Anterior Hook Plating of Patella Fractures: A Biomechanical Analysis and Clinical Series

Objectives:To compare anterior hook plating with established fixation constructs biomechanically and report outcomes and complications in a cohort of patella fractures treated with the technique.Design:Laboratory-based biomechanical study and clinical multicenter retrospective cohort study.Setting:2 US Level 1 trauma centers.Patients/Participants:51 patients (28 M and 23 F) with 30 simple transverse and 21 comminuted patella fractures. Thirty-six cadaveric patellae were used for the biomechanical study.Intervention:Biomechanical-dorsal plating was compared with cerclage wiring and modified tension band cable fixation in a comminuted patella fracture model in 36 cadaveric patellae. Constructs were tested at 0 degrees and 45 degrees of flexion. Clinical-we reviewed a consecutive series of patella fractures in 2 centers for outcome and complications.Main Outcome Measurements:Biomechanical-construct stiffness. Clinical-reduction, union, complications, and range of motion.Results:Stiffness was greatest in dorsal plating at both 0 degrees and 45 degrees. Dorsal plating (976 N, 1643 N) > modified tension band (317 N, 297 N) > cerclage (89.8 N, 150.3 N) at 0 and 45 degrees, respectively. 51 patients with patella fractures had them fixed with dorsal 2.7-mm mini fragment plates including a distal to proximal lag screw through the plate from the nose of the patella. 9 cases were small distal fragments not easily managed with screws and cables. All patients were followed up to union. There were 2 infections (1 superficial and 1 deep with nonunion), and 5 had implant removal (9.8%).Conclusions:Dorsal plating is biomechanically and clinically superior to modified tension band and cerclage techniques in comminuted patella fractures. This method allows for fixation of small distal pole fractures.