Photochemical repair of Achilles tendon rupture in a rat model

Photochemical tissue bonding (PTB) is an emerging technique for bonding or sealing tissue surfaces that requires light and a photoactive dye for its effect. The potential of PTB for tendon repair was assessed in a rat model. The optical properties of bovine tendon were determined ex vivo to gauge the depth of light penetration as a function of wavelength and dosimetry parameters were established for PTB repair of ruptured tendon. PTB was then tested in vivo to repair transected tendons in Sprague-Dawley rats. Repair strengths were measured using a strain gauge up to 14 days post treatment. The effective penetration depth in tendon was estimated to be 0.68 mm at 514 nm. Following PTB treatment of mechanically ruptured tendon, significant bonding was dependent on the presence of both light and dye and attained a plateau strength at a fluence of 125 J/cm2. In a subsequent in vivo study to investigate PTB for repair of transected rat Achilles tendon, the ultimate stress required to break the repaired tendon was measured immediately after irradiation and at 7 and 14 days post-repair. Results showed that the difference in the ultimate stress between control and PTB treatment groups was statistically significant immediately after treatment and at 7 days (p = 0.04) but not 14 days (p = 0.75) post-repair. PTB provides a benefit to tendon repair at early stages in repair and is worthy of further investigation as a potential surgical adjunct for tendon repair in orthopedic surgeries.