This study examines and compares three treatment options for patellofemoral arthritis resulting from patellofemoral malalignment: longitudinal semipatellectomy, total patellectomy, and a modified Trillat procedure. Patients returned for examination in a 3- to 12-year follow-up period. Results from longitudinal semipatellectomy were unsatisfactory, with a reoperation and failure rate of 70%. Good long-term effects were found with total patellectomy (87% good or excellent). The modified Trillat procedure was effective in preventing recurrent dislocation (94%); however, the procedure was less effective in relieving anterior knee pain (65% good or excellent). A satisfactory solution remains to be found.