The Early Effects of Sustained Platelet-Derived Growth Factor Administration on the Functional and Structural Properties of Repaired Intrasynovial Flexor Tendons: An In Vivo Biomechanic Study at 3 Weeks in Canines

Department of Biomedical Engineering, Washington University in St. Louis, San Luis, Missouri, United States
The Journal Of Hand Surgery (Impact Factor: 1.67). 04/2007; 32(3):373-9. DOI: 10.1016/j.jhsa.2006.12.009
Source: PubMed


A bioactive fibrin-based delivery system was used to provide sustained administration of platelet-derived growth factor (PDGF-BB) in a clinically relevant model of intrasynovial flexor tendon repair. We hypothesized that PDGF-BB administered in this manner would improve the sutured tendon's functional and structural properties 3 weeks after repair.
A delivery system consisting of 30 microL of fibrin matrix, peptide, heparin, and 100 ng of PDGF-BB was incorporated into the repair sites of randomly selected medial or lateral forepaw flexor digitorum profundus tendons of 8 adult mongrel dogs. The remaining forepaw flexor digitorum profundus tendons were repaired without the growth-factor and fibrin-based delivery system and served as controls. The surgically treated forelimbs were treated with controlled passive motion rehabilitation. The animals were killed at 3 weeks, at which time the tendons were tested for range of motion with a motion analysis system and for tensile properties with a materials testing machine.
Proximal interphalangeal joint and distal interphalangeal joint rotation values were significantly higher for the PDGF-BB-treated tendons compared with the repair-alone tendons. Excursion values were also significantly higher in the PDGF-BB-treated tendons. There were no significant differences in tensile properties when comparing PDGF-BB-treated with repair-alone tendons.
The functional properties of repaired intrasynovial flexor tendons were significantly improved with the sustained administration of PDGF-BB. The failure to achieve improvements in ultimate load, stiffness, and strain in the experimental group may have been due to suboptimal PDGF-BB dosage or suboptimal release kinetics.

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    • "In this manner, we can isolate the effect of each growth factor delivered to inform the next, potentially combinatorial, approach . Based on previous studies, we hypothesize that PDGF-BB would enhance flexor tendon repair [6] [7] [9] and ASC proliferation [52] [53] [54], with little effect on ASC differentiation. Other growth factors (such as the tenogenic bone morphogenetic protein 12 [24] [25] [55]) can also be examined. "
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