In some children, whose femoral head is not sufficiently round and where it will not centre deeply in the socket in abduction (outward movement of the leg), varus osteotomy is inappropriate, as is pelvic osteotomy.
In these patients where movement is limited and where the surgeon appreciates that the remodelled head will be significantly out of round, a valgus osteotomy can restore movement, restore leg length and generally improve the function of the hip.
This is a corrective osteotomy where the neck shaft angle is returned to normal. A blade plate, with one part seated into the neck of the femur and the side plate on the outside of the femur is used to provide the necessary angular correction.
The osteotomy will probably take three or four months to heal in adults, but less in children under 10. Protected weightbearing is advised for at least six to eight weeks. The plate will need to be removed at a year afterwards.
There is also evidence within the peer reviewed orthopaedic literature that because the hip moves more freely after a valgus osteotomy, the femoral head gradually rounds off over many years afterwards. Such patients are, however, sometimes left with some shallowness of the hip socket (residual acetabular dysplasia).
(Definition taken from http://www.the-hip-clinic.com/gen_Femoral_Osteotomy.htm )