Morphology and Morphometry of the Distal Articular Surface of Lunate Bone in a Kenyan Population

Abstract

SUMMARY:The morphology and morphometry of the distal articular surface of the lunate exhibits inter-population variations. They are of clinical importance to hand surgeons due to their influence on the occurrence of proximal pole arthrosis which is a cause of ulnar-side wrist pain. The objective of the study was to determine the morphology and morphometry of the distal articular surface of the lunate bone in an adult Kenyan population. A descriptive cross-sectional study at the Department of Human Anatomy, University of Nairobi. Fifty-six human hands obtained for routine dissection were used. The morphology of the distal articular surface of the lunate was classified as either Type I or Type II depending on the absence or presence of a medial facet for articulation with the hamate respectively. The width of the wrists and of the medial facet in Type II lunates was measured with SOMETTM CN-25 1234 vernier calipers (accurate to 1mm). Photomacrographs of representative lunate were taken. Data were analyzed using SPSS version 17.0. The Pearson correlation test was used to check for any correlations. Type II lunate morphology was more common with a prevalence of 34 (61 %) while 19 (34 %) were Type I. The mean width of wrists with Type I lunate was 41.1±2.8 mm while those with Type II had a mean width of 46.1±4.3 mm. The mean width of the medial facet in lunate type II was 4.4±1.4 mm. Lunotriquetral fusion was demonstrated in 3 (5 %) wrists. Prevalence of Type II lunate was higher than Type I. Wrists with a Type II lunate were wider than those with Type I. There was no correlation between the width of the wrist and the width of the medial facet of the lunate.