The effect of drill hole size on the fixation strength of a cemented prosthetic patellar button

This study used a cadaver model to analyze the fixation strength of 3 different patellar resurfacing preparations using an all-polyethylene patellar component. One of 3 drill hole sizes was randomly selected and used to prepare the patella. The entire construct was cemented, mounted to a servohydraulic testing machine, cycled between 0 and 50 N, and then tested to failure. Mean forces obtained prior to failure were 258.5, 293, and 353.1 N for the chamfer, 4.5-mm, and 9.5-mm drill holes, respectively. There was a statistically significant difference in strength to failure between the 9.5-mm and chamfer drill hole sizes. These findings may help to reduce patellar implant failures.