Autogenous iliac crest bone graft. Complications and functional assessment

Arthroscopic Treatment of Scaphoid Nonunion With Olecranon Bone Graft and Screw Fixation Leads to Union and Improved Outcomes

PURPOSE

To evaluate the outcomes of arthroscopic treatment of scaphoid nonunion using olecranon bone graft and screw fixation and to analyze the outcomes in accordance with variations in the chronicity, location, and severity of nonunion.

METHODS

Between March 2012 and December 2020, patients with diagnoses of scaphoid delayed nonunion and nonunion with substantial bone resorption (Slade and Dodds grade IV-VI) underwent arthroscopic-assisted olecranon bone graft and screw fixation. Preoperative and postoperative measurements included the visual analog scale score for pain; range of motion; grip strength; the Modified Mayo Wrist Score; the Disabilities of the Arm, Shoulder and Hand (DASH) score; and the minimal clinically important difference for the DASH score. Union rate and duration were also evaluated. The outcomes between groups of patients with different conditions were analyzed.

RESULTS

Twenty-two patients were included. The average follow-up period was 32.5 months. The visual analog scale pain score, range of motion, grip strength, Modified Mayo Wrist Score, and DASH score were significantly improved after surgery (P < .001). The minimal clinically important difference threshold for the DASH score was reached by 100% of patients. At final follow-up, all patients had united scaphoid with no complications. The average time to union was 15.3 weeks. Group analysis showed significant improvements in mean grip strength between patients with delayed union (3-6 months) and those with chronic nonunion (> 1 year) (17.75 kg vs 12.25 kg, P = .032), between grade IV nonunion and grade V nonunion (14.86 kg vs 10.43 kg, P = .035), and between grade V nonunion and grade VI nonunion (10.43 kg vs 15.63 kg, P = .013). Patients with grade VI nonunion achieved union at 17.8 weeks postoperatively, a significantly longer period than that for patients with grade IV nonunion (11.4 weeks, P = .014).

CONCLUSIONS

Arthroscopic treatment of scaphoid nonunion using olecranon bone graft and screw fixation provided satisfactory outcomes regardless of the chronicity, location, and severity of nonunion.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Management of humeral nonunions following failed surgical fixation

INTRODUCTION

Management of humerus nonunions with previously failed fixation presents a complex problem. There are multiple revision fixation strategies, of which compression plating is a mainstay. The aim of this study was to assess the results of open reduction and direct compression plating without the need for autograft or allograft in the setting of revision humerus open reduction internal fixation.

METHODS

This study is a retrospective analysis of 19 patients treated between 2008 and 2017 for humerus nonunions following failed fixation who were treated by a single surgeon using direct compression plating with bone graft substitutes. Patients were treated with neurolysis of the radial nerve, hardware removal, debridement of the nonunion site with shortening osteotomies, compression plating, and augmentation with bone graft substitutes. All patients were followed until radiographic and clinical union.

RESULTS

Nineteen patients were identified for the study and 17 had adequate follow-up for final analysis. Humeral union was achieved in 16/17 (94.1%) patients with a mean time to union of 23 weeks. Two patients required a repeat compression plating with bone graft substitute to achieve union. The one patient with a nonunion radiographically reported minimal clinical symptoms and opted for no revision surgery. An association with the index procedure was seen, as three out of four of the patients who experienced radial nerve palsies after their index procedure subsequently experienced a radial nerve palsy after the procedure to repair their nonunion. All patient's all experienced a return of function in their radial nerve either back to baseline or improved from before the revision nonunion surgery.

CONCLUSION

The use of humeral shortening osteotomy and compression plating without autograft or allograft is a viable option for management of humeral nonunions which avoids the morbidity associated with autograft harvest. The patients with radial nerve palsy after the index procedure are likely to have a transient radial nerve palsy as well after the revision surgery necessitating proper informed consent prior to the operation.

Autologous versus synthetic bone grafts for the surgical management of tibial plateau fractures: a systematic review and meta-analysis of randomized controlled trials

AIMS

Our objective was to conduct a systematic review and meta-analysis, to establish whether differences arise in clinical outcomes between autologous and synthetic bone grafts in the operative management of tibial plateau fractures.

METHODS

A structured search of MEDLINE, EMBASE, the online archives of Bone & Joint Publishing, and CENTRAL databases from inception until 28 July 2021 was performed. Randomized, controlled, clinical trials that compared autologous and synthetic bone grafts in tibial plateau fractures were included. Preclinical studies, clinical studies in paediatric patients, pathological fractures, fracture nonunion, or chondral defects were excluded. Outcome data were assessed using the Risk of Bias 2 (ROB2) framework and synthesized in random-effect meta-analysis. The Preferred Reported Items for Systematic Review and Meta-Analyses guidance was followed throughout.

RESULTS

Six studies involving 353 fractures were identified from 3,078 records. Following ROB2 assessment, five studies (representing 338 fractures) were appropriate for meta-analysis. Primary outcomes showed non-significant reductions in articular depression at immediate postoperative (mean difference -0.45 mm, p = 0.25, 95%confidence interval (CI) -1.21 to 0.31, I2 = 0%) and long-term (> six months, standard mean difference -0.56, p = 0.09, 95% CI -1.20 to 0.08, I2 = 73%) follow-up in synthetic bone grafts. Secondary outcomes included mechanical alignment, limb functionality, and defect site pain at long-term follow-up, perioperative blood loss, duration of surgery, occurrence of surgical site infections, and secondary surgery. Mean blood loss was lower (90.08 ml, p < 0.001, 95% CI 41.49 to 138.67) and surgery was shorter (16.17 minutes, p = 0.04, 95% CI 0.39 to 31.94) in synthetic treatment groups. All other secondary measures were statistically comparable.

CONCLUSION

All studies reported similar methodologies and patient populations; however, imprecision may have arisen through performance variation. These findings supersede previous literature and indicate that, despite perceived biological advantages, autologous bone grafting does not demonstrate superiority to synthetic grafts. When selecting a void filler, surgeons should consider patient comorbidity, environmental and societal factors in provision, and perioperative and postoperative care provision. Cite this article: Bone Jt Open 2022;3(3):218-228.

Fracture repair by IOX2: Regulation of the hypoxia inducible factor-1α signaling pathway and BMSCs

The treatment of fracture delayed union and nonunion has become a challenging problem. Hypoxia inducible factor-1α (HIF-1α) is reported to be a key factor in fracture healing, and is degraded by hydroxylation of prolyl hydroxylase (PHDs) under normal oxygen. Small molecules could inhibit the activity of PHDs, stabilize HIF-1α protein, regulate the expression of downstream target genes of HIF-1α, and make the body adapt to hypoxia. The migration and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) is the most promising candidate for the treatment of fracture nonunion. Here we reported that IOX2, an HIF-1α PHD inhibitor, markedly improved the proliferation and migration of BMSCs by upregulating intracellular Ca²⁺ and concomitant decreasing reactive oxygen species (ROS) in vitro, and facilitated the repair of bone fracture by increasing the number of BMSCs and cartilage formation in vivo. No significant influence of IOX2 on the proliferation and migration of BMSCs after silencing of the HIF-1α. Together, our findings indicated that IOX2 promoted the proliferation and migration of BMSCs via the HIF-1α pathway and further accelerated fracture healing. These results provide a deeper understanding of the mechanism by which HIF promotes fracture healing.

A Case of Reconstruction of an Open Tibial Fracture (Gustilo-Anderson Type IIIB) With Severe Skin and Bone Loss Using Corticocancellous Bone Plugs From the Iliac Crest and an Ilizarov Frame

Gustilo-Anderson type IIIB fractures include open fractures with extensive soft tissue injury with periosteal stripping and bony exposure. They are usually associated with massive contamination and can be challenging even for experienced surgeons. A multidisciplinary approach among plastic and trauma surgeons is often required. We present a case of a 58-year-old man with a type IIIB open tibial fracture initially managed with a bridging external fixation and primary skin closure using a fasciocutaneous sural flap. Two months later, there was no evidence of fracture healing and an Ilizarov device was applied with corticotomy at the proximal tibial metaphysis, which was modified five months later without changing the frame, placing autogenous iliac bone plugs at the fracture site using the mosaicplasty harvesting technique. Seven months after its initial placement, the Ilizarov device was removed allowing full weight-bearing, with callus formation present at 10-month follow-up. Finally, the patient showed acceptable radiological and functional outcomes after a follow-up of two years. The Ilizarov method should be considered as a therapeutic option for complicated open fractures with severe bone and skin loss. The patient should be fully informed about the complexity of these fractures and the necessity of multiple surgical interventions in order to have realistic expectations.

Low-Intensity Pulsed Ultrasound Promotes Osteogenic Differentiation of Reamer-Irrigator-Aspirator Graft-Derived Cells in Vitro

Recently, reamer-irrigator-aspirator (RIA) systems have been increasingly used to harvest autologous bone grafts. RIA graft materials contain bone marrow, which provides a viable source to derive large numbers of mesenchymal stem cells. Low-intensity pulsed ultrasound (LIPUS) significantly accelerates the differentiation of stem cells derived from bone marrow. This in vitro study investigated the effect of LIPUS on the osteogenic activity and differentiation of RIA graft-derived cells. A small amount of RIA graft was obtained from seven patients. After the cells derived from RIA grafts were cultured, they were divided into two groups: the LIPUS and control groups. LIPUS was applied once daily for 20 min (1.5 MHz, pulse duration: 200 µs, pulse repetition rate: 1 kHz, spatial average-temporal average intensity: 30 mW/cm²). Alkaline phosphatase activity (113.4% and 130.1% on days 7 and 14), expression of osteoblast-related genes (ALP, Runx2) and mineralization (135.2% on day 21) of the RIA graft-derived cells were significantly higher in the LIPUS group than in the control group. However, LIPUS did not affect the cell proliferation of RIA graft-derived cells. This study indicates that LIPUS may enhance the healing of non-union and critical bone defects treated by autologous bone grafting using the RIA system.

