Purpose: The aim of the present study is to present the outcome of a cohort of adolescent patients with trochlear dysplasia and elevated tibial tuberosity trochlear groove (TTTG) distance suffering from recurrent patellar dislocation. Treatment consisted of medial patellofemoral ligament (MPFL) reconstruction and a modified Grammont procedure.
Methods: MRI examinations were obtained pre- and postoperatively. Trochlear dysplasia was classified according to Déjour, and TTTG was measured on MRI. The Tegner Activity Scale and the Kujala Knee Score were assessed preoperatively and at follow-up. The Kujala Knee score and the IKDC 2000 knee score were documented at follow-up (median 50, range 20-61 months; SD 16.6).
Results: Seven knees of six patients (median age 16.5 years, range 14-17 years) with trochlear dysplasia and elevated TTTG distance (median 17 mm, range 16.1-21.9 mm; SD 2.8) were treated. Trochlear dysplasia was classified as Déjour type A in 1, type B in 5, and type C in 1 knee. The Kujala Knee Score significantly increased from values of 55 (range 17-88; SD 25.9) to 94 (range 73-100; SD 9.1) at follow-up (p = 0.028). TAS improved from preoperative 2 (range 0-7; SD 2.5) to 5 (range 4-9; SD 1.8) at follow-up (p = 0.034). Median IKDC 2000 Knee Score at follow-up was 89 (range 61-100, SD 13.4). No re-dislocations were encountered.
Conclusion: In selected adolescents with recurrent patellofemoral instability, MPFL reconstruction in combination with a modified Grammont technique yields excellent functional outcome and could, therefore, help to avoid major procedures, such as osteotomies.
Level of evidence: Therapeutic, Level IV.
Keywords: Grammont technique; Medial patellofemoral ligament; Patellofemoral instability; Tibial tuberosity trochlear groove; Trochlear dysplasia.