The Effect of Diclofenac on Tendon Healing: An Experimental Study in Guinea Pigs

Background: Whether non-steroidal anti-inflammatory drugs have a detrimental effect on tendon regeneration is still a matter of debate. As such, the purpose of this study is to determine the effect of diclofenac on tendon healing. Methods: Sixty four guinea pigs were randomly divided into two main groups (group A: histological study, group B: biomechanical study). Then tenotomy and repair of right Achilles tendon were done. Half of the animals in each group received diclofenac (1 mg/kg/bid) and the other half received placebo. Half of the animals in each group were sacrificed at 2 weeks and the remaining animals at 6 weeks post-operation. In group A, histological study for determining maturity of healing of tendons in diclofenac and control groups was done, and in group B, tensile force to failure of tendons at two and six weeks of post tenotomy was determined. Results: After two weeks, of the group A1, four animals in the experimental and five in the control group were labeled as relative immature. Four of the animals in the experimental and two in the control subgroups were labeled as relative immature. These differences were not significant. In group A2, five animals in the experimental and three in the control group were in the relative mature and three of those in the experimental and four of the control group were labeled as relative immature group. In group A1, the tensile force to failure was 24.175 N and 25.371 N in the experimental and control groups, respectively. In group B2, mean force to failure was 41.019 N in the experimental and 39.743 N in the control group. There was no significant difference between both groups. Conclusion: Diclofenac at the dosage of 1 mg/kg/bid did not appear to affect histological and biomechanical characteristics of tendon healing.