Rotational Alignment of the Distal Femur in the Anatolian Population - Suitability of Standard Guidelines for Knee Arthroplasty

Abstract

Objective: The rotation of the femoral component in total knee arthroplasty (TKA) is crucial for knee kinematics and functional outcomes. This study aimed to evaluate the posterior condylar angle (PCAn) and the condylar twisting angle (CTA) in an Anatolian population. Additionally, we aimed to assess the suitability of standard posterior condylar axis (PCA) reference incision blocks used in TKA for this population. Material and Methods: In this retrospective, observational, analytical study, we examined knee computed tomography (CT) images of 130 patients aged 18 to 60 years. The PCAn was measured as the angle between the axis extending from the medial epicondylar sulcus to the lateral epicondyle (cTEA) and PCA. The CTA was defined as the angle between the axis extending from the medial epicondyle to the lateral epicondyle (aTEA) and PCA. Results: The mean PCAn was measured as 3.52°±1.45° (1.8° external rotation to 8° internal rotation), and the CTA was measured as 6.58°±1.47° (range 2°-9.9° internal rotation). One hundred and five knees (80.8%) were within individual anatomic limits for PCAn, while there were 25 outliers (19.2%), 9 in the external rotation (ER) group and 16 in the internal rotation (IR) group. The angle measurements on CT had excellent intra- and inter-observer reliability. Conclusion: This study shows that in 80.8% of the Anatolian population, the posterior condylar reference is an acceptable reference for femoral component rotation in TKA surgery, but in 19.2%, it is not an appropriate reference because it will cause malrotation. Orthopedic surgeons should be ready to modify the surgical technique when necessary, considering other reference points to properly align the femoral implant along the TEA while performing TKA with posterior reference equipment.

Keywords

• Posterior condylar axis
• trans epicondylar axis
• condylar twist angle
• total knee arthroplasty
• computerized tomography

ANADOLU POPÜLASYONUNDA DİSTAL FEMURUN ROTASYONEL HİZALANMASI - DİZ ARTROPLASTİSİ İÇİN STANDART KILAVUZLARIN UYGUNLUĞU

Abstract

Amaç: Total diz artroplastisi (TDA) ameliyatında femoral komponentin rotasyonu diz kinematiği ve fonksiyonel sonuçlar açısından oldukça önemlidir. Bu çalışmanın amacı, Anadolu popülasyonunda posterior kondiler açı (PKAç) ve Kondiler bükülme açısını (KBA) değerlendirmektir. Ayrıca, TDA’da kullanılan standart posterior kondiler aks (PKA) referans insizyon bloklarının Anadolu popülasyonu için uygunluğunun değerlendirilmesidir. Gereç ve Yöntemler: Bu retrospektif, gözlemsel, analitik çalışmada 18-60 yaş arası 130 hastanın diz bilgisayarlı tomografi (BT) görüntüleri üzerinde ölçümler yapıldı. PKAç medial epikondiler sulkustan lateral epikondile uzanan aks (cTEA) ile PKA arasındaki açı, KBA ise medial epikondilden lateral epikondile uzanan aks (aTEA) ile PKA arasındaki açı olarak ölçüldü. Bulgular: Ortalama PKAç 3.52°±1.45° (1.8° dış rotasyon ile 8° iç rotasyon aralığı), KBA 6.58° ± 1.47° (2°-9.9° iç rotasyon aralığı) olarak ölçüldü. Yüz beş diz (%80.8) PKAç açısından bireysel anatomik sınırlar içindeyken, 9'u eksternal rotasyonda (ER) ve 16'sı internal rotasyonda (İR) grubunda olmak üzere 25 aykırı değer (%19.2) vardı. BT'deki açı ölçümleri, hem gözlemci içi hem de gözlemciler arası güvenilirliği mükemmeldi. Sonuç: Bu çalışma, Anadolu popülasyonun %80.8’inde posterior kondiler referansın TDA ameliyatında femoral komponent rotasyonu için kabul edilebilir bir referans olduğu, fakat %19.2’sinde ise malrotasyona neden olacağı için uygun bir referans olmadığını göstermektedir. Ortopedik cerrahlar, TDA'yı posterior referans ekipmanı ile uygularken femoral implantı TEA boyunca düzgün bir şekilde hizalamak için diğer referans noktaları dikkate alarak cerrahi tekniği gerektiğinde değiştirmeye hazır olmalıdır.

