Isolated lunocapitate osteoarthritis-an alternative pattern of osteoarthritis.

Introduction Osteoarthritis (OA) in the wrist usually develops in a pattern described as scapholunate advanced collapse (SLAC). We observed an alternative pattern of OA that involves the lunocapitate joint in isolation with minimal involvement of the radioscaphoid articulation. Case Series The series was observed from a series of 100 wrist radiographs that were retrospectively reviewed. In order to characterize the alternative pattern of OA, we compared demographic data, presentation, and physical and radiographic examination characteristics between the patients with lunocapitate OA and SLAC wrists. Fifteen radiographs showed OA, nine had a SLAC pattern, and six had lunocapitate OA. The demographics were similar, but the clinical presentation was different. The patients with lunocapitate OA had less tenderness over the snuffbox (P < 0.03), and a lower percentage of a positive scaphoid shift test (P <  0.005). Isolated lunocapitate OA had a higher association with scaphotrapeziotrapezoidal (STT) arthritis (P < 0.004). The SLAC group had an increased scapholunate gap (P = 0.0003). Discussion  The presentation of lunocapitate OA differs from SLAC wrist in a number of ways. Further study is necessary to understand the clinical implications of this pattern. Level IV evidence Case series.