Biological enhancement of tibial diaphyseal aseptic non-unions: the efficacy of autologous bone grafting, BMPs and reaming by-products

Comparative Analysis of Stromal Vascular Fraction and Alternative Mechanisms in Bone Fracture Stimulation to Bridge the Gap between Nature and Technological Advancement: A Systematic Review

BACKGROUND

Various stimulation methods, including electrical, ultrasound, mechanical, and biological interventions, are explored, each leveraging intricate cellular and molecular dynamics to expedite healing. The advent of stromal vascular fraction (SVF) marks a significant stride, offering multifarious benefits in bone healing, from enhanced bone formation to optimal vascular integration, drawing a harmonious balance between innate mechanisms and scientific advancements.

METHODS

This systematic review was conducted focusing on literature from 2016 to 2023 and encompassing various bone healing stimulation mechanisms like SVF, electrical, ultrasound, and mechanical stimulation. The extracted data underwent meticulous synthesis and analysis, emphasizing comparative evaluations of mechanisms, applications, and outcomes of each intervention.

RESULTS

The reviewed studies reveal the potential of SVF in bone fracture healing, with its regenerative and anti-inflammatory effects. The purification of SVF is crucial for safe therapeutic use. Characterization involves flow cytometry and microscopy. Studies show SVF's efficacy in bone regeneration, versatility in various contexts, and potential for clinical use. SVF appears superior to electrical, ultrasound, and mechanical stimulation, with low complications.

CONCLUSIONS

This review compares bone healing methods, including SVF. It provides valuable insights into SVF's potential for bone regeneration. However, due to limited human studies and potential bias, cautious interpretation is necessary. Further research is essential to validate these findings and determine the optimal SVF applications in bone healing.

Osteoperiosteal decortication and bone grafting combined with wave plating for femoral shaft aseptic atrophic nonunion after intramedullary nailing

OBJECTIVE

Femoral shaft nonunion after intramedullary nailing fixation remains a challenge for orthopedic surgeons. This study evaluated osteoperiosteal decortication and iliac bone grafting combined with wave plating as a treatment for aseptic atrophic nonunion of the femoral shaft after intramedullary nailing.

METHODS

The study included 22 patients (two female, 20 male; mean age 40.8 years [range, 19-61]) with aseptic atrophic nonunion of the femoral shaft who underwent osteoperiosteal decortication and iliac bone grafting combined with wave plating between January 2016 and January 2020. Cases with infected nonunion, hypertrophic nonunion, and nonunion after plate osteosynthesis were excluded. Clinical outcomes were assessed retrospectively using the Samantha X-ray and Paley scale scores.

RESULTS

The mean follow-up period was 18.8 months (range, 12-35). Bone union was achieved in all patients. The average clinical healing time was 5.7 months (range, 3-14). The mean Samantha X-ray score was 5.7 ± 0.45 and the Paley scores indicated excellent or good clinical results in all cases. One patient developed sterile wound leakage that resolved after a dressing change.

CONCLUSIONS

Osteoperiosteal decortication and bone grafting combined with wave plating is an excellent treatment for aseptic atrophic nonunion of the femoral shaft after intramedullary nailing.

Bioactive Scaffold Fabricated by 3D Printing for Enhancing Osteoporotic Bone Regeneration

We develop a poly (lactic-co-glycolic acid)/β-calcium phosphate (PLGA/TCP)-based scaffold through a three-dimensional (3D) printing technique incorporating icaritin (ICT), a unique phytomolecule, and secretome derived from human fetal mesenchymal stem cells (HFS), to provide mechanical support and biological cues for stimulating bone defect healing. With the sustained release of ICT and HFS from the composite scaffold, the cell-free scaffold efficiently facilitates the migration of MSCs and promotes bone regeneration at the femoral defect site in the ovariectomy (OVX)-induced osteoporotic rat model. Furthermore, mechanism study results indicate that the combination of ICT and HFS additively activates the Integrin-FAK (focal adhesion kinase)-ERK1/2 (extracellular signal-regulated kinase 1/2)-Runx2 (Runt-related transcription factor 2) axis, which could be linked to the beneficial recruitment of MSCs to the implant and subsequent osteogenesis enhancement. Collectively, the PLGA/TCP/ICT/HFS (P/T/I/S) bioactive scaffold is a promising biomaterial for repairing osteoporotic bone defects, which may have immense implications for their translation to clinical practice.

