Can also have shepard crook deformity. Ddx is Paget's disease
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What age group?
FD usually occurs in children ages 3-15
However, sometimes not diagnosed until adulthood
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Most common bone involvement?
Proximal femur most common ➔ rib ➔ maxilla ➔ tibia
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What is the pathology in Fibrous Dysplasia? What gene?
Mutation of GNAS1 gene resulting in abnormal GS Alpha protein resulting in overproduction of cAMP (cyclic adenosine monophosphate)in affected tissues
Increased proliferation of melanocytes resulting in cafe au lait spots
Developmental abnormality with harmatomatous proliferation of fibro-osseous tissue
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What syndrome is Fibrous Dysplasia associated with?
McCune Albright Syndrome
Triad – Café Au lait (Coast of maine) + Precocious Puberty + Fibrous dysplasia
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What other rarer syndrome is FD associated with?
Mazabraud’s syndrome
With intramuscular myxomas
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Why is there pain?
Not well understood by theorized to be due to ectopic sprouting and formation of neuroma-like structures by sensory and sympathetic nerve fibers also occur in the dysplastic skeleton
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Clinical presentation?
Presents with PAIN commonly
3 clinical presentations - Mono-ostotic, Poly-ostotic or Syndromic
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What investigation for Fibrous Dysplasia? What special histo and stain?
Bone scan - mono vs polyostotic
Classic Histology - Chinese letters on Van Giesen Stain
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Any risk of malignant change?
If malignant transformation 1% into osteosarcoma
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Management?
Dependant on symptoms - pain
If no pain ➔ observe
Painful/ impending fracture ➔ curettage and grafting and fixation
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Management of shepard crook deformity in young child? (TYS)
Realignment osteotomies with rod fixation
Sofield Miller “Shish Kebab technique”
Types of telescopic rods:
3rd gen Fassier Duval rod allows for one proximal insertion point with distal screw
1st gen Sheffield and 2nd gen Bailey Dubow rods require knee arthrotomy for distal fixation
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What will you do?
Will need fixation
Curettage, bone grafting (autologous) kiv allograft/ bone substitutes