Histological and biomechanical evaluation of effects of vitamin K2 on healing at bone-tendon junction site repair

Histological and Biomechanical Evaluation of Effects of Vitamin K2 on Healing at Bone-Tendon Junction Site Repair Objectives: In our study, we aimed to demonstrate effects of vitamin K2 on a rat bone-tendon junction site repairs, from the histological and biomechanical aspect. Material and Methods: We studied on 32 wistar rats that the weights were among 450-700 gr. Subjects were divided into four groups, each containing eight of rats. The first and third groups were chosen for histological studies; likewise, second and fourth groups were chosen for biomechanical studies. For all groups, achillotomy was applied at the level of bone-tendon junction. Two tunnels were prepared through calcaneus, tendon was repaired with pullout technique and the operation was completed. The third and fourth groups were administered by gavage at a dose of 40 mcg/5ml/kg of vitamin K2 (Eylul 150 tablets) suspended in glycerin 5 times a week for 4 weeks. Nothing was given to the subjects in the first and second groups. One of the subjects was died from each of two histological evaluation groups. 30 subjects those followed for four weeks were sacrified at the end of the fourth week and taken for histological and biomechanical evalution. Biomechanical evalution was conducted with Testometric M500-50CT. Three different scoring system as Bonar, Movin and the one that qualifying the bone-tendon junction site were used for the histological evalution. The statistical significance valu was determined as 0,025. Results: In the groups that assessed via mechanical traction test, it vas found that the group which had taken vitamin K2 had been significantly more resistant to tensile forces.(p:0,015). Changes at the bone-tendon junction and the tendon itself was evaluated. With the Bonar and Movin scores; tenocytes, collagen structures, vascularity, structure and formation of fibril, sequence and size of the nuclei, cellularity changes and hyalinization were assessed; the results were significantly in the favor of the groups that taken vitamin K2.(Bonar; p:0,007, Movin; p:0,001). With the evalution of bone-tendon junction; number of cells at the junction, quantity and formation of type 2 collagen, GAG content and chondrocyte organization were assessed. It also was concluded in the favor of the groups that had taken vitamin K2 (p:0,001). In addition to that, the correlation of the three scoring system that used at histological evalution were also assessed in our study. The results showed high correlation between those three scoring systems. Conclusion: Vitamin K2 is a drug which was previously studied experimentally and clinically, and it effects on osteoporosis and fracture healing were reported by those studies. Additionally, the positive effect of the increment in the osteoblastic activity and decrement in the osteoclastic activity on the bone-tendon junction repairs was shown bt the previous studies. In our study; vitamin K2, which was already known with those effects, was studied on the bone-tendon junction for the first time and statistically significant result were obtained. Experimental and clinical studies are needed to support our study. As a result of clinical studies, we think that vitamin K2 will increase the success of the treatment after surgical interventions such as achilles tendon repairs, rotator cuff repairs and anterior cruciate ligament reconstructions.