A prospective, randomised, controlled trial using a Mg-hydroxyapatite - demineralized bone matrix nanocomposite in tibial osteotomy

Lack of Efficacy of Bone Void Filling Materials in Medial Opening-Wedge High Tibial Osteotomy: A Systematic Review and Network Meta-Analysis

PURPOSE

To systematically review the clinical and radiologic outcomes of isolated medial opening-wedge high tibial osteotomies with different bone void filling materials and to compare the outcomes by network meta-analysis.

METHODS

This systematic review and network meta-analysis included searches of Medline, Embase, Cochrane Library, Web of Science, and Scopus from inception to July 30, 2022, for clinical comparative studies comparing 2 or more bone void filling materials in patients undergoing medial opening-wedge high tibial osteotomies. We performed Bayesian random-effect network meta-analyses to summarize the evidence and applied the Grading of Recommendations Assessment, Development, and Evaluation frameworks to rate the certainty of evidence, calculate the absolute effects, and present the findings. Cochrane Risk of Bias Tool 2.0 and modified Newcastle-Ottawa Scale were used to assess the risk of bias.

RESULTS

In total, 2,755 citations were identified by our search, of which 25 eligible trials, including 10 randomized controlled trials and 15 nonrandomized comparative trials (NCTs) enrolled 1,420 participants and 6 different interventions (autografts, allografts, synthetic grafts, mixed grafts, xenografts, and without grafts). There were some concerns on the risk of bias assessment among randomized controlled trials, and the median Newcastle-Ottawa Scale score was 6 for NCTs. All fillers showed no significantly superior treatment effects when compared with unfilled group in final Knee Society Scoring, Western Ontario and McMasters Universities score, time to bone union (TBU), and loss of correction (LOC). Exceptionally, moderate-certainty evidence suggested that autograft would produce superior incidence of complete bone union (CBU) than the unfilled at postoperative 1 year (odds ratio [OR] 13.0, 95% confidence interval [CI] 1.60-95.6), whereas low- to very low-certainty evidence suggested allografts (OR 0.2, 95% CI 0.06-0.52) and synthetic grafts (OR 0.29, 95% CI 0.10-0.68) would result in inferior CBU. Low-certainty evidence suggested allografts would result in larger LOC angle than unfilled group (mean difference 1.1, 95% CI 0.1-2.3). As for TBU, low-certainty evidence suggested mixed grafts would take longer time to reach clinical bone union (mean difference -14.04, 95% CI -21.0 to -6.9).

CONCLUSIONS

There is a lack of efficacy for different bone void filling materials to result better outcomes in Knee Society Scoring, Western Ontario and McMasters Universities score, TBU, and LOC than without graft. Although applying the autografts would produce a superior possibility of radiologic CBU than other fillers, because of the inclusion of NCTs, the overall certainty of the evidence synthesis is low.

LEVEL OF EVIDENCE

Level Ⅲ, meta-analysis of Level I randomized controlled trials and Level Ⅱ∼Ⅲ non-randomized comparative trails.

Effectiveness of bone substitute materials in opening wedge high tibial osteotomy: a systematic review and meta-analysis

BACKGROUND

A meta-analysis of eligible studies was performed to evaluate the effectiveness of bone substitute materials (BSMs) in opening wedge high tibial osteotomy (OWHTO) for knee osteoarthritis.

METHODS

A systematic review and meta-analysis were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). A comprehensive literature search was performed, and studies comparing BSM with bone graft (BG) and without bone graft (WG) were included. The Cochrane risk of bias tool (version 1.0) and Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) tool were used to assess the risk of bias for randomized controlled trials (RCTs) and non-randomized studies (NRSs), respectively. The outcomes measured were the osteotomy gap size, the occurrence rates of non-union and lateral hinge fractures, knee functional score, infection and the Visual Analogue Scale (VAS). The quality of evidences was evaluated by Grades of Recommendation, Assessment, Development and Evaluation (GRADE) Working Group system.