Injectable pH-responsive adhesive hydrogels for bone tissue engineering inspired by the underwater attachment strategy of marine mussels

A major challenge in tissue engineering is the development of alternatives to traditional bone autografts and allografts that can regenerate critical-sized bone defects. Here we present the design of injectable pH-responsive double-crosslinked adhesive hydrogels inspired by the molecular mechanism and environmental post-processing of marine mussel adhesive. Nine adhesive hydrogel formulations were developed through the conjugation of crosslinkable catechol functional groups (DOPA) and the synthetic oligomer oligo[poly(ethylene glycol) fumarate] (OPF), varying the DOPA content (w/w%) and molecular weight (MW) of the OPF backbone to produce formulations with a range of swelling ratios, porosities, and crosslink densities. DOPA incorporation altered the surface chemistry, mechanical properties, and surface topography of hydrogels, resulting in an increase in material stiffness, slower degradation, and enhanced pre-osteoblast cell attachment and proliferation. When injected within simulated bone defects, DOPA-mediated interfacial adhesive interactions also prevented the displacement of scaffolds, an effect that was maintained even after swelling within physiological conditions. Taken together, OPF-DOPA hydrogels represent a promising new material to enhanced tissue integration and the prevention of the post-implantation migration of scaffolds that can occur due to biomechanical loading in vivo.

Nanostructured Zn-Substituted Monetite Based Material Induces Higher Bone Regeneration Than Anorganic Bovine Bone and β-Tricalcium Phosphate in Vertical Augmentation Model in Rabbit Calvaria

The capacity of a nanostructured multicomponent material composed of Zn-substituted monetite, amorphous calcium phosphate, hydroxyapatite and silica gel (MSi) to promote vertical bone augmentation was compared with anorganic bovine bone (ABB) and synthetic β-tricalcium phosphate (β-TCP). The relation between biological behavior and physicochemical properties of the materials was also studied. The in vivo study was conducted in a vertical bone augmentation model in rabbit calvaria for 10 weeks. Significant differences in the biological behavior of the materials were observed. MSi showed significantly higher bone regeneration (39%) than ABB and β-TCP (24%). The filled cylinder volume was similar in MSi (92%) and ABB (91%) and significantly lower in β-TCP (81%) implants. In addition, β-TCP showed the highest amount of non-osteointegrated particles (17%). MSi was superior to the control materials because it maintains the volume of the defect almost full, with the highest bone formation, the lowest number of remaining particles, which are almost fully osteointegrated and having the lowest amount of connective tissue. Besides, the bone formed was mature, with broad trabeculae, high vascularization and osteogenic activity. MSi resorbs gradually over time with an evident increment of the porosity and simultaneous colonization for vascularized new bone. In addition, the osteoinductive behavior of MSi material was evidenced.

Outcomes and complications of the reamer irrigator aspirator versus traditional iliac crest bone graft harvesting: a systematic review and meta-analysis

BACKGROUND

The reamer irrigator aspirator (RIA) is a relatively recent device that is placed in the medullary canal of long bones to harvest a large volume of bone marrow, which is collected in a filtered canister. This study compares outcomes and complications of the RIA versus a traditional iliac crest bone graft (ICBG) for the treatment of bone defects.

METHODS

This meta-analysis was conducted according to the PRISMA guidelines. The Embase, Google Scholar, PubMed, and Scopus databases were accessed in June 2021. All clinical trials comparing the RIA and ICBG with a minimum of 6 months follow-up were included.

RESULTS

Data from 4819 patients were collected. The RIA group demonstrated lower site pain (P < 0.0001), fewer infections (P = 0.001), and a lower rate of adverse events (P < 0.0001). The ICBG group demonstrated a greater rate of bone union (P < 0.0001). There was no difference between groups in VAS (P = 0.09) and mean time to union (P = 0.06).

CONCLUSION

The current evidence supports the use of the RIA, given its low morbidity and short learning curve.

Characterizing the host response to rhPDGF-BB in a rat spinal arthrodesis model

BACKGROUND

Due to the constraints surrounding autograft bone, surgeons have turned to osteoinductive agents to augment spinal fusion. Reports of complications and questionable efficacy slowed the adoption of these alternatives. Recombinant human platelet-derived growth factor B homodimer (rhPDGF-BB) has been Food and Drug Administration (FDA)-approved (Augment) to promote fusion in other areas of orthopedics, but its characterization in spine fusion has not yet been tested. The purpose of this study is to characterize the host response to PDGF-BB in vivo.

METHODS

Eighty female Fischer rats underwent L4-5 posterolateral fusion using one of four implant types: (a) iliac crest syngeneic allograft harvested from syngeneic donors, (b) β-TCP/bovine collagen matrix (β-TCP/Col) with sodium acetate buffer, (c) β-TCP/Col with 0.3 mg/mL "low dose," or (d) β-TCP/Col with 3.0 mg/mL "high dose" of rhPDGF-BB. Animals underwent magnetic resonance imaging (MRI) and serum cytokine quantification at 4, 7, 10, and 21 days, postoperatively. Tissues were processed for immunofluorescence staining for Ki67 and von Willebrand factor (vWF) to assess neovascularization.

RESULTS

MRI demonstrated no differences in fluid accumulation among the four treatment groups at any of the time points. Serum cytokine analysis showed no clinically significant differences between treatment groups in 20 of the 27 cytokines. Inflammatory cytokines IFN-γ, IL-1β, IL-18, MCP-1, MIP-1α, TNF-α were not induced by rhPDGF-BB. Histology showed no differences in cell infiltration, and Ki67 and vWF immunofluorescence staining was similar among groups.

CONCLUSIONS

rhPDGF-BB delivered with a β-TCP/Col matrix exerts no exaggerated systemic or local host inflammatory response when compared to iliac crest syngeneic allograft bone or the control carrier. rhPDGF-BB mixed with a β-TCP/Col matrix could be a viable and safe biologic alternative to syngeneic allograft in spine fusion. Further studies need to be performed to evaluate efficacy in this setting.

Proximal tibia with an inserted nail can be an available donor site for harvesting cancellous bone

INTRODUCTION

A pre-existing implant at the harvesting site might dissuade the surgeon from considering the site as available for bone harvesting. This study aimed to investigate the quantity of cancellous bone graft that can be harvested from a proximal tibia with an inserted nail and to report the clinical outcomes of this bone graft harvesting technique.

HYPOTHESIS

Our hypothesis was that a certain amount of cancellous bone graft could be harvested from a proximal tibia with an inserted nail without compromising the surrounding environment and outcome of nonunion treatment.

MATERIAL AND METHODS

Bone grafting from an ipsilateral proximal tibia with an inserted nail was performed in 32 patients for treating defect nonunion. The amount of harvested bone was measured using three parameters (weight, height, and volume). The effects of the proximal locking screw position on the quantity and location of bone graft harvest were analyzed. Clinical outcomes were evaluated by assessing the radiologic healing of the bone graft site and by assessing the donor site complications.

RESULTS

The mean bone defect volume in the nonunion site was 31.1±18.3 (range, 10.6-87.0) cm³. The mean quantity of harvested bone from proximal tibias with an inserted nail was 21.2g, height was 3.9cm, and volume was 26.3 cm³. A positive correlation was found between the quantity of harvested bone and the level of the lateral oblique interlocking screw hole in the tibial nail. All grafted bone successfully consolidated in all cases at an average of 5.8 months postoperatively. However, joint penetration during bone harvesting occurred in one case.

DISCUSSION

The bony defect, which measured about 14.3 cm³ could be filled with cancellous bone from a PT with an existing IM nail, without additional bone graft requirements. Even if an intramedullary nail exists inside the proximal tibia, harvesting cancellous bone at this site can be a viable option without serious complications.

LEVEL OF EVIDENCE

IV; Retrospective descriptive study.

Coralline Hydroxyapatite Coated with a Layer Biomimetic Calcium Phosphate Containing BMP-2 Induces Dose-Related Ectopic Bone Formation in Wistar Rats

In order to evaluate loading methods and the dose dependency of bone morphogenetic protein 2 (BMP-2) in ectopic bone formation, an osteoinductive material consisting of commercially available coralline hydroxyapatite (CHA) was coated with a layer of biomimetic calcium phosphate (BioCaP) containing BMP-2 in different ways. Eight groups—each containing samples of 0.25 g CHA—were formed and coated with, respectively, BioCaP with internally incorporated BMP-2 in concentrations of 1, 5, 10, 20, 40 and 60 µg per sample, and the two control groups with BioCaP only and BioCaP with 20 µg of adsorbed BMP-2 per sample. The samples were implanted subcutaneously in 27 male Wistar rats. The histological results show that there is no bone formation in the group in which no BMP-2 was included. All samples with BioCaP containing BMP-2 show bone formation. The group with 20 µg of adsorbed BMP-2 per sample shows the least bone formation. Coating-incorporated BMP-2 is more efficient in inducing bone formation than adsorbed BMP-2. The group with 5 µg of coating-incorporated BMP-2 per sample shows the most bone formation. Increasing the amount of coating-incorporated BMP-2 up to 60 µg does not improve ectopic bone formation.

