The lateral patellar retinaculum is thicker in paediatric and adolescent patients with patellofemoral instability: An MRI analysis

TL;DR

This study found that children and teens with patellofemoral instability have a thicker lateral patellar retinaculum compared to those without the condition, based on MRI scans.

Contribution

The study identifies increased lateral patellar retinaculum thickness as a potential imaging marker for patellofemoral instability in young patients.

Findings

The lateral patellar retinaculum was significantly thicker in the MPFL reconstruction cohort.

Patellar tilt was significantly greater in the MPFL reconstruction group.

No difference was found in lateral release/lengthening procedure rates between groups.

Abstract

The purpose of this study was to examine the thickness of the lateral patellar retinaculum (LPR) and patellar tilt in paediatric and adolescent patients who undergo a medial patellofemoral ligament (MPFL) reconstruction. The authors hypothesise that patients undergoing MPFL reconstruction will have a thicker LPR and increased patellar tilt when compared to a comparison cohort.

Preoperative magnetic resonance imaging (MRI) of patients ≤ 18 years old who underwent an MPFL reconstruction was retrospectively reviewed. Patients were included if they had a proton density preoperative axial MRI performed internally at our institution. Included patients were matched to a comparison cohort. LPR thickness and patellar tilt were measured on MRI. LPR thickness and patellar tilt were compared between the MPFL cohort and the comparison cohort.

A total of 363 patients were identified. 145 participants were successfully matched to the comparison cohort. The mean age in the MPFL cohort was 14.4 ± 2.0 years and 68% were female. The LPR thickness in the MPFL cohort was significantly greater than the LPR thickness in the comparison cohort (p < 0.001). The patellar tilt was significantly greater in the MPFL cohort compared to the control cohort (p < 0.001). There was no statistical difference in patients undergoing MPFL reconstruction and the occurrence of a lateral release/lengthening procedure.

The LPR was significantly thicker on preoperative MRI in patients undergoing MPFL reconstruction compared to a comparison cohort, indicating that increased LPR thickness is a potential marker of patellofemoral instability on imaging.

Level III.

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