The Contribution of the Ossific Nucleus to the Structural Stiffness of the Capital Femoral Epiphysis: A Porcine Model for DDH
ABSTRACT The preosseous femoral head is thought to be vulnerable to compressive ischemic injury during the treatment of developmental dysplasia of the hip. The ossific nucleus has been proposed to increase the mechanical strength of the capital femoral epiphysis (CFE) and to decrease the risk of avascular necrosis. Sixty mixed-breed fetal and postgestational femoral head specimens were evaluated for structural stiffness in relation to the size of the ossific nucleus within the CFE. The structural stiffness of the CFE in the porcine model was found to increase exponentially with the size of the ossific nucleus. A finite-element model revealed that the presence of an ossific nucleus occupying 40% of the epiphyseal volume reduced the compressive strain in the region of the posterior-superior branch of the medial circumflex artery by an average of 54%. The results of this study support the hypothesis that the presence of the ossific nucleus may protect the CFE from compressive ischemic injury in the treatment of DDH.
- SourceAvailable from: Marcin Sibiński
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- "W oparciu o badania anatomiczne i biomechaniczne uzasadnili to zmianą unaczynienia bliższej nasady kości udowej w momencie pojawienia się JKGKU (powstawanie połączeń naczyniowych) oraz jej większą sztywnością wraz z powiększaniem się jądra i tym samym większą wytrzymałością mechaniczną   . Dowiedli oni, ż e jądro kostnienia zajmujące 40% objętości nasady kości udowej redukowało naciski na tylno-górną część gałęzi tętnicy okalającej udo przyśrodkowej o 54% . Według naszej wiedzy były to jedyne opublikowane badania doświadczalne nad tym zagadnieniem. "
ABSTRACT: The aim of the study was to compare long-term radiological results and appearance of avascular necrosis in hips with and without ossific nucleus of femoral head at the beginning of treatment. We retrospectively reviewed radiographs of 155 hips in 107 children treated for developmental dislocation of the hip. The age of children at the onset of treatment was 14.2 months. Minimal age at last follow-up was 14 years. Statistical analysis showed no correlation between presence or size of ossific nucleus and avascular necrosis of femoral head or final radiological outcomes. We do not recommend delay in the treatment of dislocated joint on the bases of presence and size of ossific nucleus. This delay may result in lost of optimal time for remodeling of affected hip joint.Chirurgia narzadow ruchu i ortopedia polska 74(2):79-81.
Article: M.Sc. of Medical Physiology
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ABSTRACT: Avascular necrosis (AVN) can be a devastating com- plication of the treatment of developmental dysplasia of the hip (DDH) and as such has received much attention. Despite this at- tention, little consensus exists regarding the definition, prevention, or treatment of AVN when it occurs. The literature is reviewed regarding the incidence, definition, and etiology of AVN. Diag- nostic criteria are evaluated and the potential role of magnetic resonance imaging (MRI) is discussed. The currently used classi- fication systems are also surveyed. More in-depth analysis is ap- plied to the controversies regarding efforts at preventing AVN. These include the protective properties of the ossific nucleus, the current role of traction, the importance of position of immobiliza- tion, and femoral shortening osteotomies.