A morphological and morphometric study of talus in relation to ankle implant

Background: The talus is the second-largest tarsal bone. Morphometric analysis of both sides of the talus is necessary to know the right–left symmetry for implant design and for mechanical testing for surgeons and orthopedicians. Hence, this study was done to observe the facets of the inferior surface of the talus and to measure the morphometric parameters of the talus. Methodology: This cross-sectional study was carried out on a total of 66 dry adult human tali (33 of the right side and 33 of the left side). Morphologically, the types of articular facets on the head of the talus were assessed and classified as done by Boyan et al. as -Type A1, Type A2, Type A3, Type A4, Type B, and Type C. Morphometric evaluation of talus was done with the help of digital vernier caliper, and anteroposterior distance (length), maximum transverse width, vertical height of talus, length of sulcus tali, width of sulcus tali, depth of sulcus tali, and head–neck length (HNL) of talus were measures. Neck-body angle of the talus was also measured. Statistical analysis was performed, and data were expressed as mean, minimum, maximum values, and standard deviation. Results: In the present study, Type A1 facet was found in 51.5% of the talus, in 28.8% of Type A2, in 12.1% of Type A3, in 1.5% of Type A4, in 6.5% of Type B, and none of Type C facet found. The mean length, width, and height of the talus were 52.74 ± 4.39 mm, 31.45 ± 2.74 mm, and 25.93 ± 2.64 mm, respectively. The width, length, and depth of sulcus tali were 5.9 ± 1.02 mm, 21.88 ± 3.07 mm, and 5.52 ± 1.25 mm, respectively. HNL of talus was 15.72 ± 2.73 mm, and neck-body angle of the talus was 153.88° ±4.64°, respectively. No statistically significant difference was found on both sides except neck-body angle, where P = 0.031 (P < 0.05). Conclusion: The values of neck-body angle of the right side talus were higher than the left side, and the difference was statistically significant. Hence, the measurement of this study may help the surgeons to choose the appropriate size of the prosthesis for talus implantation surgeries.