Keywords

• Posterior kondiler aks
• trans epikondiler aks
• kondiler bükülme açısı
• total diz artroplastisi
• bilgisayarlı tomografi

References

1. Akagi M, Matsusue Y, Mata T, et al. Effect of rotational alignment on patellar tracking in total knee arthroplasty. Clin Orthop Relat Res. 1999;366:155-163.
2. Victor J. Rotational alignment of the distal femur: a literature review. OrthopTraumatol Surg Res. 2009;95(5):365-372.
3. Poilvache PL, Insall JN, Scuderi GR, Font-Rodriguez DE. Rotational landmarks and sizing of the distal femur in total knee arthroplasty. Clin Orthop Relat Res. 1996;(331):35-46.
4. Griffin FM, Insall JN, Scuderi GR. The posterior condylar angle in osteoarthriticknees. J Arthroplasty. 1998;13(7):812-815.
5. Whiteside LA, Arima J. The anteroposterior axis for femoral rotational alignment in valgus total knee arthroplasty. Clin Orthop Relat Res. 1995;321:168-172.
6. Stiehl JB, Cherveny PM: Femoral rotational alignment using the tibial shaft axis in total knee arthroplasty. Clin Orthop Relat Res. 1996;331:47-55.
7. Yoshioka Y, Siu D, Cooke TD. The anatomy and functional axes of the femur. J Bone Joint Surg Am. 1987;69(6):873-880.
8. Kobayashi H, Akamatsu Y, Kumagai K, et al. The surgical epicondylar axis is a consistent reference of the distalfemur in the coronal and axial planes. Knee Surg Sports Traumatol Arthrosc. 2014;22(12):2947-2953.

