Osteochondral allograft reconstruction of talar body fracture with a large bone defect

Repair of segmental bone defect using tissue engineered heterogeneous deproteinized bone doped with lithium

Lithium have been shown to play an important role in improving the osteogenic properties of biomaterials. This study aims to explore the osteogenic improvement effect of tissue engineered heterogeneous deproteinized bone (HDPB) doped with lithium, and evaluate their effectiveness in the healing of bone defects. Bone marrow mesenchymal stem cells (BMSCs) were co-cultured with different concentration of lithium chloride. Cell proliferation in each group was analyzed by 3-(4, 5-dimetyl-2-thiazoly-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay. BMSCs were then co-cultured in osteogenic induction medium with different concentration of lithium chloride, and the expression of related mRNA was detected. The role of lithium in promoting BMSCs osteogenic differentiation and inhibiting BMSCs lipogenic differentiation was also investigated. Biomechanical properties of the tibia were evaluated at 8 weeks after operation. The tibial specimens of each group were collected at 4 and 8 weeks after surgery for histological examination and histological analysis. Micro-computed tomography (CT) scanning and 3D reconstruction were performed at 8 weeks. The results demonstrate that lithium can induce the osteogenic differentiation inhibit of adipogenic differentiation of BMSCs by regulating the Wnt signaling pathway. The histological evaluation further certified that average bone formation area in the group of tissue engineered HDPB doped with lithium was also significantly better than that of HDPB alone group. Based on the above evaluation, tissue engineered HDPB doped with lithium can effectively promote the regeneration of segmental bone defect, which can be used as a tissue engineering scaffold for clinical trials.

Carbon Nanomaterials in the Treatment of Infectious Bone Defects and Wound Scars after Wushu Fractures

Although modern antibiotics and surgical technology have made great progress, when using carbon nanomaterials to treat bone marrow-induced inflammation after martial arts fractures, how to simultaneously repair bone defects and control wound infections is the current focus of orthopedics research. This paper uses electrospinning technology to develop a carbon nanomaterial based on PLA, HA-g-PLA, and vancomycin. The surface morphology, biocompatibility, drug release, and osteogenesis of carbon nanomaterials are studied, selecting animal models to verify its effect in the treatment of osteomyelitis with bone defects and provide new ideas and new methods for the treatment of bone defects complicated by osteomyelitis infection. In this paper, carbon nanofibers containing doxycycline, a small molecule protease inhibitor, were prepared by simple blending. Encapsulation of carbon nanofibers can control the slow release of doxycycline and improve the effect of doxycycline in treating chronic wounds. This article uses two methods to prepare different types of osteomyelitis models and compare them. After injecting saline or bacterial solution, the two groups were sealed with bone wax and the incision was closed; the blank group did not do any treatment. Within 30 days after surgery, the appearance of the left hind limb wound and general signs of infection were closely monitored, body temperature was measured, and blood was collected from the ear veins of experimental animals to analyze the changes in C-reactive protein (CRP) and procalcitonin levels (PCT); X-ray, CT imaging, and histological observation were performed on 14 and 28 days. Studies have shown that when the drug loading of doxycycline increases from 10% to 15%, this is related to the change in properties of the polylactic acid fiber membrane from hydrophobic to hydrophilic caused by the increase in doxycycline drug loading.

Clinical applications of allografts in foot and ankle surgery

PURPOSE

The purpose of this review is to systematically analyse current literature on the use of allografts in the surgical treatment of foot and ankle disorders in adult patients. Based on this study, we propose evidence-based recommendations.

METHODS

The database for PubMed was searched for all published articles. No timeframe restrictions were applied. Clinical studies eligible for inclusion met the following criteria: performed on patients over 18 years old; subject to surgical treatment of foot and ankle disorders; with report on the outcome of the use of allografts; with a report and assessment of pain and function, or equivalent; minimum follow-up of 1 year was required. Two reviewers independently screened and selected studies for full-text analysis from title and abstract. 107 studies were included from 1113 records. Studies were grouped according to surgical indications into ten categories: musculoskeletal tumours (n = 16), chronic ankle instability (n = 15), ankle arthritis (n = 14), osteochondral lesions of the talus (n = 12), Achilles tendon defects (n = 11), other tendon defects (n = 9), fusions (n = 9), fractures (n = 8), hallux rigidus (n = 3) and other indications (n = 10).

