Six-year outcome after non-surgical versus surgical treatment of acute primary patellar dislocation in adolescents: a prospective randomized trial

Purpose: There is only one prospective randomized trial on acute primary patellar dislocation in adolescents comparing the long-term outcome after conservative versus operative procedures. Therefore, the long-term outcome, patellar redislocation rate, and functional outcome after conservative versus operative procedures were investigated in a prospective randomized study.

Methods: Initially, 36 patients with acute primary patellar dislocation were prospectively randomized to conservative (n = 20) versus operative procedures (n = 16) and 30 of them (83%), 15/20 with conservative and 15/16 with operative procedures, were reached for a follow-up interview 6 years after primary procedure.

Results: Baseline and clinical parameters were similar in the two groups. The prevalence of patellar redislocation rate at 3 and 6 years after primary procedure was higher in the conservative group (7/20, 35%, 3 years and 11/15, 73%, 6 years) versus in the operative group (0/16, 0%, 3 years and 5/15, 33%, 6 years) (p = 0.02). The knee function was slightly better 6 years after primary treatment in the operative group than in the conservative group. Most patients in both groups had excellent or good knee function at 6-year follow-up, but four patients (4/15, 27%) in conservative group and two patients (2/15, 13%) in operative group had poor knee function at 6-year follow-up. Four patients in conservative group (4/15, 27%) and two patients in the operative group (2/15, 13%) were unsatisfied with the procedure at 6-year follow-up.

Conclusions: In conclusion, the results suggest that both conservative and operative procedures are feasible options for treatment of acute primary patellar dislocation in adolescents. A new finding with clinical relevance in the present work is a significantly higher redislocation rate in conservative group compared to operative group after 6-year follow-up in acute primary patellar dislocation in adolescents.

Level of evidence: II.