Radiographic Measurements of the Foot and Ankle After Ankle Arthrodesis

Background: Ankle arthrodesis is an established treatment for ankle arthritis. For patients with ankle arthritis, the position of the talus during ankle arthrodesis may affect the radiographic parameters of the foot. The purpose of this study is to assess the radiographic relationship between talar alignment and the longitudinal arch of the foot before and after ankle arthrodesis.

Methods: We retrospectively reviewed a single-surgeon series of 30 patients who had undergone ankle arthrodesis. Measured parameters included the lateral tibiotalar angle (LTTA), lateral talometatarsal angle (LTMA), lateral talocalcaneal angle (LTCA), cuneiform height (CH), and calcaneal pitch (CP). Additional data collected included demographics, fusion construct type, and visual analog scale (VAS) measurements.

Results: LTTA was increased from 68.2 ± 7.4 degrees preoperatively to 75.0 ± 6.4 degrees postoperatively (P = .001), LTMA increased from -2.0 ± 10.7 degrees to 4.0 ± 10.1 degrees (P < .001), CH increased from 20.1 ± 7.5 mm to 26.1 ± 8.4 mm (P < .001), LTCA and CP had no statistically significant change. VAS score decreased from 5.7 ± 2.7 to 1.3 ± 1.9 (P < .001).

Conclusion: Correcting the talar alignment in the sagittal plane during ankle arthrodesis improved the radiographic parameters of the foot, contributing to restoration of the longitudinal arch. The clinical significance of these findings is that in patients undergoing ankle arthrodesis, the surgeon should be aware that the alignment of the foot will be altered at the time of ankle arthrodesis and should be considered in preoperative planning. Further research is needed to determine the effect of ankle arthrodesis in patients determined to have pes planus preoperatively.

Level of evidence: Level III, retrospective cohort study.