ALTERATIONS IN CARPAL GEOMETRY IN SCAPHOID NON-UNION

Abstract

The symptomatic non-union of the scaphoid, if left untreated, will eventually lead to established arthritis and by that time important alterations in carpal geometry will have occurred. The aim of this paper is to study the carpal geometry in patients with symptomatic scaphoid non-union without arthritis or with early arthritic changes.

The pre-operative x-rays of 58 patients were retrospectively reviewed and x-rays of 35 of those fulfilling strict criteria for true projections were included (32 posteroanterior and 31 lateral views). Patients’ mean age was 31.3 years and mean time from fracture 50.4 months. The x-rays were digitized and measured using CAD methodology. The measured variables concerned the carpal height, possible displacement of the carpal bones and carpal instability. The non-unions were classified according to the Herbert and Fisher classification and were further categorized in two subgroups concerning the absence (14) or presence (21) of early arthritic changes in the radio-carpal or in one of the mid-carpal articulations (patients with established or generalized arthritis were excluded).

In total (and varying according to the method of measurement) up to 28% of the patients were presented with an affected carpal height, up to 17% with ulnar translocation of the wrist and up to 48% with a DISI pattern of instability. 62.5% of the patients (including patients without radiologicaly obvious arthritis) had increased radial height and radial inclination. After statistical analysis (ANOVA and regression analysis) no significant differences have been found between the morphological groups or between the two subgroups concerning early arthritis. A tendency of the lunate to translocate both in the coronal and the sagital plain simultaneously was found and the measurement methods were correlated.

In conclusion the carpal geometry in scaphoid non-union although altered does not seem to change significantly with the appearance of early arthritis and from this point of view treating non-union with early arthritis with bone grafting and osteosynthesis or even with additional radial osteotomy seems justified.