Femoral Trochlear Geometry in Patients with Trochlear Dysplasia Using MRI Oblique Trochlear View

Abstract

The objective of this study was to evaluate trochlear morphology in patients with trochlear dysplasia using a new oblique trochlear magnetic resonance imaging (MRI) view (OTV) in comparison with standard axial MRI sequences. MRI exam of 73 patients with patellofemoral instability (PFI) and the same number of controls were retrospectively reviewed. The oblique trochlear sequence was acquired by inclining the axial plane parallel to the intercondylar roof of the sagittal image, showing the anterior cruciate ligament (ACL) in its entire length. Trochlear morphology was assessed on axial and oblique trochlear sequences at three levels: level 1 at 25%, level 2 at 50%, and level 3 at 75% of the length of the trochlear groove. Trochlear sulcus angle and sulcus depth were measured at these three levels and compared between the new trochlear and standard axial sequences. Trochlear sulcus angle and sulcus depth were statistically different between axial and oblique trochlear views at all three levels (p < 0,05). Additionally, OTV displayed more uniform sulcus angle and depth along the trochlea. The oblique trochlear view on the MRI can more accurately evaluate trochlear morphology and also better characterize trochlear dysplasia in patients with PFI. This is Level III, retrospective comparative study.

Unpacking the Tibial Tubercle–Trochlear Groove Distance: Evaluation of Rotational Factors, Trochlear Groove and Tibial Tubercle Position, and Role of Trochlear Dysplasia

“…The principal findings of this study are as follows: (1) rTER had a significant association with TD and patellar tilt. (2) The proximal TG, as measured by the pTGL ratio, was medialized (less lateral) in patients with PI. (3) There was no difference in the medial to lateral position of the TT on the proximal tibia, as measured by the TTL ratio, between patients with and without PI.…”

“…Thus, it is possible that an oblique view of this area would provide different results. 2,36 We minimized this potential for measurement errors by excluding MRI scans that we determined to be unreadable for any of the measures, but it is a valid critique nonetheless. Further, the interrater ICCs for the pTGL and dTGL ratios were of moderate reliability, despite the direct measures used to calculate these measurements being either good or excellent.…”

Reliability of the Oswestry-Bristol Classification for trochlear dysplasia

“…The OTV displays a more uniform sulcus angle and depth along the trochlea. 20 But this requires a modified MRI or software, which is not available on regular daily basis as patients normally present with a standard MRI of their symptomatic knee. Additionally, there are gender-related differences in the sulcus angle: females have a significantly greater sulcus angle than males.…”

Current Concepts Regarding Patellofemoral Trochlear Dysplasia

“…They recommended assessment of a full axial series of the distal femur when assessing for trochlear dysplasia. Recent work by Ambra et al 3 indicated that axial imaging alone with the knee in extension is insufficient. The authors favor an ''oblique trochlear view,'' in which the image cuts are taken at 45°rather than perpendicular to the length of the femoral shaft.…”