后交叉韧带断裂和重建对兔膝关节软骨退变的影响

目的 探讨后交叉韧带（PCL）断裂和重建对膝关节软骨退变的影响。方法将33只新西兰大白兔共分3组,实验Ⅰ组：21只兔右膝关节PCL切断,左膝行单纯关节切开术作为对照组;实验Ⅱ组：12只兔右膝关节PCL切断后即刻重建。对照组、实验Ⅰ组术后6、12、26周处死动物,实验组Ⅱ术后12、26周处死动物。通过墨汁染色、HE染色、甲苯胺蓝染色、免疫组化染色（Ⅰ型胶原,Ⅱ型胶原和Ⅲ型胶原单克隆抗体）及扫描电镜方法对各组膝关节软骨退变的情况进行观察分析。结果实验Ⅰ组：PCL切断后26周标本有明显膝关节退行性改变;PCL切断后26周标本关节软骨继发损伤明显重于对照组术后同期标本;内髁软骨可见范围较大的软骨纤维化现象,达深层,细胞数量减少,Mankin评分平均7．7;纤维化的软骨层Ⅰ、Ⅲ型胶原染色阳性,Ⅱ型胶原染色较浅。扫描电镜上股骨内髁各时间段内都可见软骨损伤,而对照组只表现有垄沟样结构的紊乱。实验Ⅱ组：仅部分标本有轻度软骨损伤,术后26周时滑车及内髁处软骨继发损伤较实验Ⅰ组明显减轻。结论PCL断裂可以继发关节软骨的退行性改变,且以内侧间室和髌股关节为主,并随时间的延长逐渐加重。PCL断裂后即刻重建可以有效阻止关节软骨继发损伤的发生。

The effect of rupture and reconstruction of posterior cruciate ligament on the degeneration of articular cartilage in rabbit knee

OBJECTIVE: To investigate the effect of rupture and reconstruction of the posterior cruciate ligament (PCL) on the degeneration of rabbit knee joint. METHODS: Thirty-three mature New Zealand white rabbits were divided into 3 groups. In experiment group I, the PCL of the right knees in 21 rabbits were resected, the contralateral joints as control group, in which only a medial arthrotomy was performed. In experiment group II, the PCL of the right knees in 12 rabbits were immediately reconstructed after PCL were resected. In experiment group I and control group the rabbits were respectively killed 6, 12 and 26 weeks after the operation. In experiment group II the rabbits were respectively killed 12, 26 weeks after the operation. The methods of ink staining, histology, immunohistochemistry and SEM were used to analyze the changes of articular cartilage of the joints. RESULTS: In experiment group I, the knee joints had obvious degeneration of articular cartilage at 26 weeks. The quantitative analysis of the results of the ink staining method showed the degeneration of knee articular cartilage was more serious at 26 weeks than that at 26 weeks in control group. Histological results demonstrated: the large area of fibrosis of cartilage could be seen in the medial condyle at 26 weeks; the fibrosis was deep into the deep layer of cartilage and the number of cells decreased; the average Mankin's score was 7.7. At 26 weeks, type I and III collagen were detected in fibrotic cartilage, while the staining of type II collagen was slight. In experiment group I, the injuries of cartilage in medial condyle could be seen at every stage through SEM, while the surface of cartilage demonstrated disorder in control group through SEM. In experiment group II, only a few specimens had mild injuries of cartilage, the degeneration of cartilage in medial condyle and trochlea were slighter at 26 weeks than that in experiment group I. CONCLUSIONS: PCL rupture can result in articular cartilage degeneration, which develops as time goes on. The degeneration of articular cartilage is more serious in medial compartment and patellofemoral joint than those in other positions. Immediate reconstruction of PCL can effectively prevent articular cartilage degeneration.