Implantation of stem cells on synthetic or biological scaffolds: an overview of bone regeneration

Humans are exposed to a wide range of bone tissue injuries. In severe cases, bone damages could be only treated with transplantation of autologous or allogeneic grafting.In recent years, tissue engineering has become a promising strategy for repairing damaged organs and tissues, providing a great opportunity to cure several diseases. Bone tissue engineering consists of three components: scaffold, cells, and growth factors. Current bone tissue engineering strategies combine the use of stem cells with biologically active materials and gene therapy to mimic the natural microenvironment of bone. The combination of the scaffold with growth factors and extracellular matrix protein molecules can promote cell attachment, proliferation, and induce osteogenesis, which could provide signals for cell migration to begin the healing process during repair and bone formation.This article reviews the principles of bone regeneration and the most current developments of bone tissue engineering related to bone growth factors, the biologically active materials, such as bacterial cellulose, and stem cells.

Osteoperiosteal Decortication and Autogenous Cancellous Bone Graft Combined with Bridge Plating for Non-hypertrophic Diaphyseal Nonunion

Backgroud

The aim of this study was to evaluate results of osteoperiosteal decortication and autogenous cancellous bone graft combined with a bridge plating technique in atrophic and oligotrophic femoral and tibial diaphyseal nonunion.

Methods

We retrospectively reviewed 31 patients with atrophic or oligotrophic femoral and tibial diaphyseal nonunion treated with osteoperiosteal decortication and autogenous cancellous bone graft between January 2008 and December 2018. Patients with hypertrophic nonunion, infected nonunion, and nonunion treated with autogenous cancellous bone graft alone were excluded. The nonunion site was exposed by using the Judet technique of osteoperiosteal decortication. Nonunion with a lack of stability was stabilized with a new plate using a bridge plating technique or augmented by supplemental fixation with a plate. Nonunion with malalignment was stabilized with a new plate after deformity correction. Autogenous cancellous bone graft was harvested from the posterior iliac crest and placed within the area of decortication. A basic demographic survey was conducted, and the type of existing implants, mechanical stability of the implants, the type of implants used for stabilization, the operation time, the time to bone union, and postoperative complications were investigated.

Results

The average follow-up period was 33.3 months (range, 8–108 months). The operation time was 207 minutes (range, 100–351 minutes). All but 1 nonunion (96.7%) were healed at an average of 4.2 months (range, 3–8 months). In 1 patient, bone union failed due to implant loosening with absorbed bone graft, and solid union was achieved by an additional surgery for stable fixation with a new plate, osteoperiosteal decortication, and autogenous cancellous bone graft. There were no other major complications such as neurovascular injuries, infection, loss of fixation, and malunion.

Conclusions

Osteoperiosteal decortication and autogenous cancellous bone graft combined with stable fixation by bridge plating showed reliable outcomes in atrophic and oligotrophic diaphyseal nonunion. This treatment modality can be effective for treating atrophic and oligotrophic diaphyseal nonunion because it is very helpful stimulating bone union.

Comparison of bone morphogenetic protein and autologous grafting in the treatment of limb long bone nonunion: a systematic review and meta-analysis

BACKGROUND

Bone morphogenetic proteins (BMPs) have strong bone induction properties and can promote healing of fractures and other defects. However, BMP treatment efficacy for long bone nonunion remains controversial. The aim of this meta-analysis was to synthetically evaluate the advantages and disadvantages of BMP plus bone grafting (observation group) versus autologous bone grafting (control group) for limb long bone nonunion.

METHODS

PubMed, Embase, Web of Science, Cochrane Library, OVID, CNKI, Weipu Journal, Chinese Biomedical Literature, and WanFang were searched for randomized and non-randomized controlled trials published before November 2019. A meta-analysis of outcome indicators was performed using RevMan 5.3 and Stata 12.0.

RESULTS

Five randomized and four non-randomized controlled trials involving 30-124 cases were included, with a total of 655 nonunion cases. There were no significant group differences in postoperative healing rate, infection, and secondary operation rates (P > 0.05), but the study group demonstrated significantly shorter mean healing time (WMD = - 1.27, 95%CI - 1.67 to - 0.88, P < 0.00001), a greater frequency of excellent/good post-treatment limb function (RR = 1.18, 95%CI 1.01-1.39, P = 0.04), and lower intraoperative blood loss (P < 0.05). Alternatively, the hospitalization cost was significantly higher in the study group (P < 0.01).

