EFFECTS OF INTRAARTICULAR DISTAL RADIUS DEPRESSION ON WRIST JOINT CONTACT CHARACTERISTICS

Twelve cadaver extremities were used to study the effect of scaphoid a nd lunate facet depressions on the contact characteristics of the radi ocarpal joint. Pressure-sensitive film was inserted into radiocarpal j oints with varying degrees of depression, and the specimens were loade d statically in neutral position, radial deviation, and ulnar deviatio n. The film was removed and analyzed for contact area and pressure. Th e only statistically significant effect of a lunate fossa depression w as an increase in scaphoid fossa pressure with a 3-mm stepoff and the hand in neutral position. Scaphoid fossa depression had more significa nt effects. With a 1-mm scaphoid fossa depression, lunate fossa pressu res increased in neutral position and in radial deviation. Lunate foss a contact area increased, compared to intact joints, in ulnar and radi al deviation with 1-mm scaphoid fossa depressions and in all loading p ositions with 3-mm scaphoid fossa depression. Therefore, it appears th at the most significant effect on radiocarpal joint contact characteri stics occurs with a depression of the scaphoid side of the joint. Even with depressions as small as 1 mm, significant changes on the lunate side of the joint were observed.