Autologous Bone Grafting in Trauma and Orthopaedic Surgery: An Evidence-Based Narrative Review

Autologous bone grafting is common in trauma and orthopaedic surgery. Both the Reamer Irrigator Aspirator (RIA) and Iliac Crest Bone Graft (ICBG) aim to obtain autologous bone graft. Although the process of harvesting a bone graft is considered simple, complications may occur. This study examined morbidity and pain at the donor site, blood loss, and iatrogenic fractures, comparing RIA and ICBG. The source of the autologous bone graft, the alternative graft sites, and the storage modalities of the harvested bone marrow were also evaluated. In May 2021, PubMed, Embase, Scopus, and Google Scholar were accessed, with no time constraints. RIA may produce greater blood loss, but with less morbidity and complications, making it a potential alternative source of bone grafting.

Berberine for bone regeneration: Therapeutic potential and molecular mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

Berberine is a quaternary ammonium isoquinoline alkaloid, mainly extracted from plants berberaceae, papaveraceae, ranunculaceae and rutaceae such as coptis chinensis Franch, Phellodendron chinense, and berberis pruinosa. The plants are extensively used in traditional medicine for treating infection, diabetes, arrhythmia, tumor, osteoporosis et al. Pharmacological studies showed berberine has effects of anti-inflammation, anti-tumor, lower blood lipid, lower blood glucose, anti-osteoporosis, anti-osteoarthritis et al. AIM OF THE STUDY: This review aims to summarize the application of natural herbs that contain berberine, the further use and development of berberine, the effects as well as mechanism of berberine on osteoblasts and osteoclasts, the recent advances of in vivo studies, in order to provide a scientific basis for its traditional uses and to prospect of the potential applications of berberine in clinics.

METHOD

The research was achieved by retrieving from the online electronic database, including PubMed, Web of Science, Google Scholar and China national knowledge infrastructure (CNKI). Patents, doctoral dissertations and master dissertations are also searched.

RESULTS

Berberine has a long history of medicinal use to treat various diseases including bone disease in China. Recent studies have defined its function in promoting bone regeneration and great potential in developing new drugs. But the systemic mechanism of berberine on bone regeneration still needs more research to clarify.

CONCLUSION

This review has systematically summarized the application, pharmacological effects, mechanism as well as in vivo studies of berberine and herbs which contain berberine. Berberine has a definite effect in promoting the proliferation and differentiation of osteoblasts as well as inhibiting the production of osteoclasts to promote bone regeneration. However, the present studies about the system mechanisms and pharmacological activity of berberine were incomplete. Applying berberine for new drug development remains an exciting and promising alternative to bone regeneration engineering, with broad potential for therapeutic and clinical practice.

Evaluation of lumbar spinal fusion utilizing recombinant human platelet derived growth factor-B chain homodimer (rhPDGF-BB) combined with a bovine collagen/β-tricalcium phosphate (β-TCP) matrix in an ovine model

BACKGROUND CONTEXT

While the clinical effectiveness of recombinant human Platelet Derived Growth Factor-B chain homodimer combined with collagen and β-tricalcium phosphate (rhPDGF-BB + collagen/β-TCP) treatment for indications involving hindfoot and ankle is well-established, it is not approved for use in spinal interbody fusion, and the use of autograft remains the gold standard.

PURPOSE

The purpose of this study was to compare the effects of rhPDGF-BB + collagen/β-TCP treatment on lumbar spine interbody fusion in an ovine model to those of autograft bone and collagen/β-TCP treatments using biomechanical, radiographic, and histological assessment techniques.

STUDY DESIGN

Thirty-two skeletally mature Columbian Rambouillet sheep were used to evaluate the safety and effectiveness of rhPDGF-BB + collagen/β-TCP matrix in a lumbar spinal fusion model. Interbody polyetheretherketone (PEEK) cages contained either autograft, rhPDGF-BB + collagen/β-TCP, collagen/β-TCP matrix, or left empty.

METHODS

Animals were sacrificed 8- or 16-weeks post-surgery. Spinal fusion was evaluated via post-sacrifice biomechanical, micro-computed tomography (μCT), and histological analysis. Outcomes were statistically compared using a two-way analysis of variance (ANOVA) with an alpha value of 0.05 and a Tukey post-hoc test.

RESULTS

There were no statistically significant differences between groups within treatment timepoints for flexion-extension, lateral bending, or axial rotation range of motion, neutral zone, neutral zone stiffness, or elastic zone stiffness. μCT bone volume fraction was significantly greater between treatment groups independent of timepoint where Autograft and rhPDGF-BB + collagen/β-TCP treatments demonstrated significantly greater bone volume fraction as compared to collagen/β-TCP (P = .026 and P = .038, respectively) and Empty cage treatments (P = .002 and P = .003, respectively). μCT mean bone density fraction was most improved in rhPDGF-BB + collagen/β-TCP specimens at the 8 week and 16-week timepoints as compared to all other treatment groups. There were no statistically significant differences in histomorphometric measurements of bone, soft tissue, or empty space between rhPDGF-BB + collagen/β-TCP and autograft treatments.

CONCLUSIONS

The results of this study indicate that the use of rhPDGF-BB combined with collagen/β-TCP promotes spinal fusion comparable to that of autograft bone.

CLINICAL SIGNIFICANCE

The data indicate that rhPDGF-BB combined with collagen/β-TCP promotes spinal fusion comparably to autograft bone treatment and may offer a viable alternative in large animal spinal fusion. Future prospective clinical studies are necessary to fully understand the role of rhPDGF-BB combined with collagen/β-TCP in human spinal fusion healing.

Structural Bicortical Autologous Iliac Crest Bone Graft Combined with the Tunnel Bone Tamping Method for the Depressed Tibial Plateau Fractures

BACKGROUND

Clinically, autologous iliac crest bone grafts (ICBG) and bone tamping methods are often applied to manage depressed tibial plateau fractures (DTPFs). The purpose of this study was to describe and evaluate the technique of using structural bicortical autologous ICBG combined with the tunnel bone tamping method (TBTM) for treating DTPFs.

METHODS

All patients with DTPFs who underwent structural bicortical autologous ICBG combined with TBTM from January 2016 to February 2018 were prospectively analysed. Demographics, injury, surgery, postoperative complications, and clinical outcomes were recorded. All patients were followed up for more than 30 months. Postoperative radiography and CT were employed to assess fracture healing and the reduction quality.

RESULTS

Forty-three of the included patients completed the follow-up. No malreduction was observed. Based on the immediate postoperative imaging, the intra-articular step-off was significantly reduced (8.19 mm preoperatively vs. 1.30 mm immediate postoperatively, P < 0.001). From the immediate operation to the latest follow-up, the reduction was maintained significantly well, with a nonnegligible absolute difference (0.18 mm, P = 0.108). A remarkable secondary loss of reduction (intra-articular step off > 3 mm) was found in two elderly patients (2/43, 4.65%). The incidence of complications related to the bone-graft donor and bone-graft site was 2.33% and 4.65%, respectively. At the final follow-up, the mean Hospital for Special Surgery (HSS) score of the knee was 98.19 ± 2.89, and the mean 36-Item Short-Form Health Survey (SF-36) score was 95.65 ± 4.59.

CONCLUSION

Structural bicortical autologous ICBG combined with TBTM is radiologically effective and stable in terms of complications for the DTPFs.

Bone Fracture-Treatment Method: Fixing 3D-Printed Polycaprolactone Scaffolds with Hydrogel Type Bone-Derived Extracellular Matrix and β-Tricalcium Phosphate as an Osteogenic Promoter

Bone formation and growth are crucial for treating bone fractures. Improving bone-reconstruction methods using autologous bone and synthetic implants can reduce the recovery time. Here, we investigated three treatments using two different materials, a bone-derived decellularized extracellular matrix (bdECM) and β-tricalcium phosphate (β-TCP), individually and in combination, as osteogenic promoter between bone and 3D-printed polycaprolactone scaffold (6-mm diameter) in rat calvarial defects (8-mm critical diameter). The materials were tested with a human pre-osteoblast cell line (MG63) to determine the effects of the osteogenic promoter on bone formation in vitro. A polycaprolactone (PCL) scaffold with a porous structure was placed at the center of the in vivo rat calvarial defects. The gap between the defective bone and PCL scaffold was filled with each material. Animals were sacrificed four weeks post-implantation, and skull samples were preserved for analysis. The preserved samples were scanned by micro-computed tomography and analyzed histologically to examine the clinical benefits of the materials. The bdECM–β-TCP mixture showed faster bone formation and a lower inflammatory response in the rats. Therefore, our results imply that a bdECM–β-TCP mixture is an ideal osteogenic promoter for treating fractures.

Open Reduction and Internal Fixation for Humeral Shaft Nonunion: Bone Grafting Is Not Routinely Required and Avoids Donor Site Morbidity

OBJECTIVES

To document union rate, complications and patient-reported outcomes after open reduction and internal fixation (ORIF), with and without bone grafting (BG), for humeral diaphyseal nonunion after failed nonoperative management.

DESIGN

Retrospective.

SETTING

University teaching hospital.

PATIENTS AND INTERVENTION

From 2008 to 2017, 86 consecutive patients [mean age 59 years (range 17-86), 71% (n = 61/86) women] underwent nonunion ORIF (plate and screws) at a mean of 7 months postinjury (range 3-21.5). Eleven (13%) underwent supplementary BG.

MAIN OUTCOME MEASUREMENTS

Union rate and complications for 83 patients (97%) at a mean of 10 months (3-61). Patient-reported outcomes (QuickDASH, EQ-5D, EQ-VAS, SF-12, satisfaction) for 53 living, cognitively-intact patients (78%) at a mean of 4.9 years (0.3-9.2).

