A novel patella fracture fixation technique: finite element analysis

Abstract

Introduction: Patella fractures account for approximately 1% of all bone fractures. The tension band wiring technique has been used in surgical treatment. However, there is no clear information about the location of the K-wires in sagittal plane. Thus, a transverse fracture line was created in the patella finite element model and fixed with Kirchner (k) wires and cerclage at different angles and compared with two different standard tension band models.

Materials and methods: A total of 10 finite element models were created to study AO/OTA 34-C1 patella fractures. Two models used the classical tension band method with either circumferential or 8-shaped cerclage wire. The other 8 models used K-wires placed at 45° or 60°, either alone or combination with cerclage wire. A force of 200 N, 400 N, and 800 N were applied at 45° knee angle and the resulting data fracture line opening, surface pressure and stress in the implants were analyzed through finite element analysis.

Results: When all the results are considered, it was determined that the K-wires 60° crossing at the fracture line and with cerclage modeling was superior to the other models. The diagonal placement of the K-wires with cerclage (could be 45° or 60° medium) was superior to the reference models.

Conclusions: This study has shown that the new fixation method we propose could come to the fore as an alternative method to be used successfully in transverse patella fractures and lower complications. In transverse patellar fractures, the use of K-wires crossed at 60° may be a good alternative to the standard method.

Keywords: Finite element method; Modified tension band wiring; Patellar fracture; Tension band fixation.