Isolated Medial Patellofemoral Ligament Reconstruction for Recurrent Patellar Dislocations With Increased Femoral Anteversion and an Absent/Mild J-sign.

BACKGROUND

The influence of greater femoral anteversion on outcomes after medial patellofemoral ligament (MPFL) reconstruction is increasingly recognized, leading to the more frequent use of combined derotational femoral osteotomy. However, the indications for this additional invasive procedure remain poorly defined, particularly in patients without severe patellar maltracking.

PURPOSE: To evaluate the clinical outcomes of isolated MPFL reconstruction in patients with recurrent patellar dislocations (RPDs), increased femoral anteversion (>30°), and an absent or mild J-sign.

STUDY

DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective cohort study was conducted on 52 consecutive patients (mean age, 19.1 ± 5.9 years) with RPDs, femoral anteversion >30°, and an absent/mild J-sign who underwent isolated MPFL reconstruction between 2018 and 2022. Rotational deformities of the lower extremities, including femoral anteversion, tibiofemoral rotation, and tibial external torsion, were assessed using computed tomography. Clinical and radiological outcomes were assessed preoperatively and at a minimum 2-year follow-up. Additionally, outcomes were compared between patients with and without severe trochlear dysplasia (Dejour type B or D) to evaluate its potential confounding effect.

RESULTS

This study evaluated the outcomes of isolated MPFL reconstruction in 52 patients with RPDs, high femoral anteversion (mean, 35.2°± 6.5°), and an absent/mild J-sign. At a mean follow-up of 2.4 ± 1.1 years, no redislocations occurred. Functional scores improved significantly from preoperatively to postoperatively: Tegner (from 3 to 5; P = .021), Kujala (from 58 ± 9 to 88 ± 9; P < .001), and Lysholm (from 62 ± 7 to 90 ± 11; P < .001). Subgroup analysis demonstrated comparable functional outcomes (all P > .05) but significantly greater patellar tilt (18°± 5° vs 13°± 4°, respectively; P < .001) in patients with severe trochlear dysplasia (n = 17) compared to those without severe trochlear dysplasia (n = 35).

CONCLUSION

Isolated MPFL reconstruction provided excellent short-term stability and functional outcomes for patients with RPDs, increased femoral anteversion (>30°), and an absent/mild J-sign. Crucially, the presence of severe trochlear dysplasia did not compromise functional results.