Three-Dimensional Morphometry of Normal Japanese Knees For Designing Total Knee Arthroplasty

Abstract Background: To examine racial and sex-related differences in bone morphology and to determine whether it is necessary to take sex-related and ethnic differences into account in designing artificial knee joints. Methods: Hundred Japanese women normal knees, 88 Japanese men normal knees, and 18 Caucasian women normal knees were examined. Knee joints were measured to enable selection and design of artificial knee joints based on assumed bone resection face dimensions in TKA. Results: The dimensional measurements were performed by reading the three-dimensional CT based bone model. F-MAP/F-ML and F-LAP/F-ML relative to F-ML dimensions and T-MAP/T-ML and T-LAP/T-ML relative to T-ML dimensions were determined in both sexes. Results: In both sexes and in both the femur and tibia, the value increased with decreasing size. Therefore, the width narrowed with decreasing size. It was considered that the width may be narrower in women than in men because women have smaller bone sizes than men. The matching ratio was considered to improve as the aspect ratio is adjusted according to the size when an artificial joint is designed. There were no significant differences in the measured sagittal flexion angle between the Japanese and Caucasian women. Conclusion: The individual differences were greater than the racial differences; therefore, we consider that there is no significant need to change the shape of the artificial knee joint according to racial differences in bone morphology.