title: Novel intramedullary-fixation technique for long bone fragility fractures using bioresorbable materials.
abstract: Almost all of the currently available fracture fixation devices for metaphyseal fragility fractures are made of hard metals, which carry a high risk of implant-related complications such as implant cutout in severely osteoporotic patients. We developed a novel fracture fixation technique (intramedullary-fixation with biodegradable materials; IM-BM) for severely weakened long bones using three different non-metallic biomaterials, a poly(l-lactide) (PLLA) woven tube, a nonwoven polyhydroxyalkanoates (PHA) fiber mat, and an injectable calcium phosphate cement (CPC). The purpose of this work was to evaluate the feasibility of IM-BM with mechanical testing as well as with an animal experiment. To perform mechanical testing, we fixed two longitudinal acrylic pipes with four different methods, and used them for a three-point bending test (N = 5). The three-point bending test revealed that the average fracture energy for the IM-BM group (PLLA + CPC + PHA) was 3 times greater than that of PLLA + CPC group, and 60 to 200 times greater than that of CPC + PHA group and CPC group. Using an osteoporotic rabbit distal femur incomplete fracture model, sixteen rabbits were randomly allocated into four experimental groups (IM-BM group, PLLA + CPC group, CPC group, Kirschner wire (K-wire) group). No rabbit in the IM-BM group suffered fracture displacement even under full weight bearing. In contrast, two rabbits in the PLLA + CPC group, three rabbits in the CPC group, and three rabbits in the K-wire group suffered fracture displacement within the first postoperative week. The present work demonstrated that IM-BM was strong enough to reinforce and stabilize incomplete fractures with both mechanical testing and an animal experiment even in the distal thigh, where bone is exposed to the highest bending and torsional stresses in the body. IM-BM can be one treatment option for those with severe osteoporosis.
authors.affiliation: Department of Hand Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Takanobu
authors.initials: T
authors.lastname: Nishizuka
authors.affiliation: Department of Hand Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Kurahashi
authors.affiliation: Department of Hand Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Hara
authors.affiliation: Department of Hand Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Hirata
authors.affiliation: Department of Frontier Materials, Nagoya Institute of Technology, Nagoya, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Kasuga
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D005240:Feasibility Studies; D005260:Female; D005594:Fracture Fixation, Intramedullary / Q000379:methods*; D050723:Fractures, Bone / Q000503:physiopathology / Q000601:surgery*; D008422:Materials Testing; D010024:Osteoporosis / Q000503:physiopathology / Q000601:surgery; D011817:Rabbits; D013314:Stress, Mechanical
references.citation: J Biomed Mater Res. 1995 Dec;29(12):1537-43
references.pmid: 8600144
references.citation: J Bone Joint Surg Am. 2008 Feb;90(2):233-40
references.pmid: 18245580
references.citation: J Neurosurg. 2002 Oct;97(3 Suppl):287-93
references.pmid: 12408381
references.citation: Biomaterials. 1998 Aug;19(16):1479-82
references.pmid: 9794522
references.citation: Biomaterials. 2004 Jun;25(13):2595-602
references.pmid: 14751745
references.citation: Expert Rev Med Devices. 2006 Nov;3(6):853-68
references.pmid: 17280548
references.citation: J Biomed Mater Res. 2002 Jun 15;60(4):613-21
references.pmid: 11948520
references.citation: Neurochirurgie. 1987;33(2):166-8
references.pmid: 3600949
references.citation: J Biomed Mater Res. 1990 Jun;24(6):721-34
references.pmid: 2361964
references.citation: J Bone Miner Metab. 2008;26(1):53-9
references.pmid: 18095064
references.citation: Biomaterials. 1997 Jan;18(2):147-51
references.pmid: 9022962
references.citation: Biomaterials. 2008 May;29(13):1989-2006
references.pmid: 18281090
references.citation: Br Med J. 1971 Aug;3(5772):460-1
references.pmid: 5567770
references.citation: FEMS Microbiol Rev. 1992 Dec;9(2-4):217-30
references.pmid: 1476773
references.citation: Artif Cells Blood Substit Immobil Biotechnol. 2009;37(1):1-12
references.pmid: 19132638
references.citation: J Prosthodont. 2006 Sep-Oct;15(5):321-8
references.pmid: 16958734