Abstract
Background:
The axis of the fibula in the sagittal plane are known as a landmark for the extramedullary guide in order to minimize posterior tibial slope measurement error in the conventional total knee arthroplasty (TKA). However, there are few anatomic studies about them. We also wondered if the fibula in the coronal plane could be reliable landmark for the alignment of the tibia. This study was conducted to confirm whether the fibula is reliable landmark in coronal and sagittal plane.
Methods:
We evaluated 60 osteoarthritic knees after TKA using Athena Knee (SoftCube Co, Ltd, Osaka, Japan) 3-D image-matching software. Angle between the axis of the fibula (FA) and the mechanical axis (MA) in the coronal and sagittal plane were measured.
Results:
The mean angle between the FA and MA was 0.86 ± 2.0° of varus in the coronal plane (range 6.0° of varus to 4.2° of valgus) and 2.6 ± 2.3° of posterior inclination in the sagittal plane (range 6.8° of posterior inclination to 2.8 of anterior inclination), respectively. The percentage of subjects in which FA was within 3° of the MA was 77% in the coronal plane and 58% in the sagittal plane, respectively.
Conclusions:
The FA used as a landmark for the alignment of the tibia in the conventional TKA differed from MA relatively in this study, and not be used safely if the differences are considered.
