RESUMO
The individual contribution of the distal radioulnar ligaments to dorsal and palmar translational stability during forearm rotation remains controversial. Furthermore, the role of the distal radioulnar joint capsule as a restraint and contributor to stability has not been investigated. A biomechanical study was performed in 11 fresh cadaver specimens to simultaneously measure dorsal and palmar radioulnar ligament tension. Joint rotation and radial translation were measured after sequential excision of the disk, interosseous membrane, joint capsule, and radioulnar ligaments. Results confirmed that the dorsal ligament tightens during pronation while the palmar ligament becomes progressively lax; the converse occurred during supination. Translational stability remained intact at all positions throughout the sectioning sequence until one of the radioulnar ligaments was sectioned. The most significant increases in translation occurred after sectioning the dorsal radioulnar ligament in pronation and after sectioning the palmar radioulnar ligament in supination. Forearm rotation increased significantly after excising either hemicapsule.