RESULTS

Ninety-three percent (n = 77/83) achieved union after nonunion ORIF. Complications included recalcitrant nonunion (7%, n = 6/83), iatrogenic radial nerve palsy (6%, n = 5/83), infection (superficial 7%, n = 6/83; deep 2%, n = 2/83), and iliac crest donor site morbidity (38%, n = 3/8). The union rate with BG was 78% (n = 7/9) and without was 95% (n = 70/74; P = 0.125), and was not associated with the nonunion type (atrophic 91%, n = 53/58; hypertrophic 96%, n = 24/25; P = 0.663). Median QuickDASH was 22.7 (0-95), EQ-5D 0.710 (-0.181-1), EQ-visual analog scale 80 (10-100), SF-12 physical component summary 41.9 (16-60.5), and mental component summary 52.6 (18.7-67.7). Nineteen percent (n = 10/53) were dissatisfied with their outcome.

CONCLUSIONS

ORIF for humeral diaphyseal nonunion was associated with a high rate of union. Routine BG was not required and avoided the risk of donor site morbidity. One in 5 patients were dissatisfied despite the majority achieving union.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Bilayer Membrane Composed of Mineralized Collagen and Chitosan Cast Film Coated With Berberine-Loaded PCL/PVP Electrospun Nanofiber Promotes Bone Regeneration

Bone defects are difficult to repair and reconstruct as bone regeneration remains technically challenging, with exogenous factors required to accelerate this process. Biodegradable synthetic scaffolds are promising materials for stimulating bone tissue repair. In this study, we investigated whether a bilayer membrane that includes mineralized collagen (MC) and chitosan (CS) delivering berberine (BER)-a typical Chinese herbal monomer-could promote bone healing in a rat model. An MC/CS cast film was coated with polycaprolactone (PCL)/polyvinylpyrrolidone (PVP) electrospun nanofibers loaded with BER, yielding the BER@PCL/PVP-MC/CS bilayer membrane. The 3-dimensional structure had nanofibers of uniform diameter and showed good hydrophilicity; the bilayer membrane showed favorable mechanical properties. BER@PCL/PVP-MC/CS enhanced the proliferation and attachment of MC3T3-E1 cells in vitro and induced bone regeneration when implanted into a rat femoral bone defect. These findings provide evidence that BER@PCL/PVP-MC/CS has clinical potential for effective bone repair.

Comparison of Individual Tissue-Engineered Bones and Allogeneic Bone in Treating Bone Defects: A Long-Term Follow-Up Study

The treatment of bone defects has always been a challenge for orthopedic surgeons. The development of tissue engineering technology provides a novel method for repairing bone defects and has been used in animal experiments and clinical trials. However, there are few clinical studies on comparing the long-term outcomes of tissue-engineered bones (TEBs) and other bone grafts in treating bone defects, and the long-term efficiency of TEBs remains controversial. Therefore, a study designed by us was aimed to compare the long-term efficacy and safety of individual tissue-engineered bones (iTEBs) and allogeneic bone granules (ABGs) in treating bone defects caused by curettage of benign bone tumors and tumor-like lesions. From September 2003 to November 2009, 48 patients who received tumor curettage and bone grafting were analyzed with a mean follow-up of 122 mo (range 60 to 173 mo). Based on implant style, patients were divided into groups of iTEBs (n = 23) and ABGs (n = 25). Postoperatively, the healing time, healing quality, incidence of complications, and functional scores were compared between the two groups. The Musculoskeletal Tumor Society functional evaluation system and Activities of Daily Living Scale scores were significantly improved in both groups with no significant difference. The average healing time of ABGs was longer than that of iTEBs (P < 0.05). At the final follow-up, iTEBs had a better performance in the bone healing quality evaluated by modified Neer classification (P < 0.05). In the group of iTEBs, the complication and reoperation rate was lower than that in the group of ABGs, with no tumorigenesis or immune rejection observed. In summary, for treating bone defects caused by tumor curettage, iTEBs were safe, effective, and tagged with more rapid healing speed, better healing outcome, and lower complication and reoperation rate, in comparison with ABGs.

Injectable Affinity and Remote Magnetothermal Effects of Bi-Based Alloy for Long-Term Bone Defect Repair and Analgesia

As alternatives, metallic/nonmetallic bone graft materials play significant roles in bone defect surgery to treat external trauma or bone disease. However, to date, there are rather limited long-term implantable materials owning to in situ molding incapability of metallics and poor mechanical property of nonmetallics. Here, Bi-based low melting point alloy, with unique properties of injectability, solid-liquid phase transition, mechanical capability, and biocompatibility, present obvious long-lasting bone affinity as the excellent artificial bone-substitute. It is particularly necessary to point out that the targeted injected Bi alloy remains in its original position for up to 210 days without moving, as well as, displays good osseointegration ability to resolve repeated revision trauma caused by losing bone repair material. Additionally, with outstanding electrical and thermal conductivity, an unconventional way using Bi alloy to realize very beneficial hyperthermia analgesia via non-invasive wireless energy delivery is first proposed, which avoids adverse effects on bone remodeling inflicted by traditional drugs. The significantly decreased expression of pain sensitizing factor, such as, interleukin-6, neuropeptide substance, and transient receptor potential vanilloid 1 reveals the potential mechanism of hyperthermia analgesia. The present findings suggest the combination therapy of Bi alloy in bone repair and analgesia, which owns far-reaching clinical application value.

Bone Defects After Surgery for Displaced Intraarticular Calcaneal Fractures Spontaneously Improve Without Bone Grafting

BACKGROUND

Most intraarticular displaced calcaneal fractures are accompanied by bone defects after surgical treatment, but the concern about negative effects of bone defects has not been resolved yet owing to the few studies on this issue. Therefore, studies on volumetric changes in bone defects over time and the correlation between postoperative outcomes and residual bone defects will be helpful to address the controversy on the necessity of bone grafting in bone defects of calcaneal fractures.

QUESTIONS/PURPOSES

(1) Do bone defects change in size in the first year after surgical treatment of displaced intraarticular calcaneal fractures? (2) Does the size of residual bone defects correlate with postoperative radiographic or clinical outcomes?

METHODS

Between 2015 and 2019, 99 patients with displaced intraarticular calcaneal fractures visited the investigators' institution, of whom 95 received surgical treatment. Of the patients treated with surgery, 25% (24 of 95) did not undergo open reduction and internal fixation via an extensile lateral approach, and 19% (18 of 95) had multiple fractures, bilateral fractures, open fractures, or a history of previous surgery on the calcaneus; all of these patients were excluded. During the study period, CT was routinely performed for calcaneal fractures immediately after and 12 months after the surgery, but 6% (6 of 95) of the patients had insufficient CT data due to loss to follow-up before 12 months or other reasons, leaving 47 patients for evaluation in this retrospective study. Fractures were fixed with plate and screws, and bone grafting was not performed in all patients. To answer our first question, which was on the changes in bone defects over time, volumetric measurements of the bone defect were performed using CT via the ITK-SNAP software. The percentage of volumetric change was calculated as a fraction of the volumetric change over 12 months from the initial volume. The percentage of the residual bone defect was calculated as a fraction of the volume of the residual bone defect relative to the volume of the entire calcaneus. To answer our second question, which was on the correlation between residual bone defects and postoperative outcomes, we assessed the Böhler angle, Gissane angle, calcaneal height, Olerud-Molander Ankle Score (OMAS), and VAS score for pain and compared these parameters with the size of the residual bone defect using the Pearson correlation coefficient. The OMAS and VAS scores for pain were evaluated and recorded during patient visits, and we obtained the scores through a chart review. All volumetric measurements and radiographic evaluations were performed by two orthopaedic surgeons, and the intraobserver and interobserver reliability were assessed using the intraclass correlation coefficient.

RESULTS

The mean volume of the bone defect measured using CT was 4 ± 3 cm3 immediately after surgery and 1 ± 1 cm3 12 months after surgery. During the first 12 months after surgery, the mean volume of the bone defect was reduced by 77% (95% confidence interval 73% to 80%). The mean residual bone defect in the entire calcaneus was 2% (95% CI 1% to 2%), and none of the postoperative outcomes were correlated with the residual bone defect.

CONCLUSION

As bone defects substantially resolve without treatment, surgeons do not need to use bone graft for the surgical treatment of displaced intraarticular calcaneal fractures. Future studies that include patients who underwent bone grafting for the treatment of calcaneal fractures are needed to confirm our findings and to further investigate whether bone grafting has additional benefits for the recovery of bone defects.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Impact of surgeon rhBMP-2 cost awareness on complication rates and health system costs for spinal arthrodesis

OBJECTIVE

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is used in spinal arthrodesis procedures to enhance bony fusion. Research has suggested that it is the most cost-effective fusion enhancer, but there are significant upfront costs for the healthcare system. The primary objective of this study was to determine whether intraoperative dosing and corresponding costs changed with surgeon cost awareness. The secondary objective was to describe surgical complications before and after surgeon awareness of rhBMP-2 cost.

METHODS

A retrospective medical record review was conducted to identify patients who underwent spinal arthrodesis procedures performed by a single surgeon, supplemented with rhBMP-2, from June 2016 to June 2018. Collected data included rhBMP-2 dosage, rhBMP-2 list price, and surgical complications. Expected Medicare reimbursement was calculated. Data were analyzed before and after surgeon awareness of rhBMP-2 cost.

