Quantitative assessment of intravascular volume of the human Achilles tendon

The pathogenesis of Achilles tendon rupture remains unclear, but vascular p atterns mag play an important role. We determined the intravascular volume of the Achilles tendon using a new method with injection of radioisotopes. A solution of Tc-99m and gelatin-ink was injected into the lower limbs of b ody donors. The intravascular volume of each 1 cm section of the Achilles t endon was measured using a gamma well counter We found that the distal part of the Achilles tendon (0-2 cm above the calcaneus) had an intravascular v olume of 59-98 mu L/g tendon tissue. In the middle part of the tendon (3-6 cm above the calcaneal insertion), the intravascular volume was much less: 27-43 mu L/g tissue. The proximal part of the tendon (7-9 cm) had an intrav ascular volume between 51-100 mu L/g tendon tissue. The reduced vasculariza tion in the middle part of the human Achilles tendon may play a role in deg eneration and spontaneous rupture of the tendon.