Talar Prosthesis Template: A Cadaveric Study of the Size Discrepancy between Right and Left Tali

CATEGORY: Ankle INTRODUCTION/PURPOSE: Nowadays, the talar prosthesis has been designed for its size and shape based on the data of its contralateral talus. However, little is known about the discrepancy of the sizes between right and left tali. The present study was to demonstrate the difference between right and left talar sizes in the matched pairs of cadaveric specimens. METHODS: A total of twenty four tali as twelve matched pairs of tali were collected in this study. All tali were measured with a Vernier caliper which provided the data for further analyzed regarding the talar size. The data was calculated to demonstrate the difference between right and left talar sizes in a matched pair method included the general size of talus. There was a talus which was not used in the data calculation due to its crystal deposition from an underlying disease of a cadaver. RESULTS: In overall, an average talar length (TaL) was 53.5 millimeters (mm). An average talar dome height (TaH) was 31.2 mm. An average talar body width (TaW) was 41.3 mm. The average anterior trochlear width (TrAW), middle trochlear width (TrMW), posterior trochlear width (TrPW), and trochlear length (TrL) were 31.8, 31.2, 28.3, and 30.7 mm. Based on eleven matched pairs of tali, the paired T-test showed the significant difference of TaH (P-value: 0.019), TrMW (P-value: 0.027), and TrPW (P-value: 0.016) between right and left tali. CONCLUSION: The present study demonstrated the discrepancy of right and left talar sizes about three important parameters in the matched pairs of tali. Talar prosthesis template may be necessary to use other method to determine its size for the prosthesis manufacturing in addition to the utilization of measured profiles from the contralateral talus.