RESULTS

Forty-eight procedures were performed using rhBMP-2, 16 before and 32 after surgeon cost awareness. Prior to cost awareness, the most frequent rhBMP-2 dosage level was x-small (38.9%, n = 7), followed by large (27.8%, n = 5) and small (22.2%, n = 4). After cost awareness, the most frequent rhBMP-2 dosage was xx-small (56.8%, n = 21), followed by x-small (21.6%, n = 8) and large (13.5%, n = 5). The rhBMP-2 average cost per surgery was $4116.56 prior to surgeon cost awareness versus $2268.38 after. Two complications were observed in the pre-cost awareness surgical group; 2 complications were observed in the post-cost awareness surgical group.

CONCLUSIONS

Surgeon awareness of rhBMP-2 cost resulted in use of smaller rhBMP-2 doses, decreased rhBMP-2 cost per surgery, and decreased overall hospital admission charges, without a detectable increase in surgical complications.

Stable osteosynthesis of cage in cage technique for surgical treatment of proximal humeral fractures

Background

The treatment of a displaced proximal humeral fracture is still a matter of controversy. The purpose of this study was to report outcomes at a long-term follow-up after fixation augmentation using peek (polyether-ether-ketone) cage and locking compression plate (LCP).

Methods

A total of 27 patients (average age 53.8 years, range 19–86 years) were treated with peek cage and LCP. All of them had a minimum radiographic and clinical follow-up of 1 years. Outcomes were assessed using the Constant-Murley score (CMS), disability of the arm, shoulder and hand (DASH) score. Complications were also recorded during follow-up.

Results

The average follow-up was 28 months (range 12–48 months). The mean functional outcomes were as follows: CMS, 73.3 (range 61–86); DASH, 45.9 (range 27–68). A total of 4 patients had complications: osteonecrosis developed in one patient, loss of reduction was observed in 1 patient and stiffness was occurred in two patients.

Conclusion

The use of peek cage and LCP has been a valuable option in the treatment of proximal humeral fractures. The complication rate was acceptable. Suitable void filler in the proximal humerus for reconstructing the medial column integrity attains mechanical stability in reducing the incidence of the complications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-021-01235-x.

A lattice topology optimization of cervical interbody fusion cage and finite element comparison with ZK60 and Ti-6Al-4V cages

BACKGROUND

In current clinical practice, the most commonly used fusion cage materials are titanium (Ti) alloys. However, titanium alloys are non-degradable and may cause stress shielding. ZK60 is a bio-absorbable implant that can effectively avoid long-term complications, such as stress shielding effects, implant displacement, and foreign body reactions. In this study, we aimed at investigating the biomechanical behavior of the cervical spine after implanting different interbody fusion cages.

METHODS

The finite element (FE) models of anterior cervical disc removal and bone graft fusion (ACDF) with a ZK60 cage and a Ti cage were constructed, respectively. Simulations were performed to evaluate their properties of flexion, extension, lateral bending, and axial rotation of the cervical spine. Moreover, a side-by-side comparison was conducted on the range of motion (ROM), the deformation of cages, the stress in the cages, bone grafts, and cage-end plate interface. Simultaneously, according to the biomechanical analysis results, the microporous structure of the ZK60 cage was improved by the lattice topology optimization technology and validation using static structure.

RESULTS

The ROMs in the current study were comparable with the results reported in the literature. There was no significant difference in the deformation of the two cages under various conditions. Moreover, the maximum stress occurred at the rear of the cage in all cases. The cage's and endplate-cage interface's stress of the ZK60 group was reduced compared with the Ti cage, while the bone graft stress in the ZK60 fusion cage was significantly greater than that in the Ti fusion cage (average 27.70%). We further optimized the cage by filling it with lattice structures, the volume was decreased by 40%, and validation showed more significant biomechanical properties than ZK60 and Ti cages.

CONCLUSION

The application of the ZK60 cage can significantly increase the stress stimulation to the bone graft by reducing the stress shielding effect between the two instrumented bodies. We also observed that the stress of the endplate-cage interface decreased as the reduction of the cage's stiffness, indicating that subsidence is less likely to occur in the cage with lower stiffness. Moreover, we successfully designed a porous cage based on the biomechanical load by lattice optimization.

Materials and Manufacturing Techniques for Polymeric and Ceramic Scaffolds Used in Implant Dentistry

Preventive and regenerative techniques have been suggested to minimize the aesthetic and functional effects caused by intraoral bone defects, enabling the installation of dental implants. Among them, porous three-dimensional structures (scaffolds) composed mainly of bioabsorbable ceramics, such as hydroxyapatite (HAp) and β-tricalcium phosphate (β-TCP) stand out for reducing the use of autogenous, homogeneous, and xenogenous bone grafts and their unwanted effects. In order to stimulate bone formation, biodegradable polymers such as cellulose, collagen, glycosaminoglycans, polylactic acid (PLA), polyvinyl alcohol (PVA), poly-ε-caprolactone (PCL), polyglycolic acid (PGA), polyhydroxylbutyrate (PHB), polypropylenofumarate (PPF), polylactic-co-glycolic acid (PLGA), and poly L-co-D, L lactic acid (PLDLA) have also been studied. More recently, hybrid scaffolds can combine the tunable macro/microporosity and osteoinductive properties of ceramic materials with the chemical/physical properties of biodegradable polymers. Various methods are suggested for the manufacture of scaffolds with adequate porosity, such as conventional and additive manufacturing techniques and, more recently, 3D and 4D printing. The purpose of this manuscript is to review features concerning biomaterials, scaffolds macro and microstructure, fabrication techniques, as well as the potential interaction of the scaffolds with the human body.

Preclinical Evaluation of an Innovative Bone Graft of Marine Origin for the Treatment of Critical-Sized Bone Defects in an Animal Model

Autogenous cancellous bone graft is the current gold standard of treatment for the management of bone defects since it possesses the properties of osteoinduction, osteoconduction, and osteogenesis. Xenografts and synthetic grafts have been widely reported as available and low-cost alternatives, which retain good osteoconductive and mechanical properties. Given the rich biodiversity of ocean organisms, marine sources are of particular interest in the search for alternative bone grafts with enhanced functionalities. The purpose of this paper is to assess the biocompatibility of a marine-derived bone graft obtained from shark tooth, which is an environmentally sustainable and abundant raw material from fishing. This research presents the findings of a preclinical trial—following UNE-EN ISO 10993—that induced a critical-sized bone defect in a rabbit model and compared the results with a commercial bovine-derived bone graft. Evaluation by micro-computed tomography and histomorphometric analysis 12 weeks after implantation revealed good osseointegration, with no signs of inflammatory foreign body reactions, fibrosis, or necrosis in any of the cases. The shark tooth-derived bone graft yielded significantly higher new bone mineral density values (54 ± 6%) than the control (27 ± 8%). Moreover, the percentage of intersection values were much higher (86 ± 8%) than the bovine-derived bone graft (30 ± 1%) used as control. The area of occupancy by bone tissue in the test material (38 ± 5%) also gave higher values than the control (30 ± 6%). The role of physicochemical properties, biphasic structure, and composition on the stimulation of bone regeneration is also discussed.

Histological and Histomorphometric Analyses of Bone Regeneration in Osteoporotic Rats Using a Xenograft Material

We evaluated the effect of osteoporotic induction after eight weeks of initial healing of bone defects grafted with a xenograft material in a rat model. Bone defects were created in the femoral condyles of 16 female Wistar rats (one defect per rat). The defects were filled with bovine bone (Inter-Oss) granules. After eight weeks of bone healing, rats were randomly ovariectomized (OVX) or sham-operated (SHAM). At 14 weeks of bone healing, all animals were euthanized. Bone specimens were harvested and processed for histological and histomorphometric analyses to assess new bone formation (N-BF%), remaining bone graft (RBG%) and trabecular bone space (Tb.Sp%) within the defect area. After 14 weeks of bone healing, histological evaluation revealed a significant alteration in trabecular bone in OVX rats compared to SHAM rats. There was lower N-BF% in OVX rats (22.5% ± 3.0%) compared to SHAM rats (37.7% ± 7.9%; p < 0.05). Additionally, the RBG% was significantly lower in OVX (23.7% ± 5.8%) compared to SHAM (34.8% ± 9.6%; p < 0.05) rats. Finally, the Tb.Sp% was higher in OVX (53.8% ± 7.7%) compared to SHAM (27.5% ± 14.3%; p < 0.05) rats. In conclusion, within the limitations of this study, inducing an osteoporotic condition in a rat model negatively influenced bone regeneration in the created bone defect and grafted with a xenograft material.

How is Biodegradable Scaffold Effective in Gap Non-union? Insights from an Experiment

OBJECTIVE

To evaluate the role of composite (Chitosan/Chondroitin sulphate/gelatin/nano-bioglass) scaffold in the union of critical size bone defect created in the rabbit's ulna.

METHODS

The composite (Chitosan/Chondroitin sulphate/gelatin/nano-bioglass) scaffold was fabricated using the freeze-drying technique under standard laboratory conditions. The scaffold was cut into the appropriate size and transferred into the defect created (critical bone size defect 1 cm) over the right ulna in the rabbit. The scaffold was not implanted on the left side thus the left side ulna served as control. Results were assessed on serial radiological examination. Rabbits were sacrificed at 20 weeks for histopathological examination (Haematoxylin-Eosin staining and Mason's trichrome staining) and scanning electron microscope observation. Radiological scoring was done by Lane and Sandhu's scoring.

RESULTS

Among 12 rabbits, 10 could complete the follow-up. Among those 10 rabbits, 8 among the test group showed good evidence of bone formation at the gap non-union scaffold implanted site. Histological evidence of new bone formation, collagen synthesis, scaffold resorption, minimal chondrogenesis was evident by 20 weeks in the test group. Two rabbits had poor bone formation.

