Objective To further investigate the possible mechanism of the correction of scol iosis with Staple by quantifying the effect of Staple on growth rate of vertebral growth plates in goat scol iosis. Methods Experimental scol iosis was created in 10 juvenile female goats by using unilateral pedicle screws asymmetric tethering. After 8-10 weeks, goats were divided randomly into Staple treated group (n=5) and control group (n=5). All tethers were removed in both groups and Staplegroup underwent anterior vertebral stapl ing with 4-5 shape memory alloy Staples along the convexity of the maximal curvature after posterior tether being removed. All goats were observed for an additional 8-13 weeks, the Cobb angle were measured to observe the correction of scol iosis. The fluorochromes Oxytetracycl ine and Calcein were administered respectively 18 and 3 days before death to label the ossifying front under the growth plates. Superior intervertebral disc of apical vertebra and two adjacent growth plates were completely harvested in all goats. All specimens were embedded with polymethyl methacrylate and sl iced undecalcified. The growth rates of the vertebral growth plates were calculated by measuring the distance between the two fluorescent l ines with fluorescence microscope. Results Nine (5 in Staple treated group and 4 in control group) of 10 tethered goats had progressive scol iotic curves of significant magnitude after 8-10 weeks of tethering. In Staple treated group, the Cobb angles were (34.8 ± 12.4)° at the instant after treatment , and (15.6 ± 11.7)° 8-13 weeks after treatment; showing statistically significant difference (P lt; 0.05). In the control group, the Cobb angles were (49.3 ± 18.0)° at the instant after treatment, and(49.0 ± 17.6)° 8-13 weeks after treatment; showing no statistically significant difference (P gt; 0.05). In Staple treated group, the growth rate of growth plate in the concavity (3.27 ± 0.96) μm/d was higher than that in convexity (1.84 ± 0.52) μm/d (P lt; 0.05), while the growth rate of the concavity did not differ significantly from that of the convexity in control group (P gt; 0.05). Conclusion Staple can significantly alter the growth rates of two sides of vertebrae in scol iosis with the growth rate of concavity exceeding the one of convexity, which results in correction of deformity.
Objective To sum up the experimental and clinical history as wellas latest development of repair of growth plate injury Methods Recent articles about repair of growth plate injury were extensively reviewed and major reparative methods were introduced, especially including tissue engineering research on growth plate.Results Repair of growth plate injury was a great difficulty inexperimental study and clinical treatment of pediatric orthopedics. Transplantation of free growth plate and cartilage were unfavorably used because of lack ofblood supplement. Although circulation problem was solved by transplantation ofvascularized growth plate, autografts of epiphyseal cartilage were involved in limitation of donor, and allografts of epiphyseal cartilage induced immunological reaction. Noncartilaginous tissue and material could only prevent formation of bony bridge in small defect of growth plate and lacked ability of regenerative repair. Transplantationof tissue engineered cartilage and chondrocytes might be a choice for repair ofgrowth plate injury Conclusion Owing to lack of safe and effective methods ofrepairing growth plate injury, research on chondrocyte and tissue engineered cartilage should be further done.
OBJECTIVE To investigate possibility of cartilage cultured in centrifuge tube as graft materials. METHODS: Articular chondrocytes isolated from a 3-week-old rabbit formed cartilage after cultivation for 2 weeks. Articular cartilage of humeral head, growth plate of proximal tibia and meniscus were collected from a 6-week-old rabbit. The ultrastructure of chondrocytes and extracellular matrix in the three kinds of cartilages and cultured cartilage were observed by transmission electronic microscopy. RESULTS: Cartilage cultured in centrifuge tube possessed unique ultrastructure and was similar to articular cartilage and growth plate, but it was markedly different from meniscus. The four kinds of cartilages were characteristic of respectively different chondrocytes and extracellular matrix. Cultured cartilage showed typical apoptosis of chondrocytes and "dark chondrocytes" appeared in growth plate. Condrocyte apoptosis was not seen in articular cartilage and meniscus. CONCLUSION: Cartilage cultured in centrifuge tube has unique ultrastructure and may be used as graft materials for articular cartilage and growth plate.
OBJECTIVE To prevent early closure of growth plate and developmental deformities of limbs by allografts of cultured cartilages into growth plate defects of rabbits. METHODS Chondrocytes isolated from articular cartilage of 1-month rabbits formed cartilage after cultivation in centrifuge tubes. The cartilages cultured for two weeks were implanted into growth plate defects of proximal tibiae of 6-weeks rabbits. At 4th and 16th weeks, X-ray, histologic and immunohistochemical examination were performed. RESULTS The tibiae had no marked deformities after 4 weeks of operation. Histologic examinations showed that the defects were filled with cartilage. Immunohistochemical results of type II collagen were positive. The tibiae with allografts of cultured cartilages had no evident deformities after 16 weeks of operation. Histologic examination showed nearly closure of growth plates. On the contrary, the tibiae on control side formed severe deformities and growth plate were closed. CONCLUSION Allograft of cultured cartilages into growth plate defects may replace lost growth plate tissues, maintain normal growth of limbs and prevent developmental deformity.
OBJECTIVE: To sum up the studying course and latter development of repair of injury of growth plate. METHODS: Recent original articles about repair of injury of growth plate were extensively reviewed, focused on the progresses in understanding repair of injury of growth plate and comparison of several major reparative methods. RESULTS: Repair of injury of growth plate is a great difficulty in experimental study and clinical treatment of pediatric orthopedics. Graft of free growth plate and cartilage were unfavorably used because of lack of blood supplement. Although graft of vascularized growth plate solved circulation problem, both two kinds of grafts were involved in limitation of donor and immunologic reaction. Non-cartilaginous tissue and material could only prevent formation of bony bridge in small defect of growth plate and lacked ability of regenerative repair. Transfer of tissue engineered cartilage might be the best choice for repair of injury of growth plate. CONCLUSION: Considering source of transplanted material, reparative effect and adverse reaction, repair of injury of growth plate with tissue engineered cartilage deserves further investigation.
ObjectiveTo summarize the research progress of pathological manifestations and mechanism of endochondral ossification in osteoarthritis (OA). MethodsThe literature about endochondral ossification, bone-cartilage remodeling in OA, and joints development was reviewed, analyzed, and summarized. ResultsChondrocyte hypertrophy and apoptosis, vascular invasion, replication of the tidemark, thickening calcified cartilage, and thinning superficial cartilage are the characteristics of cartilage degeneration in OA. Articular cartilage and growth plate are similar in structure, and cartilage degeneration in OA is similar to a process of endochondral ossification of the growth plate. ConclusionLoss of stability characterization from resting metabolic balance to a high conversion state of temporary cartilage in stimulation of abnormal mechanical stresses and cytokines would subsequently contributed to continual calcification and remodeling of articular cartilage, which may be the key link of the initiation and development of OA.