CONCLUSIONS

Bone morphogenetic protein is a viable alternative to autologous bone grafting, with potential advantages of accelerated fracture healing and improved postoperative function.

Bioactive Three-Dimensional Graphene Oxide Foam/Polydimethylsiloxane/Zinc Silicate Scaffolds with Enhanced Osteoinductivity for Bone Regeneration

Nanocomposite scaffold materials have shown great prospect in promoting bone integration and bone regeneration. A three-dimensional graphene oxide foam/polydimethylsiloxane/zinc silicate (GF/PDMS/ZS) scaffold for bone tissue engineering was synthesized via dip coating and hydrothermal synthesis processes, resulting in the interconnected macroporous structure. The scaffold was characterized with scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and thermogravimetric (TG) analysis. The result showed that scaffolds exhibiting a porous characteristic had organic-inorganic components similar to natural bone tissue. Moreover, the scaffolds possessed suitable pore size, high porosity, and good mechanical properties. In vitro experiments with mouse bone marrow mesenchymal stem cells (mBMSCs) revealed that the composite scaffold not only has great biocompatibility but also has the ability to induce mBMSC proliferation and preferential osteogentic differentiation. Thereafter, the expression of critical genes, ALP, RUNX2, VEGFA, and OPN, was activated. In vivo analysis of critical bone defect in rabbits demonstrated superior bone formation in defect sites in the GF/PDMS/ZS scaffold group at 12 weeks of post implantation without no significant inflammatory response. All the results validated that the GF/PDMS/ZS scaffold is a promising alternative for applications in bone regeneration.

Femoral non-union above a fused knee: Successful treatment with exchange nailing and intramedullary delivery of bone morphogenetic protein

Bone healing is a complex and well-orchestrated physiological process, in which bone repairs and regenerates regaining its original biomechanical and biochemical properties. It is estimated that 5 to 10% of all fractures are complicated by delayed union or non-union. Progression to non-union is thought to be multifactorial, even though the exact biological sequence remains obscure. Treatment should aim to addressing deficiencies in both the mechanical and biological components, along with eliminating co-factors that could negatively affect the locally induced fracture healing response. We report a case of a 78-year-old patient who presented with a distal femoral non-union above a previously fused knee, which was successfully managed with exchange nailing and intramedullary delivery of recombinant human bone morphogenetic protein-7 (rhBMP-7).

Nandrolone decanoate in induced fracture nonunion with vascular deficit in rat model: morphological aspects

BACKGROUND

The nonunion fracture is a relatively frequent complication in both human and veterinary medicine. Specifically, atrophic fracture nonunions are difficult to treat, with revision surgery usually providing the best prognosis. Anabolic steroids, such as nandrolone decanoate (ND), have been reported to have beneficial clinical effects on bone mass gain during osteoporosis; however, their utility in promoting regeneration in atrophic nonunions has not been documented. Our objective was to examine morphological changes induced by the ND in experimental fracture nonunion with vascular deficit in the rat model.

METHODS

Fourteen adult Wistar rats had an atrophic fracture nonunion induced in the diaphysis of their left femur. Rats were allocated into two groups: control group and nandrolone decanoate group. Rats in the latter group were given nandrolone decanoate (1.5 mg/kg IM, once a week, during 4 weeks after confirmation of fracture nonunion radiographically). Radiographic and anatomopathological examination, micro-tomography and histological analysis were assessed to characterize the morphological changes promoted by the nandrolone decanoate use.

RESULTS

Based on radiology, anatomopathological evaluation, computed micro-tomography and conventional microscopy, nandrolone decanoate promoted bone regeneration at the fracture nonunion site by increasing the cellularity at the fracture site. Percentage of collagen was not significantly different between groups, consistent with high-quality regenerated bone.

CONCLUSION

The anabolic steroid nandrolone decanoate improved bone mass and regeneration without affecting collagen production and therefore has potential for improving outcomes for atrophic fracture nonunion.

