What should you know about Perthes disease in children?

Perthes disease affects the developing top of the thigh bone inside the hip joint. The bone can become weaker and change shape while the condition runs through stages of loss, repair, and remodelling. Children may limp, develop hip or groin pain, or report pain in the thigh or knee. Stiffness and reduced hip movement can be more noticeable than pain.

The child may need periods of reduced impact, but the exact plan depends on age, symptoms, hip movement, and imaging. The aim is to keep the ball of the hip well positioned and moving as comfortably as possible while healing progresses.

Attend orthopaedic reviews and follow restrictions on running, jumping, or contact play when advised. Physiotherapy may use gentle range-of-motion work, muscle strengthening, and activities that protect hip movement. Choose low-impact options recommended by the care team, and tell them if exercises increase pain or produce a lasting limp. School staff and coaches may need clear guidance about suitable activities and rest breaks.

Contact the treating team if limping worsens, hip movement becomes more restricted, pain increases, or a child stops joining normal activities. Seek urgent assessment after an injury that causes inability to bear weight, a visibly shortened or deformed leg, severe pain, numbness, or a cold foot. Fever or a child who appears acutely unwell with hip pain also needs prompt medical attention.

Ask which activities are allowed, how hip movement should be practised, and what changes on imaging will guide the plan. Clarify school and sports restrictions, pain relief options, and which symptoms should prompt an earlier appointment.