Gender differences in morphology exist in posterior condylar offsets of the knee in Korean population

Purpose: This study aimed to analyze the morphometric data from magnetic resonance images of arthritic knees in Korean adults, and to identify the existence of morphological differences of femoral posterior condylar offset (PCO) between genders. Methods: The differences in anthropometric PCO data in 975 patients (825 female and 150 male) were evaluated. The distances from the anterior and posterior femoral shaft cortex line to the most posterior femoral condyle tangent line were defined as the anterior–posterior dimension (AP) and the PCO. The PCO ratio (PCOR) was calculated as PCO/AP. Results: The medial PCO was greater than the lateral PCO (26.3 ± 2.2 vs. 24.3 ± 2.3 mm, p < 0.01). This difference was observed in both female patients (medial: 26.2 ± 2.2 mm vs. lateral: 24.2 ± 2.2 mm, p < 0.01) and male patients (medial: 26.8 ± 2.3 mm vs. lateral: 24.8 ± 2.4 mm, p < 0.01). The medial and lateral PCO values were also greater in male patients than in female ones (p < 0.01). In contrast, PCOR was greater in female patients than in male ones, both in the medial and lateral femoral condyles (p < 0.01). Conclusions: It was shown that medial and lateral PCO and PCOR were asymmetric, and that there was gender difference in Korean population in our study. In addition, our data showed that the PCOR of contemporary TKAs may be small for Asian patients that may not be sufficient to meet the needs of the Korean patient population. These results confirm that a gender-specific femoral component design is necessary to recreate the PCO for male and female Asian populations. Level of evidence: Non-consecutive patients, Level III.