Shallow trochlear groove and narrow medial trochlear width at the proximal trochlea in patients with trochlear dysplasia: A three‐dimensional computed tomography analysis

Purpose Although the Dejour classification is the primary classification system for evaluating trochlear dysplasia, concerns have been raised about its reliability owing to its qualitative criteria and challenges associated with obtaining accurate radiographs. This study aimed to quantify trochlear dysplasia using three‐dimensional (3D) computed tomography (CT) reconstruction with novel parameters related to the transepicondylar axis (TEA). Methods Sixty patients were enrolled, including 20 with trochlear dysplasia and 40 healthy controls. The 3D CT model was generated using the Materialise Interactive Medical Image Control System software. The following six parameters were measured in eight consecutive planes at 15° intervals (planes 0–105): the distance from the TEA to the most cortical point of the lateral condyle (‘LP‐TEA’, where LP stands for lateral peak), medial condyle (‘MP‐TEA’, MP for medial peak) and deepest point of the trochlea (‘TG‐TEA’, TG for trochlear groove). The distances from the medial epicondyle (MEC) to the corresponding TEA points were measured (‘LP‐MEC’, ‘MP‐MEC’ and ‘TG‐MEC’). Results In the dysplasia group, TG‐TEA (planes 0, 15 and 30) and MP‐MEC (planes 0, 15 and 30) were significantly greater than those in the control group (all p