Abstract
Anatomic research has demonstrated significant differences in native knee morphology
between genders and ethnicities. These studies have traditionally evaluated femoral
morphology. However, no studies have yet investigated possible relationships between
the posterior femoral condyles and the tibial plateau. Our study sought to demonstrate
this relationship and evaluate its strength when stratified by gender and race. An
international database of CT scans of non-arthritic knees was accessed, and, using
computer software, length measurements of regions of interest were recorded. Measurements
included medial–lateral width of the posterior femoral condyles and width of the tibial
plateau (TW). These measurements were compared. Statistical analysis was performed
for the entire population, and subsequently for the population stratified by gender
and ethnic groupings. The review included 373 non-arthritic knees, each from a unique
patient. The cohort consisted of 184 males (49.3%) and 189 females (50.6%). About
117 patients were from Japan (31.4%), 100 were from India (26.8%), 87 were from South
Korea (23.3%), 43 were from China (11.5%), and 26 were from North America (7.0%).
The average age was 57.6 ± 8.6 years. The width of the proximal tibia was positively
correlated to posterior femoral condylar width, R
2 = 0.83. Gender stratification weakened the correlation, with female patients demonstrating
an R
2 of 0.64 and male patients an R
2 of 0.60. Ethnic stratification strengthened relationships in Japanese (R
2 = 0.87), North American (R
2 = 0.89), and South Korean (R
2 = 0.88) patients; and weakened them in Indian (R
2 = 0.72) and Chinese (R
2 = 0.82) patients. This study is the first to use CT to demonstrate the strength of
tibiofemoral relationships for individual demographic groups. These findings highlight
important differences in morphology and may be used to inform implant design, selection,
stocking, and supply. Further, these data may help identify patients who require different-sized
tibial and femoral components preoperatively.
Keywords
knee arthroplasty - knee anatomy - implant sizing - prosthesis design
