Metaphyseal changes in Perthes' disease: an experimental study

Area of Science:

• Orthopedics
• Pediatric Orthopedics
• Developmental Biology

Background:

• Perthes' disease is a childhood hip disorder of unknown etiology.
• Current understanding suggests epiphyseal ischemia may play a role.
• The specific mechanisms linking ischemia to metaphyseal and epiphyseal changes require further elucidation.

Purpose of the Study:

• To investigate the relationship between ischemia and the development of radiological and histological changes in the proximal femur.
• To determine if epiphyseal ischemia precedes or causes metaphyseal abnormalities observed in Perthes' disease.
• To explore the potential role of growth plate defects in the pathogenesis of femoral head deformity.

Main Methods:

• Induction of ischemia in the proximal femur of immature Gottingen mini-pigs via glass microsphere injection into the hind-limb circulation.
• Radiological assessment to identify abnormalities in the developing femur.
• Histological examination of the growth plate, metaphysis, and epiphysis to analyze tissue changes.

Main Results:

• One mini-pig developed radiological abnormalities in the femoral metaphysis, mimicking those seen in Perthes' disease.
• Histological findings revealed necrosis of a portion of the growth plate within the metaphysis, with a defect.
• Ischemia of the adjacent epiphysis was observed concurrently with the metaphyseal and growth plate changes.

Conclusions:

• The study supports the hypothesis that metaphyseal changes in Perthes' disease are secondary to epiphyseal ischemia.
• A growth plate defect, resulting from ischemia, may be a precursor to intrinsic deformity of the femoral head.
• This animal model provides insights into the pathogenesis of Perthes' disease, highlighting the critical role of vascular supply.