The saphenous nerve is the longest cutaneous branch of the femoral nerve, accompanying the femoral vessels through the adductor canal before emerging to supply sensation to the medial lower limb from knee to foot. As a purely sensory nerve its injury produces no weakness but significant medial lower limb dysaesthesia. It is the nerve most commonly damaged during knee surgery, particularly arthroscopy and medial meniscal procedures.
| Origin | Femoral nerve (L3, L4) |
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Saphenous nerve injury during knee arthroscopy typically occurs at the infrapatellar branch during anteromedial portal placement or at the saphenous nerve proper during posteromedial approaches. The resulting medial knee and leg numbness is often distressing to patients who are not warned pre-operatively. Entrapment of the nerve within the adductor canal (Hunter canal syndrome) produces medial knee and leg pain in cyclists and runners that is reproduced by pressure over the adductor canal and relieved by local anaesthetic injection.
Iatrogenic damage during knee surgery producing medial leg and foot numbness without weakness, the most common nerve complication of knee arthroscopy particularly from anteromedial portal placement.
Saphenous nerve compression within Hunter canal producing medial knee and leg pain in cyclists and runners, managed with activity modification and nerve block injection.
