Surgical versus conservative management of patellar re-dislocation: clinical and radiological results at a mid-term follow-up of 5 years

Background: Patellar dislocation accounts for 2–3% of all knee lesions and is the second most common cause of traumatic hemarthrosis of the knee. Proper treatment is essential to minimize long term sequelae, such as recurrent dislocation, painful subluxation, and osteoarthritis. Aim: The purposes of this perspective randomized study were: 1) to evaluate the midterm clinical and radiological results of the Elmslie–Trillat procedure for the treatment of traumatic patellar re-dislocation; and 2) to compare the results, especially radiological osteoarthritis development, with those of non-operative management for traumatic patellar re-dislocation. Methods: From June 2013 to February 2015, 65 patients were admitted to our Emergency Department for a first patellar dislocation episode. All patients were treated non-operatively. When a second episode occurred within two years, patients were randomly assigned in two groups: Group A, patients treated surgically with Elmslie-Trillat procedure, and Group B, patients were further treated non-operatively. The Knee Society Score (KSS), Lysholm scale and Kujala questionnaire were administered immediately after the re-dislocation and at the final follow-up. Tangential patella radiographs were evaluated for patellofemoral osteoarthritis and graded according to Sperner’s classification. Results: The mean follow-up was 6.4±1.7 years (range 5-8) in Group A and 6.3±2.1 years (range 5-9) in Group B. In Group A, the KSS and Lysholm scale showed significant differences between pre- and post-operatively values (p<0.05). The mean Kujala score was significantly lower in Group B when compared with the mean value of Group A (p<0.05). At the final follow-up of more than 5 five years, the mean grade of patellofemoral osteoarthritis according to Sperner’s classification changed in Group A and Group B, with respectively 25% and 29% of patients having a grade greater than or equal to 3. Conclusion: This study confirms that Elmslie-Trillat is a safe and effective procedure in the treatment of patellar instability, relieving pain and inability, and reducing recurrence risk. However, it cannot avoid the degenerative changes occurring in the natural evolution of patellar dislocation.