An Experiment Study On Correlation Between Skeletal Fixation And Tendon Repair In Chicken Metatarsal Fracture

Objective: In Chicken model fracture of metatarsal bone and rupture of tendon was made. The correlation of fracture healing and tendon adhesion are investigated in different internal fixation methods which will afford an reliable basis for clinical application.Methods: A series of 33 healthy chickens, their 3rd metatarsal bones are fractured transversely and the extensor and flexor tendons are severed at the same level. Then the models are divided randomly into 4 groups. In Group A, Kirshner' s wire is inserted longitudinally through the joint. In Group B, the fracture is immobilized by crossing Kirshner' s wire. In GroupC, The fracture is immobilized with single oblique Kirshner' s wire. In GorupD, crucial wire fixation is made. The extensor and flexor tendons are repaired with figure-of-8 suture and the leg is immobilized with plaster of Paris cast for 4 weeks. Rehabilitation is begun since the 2nd postoperative week , active and passive motion is exercised in an increasing regime. At end of 8th week, the chickens are sacrificed and the specimens taken. The fracture healing is observed with naked eye and the maximal breaking strength measured by biomechanical method. The tendon healing is observed macroscopically and histologically. The adhesion of tendon is observed with naked eye and colored sonography and the gliding distance is observed too.Result: Observation made at end of 8th week reveals that most fractures get bony union. Alignment of fracture is found to be good in Groups B and D while varying degree rotational and angulatory displacement are found in Groups A and C. In Group A, articular injury and ankylosis are present. The values of maximal fracture load in all groups have no statistical difference. (p>0. 05) All extensor and flexor tendons heal alright. The adhesion formation and excursion of tendon gliding in Group A is inferior to other 3 groups, (p<0.05). Evaluation of simulating TAM test shows Group A the toe function is not as good as other 3 groups. There is no statistical difference exists between the 3 other groups. The degrees of adhesion of extensor andflexor tendons in chicken specimens in the same group have obvious statistical difference (p<0.05). Histological observation of the specimens stained by H E stain, the tenocytes, arrangement of collagen fibers and the thickness are all shown to be well healed.Conclusion: The result shows longitudinal transarticular Kirshner's wire fixation is unfavorable to regulate tendon tension and postoperative rehabilitation. The rotational and angular displacement and tendon adhesion are apt to occur. Transarticular transfixion is apt to injure the joint cartilage and causing joint stiffness. Those methods which give strong fracture fixation without compromise the joint surface are favorable to regulate tendon tension, and promote early rehabilitation. They are important principles for preventing tendon adhesion and achieving better final function.