Comparison of Anatomic Structures at Risk With 2 Lateral Lengthening Calcaneal Osteotomies

Background: Lateral lengthening calcaneal osteotomies (LLCOT) are commonly used to treat flexible pes planovalgus deformity. Different operative techniques have been described. The aim of this study was to examine which anatomic structures were affected by 2 different osteotomy techniques. Methods: Two experienced foot and ankle surgeons each performed an Evans (E)- or Hintermann (H) osteotomy on 7 cadaver feet. The mean age of the donors was 80.4 ± 4.4 years. Eight left and 6 right feet were prepared. Previously identified structures at risk were prepared and evaluated. Results: After H-LLCOT, there was no damage of the peroneus longus tendon, whereas after E-LLCOT, damage was noted in 1 case (14.3%). The peroneus brevis tendon was once cut after H-LLCOT and eroded after E-LLCOT. In one cadaver, the sural nerve was partially damaged after H-LLCOT but in no case after E-LLOCT. The calcaneal anterior and medial articular facets were intact after H-LLCOT in 100% and 85.7% and after E-LLCOT in 42.9% and 71.4%, respectively. The posterior articular surface was not affected in any cadaver. Conclusion: Anatomic structures can be damaged after both osteotomies. With the Hintermann osteotomy, the calcaneal anterior and medial articular surface can be protected to a larger extent than with the Evans osteotomy. Clinical Relevance: The Hintermann osteotomy seems to be superior, regarding damage of the articular surfaces of the subtalar joint. These findings have to be correlated with biomechanical and clinical studies before a final recommendation can be given, which osteotomy is superior.