Histomorphologic And Immunohistochemical Studies Of Ligamentum Capitis Femoris In Developmental Dislocation Of The Hip

Objective: A morphologic, histological and immunohistochemical studies of Ligamentum Capitis Femoris (LCF) in Developmental Dislocation of the Hip (DDH) was designed to investigate the pathology and pathogenesis of formation in DDH.Materials and Methods: 36 LCF for specimens biopsy were taken during the surgery in 29 patients with 36 hips from January 2005 to November 2006. Two LCF discarded as its degeneration.Among 34 LCF in 27 patients with 34 hips, the mean age was 19.8 month (range from 9～48 month); 15 patients with 18 hips were younger than 18 month old and 12 patients with 16 hips were beyond; 20 patients with 25 hips were female and 7 patients with 9 hips were male; 20 cases were unilateral DDH and 7 were bilateral; 22 specimens came from left and 12 from right.All specimens were studied with morphologic observation, histological stain and immunohistochemistry. An immunohistochemical technique (S-P method) was applied to demonstrate the typeⅠ,Ⅲcollagen of the LCF and performed with computer imaging analysis and calculated the positive staining area, then compared the content of collagen change in semiquantitative.Results: Gross, Morphologic and histological observations: the LCF was hyperplastic, hypertrophia considerably. But there was no artery of ligamentum tere. The length was (27.56±4.84) mm, the average width was (12.41±2.69) mm, There were no statistical significant between the different age groups, different gender groups, left and right groups, unilateral and bilateral groups (P>0.05).Immunohistochemical stain: the content of collagen typeⅠincreased greatly. Positive staining area was about (93.31±3.26) %, collagen typeⅢdecreased, which was about (6.59±3.36) %, both showed negative correlation (r=–0.3480, P<0.05). There were distinctly statistical significant between the different age groups, different gender groups (P<0.01), but no statistical significant between the left and right groups, unilateral and bilateral groups (P>0.05).Conclusions:1. The LCF of patients with DDH was hyperplastic, hypertrophia; almost occupied the whole acetabular which sign was larger than the normal infant and similar to the adult.2. No artery of ligamentum tere existed in LCF. There were a large number of capillaries increasing in the LCF close to the acetabular, but no blood vessel eyeable in the LCF close to the head of femur which showed the partial hyline degeneration.3. The distribution and content of collagen of the LCF in DDH changed considerably. The collagen fiber deranged and distributed asymmetric. The content of collagen typeⅠincreased greatly, but collagen typeⅢdecreased. The above change was consistent with the tissue fibrosis and fibroelastosis.4. The hyperplastic, hypertrophia LCF in DDH was a secondary change. In earlier period it would prevent the dislocation of the femoral head, but late it started decompensation and fibrosis, which hindered the reduction of the head of femur or leaded to avascular necrosis.