Mechanical properties of biodegradable ligament augmentation device of poly(l-lactide) in vitro and in vivo

Laitinen, Outi; Törmälä, Pertti; Taurio, R.; Skutnabb, Kai; Saarelainen, Kirsi; Iivonen, Tiina; Vainionpää, S.

doi:10.1016/0142-9612(92)90152-e

Cited by 64 publications

(36 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A simple subcutaneous placement to test for tissue compatibility would not be useful for this study even though past researchers have tried this technique for biodegradable and nondegradable materials (4,15). The objective of this study was to investigate the ingrowth of new ligament tissue into the scaffolds that are seeded with ACL cells.…”

Section: Discussionmentioning

confidence: 99%

“…These stages are hydration, depolymerization, loss of mass integrity, absorption, and elimination. This polymer was chosen because of its mechanical retention and its in vitro cellular response to primary rabbit ACL cells (6,(11)(12)(13)(14).Rabbits are one of the most commonly used animals for orthopedic surgery in vivo studies (1,(15)(16)(17)(18)(19)(20)(21)(22)(23)(24). Adult New Zealand White rabbits were used in this study because rabbits are relatively high-level vertebrates, having a size that enables surgical operations, convenient histology, and mechanical analysis.…”

mentioning

confidence: 99%

“…Rabbits are one of the most commonly used animals for orthopedic surgery in vivo studies (1,(15)(16)(17)(18)(19)(20)(21)(22)(23)(24). Adult New Zealand White rabbits were used in this study because rabbits are relatively high-level vertebrates, having a size that enables surgical operations, convenient histology, and mechanical analysis.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Biomimetic tissue-engineered anterior cruciate ligament replacement

Cooper

Sahota

Gorum

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

171

128

View full text Add to dashboard Cite

There are >200,000 anterior cruciate ligament (ACL) ruptures each year in the United States, and, due to the poor healing properties of the ACL, surgical reconstruction with autograft or allograft tissue is the current treatment of these injuries. To regenerate the ACL, the ideal matrix should be biodegradable, porous, and exhibit sufficient mechanical strength to allow formation of neoligament tissue. Researchers have developed ACL scaffolds with collagen fibers, silk, biodegradable polymers, and composites with limited success. Our group has developed a biomimetic ligament replacement by using 3D braiding technology. In this preliminary in vivo rabbit model study for ACL reconstruction, the histological and mechanical evaluation demonstrated excellent healing and regeneration with our cell-seeded, tissue-engineered ligament replacement.biomaterials ͉ regenerative medicine T his study was conducted to evaluate the performance of a polymeric 3D braided fibrous tissue-engineered anterior cruciate ligament (ACL) replacement for use in ACL reconstruction. The feasibility of this approach was investigated by comparison of cell-seeded and unseeded tissue-engineered ligaments (TELs) with a rabbit model. The key concepts investigated were (i) the in vivo response of allograft cells seeded onto TELs, (ii) the effect of porosity and pore interconnectivity on cell and collagen infiltration, (iii) the capability of the implant to allow for vascularization, and (iv) the capability of the implant to maintain mechanical function and to transfer load to the neoligament.Several groups have explored ligament-like scaffolds with collagen fibers, silk, biodegradable polymers and composites with limited success (1-6). During this study, we fabricated an absorbable polyL-lactide (PLLA) 3D, braided TEL replacement capable of supporting the growth and phenotypic expression of cells when seeded in vitro. There have been several published observations of favorable PLLA device interactions in animal and human clinical studies (2, 4, 7-10). The degradation of PLLA from a chemical standpoint in vivo can be categorized into five stages (2, 7). These stages are hydration, depolymerization, loss of mass integrity, absorption, and elimination. This polymer was chosen because of its mechanical retention and its in vitro cellular response to primary rabbit ACL cells (6,(11)(12)(13)(14).Rabbits are one of the most commonly used animals for orthopedic surgery in vivo studies (1,(15)(16)(17)(18)(19)(20)(21)(22)(23)(24). Adult New Zealand White rabbits were used in this study because rabbits are relatively high-level vertebrates, having a size that enables surgical operations, convenient histology, and mechanical analysis. In addition, there was data on ACL reconstruction in rabbits with bone-patellar tendon-bone autografts (the gold standard for human reconstructions) that could be used to compare with our tissue engineered ligament results (20).The goal of this investigation was to develop and study a tissue-engineered ACL replacement that could e...

show abstract

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Biomimetic tissue-engineered anterior cruciate ligament replacement

Cooper

Sahota

Gorum

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

171

128

View full text Add to dashboard Cite

show abstract

“…In the current study, we did not examine the degradation rate of implanted PLLA fiber. Laitinen et al reported that PLLA fiber, 2.0 mm in diameter, retained 74 and 22% of initial tensile load carrying capacity at 6 and 12 weeks after the subcutaneous implantation in rabbits, respectively [25]. Bernstein et al demonstrated that cell adhesion rate of PLLA/β-tricalciumphosphate composite material is higher than PLLA alone [4].…”

Section: Discussionmentioning

confidence: 99%

Helical Conformation Endows Poly-<span style="font-variant: small-caps;">l</span>-Lactic Acid Fibers with a Piezoelectric Charge under Tensile Stress

