4, P M Rommens5. 1. Center for Muskuloskeletal Surgery, Department of Trauma Surgery, University Medical Center of the Johannes Gutenberg-University of Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany. isabella.mehling@unimedizin-mainz.de. 2. Center for Muskuloskeletal Surgery, Department of Trauma Surgery, University Medical Center of the Johannes Gutenberg-University of Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany. phoehle@gmx.de. 3. Center for Muskuloskeletal Surgery, Department of Trauma Surgery, University Medical Center of the Johannes Gutenberg-University of Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany. sternstein@unfall.klinik.uni-mainz.de. 4. Trauma Surgery Department, Stadtkrankenhaus, Worms, Germany. jochen.blum@stadtkrankenhaus-worms.de. 5. Center for Muskuloskeletal Surgery, Department of Trauma Surgery, University Medical Center of the Johannes Gutenberg-University of Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany. pol.rommens@unimedizin-mainz.de.
Abstract
PURPOSE: The purpose of our study was to determine the biomechanical properties of three different implants utilized for internal fixation of a supracondylar femur fracture. The retrograde supracondylar nail (SCN), the less invasive stabilization system plate (LISS) and the distal femoral nail (DFN) were tested and their biomechanical properties compared. METHODS: Twenty pairs of fresh-frozen human femura were used. Each femur was osteotomised to simulate a comminuted supracondylar fracture (AO/OTA 33.A3) and then randomized to fracture fixation with either SCN (n=9) or LISS (n=9). Each contralateral femur was stabilized with DFN as a control (n=18). Two femur pairs were spent on pretesting. All femura were subjected to axial (10-500 N) and torsional (0.1-14 Nm) loading. RESULTS: Eighteen matched femur pairs were analyzed. The post-loading median residual values were 49.78, 41.25 and 33.51% of the axial stiffness of the intact femur and 59.04, 62.37 and 46.72% of the torsional stiffness of the intact femur in the SCN, LISS and DFN groups. There were no significant differences between the three implants concerning axial and torsional stiffness. CONCLUSIONS: All implants had sufficient biomechanical stability under physiological torsional and axial loading. All three implants have different mechanisms for distal locking. The SCN nail with the four-screw distal interlocking had the best combined axial and torsional stiffness whereas the LISS plate had the highest torsional stiffness.
PURPOSE: The purpose of our study was to determine the biomechanical properties of three different implants utilized for internal fixation of a supracondylar femur fracture. The retrograde supracondylar nail (SCN), the less invasive stabilization system plate (LISS) and the distal femoral nail (DFN) were tested and their biomechanical properties compared. METHODS: Twenty pairs of fresh-frozen human femura were used. Each femur was osteotomised to simulate a comminuted supracondylar fracture (AO/OTA 33.A3) and then randomized to fracture fixation with either SCN (n=9) or LISS (n=9). Each contralateral femur was stabilized with DFN as a control (n=18). Two femur pairs were spent on pretesting. All femura were subjected to axial (10-500 N) and torsional (0.1-14 Nm) loading. RESULTS: Eighteen matched femur pairs were analyzed. The post-loading median residual values were 49.78, 41.25 and 33.51% of the axial stiffness of the intact femur and 59.04, 62.37 and 46.72% of the torsional stiffness of the intact femur in the SCN, LISS and DFN groups. There were no significant differences between the three implants concerning axial and torsional stiffness. CONCLUSIONS: All implants had sufficient biomechanical stability under physiological torsional and axial loading. All three implants have different mechanisms for distal locking. The SCN nail with the four-screw distal interlocking had the best combined axial and torsional stiffness whereas the LISS plate had the highest torsional stiffness.
Authors: Dirk Wähnert; Konrad L Hoffmeier; Geert von Oldenburg; Rosemarie Fröber; Gunther O Hofmann; Thomas Mückley Journal: J Bone Joint Surg Am Date: 2010-06 Impact factor: 5.284
Authors: Michael Zlowodzki; Scott Williamson; Peter A Cole; Lyle D Zardiackas; Philip J Kregor Journal: J Orthop Trauma Date: 2004-09 Impact factor: 2.512