Perthes Disease

Question 1

pathogenesis

Answer 1

Osteochondritis of the femoral head
Femoral head transiently loses its blood supply

Necrosis Subsequent abnormal growth
Femoral head may collapse/fracture

Subsequent remodelling – how shape of femoral head & congruence of joint is determined by age of onset (older children faring worse) & the amount of collapse incongruent joint to early onset arthritis

Question 2

who gets it?

Answer 2

idiopathic 4-9 yrs boys more than girls - very active boys short stature

Question 3

how is it investigated?

Answer 3

PainLimpmostly unilateralif bilateral– underlying skeletal dysplasia or thrombophiliaLoss of internal rotation – usually first clinical signLoss of abductionTrendellenburg test positive – gluteal weakness o lever arm of the abductor muscles is altered – weakness!

Question 4

how is investigated?

Answer 4

regular X-ray observation

Question 5

how is it managed?

Answer 5

regular x-ray ovbservation avoidance of physical activity 50% do well sometimes femoral head becomes aspherical, flattened, widened severe cases – hip replacement in adolescence/ early adulthood if femoral head sublux (partially dislocate) – osteotomy of femur or acetabulum