Clinical features

Clinically, Perthe's disease occurs in boys four times as frequently as girls

• the child is usually between 5 and 12 years old
• in general the child is quite well, but may be short
• usually there is no history of trauma.

The symptoms usually have been present for weeks as the child often does not complain and may include:

• an intermittent limp (abductor lurch), especially after exertion – classically painless (1)
• mild or intermittent pain in the groin area (often present only during physical activity)
  • may refer to knee and thigh in 25% of the patients
  • in some cases knee pain without groin or thigh pain will lead to delay in diagnosis (1)

On examination the hip may appear normal.

• there may be some muscle wasting, the affected leg’s thigh circumference is smaller than the other side.
• may develop hip adduction flexion contracture
• painful gait - Trendelenburg's sign may be positive
• short stature
• leg length inequality due to collapsed epiphysis or an adduction contracture (1).
• mobility of the joint is dependent on when the condition presents
  • in the early disease the hip joint is irritable and all movements are limited and their extremes are painful
  • if the condition is seen later then most movements are full. However, even in this later presentation abduction and internal rotation are usually limited. A fixed flexion deformity may be revealed by Thomas' test (1), where the uninvolved flexed leg is held against the abdomen of the supine patient to flatten the lumbar lordosis. If a hip flexion contracture is present in the opposite leg then it will not remain on the couch

Occasionally this condition may be bilateral (in 10% to 15% of children), usually in temporally staggered fashion, rather than simultaneously (1).

Reference:

1. Nelitz M, Lippacher S, Krauspe R, Reichel H. Perthes Disease Current Principles of Diagnosis and Treatment Dtsch Arztebl Int. 2009 July; 106(31-32): 517–523.