1 = Abstract = Effect of Curettage and DBM-CaSO4 Graft for the Treatment of Ischemic Necrosis of the Capital Femoral Epiphysis in Immature Pigs Ki Seok Lee, M.D., Sun-Yong Kim, M.D., In Ho Choi, M.D.* Department of Orthopaedic Surgery, Yonsei University, College of Medicine, Seoul, Korea Department of Orthopaedic Surgery, Seoul National University, College of Medicine, Seoul, Korea* Purpose: The purpose of this study was to determine the effect of curettage and DBM complex graft as a new treatment modality for LCP disease using piglet capital femoral epiphysis ischemic necrosis model. Materials and Methods: Five to six weeks old piglets were used for the experiment. Ischemic necrosis of the capital femoral epiphysis was surgically induced by cervical ligation on both sides. Three weeks following ischemic insult, the left hip joint was approached medially. About 15% of the necrotic capital femoral epiphysis was curetted through a window which was opened at medial cervical cortex, then, demineralized bone matrix complex was engrafted. The right femoral heads served as controls. Piglets were sacrificed three, six, nine, and twelve weeks following were harvested for histologic examination. Results: In control group, photomicrographs of specimens showed central necrosis and fibrovascular invasion in capital femoral necrosis at three weeks after ischemic insult. Six, nine, and twelve weeks following ischemic insult, fibrovascular invasion advanced without noticeable new bone formation and collapse of femoral head progressed. At twelve weeks, definite coxa plana developed. In curettage and DBM complex graft group, there was evident new bone formation observed in the site of DBM complex graft. At three weeks, new bone formation along with fibrovascular invasion was observed around the engrafted DBM complex mainly in the cervical metaphyseal area. At six and nine weeks, new bone formation progressed into the engrafted DBM complex in the cervical metaphysis and around the engrafted DBM complex in the capital femoral epiphysis. At twelve weeks, new bone along with new cartilage formation was observed in the capital femoral epiphysis. Conclusion: In conclusion, curettage and DBM complex graft is thought to be an effective treatment modality that promote regeneration of ischemic necrosis of capital femoral epiphysis. Key Words: Legg-Calve -Perthes disease, Ischemic necrosis, Capital femoral epiphysis, Curettage, Demineralized bone matrix (DBM)
4 Table 1. Number of piglet s femoral heads used in the study. Harvest time* Experimental group Curettage & DBM graft (N=21) Control group Simple observation (N=24) 3 weeks weeks weeks weeks 6 6 *From curettage & DBM graft.
5 Fig. 1. Photomicrographs of femur head of each groups stained with Hematoxylin and Eosin at original scale. In control (simple observation) group, collapse of femoral head progressed with time, resulted in coxa plana deformity. In experimental (DBM+CaSO4 graft) group, partial disruption of metaphyseal physis reflects the passage of previous curettage & DBM complex graft. New bone formation at the site of engrafted DBM complex was observed, but femoral head collapsed with time.
7 Fig. 2. Photomicrographs of femur head of each groups stained with Hematoxylin and Eosin at low magnification ( 20). At the top of the figure is a schematic drawing of the center of the secondary ossification center corresponding to the coronal sections of figures in the table. In control (simple observation) group, necrotic tissues are absorbed and replaced by fibrous tissue without new bone formation. In experimental (DBM+CaSO4 graft) group, active new bone formation at the site of graft is observed nine weeks after graft procedure.
8 Fig. 3. Photomicrographs of femur head of experimental (DBM+CaSO4 graft) group stained with Hematoxylin & Eosin and Masson s Trichrome at high magnification ( 40). At the top of the figure is a schematic drawing of the site of engrafted DBM complex in the secondary ossification center corresponding to the coronal sections of figures in the table. Until 6 weeks after DBM complex graft, there is no active new bone formation observed around the engrafted DBM complex in the secondary ossification center. At nine weeks after DBM complex graft, fibrous tissue and early stage of endochondral bone mixed with fibrous tissues were observe (black arrow). At twelve weeks after DBM complex graft, new bone growth as indicated by osteocytes forming cement lines on Masson s Trichrome staining sections (white arrows).
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