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Novel intramedullary-fixation technique for long bone fragility fractures using bioresorbable materials.

Nishizuka T, Kurahashi T, Hara T, Hirata H, Kasuga T - PLoS ONE (2014)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Hand Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.

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.

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Result of mechanical testing.A representative stress–strain curve 10 min after the CPC injection in group 1 (double arrow) and group 4 (arrow).
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pone-0104603-g006: Result of mechanical testing.A representative stress–strain curve 10 min after the CPC injection in group 1 (double arrow) and group 4 (arrow).

Mentions: Table 1 shows the mean maximum flexural strength values for each group at 10 min immediately following the CPC injection. The group 1 values (PLLA + CPC + PHA; 2.71±0.66 MPa) were significantly higher (p<0.001) than the values of group 3 (CPC + PHA; 0.79±0.23 MPa) and group 4 (CPC only; 0.52±0.24 MPa). Although there is no statistically significant difference, the values of group 1were higher than the values of group 2 (PLLA + CPC; 2.37±0.13 MPa) (p = 0.15). Table 1 also shows the average fracture energy at 10 min following the CPC injection. The group 1 values (PLLA + CPC + PHA; 1210±334 J/m2) were significantly higher (p<0.001) than the group 2 values (PLLA + CPC; 434±63 J/m2), the group 3 values (CPC + PHA; 19.4±6.4 J/m2) and the group 4 values (CPC only; 5.5±5.7 J/m2). Figure 6 shows the representative stress–strain curves for group 1 (PLLA + CPC + PHA) and group 4 (CPC only). In group 1, the curve can be categorized into four zones (zone 1: steep slope zone, zone 2: gentle slope zone, zone 3: almost flat slope zone, and zone 4: negative slope zone). In zones 1 and 2, the stress kept increasing and the curve did not drop until the end of zone 3. In contrast, in groups 3 and 4, the curve immediately reached the yield point. Once the curve reached the yield point, the curve dropped abruptly due to the fragmentation of the materials. The average moduli of elasticity in bending in group 1 were 179±89 MPa in zone 1 and 18.2±8.7 MPa in zone 2. The average moduli of elasticity in bending in groups 2, 3, and 4 were 144±31 MPa, 183±64 MPa and 223±69 MPa, respectively.


Novel intramedullary-fixation technique for long bone fragility fractures using bioresorbable materials.

Nishizuka T, Kurahashi T, Hara T, Hirata H, Kasuga T - PLoS ONE (2014)

Result of mechanical testing.A representative stress–strain curve 10 min after the CPC injection in group 1 (double arrow) and group 4 (arrow).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4128718&req=5

pone-0104603-g006: Result of mechanical testing.A representative stress–strain curve 10 min after the CPC injection in group 1 (double arrow) and group 4 (arrow).
Mentions: Table 1 shows the mean maximum flexural strength values for each group at 10 min immediately following the CPC injection. The group 1 values (PLLA + CPC + PHA; 2.71±0.66 MPa) were significantly higher (p<0.001) than the values of group 3 (CPC + PHA; 0.79±0.23 MPa) and group 4 (CPC only; 0.52±0.24 MPa). Although there is no statistically significant difference, the values of group 1were higher than the values of group 2 (PLLA + CPC; 2.37±0.13 MPa) (p = 0.15). Table 1 also shows the average fracture energy at 10 min following the CPC injection. The group 1 values (PLLA + CPC + PHA; 1210±334 J/m2) were significantly higher (p<0.001) than the group 2 values (PLLA + CPC; 434±63 J/m2), the group 3 values (CPC + PHA; 19.4±6.4 J/m2) and the group 4 values (CPC only; 5.5±5.7 J/m2). Figure 6 shows the representative stress–strain curves for group 1 (PLLA + CPC + PHA) and group 4 (CPC only). In group 1, the curve can be categorized into four zones (zone 1: steep slope zone, zone 2: gentle slope zone, zone 3: almost flat slope zone, and zone 4: negative slope zone). In zones 1 and 2, the stress kept increasing and the curve did not drop until the end of zone 3. In contrast, in groups 3 and 4, the curve immediately reached the yield point. Once the curve reached the yield point, the curve dropped abruptly due to the fragmentation of the materials. The average moduli of elasticity in bending in group 1 were 179±89 MPa in zone 1 and 18.2±8.7 MPa in zone 2. The average moduli of elasticity in bending in groups 2, 3, and 4 were 144±31 MPa, 183±64 MPa and 223±69 MPa, respectively.

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Hand Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.

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.

Show MeSH
Related in: MedlinePlus