Cortical evoked potentials in the ruptured anterior cruciate ligament.

The sensory role of the intact and ruptured anterior cruciate ligament was studied by the use of cortical evoked potentials during arthroscopy. This showed a response from the intact ligament in four patients that was reproducible. This response was consistent with those obtained from stimulation of the ipsilateral posterior tibial nerve. No response was elicited from either the femoral or tibial stump of ruptured ligaments using the same technique in six patients who had ruptured their anterior cruciate ligament (two femoral and four mid-substance ruptures). We believe that this demonstrates that there is no functional nervous tissue within the anterior cruciate ligament after rupture.