CONCLUSION

The chitosan-chondroitin sulphate-gelatin-nano-bioglass composite scaffold is efficient in osteoconduction and osteoinduction in the gap non-union model as it is biocompatible, bioactive, and non-immunogenic as well.

Trephine Technique for Iliac Crest Bone Graft Harvest: Long-term Results

STUDY DESIGN

Report of surgical technique and long-term outcome; review of prospectively gathered data and follow-up survey of patient cohort.

OBJECTIVE

The aim of this study was to review surgical technique for a trephine graft harvest technique and assess perioperative complications/pain, long-term outcome, and patient satisfaction after anterior iliac crest bone graft (ICBG) harvest for anterior cervical fusion.

SUMMARY OF BACKGROUND DATA

Rates of complications and residual pain after ICBG harvest have reduced its utility as a source of autograft for spinal fusion. Less invasive options reduce morbidity, and trephine harvest is a simple technique, with low morbidity and perioperative and long-term pain. It has not been presented in the peer-reviewed spine literature, and the long-term experience has not been previously reported.

METHODS

Sixty-eight patients undergoing anterior cervical discectomy and fusion (ACDF), using allograft spacers, underwent ICBG harvest using a 3.5 mm trephine by a minimally invasive approach. Perioperative complications, pain incidence and Visual Analog Scale (VAS) were analyzed. Thirty consecutive patients were subsequently surveyed for long-term follow-up regarding pain, function, and satisfaction.

RESULTS

No perioperative (0-6 weeks) graft-site complications (infection, hematoma, fracture, wound dehiscence) occurred. There were no reoperations, and no treatment required for graft-site complaints. No patient reported clinically significant perioperative pain (>3/10). At long-term follow-up (mean 45 months) no patients reported pain >3/10 at their graft-site, and the mean VAS was 0.20/10. No patient was impaired by graft-site symptoms, and all were satisfied with their graft harvest.

CONCLUSION

Trephine graft harvest minimizes soft tissue dissection, periosteal elevation, and cortical disruption. Outcome using this technique eliminated perioperative complications in this study group, and reduced pain in both perioperative and long-term assessments. Compared to historical outcomes, trephine harvest provides sufficient graft with comparable or improved results relative to other minimally invasive approaches, and significantly improved relative to traditional open techniques.

LEVEL OF EVIDENCE

4.

Japanese Orthopaedic Association 2019 Guidelines for osteonecrosis of the femoral head

PURPOSE

The Clinical Practice Guidelines for Osteonecrosis of the Femoral Head (ONFH) 2019 Edition, written by the working group for ONFH guidelines of the Japanese Investigation Committee (JIC) for ONFH under the auspices of the Japanese Ministry of Health, Labour, and Welfare and endorsed by the Japanese Orthopaedic Association, were published in Japanese in October 2019. The objective of this guideline is to provide a support tool for decision-making between doctors and patients.

METHODS

Procedures for developing this guideline were based on the Medical Information Network Distribution Service Handbook for Clinical Practice Guideline Development 2014, which proposed an appropriate method for preparing clinical guidelines in Japan.

RESULTS

This clinical practice guideline consists of 7 chapters: epidemiology; pathology; diagnosis; conservative therapy; surgical treatment: bone transplantation/cell therapy; surgical treatment: osteotomy; and surgical treatment: hip replacement. Twelve background questions and 13 clinical questions were determined to define the basic features of the disease and to be addressed when deciding treatment in daily practice, respectively.

CONCLUSIONS

The clinical practice guidelines for the ONFH 2019 edition will be useful for physicians, investigators, and medical staff in clinical practice, as well as for patients, during the decision-making process when defining how to treat ONFH.

Growth Factors, Carrier Materials, and Bone Repair

This chapter provides an overview of the growth factors active in bone regeneration and healing. Both normal and impaired bone healing are discussed, with a focus on the spatiotemporal activity of the various growth factors known to be involved in the healing response. The review highlights the activities of most important growth factors impacting bone regeneration, with a particular emphasis on those being pursued for clinical translation or which have already been marketed as components of bone regenerative materials. Current approaches the use of bone grafts in clinical settings of bone repair (including bone grafts) are summarized, and carrier systems (scaffolds) for bone tissue engineering via localized growth factor delivery are reviewed. The chapter concludes with a consideration of how bone repair might be improved in the future.

Effect of ErhBMP-2-loaded β-tricalcium phosphate on ulna defects in the osteoporosis rabbit model

Purpose

Autografts, the gold standard treatment for large bone defects, present complications, especially in conditions with reduced bone-repair capacity, such as osteoporosis. Escherichia coli-derived recombinant human bone morphogenesis protein-2 (ErhBMP-2), was used in this study to improve the osteoinductivity of β-tricalcium phosphate (β-TCP). This study evaluated the bone-repair capacity of ErhBMP-2-loaded β-TCP on osteoporosis rabbit model, relative to the sole use of autograft and β-TCP treatments.

Methods

The osteoporosis rabbit model was induced through ovariectomy and glucocorticoid dosing; 2-cm segmental ulnar defects were created, which were treated with either autograft, β-TCP alone, or ErhBMP-2-loaded β-TCP or left untreated. The quality of newly formed ulnae was evaluated 8 weeks after ulnar surgery through micro-CT, biomechanical, histological, and histomorphometric assessments.

Results

The osteoporosis rabbit model was developed and maintained till the end of the study. The maximal load and stiffness in the ErhBMP-2-loaded TCP group were significantly higher than those in the autograft group, whereas the TCP-alone group performed similarly as did the untreated group in the force loading and stiffness tests. According to the micro-CT evaluation, the ErhBMP-2-loaded TCP group had significantly higher bone volume relative to the autograft and TCP-alone groups. Histological assessments revealed better defect bridging and marrow formation in the ErhBMP-2-loaded TCP group relative to the TCP-alone group. Mineral apposition rates were significantly higher in the ErhBMP-2-loaded TCP and autograft groups than in the TCP-alone and untreated groups.

Conclusion

Relative to autografts, ErhBMP-2-loaded TCP, as an alternative grafting material, provides better or comparable healing on critical-sized long bone defects in the osteoporosis rabbit model.

•

Erh-BMP-2 promoted the bone healing ability of β-TCP in osteoporosis animal model.

•

New bone generated by Erh-BMP-2-loaded β-TCP was stiffer than that generated by autograft.

•

ErhBMP-2-loaded TCP potentially being an alternative grafting material relative to autograft.

Randomized clinical trial: expanded autologous bone marrow mesenchymal cells combined with allogeneic bone tissue, compared with autologous iliac crest graft in lumbar fusion surgery

BACKGROUND CONTEXT

Although autogenous iliac crest bone graft (AICBG) is considered the gold-standard graft material for spinal fusion, new bone substitutes are being developed to avoid associated complications and disadvantages. By combining autologous bone marrow mesenchymal stromal cells (MSCs) expanded ex vivo and allogenic cancellous bone graft, we obtain a tissue-engineered product that is osteoconductive and potentially more osteogenic and osteoinductive than AICBG, owing to the higher concentration of MSCs.

PURPOSE

This study aimed to evaluate the feasibility and safety of implanting a tissue-engineered product consisting of expanded bone marrow MSCs loaded onto allograft bone (MSC+allograft) for spinal fusion in degenerative spine disease, as well as to assess its clinical and radiological efficacy.

STUDY DESIGN/SETTING

A prospective, multicenter, open-label, blinded-reader, randomized, parallel, single-dose phase I-II clinical trial.

PATIENT SAMPLE

A total of 73 adult patients from 5 hospitals, with Meyerding grade I-II L4-L5 degenerative spondylolisthesis and/or with L4-L5 degenerative disc disease who underwent spinal fusion through transforaminal lumbar interbody fusion (TLIF).

OUTCOME MEASURES

Spinal fusion was assessed by plain X-ray at 3, 6, and 12 months and by computed tomography (CT) at 6 and 12 months post-treatment. An independent radiologist performed blinded assessments of all images. Clinical outcomes were measured as change from baseline value: visual analog scale for lumbar and sciatic pain at 12 days, 3, 6, and 12 months posttreatment, and Oswestry Disability Index and Short Form-36 at 3, 6, and 12 months posttreatment.

METHODS

Patients who underwent L4-L5 TLIF were randomized for posterior graft type only, and received either MSC+allograft (the tissue-engineered product, group A) or AICBG (standard graft material, group B). Standard graft material was used for anterior fusion in all patients. Feasibility was measured primarily as the percentage of randomized patients who underwent surgery in each treatment group. Safety was assessed by analyzing treatment-emergent adverse events (AEs) for the full experimental phase and appraising their relationship to the experimental treatment. Outcome measures, both radiological and clinical, were compared between the groups.

RESULTS

Seventy-three patients were randomized in this study, 36 from the MSC+allograft group and 37 from the AICBG group, and 65 were surgically treated (31 group A, 34 group B). Demographic and comorbidity data showed no difference between groups. Most patients were diagnosed with grade I or II degenerative spondylolisthesis. MSC+allograft was successfully implanted in 86.1% of randomized group A patients. Most patients suffered treatment-emergent AEs during the study (88.2% in group A and 97.1% in group B), none related to the experimental treatment. X-ray-based rates of posterior spinal fusion were significantly higher for the experimental group at 6 months (p=.012) and 12 months (p=.0003). CT-based posterior fusion rates were significantly higher for MSC+allograft at 6 months (92.3% vs 45.7%; p=.0001) and higher, but not significantly, at 12 months (76.5% vs 65.7%; p=.073). CT-based complete response (defined as the presence of both posterior intertransverse fusion and anterior interbody fusion) was significantly higher at 6 months for MSC+allograft than for AICBG (70.6% vs 40%; p=.0038), and remained so at 12 months (70.6% vs 51.4%; p=.023). Clinical results including patient-reported outcomes improved postsurgery, although there were no differences between groups.

