The measurement of the posterior condylar angle in distal femur with clinical application in adult / 中华骨科杂志

ABSTRACT

Objective To investigate the posterior condylar angle(PCA) of distal femur in normal adult, and provide reasonable referenced parameters of the rotational alignment for the total knee arthroplasty in Chinese. Methods This study concluded 118 volunteers(186 knees) in Suwan area (67 males 103 knees, and 51 females 83 knees), whose knees were healthy, without any malformation. The average age was 39.7 years(range, 18-69 years). All subjects were divided into three groups according to the ages group A, 18-39 years (85 knees); group B, 40-59 years(73 knees); group C, more than 60 years(28 knees). The CT scan was employed to the mechanical axis which was perpendicular to the knee joint in the distal femur. The PCA was measured from the CT film across lateral and medial femoral epicondyle. The factorial design was used to compare the data among three groups. Results First, in the 103 knees of male, 57 in left side and 46 in right side. The PCA were 5.9??1.6? in left side, 5.6??2.6? in right side(mean, 5.8??2.2?). Then in the 83 knees of female, 38 in left side and 45 in right side, the PCA was 5.5??2.5? in left side, 5.2??1.5? in right side(mean, 5.3??1.9?). And the PCA was 5.5??1.9? in group A, 5.7??1.8? in group B, 5.5??2.7? in group C, respectively, and there is no statistical significant difference in either gender or side and age. Conclusion The normal adult PCA of distal femur is 5.6??2.1? in Suwan area, without difference in gender, which is beyond the Westerns obviously. So in the total knee arthroplasty of Chinese, the malalignment will likely occur if the rotational alignment is performed according to Western style, the eversion 3? to the posterior condylar line in distal femur.