Mack scaphoid non-union natural history

The natural history of scaphoid non-union

Mack GR, Bosse MJ, Gelberman RH, et al. The Journal of bone and joint surgery. American volume 1984 · PMID 6707028 · doi:10.2106/00004623-198466040-00003

Question

What happens to the wrist over time when a scaphoid non-union is left untreated?

Design

Retrospective clinical and radiographic review of established scaphoid non-unions of long duration.

Patients

Symptomatic patients with long-standing untreated scaphoid non-unions.

Intervention

Observation of untreated non-union

Comparison

Duration of non-union

Primary outcome

Radiographic degenerative change

Key result

Three progressive radiographic groups were seen - change confined to the scaphoid, radioscaphoid arthritis, then generalised wrist arthritis - with longer non-union duration in each successive group. Displacement and carpal instability correlated with more severe arthritis, and few non-unions remained arthritis-free after ten years.

Limitations

Retrospective series of symptomatic patients, introducing selection bias, with no validated clinical outcome scores.

Impact on practice

Provides the rationale for reducing and grafting displaced scaphoid non-unions before arthritis develops (the SNAC sequence), and for counselling patients with stable undisplaced non-unions about late degeneration.