Legg-Calve-Perthes disease: what to know

The condition affects the femoral head, the rounded top of the thigh bone that sits in the hip socket. It often appears during childhood and may begin with a painless limp, hip stiffness, or pain felt in the thigh or knee. The hip can pass through loss of blood supply, fragmentation, healing, and reshaping. The final shape and fit of the joint depend on age, movement, and how well the ball remains seated in the socket.

A clinician may compare walking, hip rotation, leg length, and range of movement, then use imaging to follow the bone over time. A limp can have many causes; it does not by itself identify Perthes disease.

Care is tailored to the child’s age, hip movement, symptoms, and imaging. The team may recommend activity changes that reduce impact while preserving gentle movement, along with exercises supervised by paediatric physiotherapy. Follow-up imaging helps show whether the hip remains centred and how the bone is reshaping. Some children need a brace or an operation to improve containment; an osteotomy is one surgical approach that changes bone alignment.

Keep a record of limping, pain, stiffness, and activities that make symptoms worse. Do not force painful stretches or return to impact sports until the treating team gives specific guidance.

Arrange a medical assessment for a new or persistent limp, reduced hip movement, pain that returns with activity, or a child who avoids putting weight through one leg. Seek urgent care when a child cannot bear weight, has severe sudden pain, fever with a painful hip, or appears acutely unwell. These signs can have causes that need prompt assessment and are not specific to Perthes disease.

Ask which part of the Perthes process the imaging suggests, whether the hip is centred in its socket, which activities are suitable now, and how often follow-up is needed. Also ask what change in pain, limp, or movement should prompt an earlier review.