title: Adhesions in a murine flexor tendon graft model: autograft versus allograft reconstruction.
abstract: Reconstruction of flexor tendons often results in adhesions that compromise joint flexion. Little is known about the factors involved in the formation of flexor tendon graft adhesions. In this study, we developed and characterized a novel mouse model of flexor digitorum longus (FDL) tendon reconstruction with live autografts or reconstituted freeze-dried allografts. Grafted tendons were evaluated at multiple time points up to 84 days post-reconstruction. To assess the flexion range of the metatarsophalangeal joint, we developed a quantitative outcome measure proportional to the resistance to tendon gliding due to adhesions, which we termed the Gliding Coefficient. At 14 days post-grafting, the Gliding Coefficient was 29- and 26-fold greater than normal FDL tendon for both autografts and allografts, respectively (p < 0.001), and subsequently doubled for 28-day autografts. Interestingly, there were no significant differences in maximum tensile force or stiffness between live autograft and freeze-dried allograft repairs over time. Histologically, autograft healing was characterized by extensive remodeling and exuberant scarring around both the ends and the body of the graft, whereas allograft scarring was abundant only near the graft-host junctions. Gene expression of GDF-5 and VEGF were significantly increased in 28-day autografts compared to allografts and to normal tendons. These results suggest that the biomechanical advantages for tendon reconstruction using live autografts over devitalized allografts are minimal. This mouse model can be useful in elucidating the molecular mechanisms in tendon repair and can aid in preliminary screening of molecular treatments of flexor tendon adhesions.
authors.affiliation: The Center for Musculoskeletal Research, University of Rochester, Rochester, New York, USA.
authors.forename: Sys
authors.initials: S
authors.lastname: Hasslund
authors.forename: Justin A
authors.initials: JA
authors.lastname: Jacobson
authors.forename: Tulin
authors.initials: T
authors.lastname: Dadali
authors.forename: Patrick
authors.initials: P
authors.lastname: Basile
authors.forename: Michael
authors.initials: M
authors.lastname: Ulrich-Vinther
authors.forename: Kjeld
authors.initials: K
authors.lastname: Søballe
authors.forename: Edward M
authors.initials: EM
authors.lastname: Schwarz
authors.forename: Regis J
authors.initials: RJ
authors.lastname: O'Keefe
authors.forename: David J
authors.initials: DJ
authors.lastname: Mitten
authors.forename: Hani A
authors.initials: HA
authors.lastname: Awad
mesh_terms: D000125:Achilles Tendon / Q000473:pathology / Q000502:physiology* / Q000637:transplantation*; D000199:Actins / Q000235:genetics; D000818:Animals; D001696:Biomechanical Phenomena; D019485:Bone Morphogenetic Proteins / Q000235:genetics; D005612:Freeze Drying; D015870:Gene Expression; D055428:Growth Differentiation Factor 5; D008683:Metatarsophalangeal Joint / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D023421:Models, Animal; D019637:Orthopedic Procedures / Q000379:methods*; D016059:Range of Motion, Articular; D019651:Plastic Surgery Procedures / Q000379:methods*; D000267:Tissue Adhesions / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control*; D053773:Transforming Growth Factor beta1 / Q000235:genetics; D014182:Transplantation, Autologous; D014184:Transplantation, Homologous; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics
chemical_list: D000199:Actins; D019485:Bone Morphogenetic Proteins; C525894:Gdf5 protein, mouse; D055428:Growth Differentiation Factor 5; D053773:Transforming Growth Factor beta1; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse