Affiliation:
1. Department of Orthopaedic Surgery Seoul National University Hospital Seoul Republic of Korea
2. Department of Orthopaedic Surgery Seoul National University College of Medicine Seoul Republic of Korea
3. Imagoworks Inc. Seoul Republic of Korea
4. CONNECTEVE Co., Ltd Seoul Republic of Korea
5. Innovative Medical Technology Research Institute Seoul National University Hospital Seoul Republic of Korea
Abstract
AbstractPurposeAlthough 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).MethodsSixty 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’).ResultsIn 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 < 0.05 for planes of TG‐TEA and MP‐MEC). For type A dysplasia, LP‐MEC (plane 0) was greater than that in the control group. For type B dysplasia, the MP‐MEC (planes 0 and 15) and TG‐TEA (planes 0 and 15) were greater than those of the control group. For type D dysplasia, MP‐MEC (planes 0, 15 and 30) and TG‐TEA (planes 0 and 15) were elevated.ConclusionThe 3D CT reconstruction analysis established a reproducible method for quantifying osseous trochlear morphology. Patients with trochlear dysplasia had a shallow TG and narrow medial trochlear width at tracking angles of 0°–30°. This finding corroborates the clinical manifestations of recurrent patellar instability that occur during early flexion.Level of EvidenceLevel III.