Could fulkerson osteotomy help correct bow legs?

No. A fulkerson osteotomy involves elevating the patella tendon attachment to the tibia (shin bone) to decrease the force beteeen the femur (thigh bone) and patella. A high tibia osteotomy (or proximal tibia osteotomy) is carried out to re-align bow legs secondary to medial (inner) knee arthritis and decrease medial knee pain. They are 2 different operations.
No. Fulkerson osteotomy address patellofemoral pathology, not tibial bowing.