RESULTS

Five RCTs and eight NRS including 769 participants were included in our meta-analysis. The BSM group had a larger osteotomy gap size than the control group (MD: 0.41 mm, 95% confidence interval (CI): [0.06, 0.76], p=.02, I²=0%), with a significant difference. No significant difference was found between BSM and control group in main analysis in terms of bone non-union, but with a higher non-union rate when BSM combined with long locking plate was used. No significant differences were found in other outcome measures except for VAS from NRS subgroup. The quality of evidence for outcomes was low.

CONCLUSIONS

BSM combined with locking plate techniques offers a safe and efficient alternative option in OWHTO for osteotomy gap larger than 10 mm, but be aware of the possibility of bone non-union. Given the inherent heterogeneity and low quality of the included studies, future well-designed RCTs are essential to verify the findings.KEY MESSAGEThe treatment of the osteotomy gap is still controversial.BSM combined with a locking plate offers a safe and efficient alternative option for OWHTO with an over 10 mm of osteotomy gap over 10 mm.Due to the inherent heterogeneity and low quality of the included studies, the results should be cautiously interpreted in clinical practice.

Bone Tissue Engineering in the Treatment of Bone Defects

Bones play an important role in maintaining exercise and protecting organs. Bone defect, as a common orthopedic disease in clinics, can cause tremendous damage with long treatment cycles. Therefore, the treatment of bone defect remains as one of the main challenges in clinical practice. Today, with increased incidence of bone disease in the aging population, demand for bone repair material is high. At present, the method of clinical treatment for bone defects including non-invasive therapy and invasive therapy. Surgical treatment is the most effective way to treat bone defects, such as using bone grafts, Masquelet technique, Ilizarov technique etc. In recent years, the rapid development of tissue engineering technology provides a new treatment strategy for bone repair. This review paper introduces the current situation and challenges of clinical treatment of bone defect repair in detail. The advantages and disadvantages of bone tissue engineering scaffolds are comprehensively discussed from the aspect of material, preparation technology, and function of bone tissue engineering scaffolds. This paper also summarizes the 3D printing technology based on computer technology, aiming at designing personalized artificial scaffolds that can accurately fit bone defects.

Biomimetic and immunomodulatory baicalin-loaded graphene oxide-demineralized bone matrix scaffold for in vivo bone regeneration

The use of an artificial bone substitute is a potential strategy for repairing bone defects; however, the inadequate consideration of repair-immune system interactions, resulting in significant pathological changes in the microenvironment, is a major barrier to achieving effective regenerative outcomes. Here, we evaluated a biomimetic baicalin (BAI)-incorporating graphene oxide-demineralized bone matrix (GO-BAI/DBM) hybrid scaffold, which was beneficial for bone regeneration. First, by considering that bone is a kind of organic-inorganic composite, a biomimetic GO/DBM bone substitute with enhanced physiochemical and osteoinductive properties was fabricated. Furthermore, inherently therapeutic GO was also used as a drug delivery carrier to achieve the sustained and prolonged release of BAI. Notably, a series of experiments showed that the GO-BAI nanocomposites could transform inflammatory M1 macrophages into pro-healing M2 macrophages, which was beneficial for in vitro angiogenesis and osteogenesis. By using a rat subcutaneous model, it was revealed that the GO-BAI nanocomposites proactively ameliorated the inflammatory response, which was coupled with decreased fibrous encapsulation. Notably, obvious in situ calvarial bone regeneration was achieved using the GO-BAI/DBM hybrid scaffold. These findings demonstrated that the bifunctional GO-BAI/DBM scaffold, by enhancing beneficial cross-talk among bone cells and inflammatory cells, might be utilized as an effective strategy for bone regeneration.