CONCLUSIONS

Compared with the current gold standard, our experimental treatment achieved a higher rate of posterior spinal fusion and radiographic complete response to treatment at 6 and 12 months after surgery. The treatment clearly improved patient quality of life and decreased pain and disability at rates similar to those for the control arm. The safety profile of the tissue-engineered product was also similar to that for the standard material, and no AEs were linked to the product. Procedural AEs did not increase as a result of BM aspiration. The use of expanded bone marrow MSCs combined with cancellous allograft is a feasible and effective technique for spinal fusion, with no product-related AEs found in our study.

Supramolecular self-assembling peptides to deliver bone morphogenetic proteins for skeletal regeneration

Recombinant human bone morphogenetic proteins (BMPs) have shown clinical success in promoting bone healing, but they are also associated with unwanted side effects. The development of improved BMP carriers that can retain BMP at the defect site and maximize its efficacy would decrease the therapeutic BMP dose and thus improve its safety profile. In this review, we discuss the advantages of using self-assembling peptides, a class of synthetic supramolecular biomaterials, to deliver recombinant BMPs. Peptide amphiphiles (PAs) are a broad class of self-assembling peptides, and the use of PAs for BMP delivery and bone regeneration has been explored extensively over the past decade. Like many self-assembling peptide systems, PAs can be designed to form nanofibrous supramolecular biomaterials in which molecules are held together by non-covalent bonds. Chemical and biological functionality can be added to PA nanofibers, through conjugation of chemical moieties or biological epitopes to PA molecules. For example, PA nanofibers have been designed to bind heparan sulfate, a natural polysaccharide that is known to bind BMPs and potentiate their signal. Alternatively, PA nanofibers have been designed to synthetically mimic the structure and function of heparan sulfate, or to directly bind BMP specifically. In small animal models, these bio-inspired PA materials have shown the capacity to promote bone regeneration using BMP at doses 10-100 times lower than established therapeutic doses. These promising results have motivated further evaluation of PAs in large animal models, where their safety and efficacy must be established before clinical translation. We conclude with a discussion on the possiblity of combining PAs with other materials used in orthopaedic surgery to maximize their utility for clinical translation.

Biofabrication of 3D printed hydroxyapatite composite scaffolds for bone regeneration

Biofabrication has been adapted in engineering patient-specific biosynthetic grafts for bone regeneration. Herein, we developed a 3D high-resolution, room-temperature printing approach to fabricate osteoconductive scaffolds using calcium phosphate cement (CPC). The non-aqueous CPC bioinks were composed of tetracalcium phosphate (TTCP), dicalcium phosphate anhydrous (DCPA), and Polyvinyl butyral (PVB) dissolved in either ethanol (EtOH) or Tetrahydrofuran (THF). They were printed in an aqueous sodium phosphate bath, which performs as a hardening accelerator for hydroxyapatite (HA) formation and as a retainer for 3D microstructure. The PVB solvents, EtOH or THF, affected differently the slurry rheological properties, scaffold microstructure, mechanical properties, and osteoconductivity. Our proposed approach overcomes limitations of conventional fabrication methods, which require high-temperature (> 50 oC), low-resolution (> 400 μm) printing with an inadequate amount of large ceramic particles (> 35 μm). This proof-of-concept study opens venues in engineering high-resolution, implantable, and osteoconductive scaffolds with predetermined properties for bone regeneration.

Are recent available blended collagen-calcium phosphate better than collagen alone or crystalline calcium phosphate? Radiotextural analysis of a 1-year clinical trial

OBJECTIVES

The purpose of this study is to compare bone regeneration properties of recently available collagen-calcium phosphate (C-CP) blend as bone substitute (BS) material in oral surgery with calcium phosphate (CP) as well as collagen material (Collagen). Is C-CP better than the classic loose CP, or is it at least equally effective in the jawbone regeneration with the superiority of a coherent consistency?

MATERIALS AND METHODS

This study included 102 patients during 12-month follow-up. All patients underwent the following surgical procedures: sinus lift (52patients) and tooth extraction (50patients). Patients were divided into 3 groups which are as follows: experimental group with C-CP, CP and pure Collagen as control groups. Texture analysis was performed in intra-oral radiographs. Analyses were performed in the MaZda 4.6 software. Average 2444-pixel ROIs were established in the image of BS materials and normal trabecular bone for texture comparison to evaluate the jawbone regeneration process. Four features were calculated and investigated.

RESULTS

Texture analyses revealed that all 4 features described the healing process well. Reference textural value of feature SumOfSqrs < 102.37 was soft tissue, DifEntr < 1.1 was not the bone, Entr < 2.62 was not a bone and LngREmph > 1.8 was soft tissue. For 12 months, bone regeneration was proved by 3 of 4 investigated features. Only Entr indicated to CP remnants in the ROI (p < 0.05).

CONCLUSIONS

This study proves that blended collagen-calcium phosphate as a BS material can bring satisfactory and predictable outcomes in jawbone regeneration.

CLINICAL RELEVANCE

Clinicians can choose a satisfactory and predictable material for bone regeneration treatment.

Use of Local Morselized Bone Autograft in Minimally Invasive Transforaminal Lumbar Interbody Fusion: Cost Analysis

OBJECTIVE

Few studies have investigated the financial influence of surgical site local morselized bone autograft (LMBA) on the overall cost of spinal arthrodesis procedures. The purpose of this study is to evaluate the potential savings from introducing LMBA in spinal fusion procedures compared with no LMBA use.

METHODS

Retrospectively, cost analysis was conducted on a single-center data collected from 266 patients who underwent minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) ranging from L1 through S1 during a period of approximately 4 years. Cost data were obtained from individual patient invoices from the distributor. Sensitivity analyses were also conducted for different costs of allograft and LMBA.

RESULTS

A total of 282 levels were grafted in 266 subjects. The total quantity of LMBA harvested was 2433.5 mL, and a total of 1610 mL of allograft (Trinity Elite, ORTHOFIX, Lewisville, Texas, USA) were used. The overall cost savings from introducing LMBA in MI-TLIF surgery were $1,094,931 over the 4-year period with mean direct cost saving of $4116.28 per patient based on reduction in allograft. Results for cost savings per patient were sensitive to different direct costs of allograft and LMBA. A >95% fusion rate was achieved based on dynamic radiographs evaluated by an independent radiologist.

CONCLUSIONS

LMBA is a cost-saving bone graft extender option in MI-TLIF procedures while achieving high fusion rates. The savings are mainly achieved by reducing the amount of allograft needed and subsequent reduction in the total bone graft costs. Further research needs to be performed regarding long-term economic benefit.

Preclinical biological and physicochemical evaluation of two-photon engineered 3D biomimetic copolymer scaffolds for bone healing

A major challenge in orthopedics is the repair of large non-union bone fractures. A promising therapy for this indication is the use of biodegradable bioinspired biomaterials that stabilize the fracture site, relieve pain and initiate bone formation and healing. This study uses a multidisciplinary evaluation strategy to assess immunogenicity, allergenicity, bone responses and physicochemical properties of a novel biomaterial scaffold. Two-photon stereolithography generated personalized custom-built scaffolds with a repeating 3D structure of Schwarz Primitive minimal surface unit cell with a specific pore size of ∼400 μm from three different methacrylated poly(d,l-lactide-co-ε-caprolactone) copolymers with lactide to caprolactone monomer ratios of 16 : 4, 18 : 2 and 9 : 1. Using in vitro and in vivo assays for bone responses, immunological reactions and degradation dynamics, we found that copolymer composition influenced the scaffold physicochemical and biological properties. The scaffolds with the fastest degradation rate correlated with adverse cellular effects and mechanical stiffness correlated with in vitro osteoblast mineralization. The physicochemical properties also correlated with in vivo bone healing and immune responses. Overall these observations provide compelling support for these scaffolds for bone repair and illustrate the effectiveness of a promising multidisciplinary strategy with great potential for the preclinical evaluation of biomaterials.

Impact of Single or Combined Drug Therapy on Bone Regeneration in Healthy and Osteoporotic Rats

Complications in bone regeneration in patients with systemic impaired bone metabolism (e.g., osteoporosis) represent a rapidly increasing clinical challenge. Alendronate and simvastatin are drugs commonly used to promote bone metabolism in osteoporotic conditions. The aim of this study was to evaluate initial bone regeneration within osseous defects grafted with beta-tricalcium phosphate (β-TCP) in adjunction with systemic coadministrations of alendronate and simvastatin (i.e., daily subcutaneous injection for 3 weeks) in healthy and osteoporotic rats. Eighty Wistar female rats were ovariectomized (OVX; n = 40) or sham operated (n = 40). Six weeks later, osseous defects (a 3-mm critical-sized defect) were created in the left femoral condyles and then grafted with β-TCP. From the day following graft installation, OVX and sham animals received for 3 weeks a daily subcutaneous injection of alendronate (50 μg/kg of body weight) and simvastatin (5 mg/kg of body weight), alone or in combination. A control group was included, which received subcutaneous saline administration. At the end of the 3 weeks, rats were euthanized and specimens (femoral condyles) were retrieved for histological evaluation and histomorphometric measurements, that is, bone area (BA%) and remaining bone graft (RBG%). In osteoporotic rats, 3 weeks of daily subcutaneous injection of combined therapy (alendronate plus simvastatin) led to a significant (p < 0.05) increase in BA% and a significant decrease in RBG% compared to healthy controls in osseous defects grafted with β-TCP (BA%: 28.6 ± 12.0 vs. 18.2 ± 7.6, RBG% 61.3 ± 11.1 vs. 70.7 ± 7.3). No significant differences in BA% and RBG% were found in the OVX rats for single treatments. Furthermore, healthy controls showed similar BA% and RBG% upon single or combined therapy compared to nontreated control rats. Daily coinjections (for 3 weeks) of alendronate plus simvastatin result in a significant enhancement of bone regeneration within osseous defects grafted with β-TCP in osteoporotic rats. Despite the expected effects on osteoporotic bone, our study did not confirm the hypothesized benefit of alendronate and simvastatin on bone regeneration in osseous defects in healthy conditions. The efficacy of the combination drug therapy on bone regeneration demands further investigation to elucidate molecular and cellular aspects underlying this therapy.

