Anti-Adhesive Resorbable Indomethacin/Bupivacaine-Eluting Nanofibers for Tendon Rupture Repair: In Vitro and In Vivo Studies.

The treatment and surgical repair of torn Achilles tendons seldom return the wounded tendon to its original elasticity and stiffness. This study explored the in vitro and in vivo simultaneous release of indomethacin and bupivacaine from electrospun polylactide-polyglycolide composite membranes for their capacity to repair torn Achilles tendons. These membranes were fabricated by mixing polylactide-polyglycolide/indomethacin, polylactide-polyglycolide/collagen, and polylactide-polyglycolide/bupivacaine with 1,1,1,3,3,3-hexafluoro-2-propanol into sandwich-structured composites. Subsequently, the in vitro pharmaceutic release rates over 30 days were determined, and the in vivo release behavior and effectiveness of the loaded drugs were assessed using an animal surgical model. High concentrations of indomethacin and bupivacaine were released for over four weeks. The released pharmaceutics resulted in complete recovery of rat tendons, and the nanofibrous composite membranes exhibited exceptional mechanical strength. Additionally, the anti-adhesion capacity of the developed membrane was confirmed. Using the electrospinning technique developed in this study, we plan on manufacturing degradable composite membranes for tendon healing, which can deliver sustained pharmaceutical release and provide a collagenous habitat.

Sustained Release of Antifungal and Antibacterial Agents from Novel Hybrid Degradable Nanofibers for the Treatment of Polymicrobial Osteomyelitis.

This study aimed to develop a drug delivery system with hybrid biodegradable antifungal and antibacterial agents incorporated into poly lactic-co-glycolic acid (PLGA) nanofibers, facilitating an extended release of fluconazole, vancomycin, and ceftazidime to treat polymicrobial osteomyelitis. The nanofibers were assessed using scanning electron microscopy, tensile testing, water contact angle analysis, differential scanning calorimetry, and Fourier-transform infrared spectroscopy. The in vitro release of the antimicrobial agents was assessed using an elution method and a high-performance liquid chromatography assay. The in vivo elution pattern of nanofibrous mats was assessed using a rat femoral model. The experimental results demonstrated that the antimicrobial agent-loaded nanofibers released high levels of fluconazole, vancomycin, and ceftazidime for 30 and 56 days in vitro and in vivo, respectively. Histological assays revealed no notable tissue inflammation. Therefore, hybrid biodegradable PLGA nanofibers with a sustainable release of antifungal and antibacterial agents may be employed for the treatment of polymicrobial osteomyelitis.

Sustained relief of pain from osteosynthesis surgery of rib fracture by using biodegradable lidocaine-eluting nanofibrous membranes.

Various effective methods are available for perioperative pain control in osteosynthesis surgery, but they are seldom applied intraoperatively. The aim of this study was to evaluate a biodegradable poly([d,l]-lactide-co-glycolide) (PLGA)/lidocaine nanofibrous membrane for perioperative pain control in rib fracture surgery. Scanning electron microscopy showed high porosity of the membrane, and an ex vivo high-performance liquid chromatography study revealed an excellent release profile for both burst and controlled release of lidocaine within 30days. Additionally, the PLGA/lidocaine nanofibrous membrane was applied in an experimental rabbit rib osteotomy model. Implantation of the membrane around the osteotomized rib during osteosynthesis surgery resulted in a significant increase in weight gain, food and water consumption, and daily activity compared to the study group without the membrane. In addition, all osteotomized ribs were united. Thus, application of the PLGA/lidocaine nanofibrous membrane may be effective for sustained relief of pain in oeteosynthesis surgery.

Novel CO2-encapsulated Pluronic F127 hydrogel for the treatment of Achilles tendon injury.

