Prospective long-term results of operative treatment in primary dislocation of the patella.

Among 53 prospectively studied patients who had undergone operative treatment of primary patellar dislocation, 9 (17%) suffered recurrence within an average follow-up of 6.5 years. All the redislocations occurred in female patients. The patients with recurrence also suffered first-time patellar dislocation in their unoperated knee during the follow-up significantly more often (P < 0.01) than the patients with stable knees. Patients with redislocations were more often dissatisfied with their outcome than the stable group, mainly because of annoying anterior knee pain (P < 0.05). Preoperatively the patients with redislocation had had more pronounced pathological patellofemoral congruity (Laurin's projections) in both the operated knee (P < 0.05) and the, at the time uninjured, control knee (P < 0.05). To improve the results of operative treatment for acute patellar dislocation, surgery should be aimed at correcting the underlying pathology. In grossly and symmetrically pathological cases of patellofemoral articulation, a distal realignment procedure should be considered. Otherwise conservative treatment may be justified.