The "Yin and Yang" of Immunomodulatory Magnesium-Enriched Graphene Oxide Nanoscrolls Decorated Biomimetic Scaffolds in Promoting Bone Regeneration

Tissue regeneration driven by immunomodulatory agents has emerged as a potential solution for repairing bone defects. However, the therapeutic benefits are compromised by disturbances in the pro- and anti-inflammatory balance. Here, using magnesium nanoparticles (MgNPs) as a template, magnesium-enriched graphene oxide nanoscrolls (MgNPs@GNSs) designed for combinational modulation of the inflammatory response are reported. First, the different effects of graphene oxide (GO) and magnesium ions (Mg²⁺ ) on Raw264.7 macrophage phenotype transformation are screened. The results reveal that GO activates inflammatory M1 macrophages, and that Mg²⁺ facilitates repolarization of M1 macrophages to the pro-healing M2 phenotype. With sustained release of Mg²⁺ , the MgNPs@GNS nanoplatform can orchestrate harmonious type 1 and type 2 inflammatory responses. Mg²⁺ decrease the internalization of GO and downregulate the nuclear factor kappa-B pathway, which is profoundly involved in the inflammatory process. A series of experiments show that the ordered inflammatory response induced by MgNPs@GNSs stimulates in vitro angiogenesis and osteogenesis through chemotactic, mitogenic, and morphogenic actions. Obvious vascularized bone regeneration is achieved in a rat cranial bone defect model via MgNPs@GNS deposited decellularized bone matrix scaffold. Therefore, the potential of using inherently therapeutic nanomedicine to modulate biomaterial-induced immune responses and thus enhance bone regeneration is demonstrated.

Comparable bone union progression after opening wedge high tibial osteotomy using allogenous bone chip or tri-calcium phosphate granule: a prospective randomized controlled trial

PURPOSE

The purpose of this study is to compare the progression rate of bone union and clinical outcomes of opening wedge high tibial osteotomy (OWHTO) using allogenous bone chip or tri-calcium phosphate (TCP) granule as bone graft materials. The hypothesis was that the bone union progression in OWHTOs using TCP granule grafts would be comparable to that of OWHTOs using allogenous bone chip grafts.

METHODS

Between 2011 and 2013, 54 patients who had undergone OWHTO for genu varum and osteoarthritis were randomized to one of the two groups at five centres. TCP granule was used to fill the defect in 27 patients and lyophilized allogenous bone chip was used in the other 27 patients. The degree of bone union was classified on a five-point scale and evaluated using plain radiographs of the knee at 6 weeks, 3 months, 6 months, and 12 months postoperatively. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, pain Visual Analogue Scale (VAS) score and complications were also evaluated.

RESULTS

The highest degree of bone union observed at 6 and 12 months postoperatively was grade 4, and the number of cases of union progression at each time-point was not significantly different between the two groups (p > 0.05). WOMAC and pain VAS scores also showed no differences between the two groups. No complications were observed during the 12-month period following OWHTO in either group.

CONCLUSION

OWHTO using TCP granule bone substitute showed similar bone union rates and clinical outcomes compared to allogenous bone chip grafts. TCP granule can be used as bone substitutes instead of allogenous bone chip grafts in OWHTO.

LEVEL OF EVIDENCE

Level 1.

Nanomaterials as potential and versatile platform for next generation tissue engineering applications

Tissue engineering (TE) is an emerging field where alternate/artificial tissues or organ substitutes are implanted to mimic the functionality of damaged or injured tissues. Earlier efforts were made to develop natural, synthetic, or semisynthetic materials for skin equivalents to treat burns or skin wounds. Nowadays, many more tissues like bone, cardiac, cartilage, heart, liver, cornea, blood vessels, and so forth are being engineered using 3-D biomaterial constructs or scaffolds that could deliver active molecules such as peptides or growth factors. Nanomaterials (NMs) due to their unique mechanical, electrical, and optical properties possess significant opportunities in TE applications. Traditional TE scaffolds were based on hydrolytically degradable macroporous materials, whereas current approaches emphasize on controlling cell behaviors and tissue formation by nano-scale topography that closely mimics the natural extracellular matrix. This review article gives a comprehensive outlook of different organ specific NMs which are being used for diversified TE applications. Varieties of NMs are known to serve as biological alternatives to repair or replace a portion or whole of the nonfunctional or damaged tissue. NMs may promote greater amounts of specific interactions stimulated at the cellular level, ultimately leading to more efficient new tissue formation. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2433-2449, 2019.