Nonsurgical treatment and surgical repairment of injured Achilles tendons seldom restore the wounded tendon to its original elasticity and stiffness. Therefore, we hypothesized that the surgically repaired Achilles tendon can achieve satisfactory regeneration by applying multi-drug encapsulated hydrogels. In this study, a novel bupivacaine-eluting carbon dioxide-encapsulated Pluronic F127 hydrogel (BC-hydrogel) was developed for the treatment of Achilles tendon injuries. The rheological properties of BC-hydrogel were measured. A high-performance liquid chromatography assay was used to assess the release characteristics of bupivacaine in both in vitro and in vivo settings. Furthermore, the effectiveness of BC-hydrogel in treating torn tendons was examined in a rat model, and histological analyses were conducted. Evidently, the degradable hydrogels continuously eluted bupivacaine for more than 14 days. The animal study results revealed that the BC-hydrogel improved the post-surgery mobility of the animals compared with pristine hydrogels. Histological assay results demonstrated a significant reaction to high vascular endothelial growth factor in the surrounding tissues and expression of collagen I within the repaired tendon. This demonstrates the potential of this novel BC-hydrogel as an effective treatment method for Achilles tendon injuries.

Biodegradable Antimicrobial Agent/Analgesic/Bone Morphogenetic Protein-Loaded Nanofibrous Fixators for Bone Fracture Repair.

PURPOSE: Postoperative infection and pain management are of great concern to orthopedic surgeons. Although there are several protocols available to deal with these aspects, they are fraught with complications, such as cartilage damage, cardiovascular and neurological intoxication, and systemic adverse responses. Therefore, it is necessary to develop safe and effective perioperative protocols. In the current study, antimicrobial agents/analgesics/growth factor-embedded biodegradable hybrid fixators (polycaprolactone fixator + poly[lactide-co-glycolide] sheath-core structured nanofibers) for bone fracture repair were designed. METHODS: The biodegradable hybrid fixators were fabricated using solution-extrusion three-dimensional printing and electrospinning. In vitro, the characteristics of the hybrid fixators were examined. Additionally, the release of the incorporated vancomycin, ceftazidime, lidocaine, and bone morphogenetic protein-2 (BMP-2) was evaluated. The in vivo efficacy including drug-eluting properties, fracture repair, and pain management of the biomolecule-loaded nanofibrous fixators was investigated in rabbit rib-fracture models. RESULTS: The nanofibrous fixators released vancomycin, ceftazidime, and lidocaine in a sustained manner under both in vitro and in vivo conditions and protected BMP-2 from burst release. The implantation of these hybrid fixators around the fractured rib significantly improved animal activities and bone union, indicating that the inclusion of analgesic in the fixator effectively reduced postsurgical pain and thereby helped in recovery. CONCLUSION: The novel biomolecule-loaded nanofibrous hybrid fixators resulted in excellent therapeutic outcomes. These fixators may be effective in the repair of rib fractures in clinical settings and may help mitigate surgical complications, such as infection, nonunion, and intolerable postoperative pain.

The effects of bone-substitute augmentation on treatment of osteoporotic intertrochanteric fractures.

BACKGROUND: Osteoporotic intertrochanteric fractures often have postoperative complications despite a perfect reduction and an optimal fixation. We describe a simple technique using bone substitute augmentation and hypothesize that this method would prevent excessive sliding of the lag screw and potential subsequent complications. METHODS: Between January 2009 and July 2017, patients with osteoporotic intertrochanteric fractures who were treated with a dynamic hip screw (DHS) were enrolled in this retrospective cohort study. DHS group patients received conventional DHS treatment and BSA-DHS group patients received bone-substitute augmented DHS treatment. Factors such as demographics, Parker and Palmer mobility scores, health-related quality of life (HRQoL) scores (short-form Health Survey-12 Physical Component Summary [SF-12-PCS], and SF-12 Mental Component Summary [SF-12-MCS]), morbidities, mortality, and radiographic outcomes were compared. RESULTS: We enrolled 85 patients: DHS group = 37 and BSA-DHS group = 48. There was significant lag-screw sliding (mean: 9 mm and 3 mm, p < 0.001), varus collapse (mean: 7° and 3°, p < 0.001), and femoral shortening (mean: 10 mm and 3 mm, p < 0.001) in the DHS group compared to the BSA-DHS group. The ability to get around the house was significantly different between the DHS and BSA-DHS groups (p = 0.031) at 3 months. Postoperative scores were not significantly different after 6, 9 or 12 months, however. Scores for the ability to get out of the house and to go shopping and the SF-12-PCS were significantly worse in the DHS group at 3 and 6 months. Malunion and lag-screw cutout were also significantly worse in the DHS group (p = 0.037 and p = 0.033, respectively). CONCLUSIONS: Bone-substitute augmentation appears effective to prevent typical postoperative complications experienced by the DHS group patients, and to improve functional outcomes. Additional prospective randomized large-scale cohort studies are necessary to confirm this conclusion. LEVEL OF EVIDENCE: Therapeutic Level III.