Efficacy of bone formation of microporous sphere-shaped biphasic calcium phosphate in a rabbit skull bone defect model

Bone graft is required in various surgical procedures. Although autograft is the gold standard, it has limited availability. Various compounds have been proposed as alternatives such as biphasic calcium phosphate (BCP), which is the most widely used compound. The newly synthesized microporous sphere-shaped BCP has the advantage of increasing contact surface, and it can induce the formation of microbone structures. A putty-type contains the addition of a fluid carrier to the sphere-shaped BCP and can be easily used for a small orifice large bone defect. To compare the widely used BCP products, new bone formation and residual graft materials (RGM) were evaluated for 6 and 12 weeks in a rabbit calvarial bone defect model. Although existing BCP products and the microporous sphere-type product did not differ significantly with respect to new bone formation and RGM, the putty-type product was largely washed out and had low new bone formation at 6 and 12 weeks. Overall, the results suggest that microporous sphere-shaped BCP showed similar bone formation capability to existing products and was able to maintain higher initial mechanical stability.

Comparison of Two Bone Grafting Techniques Applied During Posterior C1-C2 Screw-Rod Fixation and Fusion for Treating Reducible Atlantoaxial Dislocation

BACKGROUND

Several bone grafting techniques for posterior atlantoaxial arthrodesis have been reported. The techniques of placing a cancellous morselized bone graft (MBG) on decorticated surfaces of the atlantoaxial complex and securing a structural iliac bone graft (SBG) between C1 and C2 have been used widely. The aim of the present study was to compare the outcomes of these 2 bone grafting techniques for atlantoaxial arthrodesis.

METHODS

The data from 64 patients with reducible atlantoaxial dislocation treated using posterior C1-C2 screw-rod fixation and fusion were retrospectively reviewed. The MBG technique had been used in 32 patients and the SBG technique in 32 patients. The time required for bone fusion was recorded. The outcomes were evaluated using the Japanese Orthopaedic Association scale score, Neck Disability Index, visual analog scale (VAS) score for neck pain, patient satisfaction, and neck stiffness and compared between the 2 groups. The donor site complications were also compared, and donor site pain was assessed using a VAS.

RESULTS

At the final follow-up, the bone fusion rate was 100% in both groups. No significant differences were found in the bone fusion time or donor site pain between the 2 groups (P > 0.05). Postoperatively, The Japanese Orthopaedic Association scale scores, Neck Disability Index, and VAS score for neck pain had improved significantly within both groups (P < 0.05), with no statistically significant differences between the 2 groups (P > 0.05). Additionally, no differences were found between the 2 groups in patient satisfaction and neck stiffness postoperatively (P > 0.05).

CONCLUSIONS

The MBG and SBG techniques were both effective for atlantoaxial arthrodesis, with the advantages of reducing the potential risk of catastrophic bleeding of the epidural venous plexus and C2 nerve root injury.

The Use of Bovine Xenogeneic Bone Graft for Dega Pelvic Osteotomy in Children with Hip Dysplasia: A Retrospective Study of 147 Treated Hips

Backgrounds: Dega pelvic osteotomy is commonly used to correct acetabular dysplasia in children with open triradiate cartilage. The use of bovine xenogeneic bone graft (Tutobone^®) for Dega osteotomy has not been reported so far. This study aimed to determine the clinical and radiological outcome in a large series of children with hip dysplasia who were treated by Dega osteotomy using a bovine xenogeneic block for stabilisation. Methods: A retrospective, single-centre study was conducted including 101 patients (147 hips) with different underlying diseases. The acetabular angle of Hilgenreiner (AA) and the lateral center-edge angle (LCA) were analysed to quantify the correction of acetabular indices. Graft incorporation was assessed using the Goldberg scoring system. Results: the mean preoperative AA improved from 28.1 (SD: 6.7) to 14.7 (SD: 5.1) after surgery (p < 0.001). The mean preoperative LCA improved from 9.9 (SD: 6.7) to 21.8 (SD: 6.8) postoperatively (p < 0.001). Both indices remained stable at the one-year follow-up examination. Graft incorporation was excellent with a mean Goldberg score of 6.6. Heterotopic ossification occurred in one hip without clinical relevance. Graft-related complications were not noted. Conclusions: Dega osteotomy using Tutobone^® is safe and effective in the treatment of acetabular dysplasia in children independent of the underlying disease.

First Human Leucocyte Antigen (HLA) Response and Safety Evaluation of Fibrous Demineralized Bone Matrix in a Critical Size Femoral Defect Model of the Sprague-Dawley Rat

Treatment of large bone defects is one of the great challenges in contemporary orthopedic and traumatic surgery. Grafts are necessary to support bone healing. A well-established allograft is demineralized bone matrix (DBM) prepared from donated human bone tissue. In this study, a fibrous demineralized bone matrix (f-DBM) with a high surface-to-volume ratio has been analyzed for toxicity and immunogenicity. f-DBM was transplanted to a 5-mm, plate-stabilized, femoral critical-size-bone-defect in Sprague-Dawley (SD)-rats. Healthy animals were used as controls. After two months histology, hematological analyses, immunogenicity as well as serum biochemistry were performed. Evaluation of free radical release and hematological and biochemical analyses showed no significant differences between the control group and recipients of f-DBM. Histologically, there was no evidence of damage to liver and kidney and good bone healing was observed in the f-DBM group. Reactivity against human HLA class I and class II antigens was detected with mostly low fluorescence values both in the serum of untreated and treated animals, reflecting rather a background reaction. Taken together, these results provide evidence for no systemic toxicity and the first proof of no basic immunogenic reaction to bone allograft and no sensitization of the recipient.

Biomechanical evaluation of autologous bone-cage in posterior lumbar interbody fusion: a finite element analysis

BACKGROUND

An autologous bone-cage made from the spinous process and laminae might provide a stability in posterior lumbar interbody fusion (PLIF) close that of the traditional-cage made of polyetheretherketone (PEEK) or titanium. The biomechanical effect of autologous bone-cages on cage stability, stress, and strains, and on the facet contact force has not been fully described. This study aimed to verify whether autologous bone-cages can achieve similar performance as that of PEEK cages in PLIF by using a finite element analysis.

METHODS

The finite element models of PLIF with an autologous bone-cage, a titanium cage, and a PEEK cage were constructed. The autologous bone-cage was compared with the titanium and PEEK cages. The mechanical properties of the autologous bone-cage were obtained through mechanical tests. The four motion modes were simulated. The range of motion (ROM), the stress in the cage-end plate interface, and the facet joint force (FJF) were compared.

RESULTS

The ROM was increased at adjacent levels but decreased over 97% at the treated levels, and the intradiscal pressure at adjacent levels was increased under all conditions in all models. The FJF disappeared at treated levels and increased under extension, lateral bending, and lateral rotation in all models. The maximum stress of the cage-endplate interface was much lower in the autologous bone-cage model than those in the PEEK and titanium cage models.

CONCLUSIONS

In a finite model of PLIF, the autologous bone-cage model could achieve stability close that of traditional titanium or PEEK cages, reducing the risk of subsidence.

Effectiveness of mesenchymal stem cell-conditioned medium in bone regeneration in animal and human models: a systematic review and meta-analysis

BACKGROUND

Given the limitations of current therapies for the reconstruction of bone defects, regenerative medicine has arisen as a new therapeutic strategy along with mesenchymal stem cells (MSCs), which, because of their osteogenic potential and immunomodulatory properties, have emerged as a promising alternative for the treatment of bone injuries. In vivo studies have demonstrated that MSCs have a positive effect on regeneration due to their secretion of cytokines and growth factors that, when collected in conditioned medium (MSC-CM) and applied to an injured tissue, can modulate and promote the formation of new tissue.

OBJECTIVE

To evaluate the effectiveness of application of conditioned medium derived from mesenchymal stem cells in bone regeneration in animal and human models.

METHODS

We conducted a systematic review with a comprehensive search through February of 2018 using several electronic databases (MEDLINE, EMBASE, SCOPUS, CENTRAL (Ovid), and LILACS), and we also used the "snowballing technique". Articles that met the inclusion criteria were selected through abstract review and subsequent assessment of the full text. We assessed the risk of bias with the SYRCLE and Cochrane tools, and three meta-analyses were performed.

RESULTS

We included 21 articles, 19 of which used animal models and 2 of which used human models. In animal models, the application of MSC-CM significantly increased the regeneration of bone defects in comparison with control groups. Human studies reported early mineralization in regenerated bones, and no bone resorption, inflammation, nor local or systemic alterations were observed in any case. The meta-analysis showed an overall favorable effect of the application of MSC-CM.

CONCLUSIONS

The application of MSC-CM to bone defects has a positive and favorable effect on the repair and regeneration of bone tissue, particularly in animal models. It is necessary to perform additional studies to support the application of MSC-CM in clinical practice.