We have compared the results of simple patellectomy (group A, n = 16) and patellectomy with advancement of the vastus medialis obliquus (group B, n = 12) in a prospective, randomised trial, with a minimum follow-up of three years. The results in group B were significantly better (p <
0.001) than those in group A. Although the patella should be preserved if possible, we advocate advancement of the vastus medialis obliquus when patellectomy is necessary.