Anatomical Variations of Accessory Bands in Semitendinosus and Gracilis Tendons Among the Asian Population

The length and number of accessory bands of gracilis and semitendinosus tendons have high variability among Asian population. Complications during graft harvesting might occur if the surgeon cannot correctly identify these complex structures.

We performed cadaveric knee specimen dissections (level of evidence: level III; descriptive laboratory study (anatomical study)). Each of the accessory bands arising from semitendinosus and gracilis tendons was identified. Size and distance from the origin of accessory bands to the tibial insertion were measured.

Eighty knees were included in the study. For the semitendinosus tendon, we found the following accessory bands in our specimens: no accessory bands in 6%, one band in 56%, and two bands in 38%. The longest distance of an accessory band from tibial insertion was 9.8 cm, with an average distance for the first band of 4.5 cm. The number of accessory bands for the gracilis tendon was, as follows: 0, 1, 2, 3 and 4 in 20, 39, 31, 9, and 1%, respectively. The longest distance of accessory band was 9.33 cm from tibial insertion, with an average distance for the first band of 4.7 cm. We found the width of accessory bands in females to be wider than males (P = 0.0001) and the width of accessory bands in right knees to be wider than those in left knees (P = 0.04).

In Asian populations, we found high variability of number of accessory bands from semitendinosus and gracilis tendons. The average distance from the tibial insertion to the first accessory band was 4.5 cm. None of the bands arised more than 10 cm from the tibial insertion.