Femorotibial offset. A morphologic feature of the natural and arthritic knee

Eccentric wear identified in retrieval studies of failed total knee arthroplasties may reflect unrecognized intrinsic morphologic characteristics of the knee. This study identifies a previously unreported morphologic offset between the center of the tibia and femur using computed tomography scans in 38 preoperative arthritic knees and 38 controls. There is a statistically significant offset between femur and tibia centers in patients and control subjects. There is no significant difference between patients and control subjects in either AP or mediolateral translation of centers. The clinical relevance of this observation is that it may prompt strategies to address morphologic offset, thereby reducing eccentric wear in total knee arthroplasty.