Mechanical evaluation of a porous bone graft substitute based on poly(propylene glycol-co-fumaric acid).
A porous, resorbable polymer composite based on poly(propylene glycol-co-fumaric acid) (PPF) was mechanically evaluated in vitro for use as a bone graft substitute and fracture fixative. The test material created a dynamic system capable of initially providing mechanical integrity to bony voids and a degradative mechanism for ingrowth by native bone. The unsaturated polymer, PPF, was crosslinked in the presence of effervescent agents to yield a porous microstructure upon curing. An in vitro degradation study first assessed the temporal mechanical properties of the test material. This research was followed by an ex vivo study using a long-bone osteotomy model to characterize the mechanics of fixation. Results showed the initial compressive strength of the cross-linked PPF system was comparable to cancellous bone. The rate of strength loss was commensurate with the predicted mechanical recovery of healing bone with analogous results in a composite that comprised also 25% (by weight) autograft. Mechanical testing in the long-bone model demonstrated that PPF-based bone-graft substitute increased the flexural strength of K-wire stabilized osteotomies. These results suggest that this type of bone graft substitute may have clinical utility in the stabilization of complex tubular bone fractures.
Hile
David D
DD
Cambridge Scientific, Inc., 180 Fawcett Street, Cambridge, Massachusetts 02138, USA. Hiledd@yahoo.com
Kirker-Head
Carl
C
Doherty
Stephen A
SA
Kowaleski
Michael P
MP
McCool
John
J
Wise
Donald L
DL
Trantolo
Debra J
DJ
D000818:Animals; D001696:Biomechanical Phenomena; D018786:Bone Substitutes; D019245:Compressive Strength; D005592:Fracture Fixation; D066298:In Vitro Techniques; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011108:Polymers; D011409:Propylene Glycols; D051381:Rats
D018786:Bone Substitutes; D011108:Polymers; D011409:Propylene Glycols; C106431:poly(propylene glycol-fumarate)