Analysis of congruence for talar dome geometry among tali of different sizes.

• 20 mm talar osteochondral grafts have similar profiles without size matching. • 30 mm talar grafts are similar within the male sex (female sex not investigated). • All tali have similar curvatures and profiles on the talar dome. • Size matching is not required for >20 mm talar ostechondral allografts. • Only sex matching is required if the graft is between 20–30 mm in length. Traumatic injury and idiopathic avascular necrosis of the talus bone can result in osteochondral lesions of the talus leading to pain, motion loss, and disability. Treatment with osteochondral allografting currently requires the donor talus to be size matched to the recipient talus to ensure precise fits. Eliminating or reducing the need for size matching would lessen costs and the delay between diagnosis and treatment. 3D models of 12 tali of varying sizes were used to analyze curvatures and profiles of select areas on the talar dome. The allograft procedure was mimicked to compare the results between using 20 mm and 30 mm osteochondral allografts with, and without, donor size matching. The observed curvatures and profiles on the talar dome were found to be consistent between tali of different sizes. Size matching was not required to have acceptable levels of deviation between donor and recipient tali when using 20 mm length segments. Deviations without size matching were found to be very similar to the deviations with size matching with only 14.8% of the fits without size matching having larger deviations (although less than 1.5 mm) than those with size matching. Using the 30 mm segments, there was a significant difference between the small female tali and the largest male tali. Thus, donor size matching is not necessary when treating large osteochondral lesions of the talus with an osteochondral allograft taken from the central 20 mm of the donor talar dome, and only sex matching may be necessary for 30 mm grafts. [ABSTRACT FROM AUTHOR]