The optimal method of lateral lengthening osteotomy of the calcaneus: CT study in the Russian population

Introduction In the current professional literature, lengthening of the lateral column is considered to be one of the most effective and pathogenetically sound joint salvage methods for correction of plano-valgus deformity of the foot. The most widely used osteotomies in clinical practice are those of Evans and Hintermann. However, the articular facets of the subtalar joint are at risk of damage due to the variety of their number, shapes and location in different nationalities. The purpose of the work was to reveal the anatomical variants of the structure of the articular facets of the subtalar joint in the Russian population in order to determine the optimal method of lateral lengthening osteotomy of the calcaneus, based on personal characteristics. Material and methods The results of multispiral computed tomography (MSCT) of the feet of 250 patients were analyzed on the basis of the Tsivyan Novosibirsk Research Institute of Traumatology and Orthopedics. After applying the exclusion criteria, the final sample consisted of 150 patients. 3D modeling of their calcaneal bones with visualization of articular facets of the subtalar joint was performed on a workstation using the syngo.via–Siemens Viewer program. Patients were systematized according to the classification of P. Bunning and C. Barnett (1965). On 3D models of calcaneal bones, the distance between the anterior and middle, as well as between the middle and posterior articular facets was measured. Results The anterior and middle articular facets of the subtalar joint were separated (type A) in 40.7 % (61 feet), the remaining 59.3 % (89 feet) had fused anterior and middle facets (type B). Fully fused anterior, middle and posterior facets (type C) were not found. The average distance between the anterior and middle articular facets was 4.2 ± 0.08 mm, and the average distance between the middle and posterior facets was 5.3 ± 0.0027 mm. Discussion Articular facets of type B prevailed in the Russian population. Evans osteotomy will damage them 100 % of the cases. Hintermann osteotomy decreases the chance of their damage. However, the distance between the facets is very small, visualization during osteotomy is difficult, what can lead to damage to the subtalar joint. Thus, the development of a new method for determining and controlling the level of calcaneal osteotomy that would exclude joint damage is an urgent problem for further research. Conclusion Hintermann’s lateral lengthening osteotomy of the calcaneus may be successfully applied in the Russian population with the least complications in the postoperative period and less damage to the articular facets of the subtalar joint.