Reconstructing Bone with Natural Bone Graft: A Review of In Vivo Studies in Bone Defect Animal Model

Bone defects caused by fracture, disease or congenital defect remains a medically important problem to be solved. Bone tissue engineering (BTE) is a promising approach by providing scaffolds to guide and support the treatment of bone defects. However, the autologous bone graft has many defects such as limited sources and long surgical procedures. Therefore, xenograft bone graft is considered as one of the best substitutions and has been effectively used in clinical practice. Due to better preserved natural bone structure, suitable mechanical properties, low immunogenicity, good osteoinductivity and osteoconductivity in natural bone graft, decellularized and demineralized bone matrix (DBM) scaffolds were selected and discussed in the present review. In vivo animal models provide a complex physiological environment for understanding and evaluating material properties and provide important reference data for clinical trials. The purpose of this review is to outline the in vivo bone regeneration and remodeling capabilities of decellularized and DBM scaffolds in bone defect models to better evaluate the potential of these two types of scaffolds in BTE. Taking into account the limitations of the state-of-the-art technology, the results of the animal bone defect model also provide important information for future design of natural bone composite scaffolds.

In vitro and in vivo evaluation of xenogeneic bone putty with the carrier of hydrogel derived from demineralized bone matrix

The demineralized bone matrix (DBM) putty is a traditional bone graft utilized to facilitate the repair and reconstruction of bone. Recent studies indicated the DBM putties with the various carriers were different in bone repairing ability. In order to prepare a kind of DBM putty with a good biocompatibility and bioactivity, the DBM gel was processed from the DBM and the feasibility as a carrier for the DBM putty was evaluated. After the bovine DBM gel was prepared, the BMPs content as well as the ability to promote osteogenic differentiation of MC3T3-E1 cells in vitro were investigated. Then the DBM putty was prepared and filled into the rat calvarial defect model to evaluate the bone repairing ability by micro-CT and histology. The result showed there was 2.953 ± 0.054 ng BMP contained in per gram of the DBM gel. And the ALP production of MC3T3-E1 cells in the DBM gels group increased with prolonged culturing, the mineralized nodules formed in MC3T3-E1 cells on 14th day after co-culture. The putty prepared by DBM gel was easy to handle without loss of DBM particles at room temperature. In the rat calvarial bone defect experiment, histological observation showed more mature bone formed in the DBM putty group than that in the type I collagen group at 12 weeks, which indicated the bone putty prepared by DBM gel exhibited a better bone repair capability.

Comparison of bone healing and outcomes between allogenous bone chip and hydroxyapatite chip grafts in open wedge high tibial osteotomy

Allogenous bone chips and hydroxyapatite (HA) chips have been known as good options for filling an inevitable void after open wedge high tibial osteotomy (OWHTO). However, there are concerns regarding bone healing after the use of these grafts. The purpose of this study was to compare the bone healing represented by the osteoconductivity and absorbability between allogenous bone chips and HA chips in OWHTO. The outcomes of bone healing of 53 patients who received an allogenous bone chip graft and 41 patients who received an HA chip graft were retrospectively evaluated, and the results were compared between the two groups. Osteoconductivity and absorbability were serially evaluated for the assessment of bone healing at 6 weeks, 3 months, 6 months, and 1 year postoperatively. The osteoconductivity of the allogenous bone chips was greater than that of the HA chips at 6 weeks postoperatively (p < 0.05). However, there were no statistically significant differences from 3 months to 1 year postoperatively. The absorbability showed no statistically significant differences 6 weeks and 3 months after OWHTO; however, the allogenous bone chip group showed a greater absorbability at 6 months and 1 year postoperatively (42.8 ± 14.2 vs. 34.6 ± 13.8, p = 0.006 at 6 months postoperatively; 54.6 ± 14.4 vs. 43.0 ± 14.0, p < 0.001 at 1 year postoperatively). However, the two graft materials showed similar results of HKA angle, WBL ratio, posterior tibial slope.