9. Newbern DG, Faris PM, Ritter MA, Keating EM, Meding JB, Berend ME. A clinical comparison of patellar tracking using the transepicondylar axis and theposterior condylar axis. J Arthroplasty. 2006;21(8):1141-1146.
10. Miller MC, Berger RA, Petrella AJ, Karmas A, Rubash HE. Optimizing femoralcomponent rotation in total knee arthroplasty. Clin Orthop Relat Res. 2001;392:38-45.
11. Asano T, Akagi M, Nakamura T. The functional flexion-extension axis of the knee corresponds to the surgical epicondylar axis: in vivo analysis using a biplanar image-matching technique. J Arthroplasty. 2005;20(08):1060-1067.
12. 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(05):683-690.
13. Churchill DL, Incavo SJ, Johnson CC, Beynnon BD. The transepicondylar axis approximates the optimal flexion axis of the knee. Clin Orthop Relat Res. 1998;356:111-118.
14. Raju S, Chinnakkannu K, Sunderayan R, Puttaswamy MK. Rotational landmarks of the distal femur in Indian population: a MRI-based study. Journal of orthopaedic surgery and research. 2015;10:186.
15. Jabalameli M, Moradi A, Bagherifard A, Radi M, Mokhtari T. Evaluation of distal femoral rotational alignment with spiral CT scan before total knee arthroplasty (A study in Iranian population). The archives of bone and joint surgery. 2016;4(2):122-127.
16. Takai S, Yoshino N, Isshiki T, Hirasawa Y. Kneeling view: a new roentgenographic technique to assess rotational deformity and alignment of the distal femur. J Arthroplasty. 2003;18(4):478-483.
17. Yue B, Varadarajan KM, Ai S, Tang T, Rubash HE, Li G. Differences of knee anthropometry between Chinese and white men and women. J Arthroplasty. 2011;26(1):124-130.
18. Poilvache PL, Insall JN, Scuderi GR, Font-Rodriguez DE. Rotational landmarks and sizing of the distal femur in total knee arthroplasty. Clinical orthopaedics and related research. 1996;331:35-46.
19. Mahran MA, Khalifa AA, Ahmed MA, Bakr HM, Khalifa YE. Evaluating distal femoral torsion and posterior condylar line reliability for adjusting femoral component rotation in TKA, Egyptian population radiographic study. J Clin Orthop Trauma. 2020;13:99-105.
20. Incesoy MA, Güngören N, Aliyev O, Elmalı N, Tuncay İ, Yıldız F. Distal femur morphology and the suitability of standard guides for knee arthroplasty in the Turkish population. Acta Orthop Traumatol Turc. 2024;58(1):39-44.
21. Yoshino 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):493-497.
22. Tan CM, Liau JJ, Chen WT, Cheng CK. The accuracy of posterior condylar angles measured by one MR image. Clin Orthop Relat Res. 2007;456:159-163.
23. Kanekasu K, Kondo M, Kadoya Y. Axial radiography of the distal femur to assess rotational alignment in total knee arthroplasty. Clin Orthop Relat Res. 2005;434:193-197.
24. Lustig S, Lavoie F, Selmi TAS, Servien E, Neyret P. Relationship between the surgical epicondylar axis and the articular surface of the distal femur: an anatomic study. Knee Surg Sports Traumatol Arthrosc. 2008;16(7):674-682.
25. Fitz DW, Johnson DJ, Hartwell MJ, Sullivan R, Keller TJ, Manning DW. Relationship of the Posterior Condylar Line and the Transepicondylar Axis: A CT-Based Evaluation. J Knee Surg. 2020;33(7):673-677.
26. Twiggs JG, Dickison DM, Kolos EC, et al. Patient Variation Limits Use of Fixed References for Femoral Rotation Component Alignment in Total Knee Arthroplasty. J Arthroplasty. 2018;33(1):67-74.
27. Chalmers BP, Kolin DA, Mayman DJ, et al. Three Degrees External to the Posterior Condylar Axis Has Little Relevance in Femoral Component Rotation: A Computed Tomography-Based Total Knee Arthroplasty Simulation Study. J Arthroplasty. 2021;36(7S):380-385.
28. Dumlao P, Fujii H, Suetomi Y, Tokushige A, Yukata K, Sakai T. Optimizing femoral component rotation in TKA: The role of posterior condylar angle and condylar twist angle. Journal of Joint Surgery and Research. 2023;214-221.
29. Fehring TK. Rotational malalignment of the femoral component in total knee arthroplasty. Clin Orthop Relat Res. 2000;380:72-79.
30. Murgier J, Chantalat É, Li K, et al. Distal femoral torsion: Differences between caucasians and asians. A multicentre computed tomography study of 515 distal femurs. Orthop Traumatol Surg Res. 2018;104(7):997-1001.
31. 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;286:40-47.
32. Griffin FM,Math K, Scuderi GR, Insall JN, Poilvache PL. Anatomy of the epicondyles of the distal femur: MRI analysis of normal knees. J Arthroplasty. 2000;15(03):354-359.
33. Thienpont E, Schwab PE, Paternostre F, Koch P. Rotational alignment of the distal femur: anthropometric measurements with CT-based patient-specific instruments planning show high variability of the posterior condylar angle. Knee Surg Sports Traumatol Arthrosc 2014;22(12):2995-3002
34. Meric G, Gracitelli GC, AramLJ, SwankML, BugbeeWD. Variability in distal femoral anatomy in patients undergoing total knee arthroplasty: measurements on 13,546 computed tomography scans. J Arthroplasty 2015;30(10):1835-1838.
35. Kobayashi H, Aratake M, Akamatsu Y, Mitsugi N, Taki N, Saito T. Reproducibility of condylar twist angle measurement using computed tomography and axial radiography of the distal femur. Orthop Traumatol Surg Res. 2014;100(8):885-890.
36. Luyckx T, Zambianchi F, Catani F, Bellemans J, Victor J. Coronal alignment is a predictor of the rotational geometry of the distal femur in the osteo-arthritic knee. Knee Surg Sports Traumatol Arthrosc. 2013;21(10):2331-2337.
37. Yip DKH, Zhu YH, Chiu KY, Ng TP. Distal rotational alignment of the Chinese femur and its relevance in total knee arthroplasty. J Arthroplasty. 2004;19(5):613-619.
38. Won YY, CuiWQ, BaekMH, Yun TB, Han SH. An additional reference axis for determining rotational alignment of the femoral component in total knee arthroplasty. J Arthroplasty. 2007;22(07):1049-1053.
39. Asada S, Akagi M, Matsushita T, Hashimoto K, Mori S, Hamanishi C. Effects of cartilage remnants of the posterior femoral condyles on femoral component rotation in varus knee osteoarthritis. Knee. 2012;19(3):185-189.