Analysis of the patellofemoral congruence angle according to the rotational alignment of the femoral component in navigation-guided TKA.

The relative femoral resection plane from the posterior condylar axis was determined by the navigation system. The investigators found that there was a relatively variable range of femoral component rotation intraoperatively (0 degrees - 6 degrees) and attempted to determine whether this would affect postoperative patellofemoral congruence. Forty-six varus knees from 34 patients were included in the study; group 1 (15 knees) with 0 degrees or 1 degrees and group 2 (31 knees) with 3 degrees to 6 degrees . The mean (P = .855) and percentage of abnormal values (patellofemoral congruence angle <16 degrees) (P = .193) in preoperative radiographs showed no significant differences between the two groups. In postoperative findings, the mean of patellofemoral congruence angles in group 1 (20.5 degrees) showed a higher tendency than that in group 2 (14.1 degrees), but no statistically significant difference between two groups (P = .089). In conclusion, there was no statistically significant difference in patellofemoral congruence between 2 groups.