小兒股骨頭壞死症

此症常發於四至八歲之間的男孩子.

症狀之出現為漸進性.病童有疼痛、跛行現象，沒有全身症狀.患側髖部活動受制.

照 骨盤 X 光 時.即可見到 股骨頭變形、崩壞、移位 現象.而髖臼本身在初期還是好好的.這足以與結核病或其他疾病區別.

因為此症的原因並不清楚，所以也沒有好的預防方法.

治療須按病人發病年齡、現在年齡、壞死程度、是否有半脫位、關節活動度等來作決定.

若病人年齡小於六歲.壞死小於一半時.多半不需治療.但若壞死超過一半.且有半脫位現象時.則需考慮外張支架治療.

發病年齡大於七歲.壞死超過一半.有半脫位現象時.最好以手術治療.可以得到較佳的結果.

不管何種治療.其目標都希望股骨頭在癒合的過程中得到保護.不致變形.若變形或半脫位.將來都容易發生關節炎.

- self limiting hip disorder caused by a varying degree of ischemia and subsequent necrosis of the femoral head; - avascular necrosis of nucleus of proximal femoral epiphysis, abnormal growth of the physis, and eventual remodeling of regenerated bone are the key features of this disorder; - loss of blood supply to the epiphysis is thought to be the essential lesion; - usually seen in 4 to 8 yr old boy with delayed skeletal maturity; - male to female ratio: 4-5 to 1; - rare in blacks; - increased incidence with a positive family history, low birth wt, and abnormal pregnancy / delivery; - upto 12% of cases are bilateral but will be at different stages & are asymmetric (vs. MED ) - ageis the key to the prognosis - after 8 yr represents poor prognosis;

- Clinical Presentation: - includes pain (often knee pain) effusion (from synovitis) & a limp; - early phase: - limited abduction of hip & limited internal rotation in both flexion & extension are seen; - antalgic gait (due to pain); - late phase: Trendelenburg gait;

- Long Term Consequences: - coxa magna - coxa plana - coxa breva - hinged abduction: - occurs when an enlarged femoral head is laterally extruded and impinges against the acetabular rim when the hip is abducted;

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