Fig 6.

Intraoperative photograph of 2 guide pins placed on the anterior surface of the medial patella. The proximal guide pin is placed transversely, 5 mm from the superior pole, adjacent to the articular margin. The second guide pin is then placed parallel and approximately 1 to 2 cm distal to the proximal pin. Proper placement of the guide pins is confirmed on fluoroscopy. The guide pins are then over-reamed using a 4-mm cannulated reamer to a depth of 20 to 25 mm. Care should be taken so that the drill does not penetrate the anterior cortex of the patella.