Watson and Ballet introduced the concept of a direct association between scapholunate (SL) dissociation and radioscaphoid (RS) arthritis with preservation of the radiolunate (RL) articulation in 1984. This principle has served as the anatomic, biomechanical, and pathophysiological basis for reconstructive surgery in the carpus. Recently, we have noted cases of concurrent SL dissociation and RL arthritis without RS arthritis, which is contrary to the accepted concept of wrist arthritis due to SL advanced collapse. The purpose of this study was to determine whether Watson and Ballet's thesis that SL dissociation results in RS joint degeneration with sparing of the RL joint can be confirmed, or whether another joint degeneration pattern can be associated with SL dissociation.
The 3 authors independently reviewed 897 radiographs of the wrist in 691 male patients (206 bilateral and 485 unilateral) with diagnosis codes of wrist osteoarthritis (715.13), wrist instability (718.83), and wrist sprain (842.00). Posterior-anterior, oblique, and lateral views were available for all wrists. Elements assessed were RS joint, RL joint, SL joint, midcarpal joint, ulnar variance, ulnolunate joint, SL angle, and lunocapitate angle.
There were 146 wrists with radiographic SL dissociation. Nine wrists in 6 patients had radiographic SL dissociation and RL arthritis but no RS arthritis. An additional 6 wrists in 6 patients had radiographic RL arthritis but no SL dissociation or RS arthritis; however, 5 of these did have an SL angle of 60 degrees or greater.
Our results show that RL arthritis can occur in association with SL dissociation, and that the generally held view that the RL articulation is spared in SL advance collapse is not universally true. Consequently, it is our recommendation that both the RL and RS joints should be carefully evaluated for degenerative changes when planning treatment for patients with SL dissociation, because it should not be assumed that the RL joint has been spared.