Treatment of displaced transverse fractures of the patella: modified tension band wiring technique with or without augmented circumferential cerclage wire fixation

BACKGROUND: Displaced transverse fractures of the body of the patella are usually associated with disruption of extensor mechanism and should be fixed surgically. The most common method is a tension band wiring (TBW) technique. Some surgeons concurrently employ an augmented circumferential cerclage wiring (ACCW) technique to help fracture stabilization and aid in fracture healing; however, its role and effect on the treatment outcomes is unclear. METHODS: We performed a STROBE-compliant retrospective observational cohort study on all cases of acute closed patella fracture that were treated at our institution between 2006 and 2012. Of 185 episodes, 72 (38.9%) were eligible for this study according to our inclusion/exclusion criteria. We classified these subjects with AO/OTA type 34-C1.1 or 34-C2 lesions into two groups for analyses: fractures treated with modified TBW and ACCW (group 1, n = 27) and those treated with modified TBW alone (group 2, n = 45). Plain radiographs were used to evaluate radiographic outcomes and the effect of potential risk factors on fixation failure was analyzed by subgroup comparisons. RESULTS: Our results revealed that there were no significant differences in the rates of fixation failure (P = 0.620), nonunion (P = 0.620), and revision surgery (P = 0.620) between the groups. Although not statistically significant, there was a trend towards a positive risk association between fixation failure and age distribution > 60 years (10.0% vs. 0.0%, P = 0.124; OR = 8.0, P = 0.168) and > 70 years (9.4% vs. 2.5%, P = 0.321; OR = 4.0, P = 0.237) and the superficial level of the K-wires (12.0% vs. 1.5%, P = 0.117; OR = 6.3, P = 0.121). Regarding those modified TBW patients concurrently treated with an ACCW, the potential risk association between fixation failure and the superficial level of the K-wire was prone to increase further (28.6% vs. 0.0%, P = 0.060; OR = 18.6, P = 0.071). CONCLUSIONS: Concurrent application of an ACCW might be needless and not efficacious to help fracture stabilization and healing in patients having been treated with modified TBW for displaced transverse fractures of the body of the patella. Adherence to correct surgical technique such as putting the K-wires at the proper level and securing control of the both ends of the K-wires may be more important and help in improving outcomes.