Original Article|Articles in Press

An appropriate method for predicting the femoral angle on whole-body X-ray images from full-spine X-ray images

Published:March 01, 2023DOI:



      The importance of lower-limb compensation in patients with spinal malalignment due to spinal pathologies has been emphasized. The latest whole-body X-ray images (WBX) have enabled evaluations of whole-body alignment from head to toe. However, WBX is still not commonly available. Thus, the present study aimed to examine an alternative measurement method of the femoral angle on usual full-spine X-ray images (FSX) that approximates the femoral angle on WBX.


      A total of 50 patients (age, 52.8 ± 25.3 years; female, n = 26; male, n = 24) underwent WBX and FSX. The following parameters were measured on lateral view X-rays: WBX and FSX femoral angle (angle between the femoral axis and a perpendicular line); FSX femoral distance (distance from the center of femoral head to the distal femur on FSX); WBX intersection length (length between the center of the femoral head and the intersection point [the point at which the line connecting the center of the femoral head and the midpoint of the femoral condyle intersects the center line of the femur] on WBX).


      The WBX femoral angle, and FSX femoral angle were 0.16 ± 4.2°, and −0.53 ± 4.1°, respectively. The FSX femoral distance was 102.7 ± 41.1 mm. An ROC curve analysis revealed that the cut-off value of the FSX femoral distance associated with minimal difference in the WBX and FSX femoral angles (<3°) was 73 mm (sensitivity 83.3%, specificity 87.5%, AUC 0.80). The WBX intersection length was 105.3 ± 27.3 mm.


      To calculate the femoral angle on FSX that approximates the WBX femoral angle, the femoral distance on FSX ≥73 mm is preferable. We suggest using the FSX femoral distance within the range of 80 mm–130 mm as a simple numerical value that meets all criteria.


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        • Ferrero E.
        • Liabaud B.
        • Challier V.
        • Lafage R.
        • Diebo B.G.
        • Vira S.
        • et al.
        Role of pelvic translation and lower-extremity compensation to maintain gravity line position in spinal deformity.
        J Neurosurg Spine. 2016 Mar; 24: 436-446
        • Barrey C.
        • Roussouly P.
        • Perrin G.
        • Le Huec J.C.
        Sagittal balance disorders in severe degenerative spine. Can we identify the compensatory mechanisms?.
        Eur Spine J. Off. Publ. Eur. Spine Soc. Eur. Spinal Deformity Soc. Eur. Section Cervical Spine Res. Soc. 2011 Sep; 20: 626-633
        • Itoi E.
        Roentgenographic analysis of posture in spinal osteoporotics.
        Spine. 1991 Jul; 16: 750-756
        • Hasegawa K.
        • Dubousset J.
        Cone of economy with the chain of balance- historical perspective and proof of concept.
        Spine Surgery and Related Research. 2022 Apr 20; 6: 337-349
        • Lazennec J.Y.
        • Folinais D.
        • Bendaya S.
        • Rousseau M.A.
        • Pour A.E.
        The global alignment in patients with lumbar spinal stenosis: our experience using the EOS full-body images.
        Eur. J. Orthopaedic Surg. Traumatol. Orthopedie Traumatologie. 2016 Oct; 26: 713-724
        • Hasegawa K.
        • Okamoto M.
        • Hatsushikano S.
        • Shimoda H.
        • Ono M.
        • Watanabe K.
        Normative values of spino-pelvic sagittal alignment, balance, age, and health-related quality of life in a cohort of healthy adult subjects.
        Eur. Spine J. Off. Publ. Eur. Spine Soc. Eur. Spinal Deformity Soc. Eur. Sec. Cervical Spine Res. Soc. 2016 Nov; 25: 3675-3686
        • Obeid I.
        • Hauger O.
        • Aunoble S.
        • Bourghli A.
        • Pellet N.
        • Vital J.M.
        Global analysis of sagittal spinal alignment in major deformities: correlation between lack of lumbar lordosis and flexion of the knee.
        Eur. Spine J. Off. Publ. Eur. Spine Soc. Eur. Spinal Deformity Soc. Eur. Sec. Cervical Spine Res. Soc. 2011 Sep; 20: 681-685
        • Abdelaal A.H.
        • Yamamoto N.
        • Hayashi K.
        • Takeuchi A.
        • Morsy A.F.
        • Miwa S.
        • et al.
        Radiological assessment of the femoral bowing in Japanese population.
        Sicot-j. 2016 Jan; 22: 2