Objective: Distal radius fractures with dorsal angulation alter wrist kinetics with a variety of sequelae including load pattern changes, painful disability, and degenerative carpal pathology. The purpose of this study was to characterize compressive force changes with increasing dorsal angulation of the distal radius through the application of novel pressure sensing technology. Methods: Four pairs of cadaver arms were harvested and standard radiographs were used to exclude radiocarpal pathology. Osteotomies were made in the distal radius followed by rigid fixation with 0° and 20° of dorsal tilt. The pressure distribution at the radiocarpal joint was measured using the Tekscan 6900 sensor which was placed in the radiocarpal joint through a limited volar arthrotomy. The biomechanical forces were measured in each pair of wrists (pre-osteotomy, 0° doral tilt, 20° dorsal tilt) via axial loading as well as flexion loading simulating the Finger Extension Test (FET). Results: Average representations of the force area of distribution were calculated at the radiolunate and radioscaphoid joints for each pair of wrists. At the radiolunate joint, there was a consistent diminution of force in axial and FET loading associated with sequential dorsal angulation. At the radioscaphoid joint, there were progressive increases in compressive forces with axial and FET loading with sequential dorsal angulation. Likewise, the pressure distribution pattern at the radioscaphoid joint narrowed and shifted radially and dorsally with increasing dorsal angulation. Conclusion: Dorsal angulation of the distal radius translates into significant changes in wrist kinetics. The data underscores the importance of the mechanical advantage of palmar tilt of the radius for appropriate wrist loading patterns. At the same time, these findings reinforce the importance of anatomic distal radius fracture reduction and offer an explanation of wrist pathology associated with distal radius malunion.

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