The prognosis of iatrogenic saphenous nerve injuries during hamstring tendon harvesting in ACL reconstruction

Abstract Purpose The purpose of this study was to evaluate the long-term prognosis of iatrogenic saphenous nerve (SN) injuries incurred during hamstring tendon harvesting for anterior cruciate ligament (ACL) reconstruction and their impact on clinical outcomes and patient satisfaction at least two years postoperatively. Materials and Methods A retrospective review was conducted on patients who underwent ACL reconstruction with hamstring tendon grafts at a single institution between January 2015 and January 2020. The study assessed the incidence of SN injuries immediately after surgery and at final follow-up, the recovery rate and time, and the impact of these injuries on functional outcomes using the Lysholm Knee Score (LKS) and patient-reported effects on daily activities. Results Out of 159 patients analyzed, iatrogenic SN injury was initially observed in 87 (54.7%) patients post-ACLR. At the final follow-up, paresthesia had resolved in 36 (22.6%) patients within an average of 11.1 months. Persistent SN injury was noted in 51 (32.1%) patients, with varying involvement of the infrapatellar branch of the saphenous nerve (IPBSN) and the sartorial branch (SBSN). Patients with consistent SN injury reported a significant impact on daily activities and had lower LKS scores compared to those without injury or with recovered injury. A higher re-rupture rate was associated with persistent SN injury. Conclusions SN injuries during hamstring graft harvesting for ACL reconstruction are common, with a significant portion of patients experiencing persistent sensory deficits at least two years postoperatively. These injuries can adversely affect patient satisfaction and functional outcomes and increase the re-rupture rate.