Injury to the infrapatellar branch of the saphenous nerve during tendon graft harvesting for knee ligament reconstruction: An ultrasound simulation study.

The clinical anatomy of the infrapatellar branch of the saphenous nerve (IPBSN) is of particular importance during operations in the area of the knee, especially when material for anterior cruciate ligament reconstruction is harvested. The nerve can easily be injured during the harvesting procedure, leading to postoperative complications that reduce quality of life. Three different skin incisions are commonly used during hamstring tendon harvesting: horizontal, vertical, and oblique. The aim of this ultrasound simulation study was to assess the risk of IPBSN injury associated with the type of skin incision and the point-of-emergence of the IPBSN relative to the sartorius muscle. Thirty healthy volunteers (60 lower limbs) were recruited for identification of the IPBSN. When it was found, using a high-frequency ultrasound probe, three different 3 cm skin incisions over the pes anserinus were simulated. Vertical, horizontal, or oblique lines simulating incisions were marked over the pes anserinus and ultrasound was used to visualize the structures that could be injured during the marked incisions. The IPBSN was visualized in 58 lower limbs (96.7%). The results of the simulation study indicated that the vertical incision should be avoided during hamstring tendon harvesting, as it is associated with a significantly higher risk of injury (25.9%) to the IPBSN than the horizontal (3.5%) or oblique (8.6%) incisions. We recommend that a preoperative ultrasound assessment of IPBSN anatomy be performed to minimize the risk of iatrogenic injury to the nerve and associated complications. Clin. Anat. 30:868-872, 2017.