Biomechanical evaluation of various forms of fixation of transverse patellar fractures.

A study was undertaken to evaluate the strength and ease of application of four different forms of patellar fracture fixation. Modified tension band, screw fixation, Lotke longitudinal anterior band (LAB), and Magnusson wiring were examined using a Materials Testing System. Using cadaver lower extremities, the tibia was mounted in a fixed base and the tibiofemoral joint was fixed at 36 degrees. Tension was applied to the patella through the quadriceps tendon and fracture displacement was measured with linear motion transducers. Based on the results, we recommend screw fixation for transverse patellar fractures in patients with adequate bone stock. In patients with patellar fractures with comminution and/or osteopenia, modified tension band fixation is recommended. Simple wiring techniques alone may not provide sufficient fixation to allow immediate range of motion.