Four strand tendon repair with uninterrupted epitendinous suture and comparison to other popular techniques: Study on rabbit model

Objective Traumatic tendon lacerations are very common in clinical practice today with potential to cause a prolonged loss of labor power and have a detrimental effect on quality of life of the injured. To find the ideal tendon repair technique; clinicians and scientists have conducted many studies in vivo and ex vivo lately, resulting in the discovery of many new repair techniques in the last few decades. Despite many widely accepted discoveries on the subject, these studies have failed to produce the one ideal repair technique to be used universally. The intricate balance between the widely accepted findings of these studies were taken into consideration and integrated during the development of the technique used in the experiment group of this study. Thus, this experimental study was designed to demonstrate the usability and effectivity of our newly developed technique. Material and Method Twenty-one male New Zealand albino rabbits with an average age of 8-12 months and 4000±500 gr in weight were used in the experiment. 2 animals from different groups were lost during the study and another animal was excluded from the other group leaving 6 animals for each of the three groups. As a result, the study was conducted and finalized with 3 groups of 6 animals with a total of 18 animals evenly distributed. First two groups were designed as the control groups and two commonly used repair techniques were assigned to each. The third group was determined as the experiment group and our new technique was used during the repairs conducted in this group. Four strand modified Kessler with a running peripheral suture technique was used in the first control group. In the second control group; six strand Tang technique was used without any peripheral sutures. Our newly developed technique with four strand repair with uninterrupted running epitendinous suture was used in the third group which was determined as the experiment group of this study. The animals were monitored for 56 days (8 weeks) after the first tendon repair surgery for all groups. At the end of this time period, contralateral calcaneal tendons of the animals were cut and repaired using the same techniques as the first surgery, after which subjects were euthanized and bilateral tendon specimens were collected for all animals. During the second surgery, repair times were recorded and noted to determine the practicality of the techniques. At the end of the experimental procedure, two tendon specimens were collected for each of the animals; one of which represented the healing model and the other representing the time of repair model. Lastly; biomechanical tests were conducted on 12 tendon specimens from each of the six animals from each group to determine mechanical strength of the three different techniques. Results To determine the statistical significance between the groups for the time of repair model, the biomechanical findings were compared using Kruskal Wallis analysis. The difference between the three groups were found to be statistically significant (p=0,002; p<0,05). Mann-Whitney U test was used for the two-way analysis between groups and the results for the experiment group were found to be significantly higher than the other two control groups for the time of repair model (p<0,05). Kruskal Wallis test was used similarly for the healing model to determine statistical significance between groups. Despite the noticeable difference between the mean values of each group, we were not able to demonstrate a statistically significant difference(p>0,05). Two way comparisons were conducted identically using Mann-Whitney U test for the analysis between groups; but this analysis too failed to show any significant differences between groups for the healing model(p>0,05). Similarly, Kruskal Wallis test was used to determine any significant difference between groups in terms of repair time. The result of the analysis showed a statistically significant difference between the three groups (p=0,001; p<0,05). Mann-Whitney U test was then conducted to analyze any two-way difference between groups. Results demonstrated that the first control group required significantly less time to repair than the second control group (p=0,026; p<0,05). In addition; the experiment group required significantly less time to apply the repair separately compared to both of the control groups with both test resulting in a p value of 0,002 (p<0,05). Therefore, it is safe to state that in terms of repair time, the experiment group was found to be superior than the both of the control groups, and the first control groups is found to be superior to the second control group Conclusion As a result of the findings of this study, it is safe to say that the technique used in the experiment group has more mechanical strength than both the four strand Modified Kessler and the six strand Tang methods. Statistically superior results for the experiment group compared to both the control groups in our post-repair model also leads to the conclusion that our technique is more suitable for the early passive mobilization and active exercise protocols which are proven to be so crucial for proper healing of repaired flexor tendons. In addition, the results of the healing model yield to the conclusion that the experiment group technique does not impair or disrupt the healing of the tendon after repair as the difference in the mean mechanical strength values suggests. Furthermore, the comparative results of the tendon repair times show that the technique used in the experiment group is superior to both the techniques used in the control groups in terms of practicality and usability.