PMC9973276_01
Intraoperative estimation of varisation (abduction then internal rotation of the hip to get the ossific nucleus completely covered by the acetabulum): Hip is in neutral position (a). Hip is being abducted (b, c, d). Hip is being internally rotated (e, f). Black line is Perkin's line. "a angle" is the amount of hip abduction which was needed to make the nucleus completely covered by the acetabulum, which equals the amount of needed varus. Note that rotation was needed (e, f) to make the ossific nucleus completely inside the acetabulum.
sicotj-9-6-fig4_small.jpg
PMC9973276_01_sicotj-9-6-fig4_small.jpg
F4
In our practice, we decided to correct the valgus angle to the degree that results in complete coverage of the head by the acetabular roof, which was estimated intraoperatively by performing hip abduction under radiographic guidance (Figure 4).