Effects of Synovial Interposition on Healing in a Canine Tendon Explant Culture Model

Purpose: To investigate whether synovium interposition between repaired tendon ends can integrate into the tendon repair and improve tendon healing strength in a canine tendon explant culture model. Methods: We used 80 flexor digitorum profundus tendons from 10 mixed-breed dogs for this study. The flexor digitorum profundus tendons were assigned to 2 groups: repaired tendons with synovium implanted between the cut tendon ends and repaired tendons without any implantation between the tendon ends. The repaired tendons were cultured for either 2 or 4 weeks and then assessed mechanically for rupture strength and histology. Results: The strength of the repaired tendons with the synovium interposition was significantly higher (p < .001) than the repaired tendons without interposition at both 2 and 4 weeks. The strength of the repaired tendons at 4 weeks was significantly higher than that at 2 weeks in both groups. Conclusions: Interpositional synovial grafts have the potential to accelerate tendon healing when they are implanted at the repair site. The exact mechanism of this effect remains to be elucidated.