An Unusual Pes Anserinus Variant Encountered During Hamstring Autograft Harvest for Anterior Cruciate Ligament Reconstruction: A Case Report

Abstract

The pes anserinus (PA) is the common anteromedial tibial insertion of the sartorius, gracilis, and semitendinosus tendons. Variations in this region are well documented and may complicate hamstring autograft harvest during anterior cruciate ligament reconstruction. We present a case of a 29-year-old male who underwent elective right knee arthroscopic anterior cruciate ligament reconstruction with partial medial and lateral meniscectomies. During routine hamstring tendon harvest, the gracilis tendon and semitendinosus tendon were identified and harvested. A third tendon-like structure was also encountered just above the pes anserinus. This structure coursed anteriorly up the thigh on limited proximal inspection, but its precise muscular origin could not be definitively established intraoperatively. It was preserved and remained separate from the harvested tendons. The patient had no immediate neurovascular or functional deficit postoperatively and reported improved knee stability and no pain at six-week follow-up. This case highlights an unusual tendon-like structure encountered during hamstring autograft harvest and emphasises the importance of careful identification of anatomical variants before dividing any unrecognised structure.