Evaluation of Distal Femoral Rotational Alignment with Spiral CT Scan before Total Knee Arthroplasty (A Study in Iranian Population)

Document Type : RESEARCH PAPER


1 Shafa Orthopedic Hospital, Iran University of Medical Sciences, Tehran, Iran

2 Tabriz Shohada Hospital, Tabriz University of Medical Sciences, Tabriz, Iran

3 Tehran University of Medical Sciences, Tehran, Iran


Background: Evaluating the landmarks for rotation of the distal femur is a challenge for orthopedic surgeons. Although the posterior femoral condyle axis is a good landmark for surgeons, the surgical transepicondylar axis may be a better option with the help of preoperative CT scanning. The purpose of this study was to ascertain relationships among the axes’ guiding distal femur rotational alignment in preoperative CT scans of Iranian patients who were candidates for total knee arthroplasty and the effects of age, gender, and knee alignment on these relationships.
Methods: One hundred and eight cases who were admitted to two university hospitals for total knee arthroplasty were included in this study. The rotation of the distal femur was evaluated using single axial CT images through the femoral epicondyle. Four lines were drawn digitally in this view: anatomical and surgical transepicondylar axes, posterior condylar axis and the Whiteside anteroposterior line. The alignment of the extremity was evaluated in the standing alignment view. Then the angles were measured along these lines and their relationship was evaluated.
Results: The mean angle between the anatomical transepicondylar axis and posterior condylar axis and between the surgical transepicondylar axis and posterior condylar axis were 5.9 ± 1.6 degrees and 1.6±1.7 degrees respectively. The mean angle between the Whiteside’s anteroposterior line and the line perpendicular to the posterior condylar axis was 3.7±2.1 degrees. Significant differences existed between the two genders in these relationships. No significant correlation between the age of patients and angles of the distal femur was detected. The anatomical surgical transepicondylar axis was in 4.3 degrees external rotation in relation to the surgical transepicondylar axis.
Conclusion: Preoperative CT scanning can help accurately determine rotational landmarks of the distal femur. If one of the reference axes cannot be determined, other reference axes can be used because of the good correlation between these landmarks.


  1. Victor J. Rotational alignment of the distal femur: a literature review. Orthop Traumatol Surg Res. 2009; 95(5):365-72.
  2. Aglietti P, Sensi L, Cuomo P, Ciardullo A. Rotational position of femoral and tibial components in TKA using the femoral transepicondylar axis. Clin Orthop Relat Res. 2008; 466(11):2751-5.
  3. Rossi R, Bruzzone M, Bonasia DE, Marmotti A, Castoldi F. Evaluation of tibial rotational alignment in total knee arthroplasty: a cadaver study. Knee Surg Sports Traumatol Arthrosc. 2010; 18(7):889-93.
  4. Zhang XL, Zhang W, Shao JJ. Rotational alignment in total knee arthroplasty: nonimage-based navigation system versus conventional technique. Chin Med J (Engl). 2012; 125(2):236-43.
  5. Sun T, Lv H, Hong N. Rotational landmarks and total knee arthroplasty in osteoarthritic knees. Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2007; 21(3):226-30.
  6. Uehara K, Kadoya Y, Kobayashi A, Ohashi H, Yamano Y. Bone anatomy and rotational alignment in total knee arthroplasty.Clin Orthop Relat Res. 2002; 402:196-201.
  7. Berhouet J, Beaufils P, Boisrenoult P, Frasca D, Pujol N. Rotational positioning of the tibial tray in total knee arthroplasty: a CT evaluation. Orthop Traumatol Surg Res. 2011; 97(7):699-704.
  8. Berger RA, Rubash HE, Seel MJ, Thompson WH, Crossett LS. Determining the rotational alignment of the femoral component in total knee arthroplasty using the epicondylar axis. Clin Orthop Relat Res. 1993; 286:40-7.
  9. Victor J, Van Doninck D, Labey L, Innocenti B, Parizel PM, Bellemans J. How precise can bony landmarks be determined on a CT scan of the knee. Knee. 2009; 16(5):358-65.
  10. Vaidya SV, Gadhiya RM, Bagaria V, Ranawat AS, Ranawat CS. Computed tomographic evaluation of femoral component rotation in total knee arthroplasty. Indian J Orthop. 2013; 47(1):40-4
  11. Stiehl JB, Abbott BD. Morphology of the transepicondylar axis and its application in primary and revision total knee arthroplasty. J Arthroplasty. 1995; 10(6):785-9.
  12. Stiehl JB, Cherveny PM. Femoral rotational alignment using the tibial shaft axis in total knee arthroplasty. Clin Orthop Relat Res. 1996; 331:47-55.
  13. Galaud B, Beaufils P, Michaut M, Abadie P, Fallet L, Boisrenoult P. Distal femoral torsion: comparison of CT scan and intra operative navigation measurements during total knee arthroplasty. A report of 70 cases. Rev Chir Orthop Reparatrice Appar mot. 2008; 94(6):573-9.
  14. Jenny JY, Boeri C. Low reproducibility of then intra-operative measurement of the transepicondylar axis during total knee replacement. Acta Orthop Scand. 2004; 75(1):74-7.
  15. Yoshioka Y, Siu D, Cooke TD. The anatomy and functional axes of the femur. J Bone Joint Surg Am. 1987; 69(6):873-80.
  16. Nagamine R, Miura H, Inoue Y, Urabe K, Matsuda S, Okamoto Y, et al. Reliability of the anteroposterior axis and the posterior condylar axis for determining rotational alignment of the femoral component in total knee arthroplasty. J Orthop Sci. 1998; 3(4):194-8.
  17. Jabalameli M, Rahbar M, Bagherifard A, Hadi HA, Moradi A, Mokhtari T. Evaluation of distal femoral rotational alignment according to transepicondylar axis and Whiteside line (A study in Iranian population). SOJ. 2013; 1(3):22-28.
  18. Griffin FM, Insall JN, Scuderi GR. The posterior condylar angle in osteoarthritic knees. J Arthroplasty. 1998; 13(7):812–5.
  19. Matsuda S, Miura H, Nagamine R, Mawatari T, Tokunaga M, Nabeyama R, et al. Anatomical analysis of the femoral condyle in normal and osteoarthritic knees. J Orthop Res. 2004; 22(1):104–9.
  20. Yosnhino N, Takai S, Ohtsuki Y, Hirasawa Y. Computed tomography measurement of the surgical and clinical transepicondylar axis of the distal femur in osteoarthritic knees. J Arthroplasty. 2001; 16(4):493-7.
  21. Arima J, Whiteside LA, McCarthy DS, White SE. Femoral rotational alignment, based on the anteroposterior axis, in total knee arthroplasty in a valgus knee. A technical note. J Bone joint Surg Am. 1995; 77(9):1331-4.
  22. Victor J, Van Doninck D, Labey L, Van Glabbeek F, Parizel P, Bellemans J. A common reference frame for describing rotation of the distal femur: a ct-based kinematic study using cadavers. J Bone Joint Surg Br. 2009; 91(5):683-90.