The use of Standing Lateral Tibial-Calcaneal Angle as a Quantitative Measurement of Achilles Tendon Contracture in Adult Acquired Flatfoot

Abstract

Background: To quantitate the association of Achilles tendon contracture (ATC) with adult acquired flatfoot, the authors hypothesized that the standing lateral tibial-calcaneal angle increases because of ATC. Methods: The standing lateral tibial-calcaneal angle, talo-first metatarsal angle, lateral talocalcaneal angle, lateral standing medial cuneiform, arch height, and anteroposterior talonavicular coverage angle were measured in 21 patients (25 feet) with clinical diagnoses of ATC and adult acquired flatfoot (AAF) and compared to the same measurements in a control group of 15 patients (30 feet) with no foot deformities or previous foot surgeries. Results: The mean lateral tibial-calcaneal angle in the control group was 64.43 degrees and in the AAF group 71.24 degrees ( p < 0.001). The mean lateral talo-first metatarsal angle in the control group was 11.77 degrees, and in the AAF group with ATC it was 25.80 degrees ( p < 0.001). The mean arch height in the control group was 17.90 mm and in the AAF group, 8.48 mm ( p < 0.001). In the ATC and AAF group an increasing standing lateral tibial-calcaneal angle was correlated with a decreasing lateral talo-calcaneal angle ( p = 0.044), and a decreasing arch height was correlated to an increasing lateral talo-first metatarsal angle ( p < 0.001). Conclusion: Adults with flatfeet and Achilles tendon contracture may have a statistically significant increase in the standing lateral tibial-calcaneal angle. This angle may be a reproducible measure of ATC. An increase in the standing lateral tibial-calcaneal angle may confirm and quantitate the clinical diagnosis of Achilles tendon contracture. Further studies with more patients are needed.