MgAl layered double hydroxide/chitosan porous scaffolds loaded with PFTα to promote bone regeneration

Poor bone formation remains a key risk factor associated with acellular scaffolds that occurs in some bone defects, particularly in patients with metabolic bone disorders and local osteoporosis. We herein fabricated for the first time layered double hydroxide-chitosan porous scaffolds loaded with PFTα (LDH-CS-PFTα scaffolds) as therapeutic bone scaffolds for the controlled release of PFTα to enhance stem cell osteogenic differentiation and bone regeneration. The LDH-CS scaffolds had three-dimensional interconnected macropores, and plate-like LDH nanoparticles were uniformly dispersed within or on the CS films. The LDH-CS scaffolds exhibited appropriate PFTα drug delivery due to hydrogen bonding among LDH, CS and PFTα. In vitro functional studies demonstrated that the PFTα molecules exhibited potent ability to induce osteogenesis of hBMSCs via the GSK3β/β-catenin pathway, and the LDH-CS-PFTα scaffolds significantly enhanced the osteogenic differentiation of hBMSCs. In vivo studies revealed significantly increased repair and regeneration of bone tissue in cranial defect model rats compared to control rats at 12 weeks post-implantation. In conclusion, the LDH-CS-PFTα scaffolds exhibited excellent osteogenic differentiation and bone regeneration capability and hold great potential for applications in defined local bone regeneration.

Ag-loaded MgSrFe-layered double hydroxide/chitosan composite scaffold with enhanced osteogenic and antibacterial property for bone engineering tissue

Bone tissue engineering scaffolds for the reconstruction of large bone defects should simultaneously promote osteogenic differentiation and avoid postoperative infection. Herein, we develop, for the first time, Ag-loaded MgSrFe-layered double hydroxide/chitosan (Ag-MgSrFe/CS) composite scaffold. This scaffold exhibits three-dimensional interconnected macroporous structure with a pore size of 100-300 μm. The layered double hydroxide nanoplates in the Ag-MgSrFe/CS show lateral sizes of 200-400 nm and thicknesses of ∼50 nm, and the Ag nanoparticles with particle sizes of ∼20 nm are uniformly dispersed on the scaffold surfaces. Human bone marrow-derived mesenchymal stem cells (hBMSCs) present good adhesion, spreading, and proliferation on the Ag-MgSrFe/CS composite scaffold, suggesting that the Ag and Sr elements in the composite scaffold have no toxicity to hBMSCs. When compared with MgFe/CS composite scaffold, the Ag-MgSrFe/CS composite scaffold has better osteogenic property. The released Sr²⁺ ions from the composite scaffold enhance the alkaline phosphatase activity of hBMSCs, promote the extracellular matrix mineralization, and increase the expression levels of osteogenic-related RUNX2 and BMP-2. Moreover, the Ag-MgSrFe/CS composite scaffold possesses good antibacterial property because the Ag nanoparticles in the composite scaffold effectively prevent biofilm formation against S. aureus. Hence, the Ag-MgSrFe/CS composite scaffold with excellent osteoinductivity and antibacterial property has a great potential for bone tissue engineering. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 863-873, 2018.

Silver nanoparticle-loaded hydroxyapatite coating: structure, antibacterial properties, and capacity for osteogenic induction in vitro

AgNP-HAC has the potential to be used on the surfaces of orthopedic and dental implants for infection prophylaxis.

Use of demineralized bone matrix in the extremities

Autologous bone graft is considered as the gold standard for all indications for bone grafting procedures but the limited availability and complications in donor site resulted in seeking other options like allografts and bone graft substitutes. Demineralized bone matrix (DBM) is an allograft product with no quantity limitation. It is an osteoconductive material with osteoinductive capabilities, which vary among different products, depending on donor characteristics and differences in processing of the bone. The purpose of the present review is to provide a critical review of the existing literature concerning the use of DBM products in various procedures in the extremities. Clinical studies describing the use of DBM alone or in combination with other grafting material are available for only a few commercial products. The Level of Evidence of these studies and the resulting Grades of Recommendation are very low. In conclusion, further clinical studies of higher quality are required in order to improve the Recommendation Grades for or against the use of DBM products in bone grafting procedures.

