Biomechanical comparison of fixation of two-part osteoporotic neck fracture of the proximal humerus using uni-planar and multi-planar Kirschner wire.

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.