Subject(s)
Clinical Trials as Topic , Disease , Health , Sex Characteristics , Clinical Trials as Topic/trends , Female , Humans , Male , PrejudiceSubject(s)
Sunlight/adverse effects , Vitamin D Deficiency/prevention & control , Adult , Aged , Child , Dietary Supplements , Humans , Middle Aged , Sunscreening AgentsABSTRACT
The purpose of this study was to establish the relationship between force at the distal radius and power grip force of the hand, a common functional and rehabilitation maneuver. This information will provide limits of allowable grip forces during postfixation rehabilitation and guide design requirements for fixation systems. By designing a model of power grip using the extrinsic hand musculotendinous units, we were able to compare grip force with force at the distal radius. Our results show that to obtain 10 N of grip force, approximately 26.3 N of force is transmitted through the distal radius, 52.4 N is transmitted through the radius and ulna combined, and 30.0 N needs to be applied to the flexor tendons. Fifty-one percent of the total forearm force was transmitted through the distal radius in this model. If all forearm forces were transmitted through the radius, 52 N of force would be transmitted through the distal radius to obtain 10 N of grip force. The clinical application of this model suggests that since failure forces of tested distal radius fixation systems range from 55 to 825 N, rehabilitation grip force should not exceed 10 to 159 N, depending on the type of fixation.
Subject(s)
Hand Strength , Radius Fractures/rehabilitation , Radius/physiopathology , Wrist Joint/physiopathology , Biomechanical Phenomena , Cadaver , Dissection , Epiphyses/physiopathology , Humans , Linear Models , Models, Biological , Radius Fractures/physiopathology , Stress, MechanicalABSTRACT
A dorsal plate for the distal radius was designed to provide rigid fixation and thus allow early motion. It functions as a blade plate, lessening the role of metaphyseal screws, and providing internal neutralization rather than compression. The rigidity and strength of the plate were compared to the existing T-plate in an unstable, extra-articular fracture model in paired, fresh-cadaver, axially loaded radii. The dorsal plate construct was significantly stronger and more rigid than the T-plate construct. The failure mode was similar for both plate types; 8 of 10 constructs failed with plate bending and screw loosening, while the oldest specimen pair showed primary bone failure. Compared to the T-plate, the dorsal plate transmitted a greater single axial load from the articular surface to the shaft.
