Evaluation of radiological parameters for determining the knee joint line level

Aim: Accurate positioning of the knee joint line during primary and revision total knee arthroplasty is a crucial step that directly affects clinical outcomes. This study aimed to determine the location of the knee joint line based on specific anatomical landmarks around the knee. Materials and Methods: Patients who presented to the Orthopedics and Traumatology outpatient clinic or emergency department of Dicle University Faculty of Medicine between January 1, 2019, and January 1, 2024, were screened for inclusion in the study. Patients who underwent plain radiography, computed tomography (CT), and magnetic resonance imaging (MRI) of the knee joint were included. Results: A total of 186 patients, comprising 98 males (52.7%) and 88 females (47.3%), were included in the study. The mean femoral width measured on plain radiographs, CT, and MRI was 85.69 ± 8.45 mm, 78.83 ± 7.11 mm, and 78.88 ± 7.73 mm, respectively. The distance between the adductor tubercle and the joint line was 43.10 ± 4.45 mm on plain radiographs, 39.77 ± 3.88 mm on CT, and 39.69 ± 4.32 mm on MRI. The distance between the medial epicondyle and the joint line was 30.94 ± 3.26 mm on plain radiographs, 28.56 ± 2.78 mm on CT, and 28.46 ± 2.97 mm on MRI. The distance between the lateral epicondyle and the joint line was 24.21 ± 2.27 mm on plain radiographs, 22.33 ± 2.01 mm on CT, and 22.29 ± 2.18 mm on MRI. A strong correlation was found between femoral width and the distance from the adductor tubercle to the joint line. Conclusion: Based on the results of this study, the use of the adductor tubercle appears to be the most accurate method for determining the knee joint line. Key words: Adductor tubercle, joint line, revision total knee arthroplasty