This study aims to report the incidence of patellar fracture after patellofemoral arthroplasty (PFA) and to determine associated factors as well as outcomes of patients with and without this complication. 77 knees in 59 patients with minimum two-year follow-up were included. Seven (9.1%) patients experienced a patellar fracture at a mean of 34 (range 16-64) months postoperatively. All were treated nonoperatively. Lower BMI (P = 0.03), change in patellar thickness (P < 0.001), amount of bone resected (P = 0.001), and larger trochlear component size (P = 0.01) were associated with a greater incidence of fracture. Fewer fractures occurred when the postoperative patellar height exceeded the preoperatively measured height. No statistically significant differences were found in outcome scores between groups at mean four-year follow-up.