The natural history of scaphoid non-union

Abstract

A retrospective radiographic and clinical analysis of 102 symptomatic patients with 104 scaphoid non-unions of at least 1 year's duration was conducted. Osteoarthritis occurred in 22% of non-unions of less than 5 years' duration, 75% of those of 5 to 9 years' duration, and 100% of those of 10 years' duration or more. An all-over incidence of osteoarthritis in the wrist was 55%. Osteoarthritic changes occurred initially at the scaphoid-radial styloid joint which were manifested by radial styloid pointing and/or dorsal radioscaphoid osteophyte formation, later progressing to the midcarpal joint. Osteoarthritis at the scaphoid-radial styloid joint was significantly associated with dorsiflexed intercalated segment instability (DISI) deformity. An overall incidence of DISI deformity of the wrist was 56%, and the frequency of DISI pattern increased with longer duration of non-union. There was an increased incidence of avascular necrosis of the proximal fragment with time, especially after 20 years. There was no correlation between symptoms of pain and the severity of arthritis or the duration of non-union, but a good correlation between the duration of non-union and reduced grip strength or decreased wrist motion. A symptomatic non-union of the scaphoid is significantly likely to progress to osteoarthritis according to a predictable sequence, becoming worse both radiographically and clinically with time.