One thousand, one hundred forty-six Anatomic Graduated Component total knee arthroplasties performed between 1987 and 1989 were used to investigate the effects of patellar thickness alone or coupled with lateral retinacular release on initial patellar complications and maximal flexion. Lateral release was found not to be statistically significant regarding radiolucency, patellar prosthesis loosening, or an increase or decrease in flexion. However, total knee arthroplasties in which a lateral release was done, which either saved the superior lateral genicular artery or sacrificed the superior lateral genicular artery, were found to increase the incidence of initial patellar fractures and/or loosening (complications within 1 year) when compared with total knee arthroplasties in which a lateral release was not performed. There was no statistical difference in failure rates regarding fractures and/or loosening of the patella between lateral releases in which the superior lateral genicular artery was saved and the lateral releases in which the superior lateral genicular artery was sacrificed. A difference in postoperative patellar thickness compared with preoperative patellar thickness was found not to be significant to initial patellar fracture and/or loosening, patellar fracture alone, patellar loosening alone, radiolucency, the need for a lateral release, or to an increase or decrease in flexion. Lateral release and patellar thickness had no significant effect on patellar fracture and/or loosening.