Hierarchically nanostructured hydroxyapatite microspheres as drug delivery carriers and their effects on cell viability

The hydroxyapatite microspheres prepared by hydrothermal synthesis exhibit excellent biocompatibility, high GS-loading efficiency, controllable GS release property and bactericidal property.

Osteotomy for treating knee osteoarthritis

BACKGROUND

Patients with unicompartmental osteoarthritis of the knee can be treated with an osteotomy. The goal of an osteotomy is to unload the diseased compartment of the knee. This is the second update of the original review published in The Cochrane Library, Issue 1, 2005.

OBJECTIVES

To assess the benefits and harms of an osteotomy for treating patients with knee osteoarthritis, including the following main outcomes scores: treatment failure, pain and function scores, health-related quality of life, serious adverse events, mortality and reoperation rate.

SEARCH METHODS

The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE (Current Contents, HealthSTAR) were searched until November 2013 for this second update.

SELECTION CRITERIA

Randomised and controlled clinical trials comparing an osteotomy with other treatments for patients with unicompartmental osteoarthritis of the knee.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, extracted data and assessed risk of bias using the domains recommended in the 'Risk of bias' tool of The Cochrane Collaboration. The quality of the results was analysed by performing overall grading of evidence by outcome using the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) approach.

MAIN RESULTS

Eight new studies were included in this update, for a total of 21 included studies involving 1065 people.In four studies, the randomised sequence was adequately generated and clearly described. In eight studies, allocation concealment was adequately generated and described. In four studies, the blinding procedures were sufficient. In six studies, incomplete outcome data were not adequately addressed. Furthermore, in 11 studies, the selective outcome reporting item was unclear because no study protocol was provided.Follow-up of studies comparing different osteotomy techniques was too short to measure treatment failure, which implicates revision to a knee arthroplasty.Four studies evaluated a closing wedge high tibial osteotomy (CW-HTO) with another high tibial osteotomy (aHTO). Based on these studies, the CW-HTO group had 1.8% (95% confidence interval (CI) -7.7% to 4.2%; low-quality evidence) more pain compared with the aHTO group; this finding was not statistically significant. Pooled function in the CW-HTO group was 0.5% (95% CI -3.8% to 2.8%; low-quality evidence) higher compared with the aHTO group; this finding was not statistically significant. No data on health-related quality of life and mortality were presented.Serious adverse events were reported in only four studies and were not significantly different (low-quality evidence) between groups. The reoperation rate were scored as early hardware removal because of pain and pin track infection due to the external fixator. Risk of reoperation was 2.6 (95% CI 1.5 to 4.5; low-quality evidence) times higher in the aHTO group compared with the CW-HTO group, and this finding was statistically significant.The quality of evidence for most outcomes comparing different osteotomy techniques was downgraded to low because of the numbers of available studies, the numbers of participants and limitations in design.Two studies compared high tibial osteotomy versus unicompartmental knee replacement. Treatment failure and pain and function scores were not different between groups after a mean follow-up of 7.5 years. The osteotomy group reported more adverse events when compared with the unicompartmental knee replacement group, but the difference was not statistically significant. No data on health-related quality of life and mortality were presented.No study compared an osteotomy versus conservative treatment.Ten included studies compared differences in perioperative or postoperative conditions after high tibial osteotomy. In most of these studies, no statistically significant differences in outcomes were noted between groups.

AUTHORS' CONCLUSIONS

The conclusion of this update did not change: Valgus high tibial osteotomy reduces pain and improves knee function in patients with medial compartmental osteoarthritis of the knee. However, this conclusion is based on within-group comparisons, not on non-operative controls. No evidence suggests differences between different osteotomy techniques. No evidence shows whether an osteotomy is more effective than alternative surgical treatment such as unicompartmental knee replacement or non-operative treatment. So far, the results of this updated review do not justify a conclusion on benefit of specific high tibial osteotomy technique for knee osteoarthritis.