Effects of Bone Morphogenetic Protein-2 on Neovascularization During Large Bone Defect Regeneration

Insufficient blood vessel supply is a primary limiting factor for regenerative approaches to large bone defect repair. Recombinant bone morphogenetic protein-2 (BMP-2) delivery induces robust bone formation and has been observed to enhance neovascularization, but whether the angiogenic effects of BMP-2 are due to direct endothelial cell stimulation or due to indirect paracrine signaling remain unclear. In this study, we evaluated the effects of BMP-2 delivery on vascularized bone regeneration and tested whether BMP-2 induces neovascularization directly or indirectly. We found that delivery of BMP-2 (5 μg) enhanced both bone formation and neovascularization in critically sized (8 mm) rat femoral bone defects; however, BMP-2 did not directly stimulate angiogenesis in vitro. In contrast, conditioned medium from both mesenchymal progenitor cells and osteoblasts induced endothelial cell migration in vitro, suggesting a paracrine mechanism of BMP-2 action. Consistent with this inference, codelivery of BMP-2 with endothelial colony forming cells to a heterotopic site, distant from the skeletal stem cell-rich bone marrow niche, induced ossification but had no effect on neovascularization. Taken together, these data suggest that paracrine activation of osteoprogenitor cells is an important contributor to neovascularization during BMP-2-mediated bone regeneration. Impact Statement In this study, we show that bone morphogenetic protein-2 (BMP-2) robustly induces neovascularization during tissue-engineered large bone defect regeneration, and we found that BMP-2 induced angiogenesis, in part, through paracrine signaling from osteoprogenitor cells.

Non-union after plate fixation

Approximately a third of patients presenting with long-bone non-union have undergone plate fixation as their primary procedure. In the assessment of a potential fracture non-union it is critical to understand the plating technique that the surgeon was intending to achieve at the primary procedure, i.e. whether it was direct or indirect fracture repair. The distinction between delayed union and non-union is a diagnostic dilemma especially in plated fractures, healing by primary bone repair. The distinction is important as nonunions are not necessarily part of the same spectrum as delayed unions. The etiology of a fracture non-union is usually multifactorial and the factors can be broadly categorized into mechanical factors, biological (local and systemic) factors, and infection. Infection is present in ~40% of fracture non-unions, often after open fractures or impaired wound healing, but in 5% of all non-unions infection is present without any clinical or serological suspicion. Methods to improve the sensitivity of investigation in the search of infection include the use of; sonication of implants, direct inoculation of theatre specimens into broth, and histological examination of non-union site tissue. Awareness should be given to the potential anti-osteogenic effect of bisphosphonates (in primary fracture repair) and certain classes of antibiotics. Early cases of delayed/non-union with sufficient mechanical stability and biologically active bone can be managed by stimulation of fracture healing. Late presenting non-union typically requires revision of the fixation construct and stimulation of the callus to induce fracture union.

Pedicled iliac crest bone flap transfer for the treatment of upper femoral shaft fracture nonunion: An anatomic study and clinical applications

PURPOSE

We present the results of a study on the anatomy of the ascending branch of the lateral circumflex femoral artery (AB-LCFA) and the use of the pedicled iliac bone flap transfer perfused by AB-LCFA combined with external fixation for the treatment of the nonunion of upper femoral shaft fractures.

METHODS

The orientation, diameter, length, and distribution of the AB-LCFA from 40 lower limbs of adult cadavers were dissected and measured. From 2000 to 2012, 13 patients with nonunion of upper femoral shaft fractures underwent pedicled iliac bone flap transfer perfused by the AB-LCFA combined with external fixation. The time of bone fracture union was recorded based on X-ray examination. The functional results of the femoral shaft were evaluated by the Klemm classification.

RESULTS

The lateral circumflex femoral artery (LCFA) divided into ascending, transverse, and descending branches in 32 specimens (80%). The diameter of the AB-LCFA at the origin was 3.15 ± 0.9 mm and the length of the AB-LCFA was 8.51 ± 3.06 cm. The postoperative course of the procedure was uneventful in all 13 patients. The average follow-up was 15 months. Bone union was achieved in all patients and the average union time was 5.3 months. 12 patients achieved excellent or good functional results based on the Klemm classification.

CONCLUSION

The AB-LCFA has a consistent orientation and abundant blood flow. The transfer of the iliac crest bone flap perfused by the AB-LCFA while combined with external fixation could be an option for treating the nonunion of upper femoral shaft fractures.

