Biomechanical Comparison of 2.4 mm LCP Radial Head Plate and Tripod Fixation in Mason Type III Radial Head Fractures: A Human Cadaveric Study.

Background: Proximal radius fractures, particularly Mason Type III, represent a challenge in elbow surgery due to their complexity and impact on joint function. Using the conventional radial neck plate is a reliable treatment option, however, it can cause soft tissue irritation and restricted range of motion. A novel tripod fixation approach, using three crossed screws, should minimize such complications and preserve range of motion. This study aims to compare the biomechanical competence of conventional radial neck plating using a LCP Radial Head Neck Plate 2.4 mm (DePuy Synthes, West Chester, PA, USA) versus tripod fixation in a Mason Type III fracture model.

Methods: Sixteen paired human cadaveric radii underwent a standardized osteotomy to simulate a transverse neck fracture with an additional 50:50 head split component and split into two groups - Group 1 fixed with a conventional radial neck plate with two additional canulated headless compression screws (HCS) and Group 2 stabilized with tripod fixation (three cruciated 40 mm HCS) and two additional HCS. Biomechanical tests assessed stiffness in anteroposterior and mediolateral bending, axial compression, pronation, and supination.

Results: No significant differences were found in stiffness across the comparisons: mediolateral bending: tripod:195±132 N/mm, plate: 91±47 N/mm (p = 0.067), anteroposterior bending: plate: 168±105 N/mm tripod: 145±108 N/mm (p = 0.670), axial compression: plate: 643±337 N/mm vs. tripod: 642±188 N/mm (p = 0.998), pronation: plate 0.15±0.10 Nm/°, tripod: 0.23±0.23 Nm/° (p = 0.336), and supination: plate: 0.17 Nm/°, Tripod: 0.25±0.21 Nm/° (p = 0.351). Cycles to failure under axial compression were recorded with the plate group showing 4,078±3,173 cycles and the tripod group 4,763±5,288 cycles, p ≥ 0.4. Load to failure was noted at 586±222 N for the plate and 789±337 N for the tripod, p ≥ 0.4.

Conclusion: From a biomechanical perspective the tripod technique with two additional HCS showed comparable performance compared to plate fixation with two additional HCS in transverse radial neck fractures with an additional head split component. With potentially less soft tissue irritation and necessary secondary hardware removal the tripod technique seems to be a valid alternative to conventionally used plate osteosynthesis techniques. However, further randomized clinical trials are needed to fully evaluate its clinical value.