Perthes disease is a “Self-limiting, non-inflammatory condition, affecting the capital femoral epiphysis with stages of degeneration & regeneration, leading to the restoration of the bone nucleus”.

It is the ischemic necrosis of the growing femoral head.

The exact cause is not known.

Factors that may be causative are trauma, hyperactivity, passive smoking, Protein C deficiency, Protein S deficiency, Antithrombin III deficiency, susceptible child, and hereditary factors – Type II collagen missense mutation.

Usually, children between 5 to 8 years are commonly affected.

Boys are more commonly affected than girls and 10 to 15% of cases affect the bilateral hip joint.

Children usually present with groin pain, pain around the knee joint, and abnormal walking patterns.

On examination, limp with decreased in the abduction and internal rotation is present. There will be thigh and calf wasting with limb length discrepancy.

Radiographs of the pelvis with both hip – Anteroposterior and Frog leg lateral view is the minimum investigation needed to make the diagnosis.

Other imaging includes hip arthrogram and magnetic resonance imaging [MRI](Perfusion).

Treatment early in the course of the disease includes containment procedure by non-operative methods like bracing or by operative methods which involve femoral [Varus derotation osteotomy] or pelvic surgery [Salters or Triple Osteotomy].

Treatment late in the course of the disease includes valgus femoral osteotomy.

Treatment in the healing stage of the disease includes trochanteric advancement with or without lengthening of the femoral neck.

Newer treatment modalities include bisphosphonates, hip arthrodiastasis, femoral head osteoplasty, femoral head reduction Osteotomy, Periacetabular osteotomy, and hip arthroscopy.

Usually, those with early-onset (before 6 years of age) have mild disease, those with onset between 6 and 9 years of age have moderate symptoms, and those with onset at 9 years of age or later have the most severe course and worst outcome.

The worst outcome is early arthritis of the hip joint.