Saphenous nerve entrapment at the adductor canal.

A retrospective study of 30 patients who met the clinical criteria for saphenous nerve entrapment at the adductor canal is described. Patients experienced symptoms, usually anterior knee pain, for an average of 36 +/- 7 months. Each patient received an average of 1.9 +/- 0.4 saphenous nerve blocks at the adductor canal during treatment. Baseline pain level (measured by the visual analog scale) was 6.4 +/- 0.3. Final pain level at followup was significantly decreased (2.8 +/- 0.5, P less than 0.001). Eighty percent of patients had improved after a series of blocks. Age, medications taken, number of blocks performed, and length of followup were unrelated to outcome. Length of symptoms did significantly correlate with final pain level (r = 0.39, P less than 0.05). The diagnosis of this syndrome, description of the saphenous nerve block at the adductor canal, and the possible etiology are presented.