Biomechanical comparison of radiopalmar double plating with conventional palmar plating in comminuted distal radius fractures

The aim of this study is to analyse the effect of an additional radial buttress plate for palmar plate osteosynthesis in an AO/OTA 2R3 C2.1 fracture model. Nine pairs of freshly frozen radii were analysed for pathology and bone mineral density and divided into two matched groups. One group was treated with a variable-angle palmar locking plate alone, while the second group received an additional radial buttress plate for radiopalmar double plating. An AO/OTA 2R3 C2.1 fracture was created in all specimens. The biomechanical tests were performed according to previously published protocols. Stiffness, axial displacement of the construct, as well as fragment-specific movements and rotations were assessed. No implant failure was observed. In the total cohort, stiffness increased (p < 0.01) and axial construct displacement decreased (p < 0.05). The mobility of the ulnar fragment to the shaft during cyclic testing was lower with double plating, both at baseline and endpoint (all p < 0.01). Fragment movements increased over the course of testing and were significant for the radial articular fragment relative to the shaft in the total cohort (p < 0.01). Baseline rotation of the ulnar fragment and endpoint rotation of the radial fragment in relation to the shaft were lower with double plating (all p < 0.05). In both constructs, the rotation of the ulnar fragment relative to the shaft was lower than that of the radial fragment at both timepoints (all p < 0.05). Biomechanically, the addition of a radial buttress plate to a standard palmar locking plate did not alter global construct stiffness, but demonstrated advantages in fragment-specific stability in comminuted distal radius fractures.