RESULTS

Most studies displayed evidence level of IV (n = 57) and V (n = 39). There was one level I, one level II and nine level III studies. Most studies reported allografting as a good option (n = 99; 92.5%). Overall complication rate was 17% (n = 202).

CONCLUSIONS

Fair evidence (Grade B) was found in favour of the use of allografts in lateral ankle ligament reconstruction or treatment of intra-articular calcaneal fracture. Fair evidence (Grade B) was found against the use of allogeneic MSCs in tibiotalar fusions.

LEVEL OF EVIDENCE

V.

[Biomechanical study on repair and reconstruction of talar lesion by three-dimensional printed talar components]

Objective

To explore the feasibility of the repair and reconstruction of large talar lesions with three-dimensional (3D) printed talar components by biomechanical test.

Methods

Six cadaveric ankle specimens were used in this study and taken CT scan and reconstruction. Then, 3D printed talar component and osteotomy guide plate were designed and made. After the specimen was fixed on an Instron mechanical testing machine, a vertical pressure of 1 500 N was applied to the ankle when it was in different positions (neutral, 10° of dorsiflexion, and 14° of plantar flexion). The pressure-bearing area and pressure were measured and calculated. Then osteotomy on specimen was performed and 3D printed talar components were implanted. And the biomechanical test was performed again to compare the changes in pressure-bearing area and pressure.

Results

Before the talar component implantation, the pressure-bearing area of the talus varied with the ankle position in the following order: 10° of dorsiflexion > neutral position > 14° of plantar flexion, showing significant differences between positions ( P<0.05). The pressure exerted on the talus varied in the following order: 10° of dorsiflexion < neutral position < 14° of plantar flexion, showing significant differences between positions ( P<0.05). The pressure-bearing area and pressure were not significantly different between before and after talar component implantations in the same position ( P>0.05). The pressure on the 3D printed talar component was not significantly different from the overall pressure on the talus ( P>0.05).

Conclusion

Application of the 3D printed talar component can achieve precise repair and reconstruction of the large talar lesion. The pressure on the repaired site don't change after operation, indicating the clinical feasibility of this approach.

Lithium-incorporated deproteinized bovine bone substitute improves osteogenesis in critical-sized bone defect repair

This study aimed to explore the surface modification of deproteinized bovine bone using lithium-ion and evaluate its efficacy on osteogenesis improvement and critical-sized bone defect repair. Hydrothermal treatment was performed to produce lithium-incorporated deproteinized bovine bone. In vitro study, human osteosarcoma cell MG63 (MG63) was cultured with the bone substitute to evaluate the cell viability and then calcium deposition was measured to analyze the osteogenesis. In vivo studies, male adult goats were chosen to build critical-sized bone defect model and randomly divided into three groups. The goats were treated with autogenous cancellous bone, lithium-incorporated deproteinized bovine bone, and deproteinized bovine bone. Animals were evaluated using radiological analysis including X-ray, computed tomography, and Micro-CT; histological methods involving hematoxylin-eosin dyeing, Masson dyeing, and immunofluorescence detection at 4 and 12 weeks after surgery were carried out. According to the results, lithium-incorporated deproteinized bovine bone produced nano-structured surface layer. The lithium-incorporated deproteinized bovine bone could promote the osteoblast proliferation and increase the calcium deposition. In vivo studies, radiographic results revealed that lithium-incorporated deproteinized bovine bone scaffolds provided better performance in terms of mean gray values of X films, mean pixel values of computed tomography films, and bone volume and trabecular thickness of micro-computed tomography pictures when compared with the deproteinized bovine bone group. In addition, histological analysis showed that the lithium-incorporated deproteinized bovine bone group also significantly achieved larger new bone formation area. At the same time, when the expression of osteogenic factors in vivo was evaluated, runt-related transcription factor 2 (Runx2) and collagen type one (Col-1) were expressed more in lithium-incorporated deproteinized bovine bone group than those in deproteinized bovine bone group. However, the bone defect repair effect using autograft is still a little better than that of lithium-incorporated deproteinized bovine bone substitute based on our results. In conclusion, surface lithium-incorporated deproteinized bovine bone achieved improvement of osteogenesis effect and could enhance the new bone formation in critical-sized bone defects.