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

ABSTRACT

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° 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° 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. LEVEL OF EVIDENCE Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.