Potential pitfall of the EndoButton.

A clinical and cadaveric example show the EndoButton (Acufex Microsurgical Inc, Mansfield, MA), used for anterior cruciate ligament endoscopic fixation, flipping outside the extensor mechanism or vastus lateralis rather than flipping directly outside the lateral femoral cortex. This pitfall was caused by overdrilling the femoral socket beyond the recommended 6 mm and overadvancing the EndoButton beyond the required depth to flip the EndoButton. Overdrilling the femoral socket to a depth of 10 mm still allows the EndoButton to rest properly on the cortex without soft tissue interposition. Increasing angles of knee flexion at the time of Endobutton placement decrease the safe distance beyond the lateral femoral cortex for flipping without soft tissue interposition. There is also potential to flip the EndoButton within the substance of the vastus lateralis, but the flipping action is blunted and not discrete.