Definately it's expected only after surgery with immobility all the muscle will stiff it needs physiotherapy

Greetings Severe muscle stiffness, leg weakness, and a temporary loss of motor milestones like sitting or walking are entirely expected reactions after 6 weeks of rigid hip spica immobilization.Typical recovery times for full mobility and independent walking range between 3 to 6 months after cast removal as the muscles slowly rebuild strength.do physiotherapy and exercise

How old is the girl? Mostly after surgery and immobilisation, she requires training and physiotherapy for complete movement.

It is quite common for children to have stiffness, weakness, and reduced use of the operated leg after DDH surgery and 6 weeks of hip spica immobilization. Even if your daughter was previously sitting and walking independently, she may temporarily lose these skills and take several weeks to months to regain them. The fact that her follow-up X-rays are satisfactory is reassuring. Encourage gentle movement and normal play as advised by her orthopedic surgeon, and discuss whether physiotherapy would be beneficial. However, if she develops increasing pain, swelling, worsening weakness, or shows no gradual improvement over time, she should be reassessed by her treating orthopedic surgeon.