Biomechanical comparison of fixation of two-part osteoporotic neck fracture of the proximal humerus using uni-planar and multi-planar Kirschner wire
Erdinç Esen1, Yunus Doğramacı2, Mahmut Kömürcü3, Ulunay Kanatlı4, Selçuk Bölükbaşı, Ali Osman Atahan
1Department of Orthopedics and Traumatology, Medical Faculty of Gazi University Ankara, Turkey
2Department of Orthopedics and Traumatology, Medicine Faculty of Mustafa Kemal University, Antakya, Hatay, Turkey
3Department of Orthopedics and Traumatology, Gülhane Military Medical School, Ankara, Turkey
4Department of Engineering, Worcester Polytechnic Institute, Massachusetts, USA
Keywords: Proximal humerus; osteoporosis, fracture; biomechanics.
Objectives: The stability and effectiveness of uni-planar Kirschner wire (K-wires) was compared to multi-planar K-wires osteosynthesis combined with tension band wiring for fixation of two-part osteoporotic surgical neck fracture of the proximal humerus. Materials and methods: Two groups each with eight cadaveric elderly (mean age 72.6; range 70 to 80 year) frozen human humeri were used in the study. Transverse osteotomy of the proximal humerus was performed using a thin oscillating saw. The first group (group A) was fixed using two anterograde smooth K-wires, sent from lateral cortex, combined with tension band wiring. The second group (group B) was fixed using multi-planar (anterograde and retrograde) four smooth K-wires combined with tension band wiring on the lateral cortex. Biomechanical tensile properties for 3 mm displacement (gap load) and maximum load were assessed.
Results: The mean value for the gap load was 1045.0±45.4 N (Newton) for group A and 1238.1±115.8 N for group B. Gap load values of groups were similar (p=0.01). The maximum load was 1261.8±52.4 N in group A and 1471.1±107.3 N in group B. The maximum load values were statistically higher in the multiplanar fixation technique (group B) when compared to that of the uniplanar fixation technique (group A), (p=0.004).
Conclusion: Fixation in osteoporotic two-part surgical neck fractures of the proximal humerus using multiplanar K-wires combined with tension band wire provides substantially more effective stability compared to that of uniplanar fixation.