Regenerative nanotechnology in oral and maxillofacial surgery

Regenerative nanotechnology is at the forefront of medical research, and translational medicine is a challenge to both scientists and clinicians. Although there has been an exponential rise in the volume of research generated about it for both medical and surgical uses, key questions remain about its actual benefits. Nevertheless, some people think that therapeutics based on its principles may form the core of applied research for the future. Here we give an account of its current use in oral and maxillofacial surgery, and implications and challenges for the future.

Hydroxyapatite-Based Biomaterials Versus Autologous Bone Graft in Spinal Fusion: An In Vivo Animal Study

STUDY DESIGN

An in vivo study was designed to compare the efficacy of biomimetic magnesium-hydroxyapatite (MgHA) and of human demineralized bone matrix (HDBM), both dispersed in a mixture of biomimetic MgHA nanoparticles, with that of an autologous bone graft.

OBJECTIVE

The objective of this study was to evaluate 2 new bone substitutes as alternatives to a bone autograft for spinal fusion, determining their osteoinductive and osteoconductive properties, and their capacity of remodeling, using a large animal model.

SUMMARY OF BACKGROUND DATA

Spinal fusion is a common surgical procedure and it is performed for different conditions. A successful fusion requires potentially osteogenic, osteoinductive, and osteoconductive biomaterials.

METHODS

A posterolateral spinal fusion model involved 18 sheep, bilaterally implanting test materials between the vertebral transverse processes. The animals were divided into 2 groups: 1 fusion level was treated with MgHA (group 1) or with HDBM-MgHA (group 2). The other fusion level received bone autografts in both groups.

RESULTS

Radiographical, histological, and microtomographic results indicated good osteointegration between the spinous process and the vertebral foramen for both materials. Histomorphometry revealed no significant differences between MgHA and autologous bone for all the parameters examined, whereas significantly lower values of bone volume were observed between HDBM-MgHA and autologous bone. Moreover, the normalization of the histomorphometric data with autologous bone revealed that MgHA showed a significantly higher value of bone volume and a lower value of trabecular number, more similar to autologous bone than HDBM-MgHA.

CONCLUSION

The study showed that the use of MgHA in an ovine model of spinal fusion led to the deposition of new bone tissue without qualitative and quantitative differences with respect to new bone formed with autologous bone, whereas the HDBM-MgHA led to a reduced deposition of newly formed bone tissue.

LEVEL OF EVIDENCE

N/A.

Enhanced healing of rat calvarial critical size defect with selenium-doped lamellar biocomposites

A 3D porous lamellar selenium-containing nano-hydroxyapatite (SeHAN)/chitosan (CS) biocomposite was synthesized. The selenium-containing hydroxyapatite (HA) grains of 150~200 nm in length and 20~30 nm in width were observed by dynamic light scattering and transmission electron microscopy. A combination of X-ray diffraction, Fourier-transform infrared spectroscopy, and SEM indicated that HA particles were uniformly dispersed in chitosan matrix and there was a chemical interaction between chitosan and HA. Then, a standard critical size calvarial bone defect was created in Wistar rats. In group 1, no implant was made in the defect. In groups 2 and 3, HA nanoparticles (HAN)/CS biocomposite and SeHAN/CS biocomposite were implanted into the defect, respectively. After 4 weeks, the histological assessment clearly exhibited no significant changes, only found some living cells anchored in the periphery of the implants. After 8 and 12 weeks, most newly formed osteoid tissue was found in the SeHAN/CS implant group. Additionally, the newly formed osteoid tissue, both at the edge and in the center of implants, was bioactive and neovascularized. Microfocus computerized tomography measurements also confirmed the much better quality of the newly formed bone tissue in SeHAN/CS implant group than that in HAN/CS implant group (p < 0.01). Collectively, the SeHAN/CS biocomposite, as a bioactive bone grafting substitute, significantly enhanced the repair of bone defect.

