The Early Tissue Morphological Study on Articular Cartilage Following the Repair of Subchondral Bone Defects

Abstract：Objective To study the early tissue morphologic changes of articular cartilage with bone grafting or bone ce-ment filling subchondral bone defects. Methods 32 New Zealand white rabbits were randomly divided into A,B,C and D groups. In the medial tibial condyle of the tibial plateau 5 mm below articular surface,simulated the local lesions of the benign bone tumor around the joints in the New Zealand white rabbits,we built an animal model of articular cartilage defect,and then filled with different materials(A group of autologous iliac bone,B group of bone cement,C group of bone cement combined with autologous iliac bone,D group blank control). The articular cartilage above the fillers was harvested 4 weeks postoperatively. Gross observation,histological examination. At the same time,the pathological the pathological changes of the cartilage degener-ation were observed in all groups by Mankin score,and the results were statisticaly analyzed. Results Gross observation:The A group was close to the normal articular cartilage,smooth surface,light blue and white,no having crack,erosion and ulcer;In group B,the surface was rough,pale or sallow,synovial hyperplasia,cartilage collapse and part of osteophyte formation;Group C,smooth surface,the color was yellow;The surface of the articular cartilage of the D group was smooth,and the color was slightly darker than that in the A group,and the group was similar to that of the A group. Histological examination:6 cases in group A were normal,2 cases showed early degeneration,the Mankin score was(0. 875 ± 1. 642)points;In the B group,7 cases showed intermediate degeneration,1 cases showed advanced degeneration,the Mankin score was(6. 875 ± 0. 991)points;In C group,6 cases showed early degeneration,2 cases were normal,the Mankin score was(3. 250 ± 2. 053)points;In D group,5 ca-ses were normal,3 cases showed early degeneration,the Mankin score was(1. 500 ± 2. 138)points. There was no significant difference between A group and D group(P > 0. 05),and there was significant difference between B group and A group(C)and B group(P < 0. 01,P < 0. 01). Conclusion In the case of the same degree of articular cartilage bone defect,the lesion of autogenous bone on early articular cartilage is the least,and the bone cement increases the damage of articular cartilage. How-ever,autogenous bone filled between bone cement and articular cartilage can reduce the injury of articular cartilage by bone ce-ment.