Comparison of three fixation methods in transverse fractures of the patella in a calf model

OBJECTIVES: We evaluated the strength of three different fixation methods against distraction forces in a transverse fracture model of calf patellae. METHODS: Thirty calf patellae were randomly divided into three groups equal in number. Transverse fractures were induced at the same localization in all the samples. The fractures were fixed with a modified anterior tension band technique, Acutrak 4/5 screws, and a combination of Acutrak 4/5 screws and tension band technique in three groups, respectively. Following fixation, each patella was mounted in a compression-distraction testing machine from the quadriceps and patellar tendons on each side of the patella, and equal distraction forces were applied to each patella. The average load to failure at the fracture site was calculated and the results were compared with the Friedman test. RESULTS: The mean failure loads were significantly different in three groups, being 288.8+/-40.1 newton (N), 878.5+/-68.6 N, and 938.6+/-38.8 N, respectively (p<0.001). The most efficient stabilization was obtained in the third group in which Acutrak 4/5 screws and the tension band application were used in combination, while the modified anterior tension band technique alone was found to be the weakest fixation technique. CONCLUSION: Our results showed that Acutrak 4/5 screws enabled a rigid fixation in the surgical treatment of patellar fractures.