磷酸镁骨粘合剂粘接骨折的实验研究

目的 探讨磷酸镁骨粘合剂（magnesium phosphate cement,MPC）粘接固定骨折的治疗效果。方法实验分为体外及体内两部分。体外部分：取54对新鲜猪股骨头标本,制备1cm^2骨折断面,随机分为6组,每组9对。分别用MPC粘接,在室温25℃和37℃、100％湿度两种不同条件下粘合固化30min,2、24h,行抗拉强度测试。体内部分：健康新西兰大白兔24只,通过开放截骨法制备兔双侧胫骨平台骨折模型。随机选取一侧为实验侧,采用MPC粘接;另一侧为对照侧,采用L形钢板内固定,术后均不作外固定。于术后3d,3、6和9周行X线片、周围血电解质、大体观察及组织学观察。结果体外部分：猪股骨头粘接体于两种不同条件下固化相同时间后其平均抗拉强度比较,差异无统计学意义（P〉0．05）。体内部分：X线片可见实验侧和对照侧骨折均于术后9周愈合,MPC随骨折愈合而逐渐被吸收。术后不同时间点周围血钙、镁浓度与术前比较,差异无统计学意义（P〉0．05）;磷浓度术后6周出现一过性升高,与术前比较差异有统计学意义（P〈0．05）。大体观察：术后3d,实验侧和对照侧均可见骨折块复位良好;3周,实验侧骨折处有部分MPC残留,对照侧可见部分骨折线;6周,实验侧骨折线消失,对照侧周围瘢痕组织和骨痂出现过度增生;9周,实验侧骨折处塑形良好,对照侧可见钢板遗留痕迹。组织学观察：实验侧术后3d,MPC与骨间界面清晰;3周,MPC开始降解,骨小梁长入其中;6周骨折愈合,仅少量MPC未吸收;9周MPC骨折愈合良好,MPC全部吸收。结论MPC的粘接强度高、能降解、对体内电解质离子浓度干扰小,是一种较为理想的骨粘合剂,可用于骨折的粘接固定。

EXPERIMENTAL STUDY ON MAGNESIUM PHOSPHATE CEMENT IN FRACTURE TREATMENT

OBJECTIVE: To investigate the effect of magnesium phosphate cement (MPC) to fix fractures. METHODS: In vitro: fifty-four pairs of fresh pig femoral heads were made 1 cm2 fracture and divided into 6 groups (n=9 pairs ). MPC was used to agglutinate fracture of femoral heads at 100% humidity and at 25 degrees C, 37 degrees C respectively. At 30 minutes, 2 and 24 hours after agglutination, the biomechanical strength was measured. In vivo: the tibia plateau fracture models on both sides of 24 rabbits were made, one side was fixed with "L" shaped plate, and the other side was fixed with MPC. Then the effect of treatment was investigated by macrography, micrography, radiography and the In vitro: the adhesive ability of changes of serum electrolyte levels at 3 days, 3, 6 and 9 weeks after operation. RESULTS: MPC was strong. At 24 hours after MPC agglutination, the average tensile strength was 117.16 +/- 23.29 N/cm2. In vivo: after 6 weeks of fixation, the X-ray results showed that all rabbits' tibia plateau fractures were healed without displacement, and MPC was absorbed gradually. The changes of serum electrolyte levels were very minimal. The macrography observation showed that reduction of fracture were good at 3 days after operation, partial MPC remained in fracture end at 3 weeks, fracture line disappeared at 6 weeks and good remodeling was achieved at 9 weeks after operation in the experimental group. The micrography observation showed that the interface between bone and MPC was distinct at 3 days, MPC was degraded gradually and trabeculae began to grow into MPC at 3 weeks, and almost all MPC was degraded at 6 and 9 weeks of operation. CONCLUSION: MPC is a promising biomaterial, and might potentially be used for fracture treatment.