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.
OBJECTIVE
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Gelberman
Richard H
RH
Department of Orthopaedic Surgery, Barnes-Jewish Hospital at Washington University, St. Louis, MO 63110, USA. gelbermanr@wustl.edu
Thomopoulos
Stavros
S
Sakiyama-Elbert
Shelly E
SE
Das
Rosalina
R
Silva
Matthew J
MJ
D000818:Animals; D000925:Anticoagulants / Q000494:pharmacology*; D000077214:Becaplermin; D004285:Dogs; D016503:Drug Delivery Systems; D006820:Hyaluronic Acid / Q000096:biosynthesis; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D020574:Proto-Oncogene Proteins c-sis; D016059:Range of Motion, Articular; D013708:Tendon Injuries / Q000378:metabolism / Q000503:physiopathology* / Q000601:surgery; D013710:Tendons / Q000187:drug effects* / Q000601:surgery; D013718:Tensile Strength; D013997:Time Factors
D000925:Anticoagulants; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D000077214:Becaplermin; D006820:Hyaluronic Acid