Thank you for your query. You mention the that 4 year girl is walking, runs and plays without any apparent discomfort. These are good signs but without looking at the child and the x-rays I will not do justice to the case. You should get the child examined by an orthopedic doctor who shall review the case and the x-rays to come to a diagnosis. Congenital hip dislocation
can be handled conservatively and there should not be long lasting deformity
. Rarely surgery will be required but I would leave it for the orthopedic surgeon to decide.
I hope I have answered your query to your satisfaction.
Wishing you all the best.