Abstract
Purpose
Tibial and femoral component overhang in total knee arthroplasty (TKA) is a source of pain, thus is it important to understand anatomic differences between races to minimize overhang by matching the tibial and femoral shaft axis to the knee articular surface. Thus, this study compared knee morphology between Caucasian and East Asian individuals to determine the optimal placement of tibial and femoral stems.
Methods
A retrospective study was conducted on a matched cohort of 50 East Asians (21F, 29M) and 50 Caucasians (21F, 29M) by age and gender. CT scans were obtained in healthy volunteers using <2mm slices. The distance from the proximal tibial diaphysis axis to the tibial plateau center was measured, and the distance from the distal femoral diaphysis axis to the center of distal femoral articular surface was measured. Tibial measurements were made using Akagi's AP axis and the widest ML diameter, and femoral measurements were based on Whiteside's line and the surgical epicondylar axis.
Results
The ML distance between the tibial shaft center and Akagi line was significantly higher for Asians (9.9mm±2.7, Caucasians 7.7mm±3.1, p<0.001). The distance between the femoral shaft center and Whiteside line was lower, although not significantly different (Asians 1.9mm±1.0, Caucasians 2.2mm±1.1, p=0.11). However, there were no differences in the AP dimension for the femur or tibia comparing Asians to Caucasians.
Conclusion
East Asian individuals have more offset in the ML dimension for the tibia. This should be taken into consideration when designing primary and revision TKA stemmed tibial implants for East Asian patients.
