AJR:193, November 2009
Michel D. Crema, Monica D. Marra, Ali Guermazi, Frank W. Roemer, Klaus Bohndorf, Nabil Jomaah
Ulnocarpal impaction syndrome is a degenerative condition caused by increased load transmission through the ulnar aspect of the wrist. The triangular fibrocartilage complex (TFCC) has three major functions [1, 2]: It acts as a cushion for the ulnar carpus that carries approximately 20% of the axial load of the forearm, it is the major stabilizer of the distal radioulnar joint, and it is a stabilizer of the ulnar carpus. The lunotriquetral ligament stabilizes the lunate and triquetrum and has dorsal, volar, and membranous components. Although the volar component is the thickest and strongest part, both dorsal and volar are important in resisting distraction [3]. Repetitive and increased loading of the ulnar aspect of the wrist caused by conditions such as congenital positive ulnar variance, distal radius fractures, premature physeal closure of the distal radius, Madelung's deformity, and radial head resection will lead to degeneration of the TFCC and ulnocarpal joint and occasionally also of the distal radioulnar joint. Positive ulnar variance is usually present; however, cases with neutral and negative ulnar variance have been described [4]. Clinical symptoms include ulnar wrist pain, swelling, and limitation of motion. Movements that increase ulnar variance (firm grip, pronation, ulnar deviation of the wrist) often exacerbate symptoms. Relief of symptoms is usually obtained with rest [5, 6].