Solayar G N, Chinappa J, Harris I A, Chen D B, Macdessi S J
Department of Orthopaedics, International Medical University (IMU), Seremban, Malaysia.
Department of Orthopaedics, Canterbury Hospital, Sydney, Australia.
Malays Orthop J. 2017 Jul;11(2):45-52. doi: 10.5704/MOJ.1707.006.
Optimal coronal and sagittal component positioning is important in achieving a successful outcome following total knee arthroplasty (TKA). Modalities to determine post-operative alignment include plain radiography and computer tomography (CT) imaging. This study aims to determine the accuracy and reliability of plain radiographs in measuring coronal and sagittal alignment following TKA. A prospective, consecutive study of 58 patients undergoing TKA was performed comparing alignment data from plain radiographs and CT imaging. Hip-knee-angle (HKA), sagittal femoral angle (SFA) and sagittal tibial angle (STA) measurements were taken by two observers from plain radiographs and compared with CT alignment. Intra- and inter-observer correlation was calculated for each measurement. Intra-observer correlation was excellent for HKA (r>0.89) with a mean difference of <1.9°. The least intra-observer correlation was for SFA (mean r=0.58) with a mean difference of 8°. Inter-observer correlation was better for HKA (r>0.95) and STA (r>0.8) compared to SFA (r=0.5). When comparing modalities (radiographs vs CT), HKA estimations for both observers showed the least maximum and mean differences while SFA observations were the least accurate. Radiographic estimation of HKA showed excellent intra- and inter-observer correlation and corresponds well with CT imaging. However, radiographic estimation of sagittal plane alignment was less reliably measured and correlated less with CT imaging. Plain radiography was found to be inferior to CT for estimation of biplanar prosthetic alignment following TKA.
在全膝关节置换术（TKA）后要取得成功的结果，冠状面和矢状面组件的最佳定位非常重要。确定术后对线的方法包括X线平片和计算机断层扫描（CT）成像。本研究旨在确定X线平片测量TKA后冠状面和矢状面对线的准确性和可靠性。对58例行TKA的患者进行了一项前瞻性、连续性研究，比较了X线平片和CT成像的对线数据。两名观察者从X线平片上测量髋膝角（HKA）、股骨矢状角（SFA）和胫骨矢状角（STA），并与CT对线进行比较。计算每个测量值的观察者内和观察者间相关性。观察者内HKA相关性极佳（r>0.89），平均差异<1.9°。观察者内相关性最低的是SFA（平均r=0.58），平均差异为8°。与SFA（r=0.5）相比，观察者间HKA（r>0.95）和STA（r>0.8）的相关性更好。在比较不同方式（X线平片与CT）时，两名观察者对HKA的估计显示最大差异和平均差异最小，而对SFA的观察最不准确。X线平片对HKA的估计显示出极佳的观察者内和观察者间相关性，且与CT成像非常吻合。然而，矢状面对线的X线平片估计测量可靠性较低，与CT成像的相关性也较小。发现X线平片在估计TKA后双平面假体对线方面不如CT。
