Matthias Knobe1, Gertraud Gradl2, Benjamin Buecking3, Stefan Gackstatter4, Tolga Taha Sönmez5, Alireza Ghassemi6, Jan-Philipp Stromps7, Andreas Prescher8, Hans-Christoph Pape9. 1. Department of Orthopaedic Trauma, University of Aachen Medical Center, Aachen, Germany. Electronic address: mknobe@ukaachen.de. 2. Department of Orthopaedic Trauma, University of Aachen Medical Center, Aachen, Germany. Electronic address: ggradl@ukaachen.de. 3. Department of Trauma, Hand and Reconstructive Surgery, University Hospital Gießen and Marburg GmbH, Campus Marburg, Marburg, Germany. Electronic address: buecking@med.uni-marburg.de. 4. Department of Orthopaedic Trauma, University of Aachen Medical Center, Aachen, Germany. Electronic address: stefan_gackstatter@web.de. 5. Department of Oral and Maxillofacial Surgery, University of Aachen Medical Center, Aachen, Germany. Electronic address: ttahastt@gmail.com. 6. Department of Oral and Maxillofacial Surgery, University of Aachen Medical Center, Aachen, Germany. Electronic address: aghassemi@ukaachen.de. 7. Department of Plastic Surgery, Reconstructive and Hand Surgery, University of Aachen Medical Center, Aachen, Germany. Electronic address: jstromps@ukaachen.de. 8. Department of Molecular and Cellular Anatomy, University of Aachen Medical Center, Aachen, Germany. Electronic address: aprescher@ukaachen.de. 9. Department of Orthopaedic Trauma, University of Aachen Medical Center, Aachen, Germany. Electronic address: hpape@ukaachen.de.
Abstract
INTRODUCTION: Locked minimally invasive plating and fourth generation nailing potentially could reduce the complication rate in the treatment of trochanteric femur fractures by its rotational stability and providing better lateral cortical support. The purpose of this study was (1) to compare the biomechanical properties of the Percutaneous compression plate (PCCP) and the Intertan nail (IT) with regards to implant failure and (2) to assess dynamic stability coefficients in an unstable AO/OTA 31A2.2 fracture model. METHODS: In paired femurs, a standardised unstable trochanteric femur fracture was induced by an oscillating saw. The fractures were stabilised by either the PCCP (Orthofix, McKinney, TX, USA) or the IT (Smith & Nephew, Memphis, TN, USA). All femurs were loaded with 300N, followed by an increase in load until failure using 300N each time (2000 cycles each, 0.5Hz). After every load step the samples were assessed visually and radiographically. We measured migration and performed a survival analysis. RESULTS: 16 fractures were induced in 8 paired human specimens (mean age: 84 years, 61-100 years). The mean stiffness (PCCP vs. IT: 249±124N/mm vs. 273±153N/mm; p=0.737) was comparable. The IT proved superior to the PCCP with regard to the number of cycles reached before failure occurred (PCCP vs. IT: 12,691±4733 vs. 15,313±4875 cycles; p=0.023). Except for a higher axial migration of the IT at failure point (PCCP vs. IT: 1.3mm vs. 4.3mm; p=0.028) there were no differences between the intra- and extramedullary implants, not even in terms of rotational stability along the femoral neck axis. A fracture of the femoral neck caused test abortion in both implants in most cases. CONCLUSION: This study showed a superiority of the IT compared with the PCCP with regards to number of cycles achieved under sequential load increases for unstable trochanteric femur fractures. The stiffness was comparable. Both implants showed a high rotational stability and a support of the lateral wall. STUDY TYPE: Biomechanical study.
INTRODUCTION: Locked minimally invasive plating and fourth generation nailing potentially could reduce the complication rate in the treatment of trochanteric femur fractures by its rotational stability and providing better lateral cortical support. The purpose of this study was (1) to compare the biomechanical properties of the Percutaneous compression plate (PCCP) and the Intertan nail (IT) with regards to implant failure and (2) to assess dynamic stability coefficients in an unstable AO/OTA 31A2.2 fracture model. METHODS: In paired femurs, a standardised unstable trochanteric femur fracture was induced by an oscillating saw. The fractures were stabilised by either the PCCP (Orthofix, McKinney, TX, USA) or the IT (Smith & Nephew, Memphis, TN, USA). All femurs were loaded with 300N, followed by an increase in load until failure using 300N each time (2000 cycles each, 0.5Hz). After every load step the samples were assessed visually and radiographically. We measured migration and performed a survival analysis. RESULTS: 16 fractures were induced in 8 paired human specimens (mean age: 84 years, 61-100 years). The mean stiffness (PCCP vs. IT: 249±124N/mm vs. 273±153N/mm; p=0.737) was comparable. The IT proved superior to the PCCP with regard to the number of cycles reached before failure occurred (PCCP vs. IT: 12,691±4733 vs. 15,313±4875 cycles; p=0.023). Except for a higher axial migration of the IT at failure point (PCCP vs. IT: 1.3mm vs. 4.3mm; p=0.028) there were no differences between the intra- and extramedullary implants, not even in terms of rotational stability along the femoral neck axis. A fracture of the femoral neck caused test abortion in both implants in most cases. CONCLUSION: This study showed a superiority of the IT compared with the PCCP with regards to number of cycles achieved under sequential load increases for unstable trochanteric femur fractures. The stiffness was comparable. Both implants showed a high rotational stability and a support of the lateral wall. STUDY TYPE: Biomechanical study.
Authors: Juliane Carow; John Bennet Carow; Mark Coburn; Bong-Sung Kim; Benjamin Bücking; Christopher Bliemel; Leo Cornelius Bollheimer; Cornelius Johannes Werner; Jan Philipp Bach; Matthias Knobe Journal: Int Orthop Date: 2018-01-02 Impact factor: 3.075