Anatomical and clinical study of distal radioulnar joint stability

Objective To evaluate the main factors influencing the stability of the distal radioulnar joint(DRUJ) so as to provide an anatomical basis for further biomechanical research and to analyze the relationship between the stability of DRUJ and wrist function following distal radial fracture, so to provide a reference for clinical management. Methods Anatomical study of the wrist joint was done in 14 cadaver's upper extremities, to evaluate the factors influencing the stability of the DRUJ. The displacement of the distal ulna in relation to the radius was measured while a force of 20 N was applied on the distal ulna in both the palmar and dorsal direction perpendicular to its long axis with the radius in neutral position. So was done when the dorsal radioulnar ligament and the palmar radioulnar ligament were cut one after another. Clinically, 27 patients with distal radial fracture were treated nonsurgically and followed up for a mean of 5 months (4～6 months). All patients had their wrist joints and DRUJ detected for their stability and undergone functional and radiographic evaluation by Gartland and Werley scoring system. Results The palmar-dorsal radioulnar ligaments were the thickened part of the peripheral portion of the articular disc of the TFCC. Excision of the P-DRULs lead to significant instability of the DRUJ. Clinically, there were ten patients with DRUJ instability. DRUJ instability following distal radial fracture had a worse G.W. score. Conclusion P-DRULs is one of the main factors maintaining DRUJ instability. Excision of the P-DRULs lead to significant instability of the DRUJ. Clinically, it has been proposed that injury to the P-DRULs is the main cause of the instability of DRUJ, leading to chronic ulnar wrist pain and dysfunction of rotation of the forearm.