Bone graft substitutes currently available in orthopaedic practice: the evidence for their use

We reviewed 59 bone graft substitutes marketed by 17 companies currently available for implantation in the United Kingdom, with the aim of assessing the peer-reviewed literature to facilitate informed decision-making regarding their use in clinical practice. After critical analysis of the literature, only 22 products (37%) had any clinical data. Norian SRS (Synthes), Vitoss (Orthovita), Cortoss (Orthovita) and Alpha-BSM (Etex) had Level I evidence. We question the need for so many different products, especially with limited published clinical evidence for their efficacy, and conclude that there is a considerable need for further prospective randomised trials to facilitate informed decision-making with regard to the use of current and future bone graft substitutes in clinical practice.

How Can Nanotechnology Help to Repair the Body? Advances in Cardiac, Skin, Bone, Cartilage and Nerve Tissue Regeneration

Nanotechnologists have become involved in regenerative medicine via creation of biomaterials and nanostructures with potential clinical implications. Their aim is to develop systems that can mimic, reinforce or even create in vivo tissue repair strategies. In fact, in the last decade, important advances in the field of tissue engineering, cell therapy and cell delivery have already been achieved. In this review, we will delve into the latest research advances and discuss whether cell and/or tissue repair devices are a possibility. Focusing on the application of nanotechnology in tissue engineering research, this review highlights recent advances in the application of nano-engineered scaffolds designed to replace or restore the followed tissues: (i) skin; (ii) cartilage; (iii) bone; (iv) nerve; and (v) cardiac.

Bovine xenograft locking Puddu plate versus tricalcium phosphate spacer non-locking Puddu plate in opening-wedge high tibial osteotomy: a prospective double-cohort study

PURPOSE

The aim of the study was to compare clinical and radiographic outcomes of opening-wedge high tibial osteotomy (HTO) augmented with either xenograft or tricalcium phosphate spacer for the management of medial compartment osteoarthritis (OA) with genu varum.

METHODS

Between 2004 and 2007, we prospectively enrolled 52 patients with medial compartment knee OA who underwent opening-wedge HTO fixed with locking Puddu plate and xenograft (n = 26) or non-locking Puddu plate and tricalcium phosphate spacer (n = 26). The alignment of the lower limb was assessed by measuring the hip-knee-ankle (HKA) angle. Clinical outcomes were assessed with the Knee Society Score, Western Ontario and McMaster Universities Osteoarthritis Index, SF-36 and European Quality of Life-5 Dimensions scale. All patients were followed up at six weeks and at three, six, 12 and 24 months post-operatively. Clinical outcomes were assessed preoperatively and at 24 months post-operatively.

RESULTS

All clinical scores improved significantly in both groups after surgery, without any significant difference between the two groups. Immediately after surgery, the HKA angle went from 9.1 ± 5.2° in varus to 3.1 ± 4.8° in valgus (P = 0.01) in the xenograft group, and from 8.5 ± 5.9° in varus to 3.4 ± 4.2° in valgus (P = 0.01) in the tricalcium phosphate group. At the last follow-up, the tricalcium phosphate group showed a significant loss of correction (P = 0.03).

CONCLUSIONS

HTO performed with xenograft locking plate and tricalcium phosphate non-locking plate constructs showed good clinical outcomes. However, the xenograft locking plate construct is superior to the tricalcium phosphate spacer non-locking plate to prevent the loss of correction in the middle term.

Application of scaffolds for bone regeneration strategies: current trends and future directions

Scaffolds are extensively used in surgery to replace missing bone and to achieve bony union and fusion. An ideal scaffold should not only maintain, induce, and restore biological functions where cells, extracellular matrix, and growth factors are needed, but also have the right properties with respect to degradation, cell binding, cellular uptake, non-immunogenicity, mechanical strength, and flexibility. Here we examine both the basic science behind the development of scaffolds and comprehensively and systematically review the clinical applications.