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Upright CT of the knee: the effect of weight-bearing on joint alignment

Hirschmann, Anna ; Buck, Florian ; Fucentese, Sandro ; Pfirrmann, Christian

In: European Radiology, 2015, vol. 25, no. 11, p. 3398-3404

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    Titre
    • Upright CT of the knee: the effect of weight-bearing on joint alignment
    Auteur
    • Hirschmann, Anna. Department of Radiology, Orthopedic University Hospital Balgrist, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
    • Buck, Florian. Department of Radiology, Orthopedic University Hospital Balgrist, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
    • Fucentese, Sandro. Orthopedic Surgery, Orthopedic University Hospital Balgrist, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
    • Pfirrmann, Christian. Department of Radiology, Orthopedic University Hospital Balgrist, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
    Type de document
    • Postprint
    Langue
    • Inglese
    Publié dans
    • European Radiology, 2015, vol. 25, no. 11, p. 3398-3404. Springer Berlin Heidelberg
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:332899
    Summary
    Objectives: To prospectively compare patellofemoral and femorotibial alignment in supine non-weight-bearing computed tomography (NWBCT) and upright weight-bearing CT (WBCT) and assess the differences in joint alignment. Methods: NWBCT and WBCT images of the knee were obtained in 26 patients (mean age, 57.0 ± 15.9years; range, 21-81) using multiple detector CT for NWBCT and cone-beam extremity CT for WBCT. Two musculoskeletal radiologists independently quantified joint alignment by measuring femorotibial rotation, tibial tuberosity-trochlear groove distance (TTTG), lateral patellar tilt angle, lateral patellar shift, and medial and lateral femorotibial joint space widths. Significant differences between NWBCT and WBCT were sought using Wilcoxon signed-rank test (P-value < 0.05). Results: Significant differences were found for femorotibial rotation (the NWBCT mean changed from 2.7° ± 5.1 (reader 1)/2.6° ± 5.6 (reader 2) external rotation to WBCT 0.4° ± 7.7/0.2° ± 7.5 internal rotation; P = 0.009/P = 0.004), TTTG (decrease from NWBCT (13.8mm ± 5.1/13.9mm ± 3.9) to WBCT (10.5mm ± 5.0/10.9mm ± 5.2; P = 0.008/P = 0.002), lateral patellar tilt angle (decrease from NWBCT (15.6° ± 6.7/16.9° ± 7.4) to WBCT (12.5° ± 7.7/15.0° ± 6.2; P = 0.011/P = 0.188). The medial femorotibial joint space decreased from NWBCT (3.9mm ± 1.4/4.5mm ± 1.3) to WBCT (2.9mm ± 2.2/3.5mm ± 2.2; P = 0.003/P = 0.004). Inter-reader agreement ranged from 0.52-0.97. Conclusion: Knee joint alignment changes significantly in the upright weight-bearing position using CT when compared to supine non-weight-bearing CT. Key Points : • Cone-beam extremity CT offers upright weight-bearing examinations of the lower extremities. • Knee alignment changes significantly in an upright position compared to supine position. • Tibial tuberosity-trochlear groove distance (TTTG) is less pronounced in a weight-bearing position. • The weight-bearing position leads to a decrease of the lateral patellar tilt angle.