上肢骨干骨折内固定实验动物模型的建立

目的：建屯内固定术治疗上肢骨干骨折的实验动物模型，为研究不同内固定下骨折愈合的机制提供实验对象。方法：新西兰大白兔25只，随机选择一侧前肢上臂，取外侧切口显露肱骨，以线锯在其中段截骨，复位后植入天鹅记忆接骨器(SMC组)；同法在对侧植入4孔动力加压接骨板(DCP组)。分别在术后l、2、48、12周摄片观察骨折愈合情况，并处死5只动物取材，HE染色，行病理学观察。结果：术后动物全部成活，前肢负重明显低于后肢。X线片显示：SMC组在术后8周骨折愈合，愈合过程中未见明显外骨痂及板下皮质骨疏松；DCP组骨折愈合速度较慢，术后12周时骨折端仍有骨痂，伴局部皮质骨疏松。，病理学观察：术后8周，SMC组骨折端直接由板层骨替代；术后12周，DCP组形成骨性连接，处于改建塑形期。结论：SMC固定下实验性兔肱骨干骨折愈合过程与临床相似，愈合速度和质量优于DCP固定。兔肱骨干骨折内固定模型是一种较为理想的上肢骨干骨折内固定实验模型。

Experimental model for internal fixation of fracture of shaft of upper extremity

Objective:To establish the experimental model for various internal fixation devices treating fracture of shaft of upper extremity.Methods:25 rabbits were used for experiment.The bi-lateral humerus were exposed via lateral incision,then transverse osteotomies was made at midshafts by a wire saw.After reduction,one humeral fracture was fixed by swan-like memory connector (SMC group) at random,the contralateral humerus fracture was fixed by 4-hole dynamic compressive plate (DCP group ).At 1,2,4,8,12 weeks after operation,X-ray examination were taken,and at each time internal 5 rabitts were sacrificed to harvest samples for pathological observation.Results:All the animals survived,the forelimb loaded less weight than hindlimb obviously.In SMC group,the fracture achieved healing with replacement of lamellar bone at 8 weeks after operation,without external callus or osteoporosis.In DCP group,fracture achieved bone healing with external callus and osteoporosis at 12 weeks after operation,when it was the period of bone reconstruction and remolding.Conclusion:The healing process of experimental humeral fracture of rabbit fixed by SMC imitates the process of humeral fracture of human,healing speed being faster than that fixed by DCP,healing quality being better than that fixed by DCP.The rabbit model is an ideal experimental model for internal fixation treating fracture of shaft of upper extremity.