Posterior femoral condylar offsets of a Chinese population

Abstract

Background: The effect of posterior condylar offset (PCO) on maximal flexion of the knee after TKA is controversial. Another parameter, the posterior condylar offset ratio (PCOR), has been recently introduced to describe the posterior condylar geometry. This study measured the posterior femoral condyle geometry of a Chinese population and compared with those of a Western population published in the literature.

Methods: We measured the PCO and PCOR of 100 Chinese knees (50 males, 50 females). 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 (ACP) and posterior condylar offset (PCO). The PCOR was calculated as PCO/ACP. The measured PCO and PCOR were compared to those of a Western population reported in the literature.

Results: The PCOs were 25.80±2.71 and 27.32±2.34 mm for the Chinese females and males, respectively, where the PCO of the females was significantly smaller than that of the males (p<0.05). The PCORs were 0.47±0.04 and 0.46±0.03 for the Chinese females and males, respectively, where the PCORs were similar among the Chinese males and females (p>0.05).

Conclusions: While the PCO of the Chinese females was smaller than that of the males, their PCORs were similar. Compared to the data of a Western population reported in literature, the PCO of the Chinese population is significantly smaller, but the PCOR is significantly larger.

Keywords: Arthroplasty; Knee; Knee replacement; Posterior condylar offset; Posterior condylar offset ratio.