Optimization of surgical exposure for harvesting gracilis-semitendinosus tendons

Purpose This study was conducted to provide anatomical data and surface markers for the safe and efficient exposure of surgical incisions for harvesting gracilis tendons (GT) and semitendinosus tendons (STT) while avoiding technical pitfalls and nerve injury during harvest for ligament reconstruction. Methods Seventy-four Chinese cadaveric lower limbs were dissected to expose the infrapatellar branch of the saphenous nerve (IPBSN) and pes anserinus (PA). Measurements of the borders and accessory bands of the PA tendons were taken. The arrangement of PA tendons and distribution of the IPBSN were assessed. Results The PA was roughly shaped like a quadrangle, with its superior border at the horizontal plane of the tibial tuberosity (TT). The GT and STT bifurcation point was located on the medial border of the PA. From medial side to lateral side, the sartorius tendons (ST), GT, and STT fused gradually and formed the lateral border of the PA at the distal end. The tendon arrangement of the PA was primarily affected by ST, which commonly covered GT and STT completely. Variant tendons were found in 41.9% of specimens. The insertion of the accessory bands was distal but close to the inferior border of the PA. Accessory bands were observed only in STT and ST, and STT accounted for the most. The width of the first accessory band of STT was similar to the width of the STT. Additionally, most of the IPBSNs were proximal to the horizontal plane of the TT. Conclusion For clearly exposing the GT and STT, it is crucial to expose the GT and STT bifurcation point on the medial border of the PA, whether directly or indirectly through the incision.The influence of ST insertion and the variability of tendons within the PA must be paid attention to during the operation. To protect IPBSNs highly, the incision should not be higher than the TT level.