Biomechanical comparison of a 3.5 mm anterior locking plate to cannulated screws with anterior tension band wiring in comminuted patellar fractures. Issue 6 (June 2020)

• Record Type: Journal Article
• Authors: Wagner, Ferdinand C; Neumann, Mirjam V; Wolf, Steffen; Jonaszik, Alexander; Izadpanah, Kaywan; Piatek, Stefan; Südkamp, Norbert P
• Is Part Of: Injury. Volume 51:Issue 6(2020)
• Page Start: 1281
• Page End: 1287
• Publication Date: 2020-06
• Subjects: Multifragmentary patella fracture -- Cyclic loading -- Anterior locking plate -- Cannulated screws -- Anterior tension band wiring -- Biomechanics Level of evidence -- Basic science study; Wounds and injuries -- Surgery -- Periodicals; Accidents -- Periodicals; Wounds and Injuries -- surgery -- Periodicals; Lésions et blessures -- Chirurgie -- Périodiques; Electronic journals; Electronic journals; 617.1
• DOI: 10.1016/j.injury.2020.03.030
• Languages: English
• ISSNs: 0020-1383

Abstract

Highlights: From a biomechanical point of view, the application of anterior locking plate osteosynthesis in complex patellar fractures provides better primary stability compared to cannulated lag screws with anterior tension band wiring (hybrid osteosynthesis). Hybrid osteosynthesis seems to be more susceptible to failure in patellae with low bone mineral density. Abstract: Purpose: : To date, surgically treated multifragmentary patellar fractures are still associated with high rates of complications, such as i.e. secondary fracture displacement. Osteosynthesis is most frequently performed with screws and cerclages. To increase primary stability, locking plates have been introduced. However, there is still a lack of biomechanical data supporting the superiority of plate fixation compared to screw fixation with cerclages in these cases. The goal of the present study was to conduct biomechanical comparison of these two techniques under dynamic loading conditions. Methods: : A standardized 34-C3 fracture was created in eight pairs of human cadaveric knee joints. Following a randomization protocol, they were fixed with a 3.5 mm anterior locking plate (LP) or cannulated screws with anterior tension band wiring (hybrid osteosynthesis, HO).Subsequently, all constructs were tested for 100 cycles from 90° of knee-flexion to full extension by applying a pulling force to the quadriceps tendon. Outcome parameters were fracture displacement after one cycle, after 100 cycles and implant loosening. Failure was defined as fracture displacement > 2 mm. Results: : Biomechanical testing showed significantly less fracture displacement following LP compared to HO both after the first ( p = 0.042) and after 100 cycles ( p = 0.025). The difference in loosening was significant as well ( p = 0.017). Following HO, 5/8 constructs failed during cyclic loading. There was no failure in the LP group. In the HO group, loosening correlated with bone mineral density (R = - 0.857) which was not observed in the LP group (R = - 0.429). Conclusion: : Anterior locking plate osteosynthesis of comminuted patellar fractures biomechanically provides better primary stability compared to cannulated screws with anterior tension band wiring.