Analysis of factors that affect the precision of the radiographic lateral femoral bowing angle using a three-dimensional computed tomography-based modelling technique
Tóm tắt
Precise measurement of lateral femoral bowing is important to achieve postoperative lower limb alignment. We aimed to investigate factors that affect the precision of the radiographic lateral femoral bowing (RLFB) angle using three-dimensional (3D) models and whether the angle affects surgery design. Forty femurs in total were divided into two groups based on their preoperative RLFB angle. The flexion contracture angle, preoperative and postoperative RLFB angles, and intersection angle between the mechanical and anatomical axes were compared. The angle between the arc and sagittal planes, varus and valgus angles, and intersection angle between the mechanical and anatomical axes were measured on a 3D model. There was no significant between-group difference in 3D model measurements of the angle between the arc and sagittal planes (p = 0.327). There was no significant difference between the mechanical and anatomical axes measured by both imaging modalities (p > 0.258). When the RLFB was >5°, the flexion contracture angle and radiographic femoral bowing angle were positively correlated (r = 0.535, p < 0.05). Distal femur varus and valgus angles significantly differed between the two groups (p = 0.01). After total knee arthroplasty, the radiographic femoral bowing angle decreased significantly. When the cases’ radiographic femoral bowing angle is larger and the angle between the arc and sagittal planes is smaller as measured in 3D models, the angle between the arc and coronal planes is larger. The radiographic femoral bowing angle does not reflect the actual size of lateral femoral bowing, does not greatly affect surgery design, and is greatly affected by flexion contracture deformity. A RLFB angle larger than 15° indicates real lateral femoral bowing.
Tài liệu tham khảo
Bäthis H, et al. Alignment in total knee arthroplasty. A comparison of computer-assisted surgery with the conventional technique. J Bone Joint Surg (Br). 2004;86(5):682–7.
Rand J, Coventry M. Ten-year evaluation of geometric total knee arthroplasty. Clin. Orthop. Relat. Res. 1988;232:168–73.
Mullaji AB, et al. Which factors increase risk of malalignment of the hip-knee-ankle axis in TKA? Clin Orthop Relat Res. 2013;471(1):134–41.
Yau W, et al. Coronal bowing of the femur and tibia in Chinese: its incidence and effects on total knee arthroplasty planning. J Orthop Surg (Hong Kong). 2007;15(1):32–6.
Lee SA, Choi SH, Chang MJ. How accurate is anatomic limb alignment in predicting mechanical limb alignment after total knee arthroplasty? BMC Musculoskelet Disord. 2015;16:323.
Kim JM, et al. Femoral shaft bowing in the coronal plane has more significant effect on the coronal alignment of TKA than proximal or distal variations of femoral shape. Knee Surg Sports Traumatol Arthrosc. 2015;23(7):1936–42.
Akamatsu Y, et al. Femoral shaft bowing in the coronal and sagittal planes on reconstructed computed tomography in women with medial compartment knee osteoarthritis: a comparison with radiograph and its predictive factors. Arch Orthop Trauma Surg. 2016;136(9):1227–32.
Sebastian AS, et al. Femoral bow predicts postoperative malalignment in revision total knee arthroplasty. J Arthroplasty. 2014;29(8):1605–9.
Buford W, et al. Three-dimensional computed tomography-based modeling of sagittal cadaveric femoral bowing and implications for intramedullary nailing. J Orthop Trauma. 2014;28(1):10–6.
Mullaji AB, Marawar SV, Mittal V. A comparison of coronal plane axial femoral relationships in Asian patients with varus osteoarthritic knees and healthy knees. J Arthroplasty. 2009;24(6):861–7.
Dutton AQ, Yeo SJ. Computer-assisted minimally invasive total knee arthroplasty compared with standard total knee arthroplasty. Surg Technique J Bone Joint Surg Am. 2009;91(Suppl 2 Pt 1):116–30.
Victor J, et al. How precise can bony landmarks be determined on a CT scan of the knee? Knee. 2009;16(5):358–65.
Yoshino N, et al. Computed tomography measurement of the surgical and clinical transepicondylar axis of the distal femur in osteoarthritic knees. J Arthroplasty. 2001;16(4):493–7.
Victor J, Hoste D. Image-based computer-assisted total knee arthroplasty leads to lower variability in coronal alignment. Clin. Orthop. Relat. Res. 2004;428:131–9.
Patil S, et al. Improving tibial component coronal alignment during total knee arthroplasty with use of a tibial planning device. J Bone Joint Surg Am. 2007;89(2):381–7.
Thippanna RK, Kumar MN. Lateralization of femoral entry point to improve the coronal alignment during total knee arthroplasty in patients with bowed femur. J Arthroplasty. 2016;31(9):1943–8.
Shi X, et al. Comparison of postoperative alignment using fixed vs individual valgus correction angle in primary total knee arthroplasty with lateral bowing femur. J Arthroplasty. 2016;31(5):976–83.