International Orthopaedics / The impact of different types of talus deformation after treatment of clubfeet

Purpose Deformation of the talus in idiopathic congenital clubfeet is a known problem after treatment. However evidence on types of talus deformation and clinical relevance is rare. The aims of this study were first to define different types of talus deformation, and second, to evaluate the impact of these types on long-term results. Methods At a minimum follow-up of ten years 40 idiopathic clubfeet treated by a modified dorsomedial release were analyzed. Based on morphological appearance and the widened range of radius to length ratios (R/L-ratio) in treated clubfeet deformed tali were divided into two groups: tali with decreased R/L-ratios were classified as small-dome talus deformation (SD), tali with increased R/L-ratios were classified as flat-top talus deformation (FT). The impact on degree of arthrosis in the ankle joint, clinical outcome, and ankle range of motion was analyzed. Results Small-dome talus deformation (SD) was found in nine feet. This group showed decreased R/L-ratios and increased talus opening angles, which were linked to an increased range of motion of the ankle joint (p=0.033). The impact on onset of arthrosis was not significant for this group (p=0.056). The group of flat top talus deformation (nine feet) showed increased R/L-ratios and decreased talus opening angles, decreased range of motion (p=0.019), and a significant impact on onset of arthrosis (p=0.010). Conclusion Our study defines a new subgroup of talus deformation: the small dome talus deformation tends to show a better ankle joint range of motion and a lower risk of arthrosis compared to the classical flat dome talus deformation.(VLID)349715