A Biomechanical Study of an Alternative Internal Fixation Method for Transverse Patella Fractures

Pain and reoperation after fixation using tension band wiring and K-wires is not uncommon. A novel hook plate was designed to improve the treatment of patella fractures. The aim of this study was to compare the stability of the hook plate with that of tension band wiring and K-wires in a simulated patellar transverse fracture model (AO/OTA classification 34-C1.1). The authors tested 16 embalmed cadaver knee joints fixed with the hook plate and tension band wiring and K-wires under cyclic loading. Specimens underwent 100 cycles extending the knee joint from 90° of flexion to full extension at a velocity of 50 mm/min. The fracture gap was measured after the initial and last cycles. Data were assessed statistically using the t test, with significance set as P<.05. The fatigue test showed that the fracture gap after 100 cycles was 2.97±1.39 mm using tension band wiring and K-wires and 1.53±0.93 mm for the hook plate (P=.029). Six of 8 specimens in the tension band wiring and K-wires group met the failure criterion of fracture gap greater than 2 mm vs 1 in the hook plate group (P=.041). From a biomechanical point of view, the hook plate is a valid alternative to tension band wiring and K-wires for fixing patella transverse fractures. Compared with tension band wiring and K-wires, the hook plate may have superior ability in sustaining a reduced transverse patella fracture. [Orthopedics. 2018; 41(5):e643-e648.].