When should you worry about limping with Perthes disease?

Perthes disease affects the developing hip. A child may protect the hip by shortening steps, turning the leg, or avoiding running; pain may be felt in the groin, thigh, or knee. Limping can vary from day to day, but a clear increase may mean the hip needs reassessment. Knee pain alone can still come from the hip, so the painful area does not always identify the source.

Follow the child’s activity and weight-bearing plan from the treating team. Avoid activities that cause pain or a more pronounced limp, and do not push through running or jumping. Record the start of the change, walking distance, pain location, stiffness, and any difficulty moving the hip. Keep scheduled follow-up appointments because hip movement and walking pattern may need repeated checks.

Contact the treating team promptly if the limp becomes noticeably worse, pain persists at rest, hip movement becomes more restricted, or the child cannot comfortably bear weight. Seek urgent care after a significant fall, with fever and a hot swollen joint, or if the leg appears deformed or becomes numb or cold.

Ask whether the change in walking suggests a new hip assessment, which activities are currently suitable, and how much weight the child may place on the leg. Ask which movement changes should lead to an earlier appointment.