Dynamic hip screws for unstable intertrochanteric fractures in elderly patients--encouraging results with a cement augmentation technique.

BACKGROUND: Despite the good and reliable results of the dynamic hip screw (DHS) for stable fracture patterns, complications of excessive sliding of the lag screw and inadequate bone anchorage occur frequently in elderly patients with unstable intertrochanteric fractures. Although polymethylmethacrylate (PMMA) bone cement has been widely used as a secondary fixation to facilitate fixation stability, there has been no prospective study on the clinical significance of PMMA cement to prevent these two complications in unstable fracture patterns. METHODS: A prospective study was conducted. The DHS was applied either with or without PMMA cement augmentation in 108 elderly patients. The Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association fracture classification was 31-A2 in 91 patients and 31-A3 in 17 patients. The average age of the patients was 81.9 years (range, 75-96 years). The average follow-up period was 13.9 months (range, 12-30 months). PMMA cement was injected precisely into the proximal fragment with an average amount of 13.7 mL (range, 10-19 mL) in 55 patients. RESULTS: All but six patients (5.6%) had eventual bone union, and the average time to union was 18.1 week (range, 12-36 weeks). Screw sliding, femoral shortening, and varus collapse of the proximal fragment were all significantly reduced in the cemented group at the 1-year follow-up (p < 0.001, p < 0.001, p < 0.001, respectively). The mean hip pain score was 1.9 (range, 1-4) in all 102 patients and was significantly lower in the cemented group (p = 0.008). One patient with a deep infection in the cemented group and five patients with lag screw penetration in the noncemented group received a total hip replacement. All 18 patients with malunion were in the noncemented group. Of these 18 patients, 14 patients (77.8%) had excessive sliding of the lag screw. The overall complication rate was significantly higher in the noncemented group (p < 0.001). CONCLUSIONS: With the meticulous augmentation technique demonstrated in this study, the PMMA cemented DHS proved to have better outcome than a conventional DHS for unstable intertrochanteric fractures in elderly patients. Typical complications related to a conventional DHS device for the treatment of such fractures were successfully prevented.

A Three-Dimensional Printed Polycaprolactone Scaffold Combined with Co-Axially Electrospun Vancomycin/Ceftazidime/Bone Morphological Protein-2 Sheath-Core Nanofibers for the Repair of Segmental Bone Defects During the Masquelet Procedure.

INTRODUCTION: Masquelet proposed a new solution for the healing of segmental bone defects, thus minimizing the disadvantages associated with traditional bone grafting. However, a major factor leading to the failure of this technique pertains to be the residual infection. Accordingly, we developed an antibiotic- and osteo-inductive agent-loaded composite scaffold to solve this problem. METHODS: A mesh-like polycaprolactone scaffold was prepared using a lab-exploited solution-type three-dimensional printer, and hybrid sheath-core structured poly(lactic-co-glycolic-acid) nanofibers were fabricated using co-axial electrospinning technology. Vancomycin, ceftazidime, and bone morphological protein (BMP)-2 were employed. The in vitro and in vivo (rabbit fracture model) release patterns of applied agents from the composite scaffold were investigated. RESULTS: The results revealed that the drug-eluting composite scaffold enabled the sustainable release of the medications for at least 30 days in vitro. Animal tests demonstrated that a high concentration of medications was maintained. Abundant growth factors were induced within the bioactive membrane stimulated by the applied scaffold. Finally, satisfactory bone healing potential was observed on radiological examination and biomechanical evaluation. DISCUSSION: The developed composite scaffold may facilitate bone healing by inducing bioactive membrane formation and yielding high concentrations of antibiotics and BMP-2 during the Masquelet procedure.

Combination of a biodegradable three-dimensional (3D) - printed cage for mechanical support and nanofibrous membranes for sustainable release of antimicrobial agents for treating the femoral metaphyseal comminuted fracture.