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for the prediction of non-union consolidation

INTRODUCTION

Non-union perfusion can be visualized with dynamic contrast-enhanced (DCE) MRI. This study evaluated DCE-MRI to predict non-union consolidation after surgery and detect factors that affect bone healing.

MATERIALS AND METHODS

Between 2010 and 2015 non-union perfusion was prospectively quantified in 205 patients (mean age, 51.5 years, 129 men, 76 women) before intervention and at 6, 12, 26, 52 and more weeks follow-up. DCE-MRI results were related to the osseous consolidation, the ability to predict successful outcome was estimated by ROC analysis. The relevance of the body mass index (BMI) and the non-union severity score (NUSS) to the healing process was assessed.

RESULTS

Tibial (n=99) and femoral (n=76) non-unions were most common. Consolidation could be assessed in 169 patients, of these 103 (61%) showed eventual healing and demonstrated higher perfusion than in failed consolidation at 6 (p=0.0226), 12 (p=0.0252) and 26 (p=0.0088) weeks follow-up. DCE-MRI at 26 weeks follow-up predicted non-union consolidation with a sensitivity of 75% and a specificity of 87% (false classification rate 19%). Higher BMI (p=0.041) and NUSS (p<0.0001) were associated with treatment failure.

CONCLUSIONS

DCE-MRI perfusion analysis after non-union surgery predicts successful outcome and could facilitate the decision of early intervention. NUSS and BMI are important prognostic factors concerning consolidation.

Upper limb non-unions treated with BMP-7: efficacy and clinical results

The management of upper limb non-unions can be challenging and often with unpredictable outcomes. In this study we present our experience with the use of BMP-7 in the treatment of upper limb non-unions. Between 2004 and 2011 all consecutive patients who were treated with BMP-7 were followed up prospectively until fracture union. Fracture union was assessed with regular radiological and clinical assessment. At the final follow up clinical assessment included the short Disabilities of the Arm, Shoulder and Hand (DASH) score. The minimum follow up was 12 months (12-36). In total 42 patients met the inclusion criteria with a mean age of 47 years. Anatomical distribution of the nonunion sites included 19 cases of mid/proximal forearm, 14 humeri, 6 distal radius and 3 clavicle. 35 patients had atrophic non-union, 11 had previous open fractures, and 10 had bone loss (range 1-3 cm). The mean number of operations performed and the mean time from injury to BMP-7 application was 1.5 and 26 months, respectively. 40 fractures had both clinical and radiological union whereas 2 patients had partial radiological union but a pain free range of motion. BMP-7 was applied in isolation in 1 case and in 41 cases the application was combined with autologous bone grafting. DASH scores were available at final follow up in 23 (55%) patients with a mean of 33 score (range 2-86.4). This study supports the view that the combination of ABG and BMP-7 can be considered as a successful treatment modality for the treatment of recalcitrant upper limb non-unions. Further studies preferably randomised controlled trials are desirable to throw more light into the role of BMP-7 in the treatment of upper limb nonunions.

Extracorporeal shockwave therapy (ESWT) ameliorates healing of tibial fracture non-union unresponsive to conventional therapy

Tibial non-unions are common cause of demanding revision surgeries and are associated with a significant impact on patients' quality of life and health care costs. Extracorporeal shockwave therapy (ESWT) has been shown to improve osseous healing in vitro and in vivo. The main objective of present study was to evaluate the efficacy of ESWT in healing of tibial non-unions unresponsive to previous surgical and non-surgical measures. A retrospective multivariant analysis of a prospective open, single-centre, clinical trial of tibia non-union was conducted. 56 patients with 58 eligible fractures who met the FDA criteria were included. All patients received 3000-4000 impulses of electrohydraulic shockwaves at an energy flux density of 0.4mJ/mm(2) (-6dB). On average patients underwent 1.9 times (±1.3SD) surgical interventions prior to ESWT displaying the rather negatively selected cohort and its limited therapy responsiveness. In 88.5% of patients receiving ESWT complete bone healing was observed after six months irrespective of underlying pathology. The multivariant analysis showed that time of application is important for therapy success. Patients achieving healing received ESWT earlier: mean number of days between last surgical intervention and ESWT (healed - 355.1 days±167.4SD vs. not healed - 836.7 days±383.0SD; p<0.0001). ESWT proved to be a safe, effective and non-invasive treatment modality in tibial non-unions recalcitrant to standard therapies. The procedure is well tolerated, time-saving, lacking side effects, with potential to significantly decrease health care costs. Thus, in our view, ESWT should be considered the treatment of first choice in established tibial non-unions.

