Jiang C C, Insall J N
Hospital for Special Surgery, New York, NY 10021.
Clin Orthop Relat Res. 1989 Nov(248):50-6.
Intramedullary alignment guides for total knee arthroplasty are currently routine instruments. However, in some cases, the intramedullary guide can be misleading because of unusual femoral bowing and the rotational position of the femur. To determine the effect of rotation, an intramedullary guide was inserted into seven normal adult anatomic specimen femurs that were then examined roentgenographically in known positions of internal and external rotation. A variation of 2.5 degrees was found between the positions of 20 degrees of internal rotation and 20 degrees of external rotation of the femur. Intramedullary instrumentation provides sufficient accuracy when the femur has a normal anatomic shape. However, when an excessive degree of femoral bowing is present, rotational attitudes can affect the roentgenographic measurements, and thus it is prudent to use the intramedullary and extramedullary alignment guides whenever the roentgenogram indicates an unusual angle of femoral resection.
全膝关节置换术中的髓内对线导向器目前是常规器械。然而，在某些情况下，由于股骨异常弯曲和股骨的旋转位置，髓内导向器可能会产生误导。为了确定旋转的影响，将一个髓内导向器插入七个正常成年人体解剖标本股骨中，然后在已知的内旋和外旋位置进行X线检查。发现在股骨内旋20度和外旋20度位置之间存在2.5度的差异。当股骨具有正常解剖形状时，髓内器械提供足够的准确性。然而，当存在过度的股骨弯曲时，旋转姿态会影响X线测量，因此，每当X线片显示股骨切除角度异常时，谨慎的做法是同时使用髓内和髓外对线导向器。