The aim of this study was to develop a biodegradable three-dimensional-printed polylactide (PLA) cage for promoting bony fixation and an antibiotics-embedded poly(d,l)-lactide-co-glycolide (PLGA) nanofibrous membrane for infectious prophylaxis during treating the comminuted metaphyseal fracture in a rabbit femoral model. The in vitro studies included measuring the mechanical properties of the 3D printed cage and determining release activities of vancomycin and ceftazidime from the nanofibers. The in vivo study included comparisons of rabbits of the femoral metaphyseal comminuted fracture treated with or without the combined biodegradable polymers. The results showed that vancomycin and ceftazidime were sustainably detected above the effective levels in the local tissue fluid around the fracture site for 3 weeks. The animal studies showed that rabbits with the 3D cage implantation possessed better cortical integrity, leg length ratio, and maximal bending strengths. The study results indicate that these combined polymers may promote fracture fixation during treating the rabbit femoral metaphyseal comminuted fracture.

A bio-artificial poly([D,L]-lactide-co-glycolide) drug-eluting nanofibrous periosteum for segmental long bone open fractures with significant periosteal stripping injuries.

Biodegradable poly([D,L]-lactide-co-glycolide) (PLGA) nanofibrous membrane embedded with two drug-to-polymer weight ratios, namely 1:3 and 1:6, which comprised PLGA 180 mg, lidocaine 20 mg, vancomycin 20 mg, and ceftazidime 20 mg, and PLGA 360 mg, lidocaine 20 mg, vancomycin 20 mg, and ceftazidime 20 mg, respectively, was produced as an artificial periosteum in the treatment of segmental femoral fractures. The nanofibrous membrane's drug release behavior was assessed in vitro using high-performance liquid chromatography and the disk-diffusion method. A femoral segmental fracture model with intramedullary Kirschner-wire fixation was established for the in vivo rabbit activity study. Twenty-four rabbits were divided into two groups. Twelve rabbits in group A underwent femoral fracture fixation only, and 12 rabbits in group B underwent femoral fracture fixation and were administered the drug-loaded nanofibers. Radiographs obtained at 2, 6, and 12 weeks postoperatively were used to assess the bone unions. The total activity counts in animal behavior cages were also examined to evaluate the clinical performance of the rabbits. After the animals were euthanized, both femoral shafts were harvested and assessed for their torque strengths and toughness. The daily in vitro release curve for lidocaine showed that the nanofibers eluted effective levels of lidocaine for longer than 3 weeks. The bioactivity studies of vancomycin and ceftazidime showed that both antibiotics had effective and sustained bactericidal capacities for over 30 days. The findings from the in vivo animal activity study suggested that the rabbits with the artificial drug-eluting periosteum exhibited statistically increased levels of activity and better clinical performance outcomes compared with the rabbits without the artificial periosteum. In conclusion, this artificial drug-eluting periosteum may eventually be used for the treatment of open fractures.

Biodegradable nanofiber-membrane for sustainable release of lidocaine at the femoral fracture site as a periosteal block: In vitro and in vivo studies in a rabbit model.

The aim of this study was to evaluate the efficacy of a biodegradable, lidocaine-embedded, nanofibrous membrane for the sustainable analgesic release onto fragments of a segmental femoral fracture site. Membranes of three different lidocaine concentrations (10%, 30%, and 50%) were produced via an electrospinning technique. In vitro lidocaine release was assessed by high-performance liquid chromatography. A femoral segmental fracture, with intramedullary Kirschner-wire fixation and polycaprolactone stent enveloping the fracture site, was set-up in a rabbit model for in vivo assessment of post-operative recovery of activity. Eighteen rabbits were randomly assigned to three groups (six rabbits per group): group A comprised of rabbits with femoral fractures and underwent fixation; group B comprised of a comparable fracture model to that of group A with the implantation of lidocaine-loaded nanofibers; and group C, the control group, received only anesthesia. The following variables were measured: change in body weight, food and water intake before and after surgery, and total activity count post-surgery. All membranes eluted effective levels of lidocaine for more than 3 weeks post-surgery. Rabbits in group B showed faster recovery of activity post-operatively, compared with those in group A, which confirmed the pain relief efficacy of the lidocaine-embedded nanofibers. Nanofibers with sustainable lidocaine release have adequate efficacy and durability for pain relief in rabbits with segmental long bone fractures.