Long bone non-unions treated with the diamond concept: a case series of 64 patients

The aim of this retrospective study with prospectively documented data was to report the clinical results of treatment of long bone non-unions using the "diamond concept". Over a 4-year period, patients that presented with a long bone non-union and were managed with the diamond conceptual framework of bone repair were evaluated. Exclusion criteria were hypertrophic, pathological, and infected non-unions. Fixation was revised as it was indicated whilst biological enhancement included the implantation of RIA graft, BMP-7 and concentrated bone marrow aspirate. Data recorded included patient demographics, initial fracture pattern and type of stabilisation, number of previous interventions, time to reoperation, time to union and functional outcome. Painless full weight bearing defined clinical union. Radiological union was defined as the presence of mature callous bridging to at least 3 bone cortices. The minimum follow up was 12 months (range 12-32). In total 64 patients (34 males) with a mean age of 45 years (17-83) were evaluated. Anatomical distribution of non-unions included the femur (54.68%), tibia (34.38%), humerus (4.68%), radius (3.13%) and clavicle (3.13%). The median number of previous interventions was 1 (range 1-5). The majority of patients (82.62%) underwent revision of fixation whereas only bone grafting was performed 9.38% of patients. Three patients developed superficial wound infection (one was MRSA), 1 had deep vein thrombosis and 1 developed heterotopic bone formation. Union was successful in 63/64 (98.4%) non-unions at a mean time of 6 months (range 3-12). All patients were mobilising pain free and returned to their daily living activities at the final follow up. The application of the "diamond concept" in this cohort of patients was associated with a high union rate by providing an optimal mechanical and biological environment. Such an approach should be considered in the surgeon's armamentarium particularly in such cases where difficulty of bone repair is foreseen.

Spontaneous Bilateral Femoral Fractures After High-Dose Zoledronic Acid

The authors report a case of spontaneous bilateral diaphyseal femoral fractures believed to be caused by oversuppression of bone remodeling as a result of long-term, high-dose treatment with bisphosphonate. The patient reported pain in both thighs before the fractures. Typical pathologic changes appeared on both femoral radiograph and bone scan before the fractures. Several hours after admission to the emergency department of the authors' institution, the patient underwent closed reduction and internal fixation with intramedullary nails for the bilateral femoral diaphyseal fractures. Treatment with zoledronic acid was immediately discontinued. In recent years, low-energy femoral diaphyseal fractures in patients undergoing long-term bisphosphonate treatment have been reported. It is believed that the prolonged treatment causes long-term suppression of bone remodeling and accumulation of microdamage. It is important to observe patients who are undergoing bisphosphonate treatment carefully. In this case study, the authors report the patient's unique medical history.

Treatment of a diaphyseal long-bone defect with autologous bone grafts and platelet-rich plasma in a rabbit model

INTRODUCTION

Large bone defects are a therapeutic challenge to surgeons and are often associated with a high morbidity. The use of autologous cancellous bone graft represents an essential therapeutic option and is considered the gold standard. However, the use of platelet-rich plasma (PRP) for improving bone defect healing has been discussed controversially. The aim of this study was to evaluate the treatment of a diaphyseal long-bone defect in a rabbit model with a combination of PRP and autologous cancellous bone.

MATERIAL AND METHODS

A monocortical long-bone defect in the radial diaphysis of 24 New Zealand white rabbits was filled either with autologous cancellous graft as a control group or with autologous cancellous graft combined with autologous PRP. Histomorphometrical and radiological analysis as well as quantification of platelets and growth factors were performed. The animals were euthanatized after three and six weeks according to the study arms.

RESULTS

A significant improvement in bone healing was observed histomorphometrically in the PRP group in the central area of the defect zone (p <0.01) as well as the cortical defect zone (p <0.01). The radiological findings were in accordance with the histomorphometrical results. Comparing native blood and PRP, an enrichment of growth factors and platelets was detectable in the PRP.

CONCLUSION

Within this animal study, the combination of PRP and autologous cancellous bone grafts improved bone healing significantly compared to the sole application of autologous bone. Therefore, further efforts should be initiated to establish the composite of PRP and autologous bone for bone healing disorders in clinical use.

