Study of the morphologic and morphometric patterns of talar articular facets on dry adult calcaneal bones in South-Eastern Nigerian population.

Background: Calcaneum is the largest and longest tarsal bone in the foot and forms the prominence of the heel. The middle third of the superior surface of calcaneus provides an articular facet for the talus bone. Objective: The study seeks to observe the variations in the morphology and morphometry of the talar articular facets on the superior surface of dry calcaneal bones of adult human in South-Eastern Nigerian population. Materials and methods: The study was carried out with 220 adult non-pathological dry calcanei, 111 bones of left side and 109 bones of right side of unknown sex from bone banks of various medical colleges in South-Eastern Nigeria. Each calcaneus was examined for various patterns of articulating facets for talus, the shapes of the facets and the length, width and interfacetal distances were also documented. Results: Pattern 1 was common in the present study (59.6% right and 51.4% left). Pattern 2 has an incidence of 7.3% on the right and 8.1% on the left side. Pattern 3 was found with an incidence of 11.9% on the right and 13.5% on the left side and pattern 4 was found with an incidence of 21.1% on the right and 27% on the left side constituting the second most common pattern of talar articular facets on the superior surface of the calcaneus. The oval shape was common in the anterior and middle talar articular facets with an incidence of 52.86% and 64.39% respectively, oval and convex was common in the posterior facet (70% cases) and the elongated shape was common among the fused anterior and middle facet (63.12%) with elongated oval common in subtype 2 (27.87%) and elongated constricted common in subtype 1 (35.25%). The length of the calcanei was recorded at a mean±SD of 7.10±0.70cm (left side) and 7.01±0.72cm (right side) and that of the width was recorded at 2.77±0.38cm (left side) and 2.77±0.37cm (right side). The distance between the Anterior and Middle facets was mean±SD of 0.50±0.15cm (left side) and 0.48±0.15cm (right side), the Posterior and Middle facets at 0.59±0.20cm (left side) and 0.56±0.17cm (right side) and that between the Anterior and Posterior facets at 1.43±0.27cm (left side) and 1.42±0.29cm (right side). Conclusion: The individual and racial differences of the anatomic construction of calcaneal talar articular facets influence the static and kinetic dynamics of foot. A good knowledge of the calcaneal facet pattern and shape would assist better treatment and management options for calcaneal fractures. It also necessitates a modification of western surgical techniques to suit the Nigerian scenario for calcaneal osteotomy. [ABSTRACT FROM AUTHOR]