Abstract
Purpose
One of the current research topics is the aim to produce tissue engineered osteochondral grafts for future treatment of osteochondral lesions (OCL) of the talus. For the exact anatomic reconstruction, the dimensions of the medial and lateral talar dome must be considered.
Sparse data is available regarding the normal anatomic talar dimensions on standard radiographs of ankle joints [1, 2]. The purpose of this study was to describe normal anatomy of different sections of the talar dome on 3D reconstructions of computertomographic (CT) images.
Method
CT data sets (Somatom 10, Siemens Erlangen, Germany) of 82 patients (86 ankles) (28 female, 54 male; average age 41.9y (range 15–76y)) without talar pathologies were included. Measurements were performed with a geometry analysis software (VGStudio MAX 2.0, Volume Graphics, Heidelberg, Germany). To assure measurement reproducibility, the reference planes were defined in a first step. To measure the frontal talar edge radius, circles were fitted into the medial and lateral talar edge on frontal planes. To allow measurement of different segments of the talus, the frontal plane was tilted through the center of the talus (defined as a circle fitted to the talus on sagittal view) at 15 and 30 anteriorly and posteriorly.
To measure the sagittal radius of the medial and talar edge, ircles were fitted into the medial and lateral talar edge on sagittal planes.
Results
The talar edge radius in the frontal plane at 0 wa s 4.9 mm medially (3.0 mm laterally), at 15 ant. 4.2 mm (3.1 mm), at 30 ant. 4.6 mm (3.1 mm), at 15 post. 4.5 mm (3.9 mm), and at 30 post 4.1 mm (6 mm). There was a significant difference (p<0.01) between the mean medial and lateral talar edge radius at all angles. The talar edge radius in the sagittal plane was 20.4 mm medially and 20.3 laterally. There was no significant difference between the mean medial and lateral sagittal talar edge radius.
Conclusion
This study shows a significant difference between physiological medial and lateral edge configuration at different frontal planes of the talar dome. No difference was found comparing the sagittal radius of the medial and talar dome. The assessed data provides important aid for engineering of pre-formed, pre-sized osteochondral grafts. Such pre-shaped grafts could help restoring the physiological joint surface by matching exactly into the lesion and consequently achieving the recovery of the physiological joint biomechanics and prevention of secondary degenerative disease.
