Morphometric measurement of the talus in a South-East Asian population

Background The talus, as the structure bearing the entire compressive load between the leg and the foot, serves an extremely important biomechanical function. Fractures of the talus tend to heal poorly due to its retrograde blood supply, resulting in complications such as avascular necrosis (AVN) and osteoarthritis which lead to the need for eventual fusion surgery or arthroplasty. Computed Tomography (CT) imaging is a valuable tool which for the imaging of bony pathology and can be utilized to evaluate morphometric parameters of the talus. Knowledge of baseline parameters and differences in gender provides insight which will aid not only fracture fixation, but also in the design of implants and prostheses. Objectives This study aims to evaluate talar morphology in the South-East Asian population based on CT imaging, to quantify talar morphometrics. Study Design and Methods A convenience sample study was carried out at our institution by screening patients who had a CT foot or ankle scan performed. Inclusion criteria were patients who were skeletally mature (taken as aged 18 and above) and had imaging of the entire hindfoot of adequate quality. Exclusion criteria included skeletally immature patients (aged 18 and below), and patients who had previous surgery or pathology affecting the imaged foot. Morphometric parameters were measured using a computer software based on anatomical landmarks and current measurements reported in the literature. Measurements were performed independently by three authors, and the mean values for each parameter taken. The talar length was measured at the midline on the sagittal cut. The talar height was measured at 3 points, at the head and neck parallel to the talonavicular joint, and at the maximum height of the dome to the sinus tarsi. The talar width was measured at 4 points, at the width of the dome, the widths of the head, neck, and body taken parallel to the talonavicular joint. Mean values were calculated for each measurement. T-tests were performed to determine if there was any significant difference between measurements taken from male or female patients. Results were deemed to be significant if the p-value was less than 0.05. Results There was a total of 122 patients included in our study, 41 female and 81 male patients. The mean age of the patients was 44.1 years (Range 20 – 91), and the mean BMI was 24.4 (± 5.1). In terms of laterality, there was imaging performed on 57 left, and 65 right feet. Males had larger talar dimensions that females in all parameters measured. Talus length measured 44.72mm in females, compared to 50.72mm in males (p <0.001). Talus height in females was found to be 20.88mm, 17.14mm, and 18.35mm at the head, neck and maximum dome height respectively. In comparison, these measurements in male patients were 24.31mm, 19.80mm, and 21.49mm respectively (p < 0.001 in all measurements). The width of the talar dome was 27.95mm in females, but 31.93mm in males (p <0.001). Talar widths in females were also significantly smaller (p < 0.001) in females compared to males at the talar head, neck, and body, with respective measurements in females of 23.74mm, 21.34mm, and 30.48mm, compared to measurements of 27.93mm, 24.81mm, and 35.07mm in male patients. Conclusions Male patients have significantly larger talar dimensions than female patients in the South-East Asian population. This highlights an importance consideration in the sizing and design of implants and prostheses for use in the 2 patient groups.