Effects of Trochlear Dysplasia on Outcomes For Patellar Instability After Isolated Medial Patellofemoral Ligament Reconstruction Compared to a Combined Procedure With Tibial Tubercle Osteotomy
L.F.M. Ambra, D.T. De Oliveira, E.S. Mameri, M.S. Kubota, M.V.M. Luzo, C.E.D.S. FrancioziObjectives:
To evaluate the influence of trochlear dysplasia (TD) on the clinical outcomes of patients with recurrent patellar instability (RPI) treated with isolated medial patellofemoral ligament reconstruction (MPFLR) compared to a combined procedure of MPFLR with tibial tubercle osteotomy (TTO).
Methods:
A retrospective review was conducted from patients with RPI treated by a single surgeon. Clinical outcomes were evaluated using patient-reported outcome measures (PROMs). Radiographic parameters and patellofemoral physical examination (J sign, patellar glide, and apprehension test) were also assessed. TD was graded according to the Dejour classification, and patients were stratified into low-grade (type A) and high-grade (types B–D) dysplasia.
Results:
A total of 31 patients meet the inclusion criteria and completing follow-up. Both groups demonstrated statistically significant improvements in PROMs postoperatively. However, patients in the TTO + MPFLR group showed significantly greater improvements in Kujala (p = 0.0018) and IKDC (p = 0.011) scores. Patients with high-grade TD benefited more from the combined procedure, with superior outcomes in Kujala (p = 0.0001), Lysholm (p = 0.01), and IKDC (p = 0.002) scores. Additionally, all patients in the TTO + MPFLR group demonstrated normalization of the J sign, while 40% of MPFLRa patients had residual grade II J sign, especially in those with patella alta.
Conclusion:
Trochlear dysplasia significantly influences outcomes in the surgical treatment of recurrent patellar instability. While both groups result in clinical improvement, the combined procedure offers superior outcomes in patients with high-grade TD by improving patellar tracking and correcting biomechanical abnormalities.