Experimental Research On PDS Reinforced Suture Combined With Early Functional Exercise To Prevent Tendon Adhesion

Objective:Tendon adhesion during trauma healing procedure has been one of the problems that surgeons encounter in daily clinical work. Severe adhesion requires a secondary or even multiple surgical interventions, which would not only cause additional suffering and economic burdens to patients, but also lead to a waste in medical resources. Therefore, the prevention of tendon adhesion has been a worldwide hot spot for years. Tendons were considered unable to regenerate by surgeons in the early 20 th century. Based on their theory, epitendineum and surrounding tissues were must parts for the healing procedure of tendon damage, which could form granulation tissue to fill the lesions lead to re-union of a damaged tendon. Thus tendon adhesion seemed to be inevitable. Nevertheless, the regenerative ability of tendons was revealed as people’s knowledge in histology accumulated. There now considered to be two types of healing procedure in tendon damage. While the exogenous healing is led by epitendineum and surrounding tissues as mentioned above, endogenous healing is caused by the regeneration and rearrangement of fibroblasts and the tendon cells. Consequently, to reduce the risk of tendon adhesion,endogenous healing should be enhanced while exogenous healing should be inhibited at the same time.By comparing the changes of the gross anatomy, histology, biomechanics and hydroxyproline(HYP) content of the injured flexor tendon which gets PDS reinforced suture and early functional exercise with the control group, to study the curative effect and mechanism of PDS reinforced suture and early functional exercise to prevent tendon adhesion.Methods:Sixty healthy adult Leghorn chickens weighing 2.0-2.5Kg(male or female) were randomly divided into three groups according to the treatment method. Group A:simple suture; Group B: ordinary suture and early functional exercise; Group C: PDS reinforced suture and early functional exercise. Each group got20 chickens. At the 4th and8 th week after operation, 3 chickens were randomly chosen from each group. And the third toe of each limb were taken to microanatomical observation and the degree of adhesion was assessed by Tao’s. Then the above six samples were made HE staining to observe the tendon histology.4chickens were randomly selected, and the third toe of their feet were taken to measure the biomechanics. As for the other chickens, the corresponding parts of the sutured tendon were taken to analyze the content of HYP. The experimental result was analyzed by SPSS 17.0, and P<0.05 was considered statistically.Results:1. general observationAt the 4th week, the result of group A was that the movement of tendon was restricted,granulation tissue proliferated, the adhesion at the anastomotic site was obvious which was dilated, dense and presented irregular oval. The demarcation between the tendon and surrounding tissue was less clear, anastomotic was firmly healed and there was still some fibrous connective tissue attached. The adhesion between the anastomotic site and surrounding tissue could be seen in group B and C, but the structure can be identified. The PDS suture still remained in group C. The degree of peritendinous adhesion was A>B、C,according to the result of statistical analysis.At the 8th week, the result of group A was that the movement of tendon was limited significantly, the tendon adhered obviously which was difficult to dissect bluntly, and the anastomotic tendon swelled, presented irregular oval and healed firmly. A little fibrous adhered between the anastomotic site and surrounding tissue, and the demarcation was clear in group B and C. The PDS sutures was still clearly visible in group C. The degree of peritendinous adhesion was A>B、C, according to the result of statistical analysis.2. histology observationAt the 4th and the 8th week, the result of group A was that the inflammatory cells infiltrated, fibroblasts and tendon cells proliferated obviously and presented irregular arrangement. The collagen fiber inserted into the anastomotic site. The fibroblast cells were rich and presented regular arrangement in group B and C, paralleling to the long axis of the tendon.3. biomechanical observation3.1 tendon glide distanceAt the 4th week, under the condition of tensile force 5N, velocity 10mm/min,the maximum glide distance was A<B、C, there is statistical significance between group A and B, C.(P < 0.05).At the 8th week, under the condition of tensile force 5N, velocity 10mm/min,the maximum glide distance was A<B、C, there is statistical significance between group A and B, C(P < 0.05).3.2 tendon tensile strengthAt the 4th week, under the condition of velocity 10mm/min, the pulling force measuring tendon rupture was the tensile strength. The statistical analysis result was C>B>A, there is significant difference between each two of the three groups(P < 0.05).At the 8th week, under the condition of velocity 10mm/min, the pulling force measuring tendon rupture was the tensile strength. There is no statistical significance to one another among the three groups.(P>0.05)4. determination of HYP contentAt the 4th week, according to the statistical analysis, the determination result of the HYP content was A<B、C. There is significant difference between group A and B、C but no difference between group B and C.(P>0.05)At the 8th week, according to the statistical analysis, the determination result of the HYP content was A<B、C. There is significant difference between group A and B、C but no difference between group B and C.(P>0.05)Conclusions:1. Tendon tensile strength of PDS reinforced suture is greater than that of the ordinary suture, which can provide enough strength for early tendon activities.2. Early functional exercise is the most effective method to prevent or reduce tendon adhesion and avoid interphalangeal joint(DIP or PIP) stiffness after the repair of tendon.So the combination of initiative exercise with passive training is advocated in the early postoperative functional exercise.3. At the 8th week after the operation, the PDS suture hasn’t been absorbed, which can play a role of pillar in the whole process of tendon healing.