Enhancement of tendon-bone healing via the combination of biodegradable collagen-loaded nanofibrous membranes and a three-dimensional printed bone-anchoring bolt.

A composite biodegradable polymeric model was developed to enhance tendon graft healing. This model included a biodegradable polylactide (PLA) bolt as the bone anchor and a poly(D,L-lactide-co-glycolide) (PLGA) nanofibrous membrane embedded with collagen as a biomimic patch to promote tendon-bone interface integration. Degradation rate and compressive strength of the PLA bolt were measured after immersion in a buffer solution for 3 months. In vitro biochemical characteristics and the nanofibrous matrix were assessed using a water contact angle analyzer, pH meter, and tetrazolium reduction assay. In vivo efficacies of PLGA/collagen nanofibers and PLA bolts for tendon-bone healing were investigated on a rabbit bone tunnel model with histological and tendon pullout tests. The PLGA/collagen-blended nanofibrous membrane was a hydrophilic, stable, and biocompatible scaffold. The PLA bolt was durable for tendon-bone anchoring. Histology showed adequate biocompatibility of the PLA bolt on a medial cortex with progressive bone ingrowth and without tissue overreaction. PLGA nanofibers within the bone tunnel also decreased the tunnel enlargement phenomenon and enhanced tendon-bone integration. Composite polymers of the PLA bolt and PLGA/collagen nanofibrous membrane can effectively promote outcomes of tendon reconstruction in a rabbit model. The composite biodegradable polymeric system may be useful in humans for tendon reconstruction.

Dual delivery of active antibactericidal agents and bone morphogenetic protein at sustainable high concentrations using biodegradable sheath-core-structured drug-eluting nanofibers.

In this study, we developed biodegradable sheath-core-structured drug-eluting nanofibers for sustainable delivery of antibiotics (vancomycin and ceftazidime) and recombinant human bone morphogenetic protein (rhBMP-2) via electrospinning. To prepare the biodegradable sheath-core nanofibers, we first prepared solutions of poly(d,l)-lactide-co-glycolide, vancomycin, and ceftazidime in 1,1,1,3,3,3-hexafluoro-2-propanol and rhBMP-2 in phosphate-buffered solution. The poly(d,l)-lactide-co-glycolide/antibiotics and rhBMP-2 solutions were then fed into two different capillary tubes controlled by two independent pumps for coaxial electrospinning. The electrospun nanofiber morphology was observed under a scanning electron microscope. We further characterized the in vitro antibiotic release from the nanofibers via high-performance liquid chromatography and that of rhBMP-2 via enzyme-linked immunosorbent assay and alkaline phosphatase activity. We showed that the biodegradable coaxially electrospun nanofibers could release high vancomycin/ceftazidime concentrations (well above the minimum inhibition concentration [MIC]90) and rhBMP-2 for >4 weeks. These experimental results demonstrate that novel biodegradable nanofibers can be constructed with various pharmaceuticals and proteins for long-term drug deliveries.

Biodegradable drug-eluting nanofiber-enveloped implants for sustained release of high bactericidal concentrations of vancomycin and ceftazidime: in vitro and in vivo studies.

We developed biodegradable drug-eluting nanofiber-enveloped implants that provided sustained release of vancomycin and ceftazidime. To prepare the biodegradable nanofibrous membranes, poly(D,L)-lactide-co-glycolide and the antibiotics were first dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol. They were electrospun into biodegradable drug-eluting membranes, which were then enveloped on the surface of stainless plates. An elution method and a high-performance liquid chromatography assay were employed to characterize the in vivo and in vitro release rates of the antibiotics from the nanofiber-enveloped plates. The results showed that the biodegradable nanofiber-enveloped plates released high concentrations of vancomycin and ceftazidime (well above the minimum inhibitory concentration) for more than 3 and 8 weeks in vitro and in vivo, respectively. A bacterial inhibition test was carried out to determine the relative activity of the released antibiotics. The bioactivity ranged from 25% to 100%. In addition, the serum creatinine level remained within the normal range, suggesting that the high vancomycin concentration did not affect renal function. By adopting the electrospinning technique, we will be able to manufacture biodegradable drug-eluting implants for the long-term drug delivery of different antibiotics.