Harada

Kadono

Terao

et al. 2013

The Journal of Veterinary Medical Science

View full text Add to dashboard Cite

ABSTRACT. Poly-l-lactic acid (PLLA) has been clinically used as a bioabsorbable material and attains a piezoelectric charge upon molecular orientation by the application of a shear force to the C-axis of the crystal line region. Previous studies showed that implanted drawn PLLA films or rods accelerate the ossification due to piezoelectric effect. In this study, we originally designed helically-twisted PLLA fiber to produce piezoelectricity in bioabsorbable suture upon tensile stress. The piezoelectricity of the helical PLLA fibers was evaluated using a lock-in amplifier system in vitro. The ossification induced by helical PLLA fibers was examined by implanting them in the rat patellar ligament supporting a physiological tensile load. We observed that 57° and 45° twisted PLLA fibers generated a higher piezoelectric potential than did 27° twisted fibers. The animal experiment showed that the formation of osseous tissue around helical PLLA fibers was more significant than around non-helical control fibers at 4 weeks after their implantation. These results suggest that helical PLLA fiber may be useful for the surgical suture or artificial ligament, which connects to the bone. KEW WORDS: animal model, helical conformation, ossification, piezoelectricity, poly-l-lactic acid.doi: 10.1292/jvms.12-0323; J. Vet. Med. Sci. 75(9): 1187-1192, 2013 Ligament injury, such as anterior cruciate ligament rupture, is a common cause of lameness in small animal practice [6,15]. Various types of artificial ligaments including bioabsorbable material have been studied to reconstruct the injured ligament [3,27,31]. It has been suggested that early osteointegration of the grafted artificial ligament to the bone is important to improve the ligament function and durability [39].Poly-l-lactic acid (PLLA) is well known as a bioabsorbable material and has been clinically used as bioabsorbable mini-plate, screw and pin [2,13,14,30,33]. On the other hand, PLLA is known as a piezoelectric material. Fukada reported that an external mechanical stress to a drawn PLLA film gives rise to electrical polarization [10], and this piezoelectric effect is ascribed to the change in the microscopic orientation of crystals with a fundamentally asymmetrical structure [5,10,22,23]. Animal experiments showed that the piezoelectricity of drawn PLLA films and rods accelerated callus formation on bone [10,22,35]. Shimono et al. prepared three types of PLLA piezoelectric films with different oriented directions (0°, 45° or 90° to the drawing direction) and implanted them on the periosteum of the rabbit tibia [35]. These drawn PLLA films promoted ossification to a greater extent than undrawn PLLA films, and the effect of drawn PLLA films in promoting ossification was greatest when a shearing stress was applied at 45° to the axis of orientation. Ikada et al. prepared drawn PLLA rods with different draw ratios and implanted these rods intramedullary in the osteotomized tibia of cats [22]. Fracture healing was clearly promoted with increased callus formation as the draw...

show abstract

“…Previous studies reported the stiffness of poly(L-lactide) fibers decreased at much lower rates than their strength. [6][7][8] This property of poly(L-lactide) is attributed to a high crystallinity and low monomer content. 6 Consequently, an augmentation stiffness that does not change much versus time cannot provide a gradual increase in graft load.…”

Section: Introductionmentioning

confidence: 99%

Control of material stiffness during degradation for constructs made of absorbable polymer fibers

et al. 2003

View full text Add to dashboard Cite

Augmentation devices for cruciate ligament surgery should provide gradually decreasing mechanical properties with a half-time strength of at least 6 months to temporarily protect healing tendon grafts or sutured ligaments against high tensile loads during the postoperative healing period. The absorbable material of choice that shows such slow degradation kinetics is poly(L-lactide). However, previous studies have shown that poly(L-lactide) fulfills the requirement of a long half-time strength, while the corresponding stiffness decreases at a much slower rate. An augmentation stiffness that does not change much versus time cannot provide a gradual increase in graft load, which is important to stimulate the orientation of the collagenous tissue. Therefore a new augmentation device was designed, which should decrease both in strength and stiffness during degradation. The cord was braided out of two fibers made of poly(L-lactide) and poly(Llactide-co-glycolide), which degrade at different rates. The cord prototype was degraded in vitro and the rupture force and stiffness was tested at eight different time points up to 60 weeks. The initial rupture force and stiffness was 522.7 ؎ 2.8 N and 104.1 ؎ 3.8 N/%, respectively. Both strength and stiffness decreased continuously with a half-time strength of 18 weeks and a half-time stiffness of 39 weeks. The gradually decreasing stiffness was achieved by the breakdown of the faster-degrading fiber component made of poly(Llactide-co-glycolide). Thus the new augmentation device can provide a continuous increase of forces in a tendon graft or in a healing ligament.

show abstract

Mechanical properties of biodegradable ligament augmentation device of poly(l-lactide) in vitro and in vivo

Cited by 64 publications

References 21 publications

Biomimetic tissue-engineered anterior cruciate ligament replacement

Biomimetic tissue-engineered anterior cruciate ligament replacement

Helical Conformation Endows Poly-<span style="font-variant: small-caps;">l</span>-Lactic Acid Fibers with a Piezoelectric Charge under Tensile Stress

Control of material stiffness during degradation for constructs made of absorbable polymer fibers

Contact Info

Product

Resources

About