Two-tendon accessory fusion of the pes anserinus: coalescence of accessory semitendinosus and gracilis tendons in a left knee.

BACKGROUND

The pes anserinus (PA) is one of the crucial structures in reconstructive orthopedic surgery. It comprises semitendinosus, gracilis, and sartorius tendons, which are often harvested to reconstruct other tendons, ligaments, and other soft tissue structures of joints. The morphology of PA is highly variable; therefore, the presence of an accessory or the lack of some tendons that create it may affect the whole reconstruction surgery. The purpose of this article is to present an unusual arrangement of PA and highlight the great variability of this structure.

CASE REPORT: During the routine dissection of the knee area of a 70-year-old female, an unusual variant of PA was encountered. Morphometric parameters were assessed. A PA variant with an additional tendon of the gracilis muscle and an additional tendon of the semitendinosus muscle occurred in the left lower limb. Both tendons merged into a single band that descended and attached as a unified tendon on the medial surface of the tibia, slightly below the usual PA insertion site.

CONCLUSIONS

Knowledge of possible anatomical variants of PA may be beneficial for surgeons as changes in its morphology can cause misinterpretation of tendons during surgeries and result in impaired treatment.