Surgical treatment of aseptic forearm nonunion with plate and opposite bone graft strut. Autograft or allograft?

PURPOSE OF THE STUDY

Adequate treatment of forearm nonunion should achieve both biological stimulation of the bone and mechanical stability. The use of bone graft could enhance the healing of a nonunion providing osteogenic, osteoconductive and osteoinductive stimulation and an optimal stability of the fixation. We retrospectively reviewed two cohorts of patients affected by forearm nonunion and treated with plate and opposite bone graft to determine whether the use of autograft versus allograft differs in terms of (1) rate of healing of the nonunion and (2) time of healing.

MATERIALS AND METHODS

Thirty-four patients were treated for aseptic forearm nonunion with cortical graft strut with opposite plate and intercalary graft in case of segmental bone defect. In 20 patients an autograft harvest from the fibula (group A) and in 14 (group B) an allograft provided by the bone bank of our institution were used.

RESULTS

All the nonunions healed in a mean of four months in both groups, ranging from two to 12 months in group A and from three to ten months in group B. At the latest follow up forearm function and pain were satisfactory in both groups.

CONCLUSION

The use of plate and opposite bone graft demonstrated to be effective in promoting the healing of forearm nonunions, without significant differences in terms of rate and time of healing in the two groups. Considering the higher surgical time and the comorbidity of the donor site, if a bone bank is available, we suggest to use homologous cortical bone strut graft with opposite plate and screw fixation for the treatment of aseptic forearm nonunion rather than autograft.

Ethyl-3,4-dihydroxybenzoate with a dual function of induction of osteogenic differentiation and inhibition of osteoclast differentiation for bone tissue engineering

The current approach in biomaterial design of bone implants is to induce in situ regeneration of bone tissue, thus improving integration of the implants and reducing their failure. Therefore, ethyl-3,4-dihydroxybenzoate (EDHB), which stimulates differentiation of osteoblasts and the resultant bone formation, should be studied. In this study, the osteoinductive ability of EDHB in preosteoblasts and human mesenchymal stem cells was examined. EDHB for future use in bone tissue engineering was evaluated by examination of early markers of differentiation (such as alkaline phosphatase [ALP] activity and collagen type I expression) and late markers of osteoblast differentiation (bone nodule formation). As bone remodeling and implant osteointegration depend not only on osteoblast response but also on interaction of the biomaterial with bone-resorbing osteoclasts, differentiation of osteoclasts in response to the compounds was also observed. For in vivo study, alginate gel comprised of EDHB and cells was transplanted into the back subcutis of mice. Our results show that EDHB might have beneficial effects through regulation of both osteoblast and osteoclast differentiation. Therefore, we suggest that EDHB could be a strong candidate for dual regulation to increase osteoblast differentiation and decrease osteoclast differentiation.

Outcomes and complication rates of different bone grafting modalities in long bone fracture nonunions: a retrospective cohort study in 182 patients

BACKGROUND

Novel bone substitutes have challenged the notion of autologous bone grafting as the 'gold standard' for the surgical treatment of fracture nonunions. The present study was designed to test the hypothesis that autologous bone grafting is equivalent to other bone grafting modalities in the management of fracture nonunions of the long bones.

METHODS

A retrospective review of patients with fracture nonunions included in two prospective databases was performed at two US level 1 trauma centers from January 1, 1998 (center 1) or January 1, 2004 (center 2), respectively, until December 31, 2010 (n = 574). Of these, 182 patients required adjunctive bone grafting and were stratified into the following cohorts: autograft (n = 105), allograft (n = 38), allograft and autograft combined (n = 16), and recombinant human bone morphogenetic protein-2 (rhBMP-2) with or without adjunctive bone grafting (n = 23). The primary outcome parameter was time to union. Secondary outcome parameters consisted of complication rates and the rate of revision procedures and revision bone grafting.

RESULTS

The autograft cohort had a statistically significant shorter time to union (198 ± 172-225 days) compared to allograft (416 ± 290-543 days) and exhibited a trend towards earlier union when compared to allograft/autograft combined (389 ± 159-619 days) or rhBMP-2 (217 ± 158-277 days). Furthermore, the autograft cohort had the lowest rate of surgical revisions (17%) and revision bone grafting (9%), compared to allograft (47% and 32%), allograft/autograft combined (25% and 31%), or rhBMP-2 (27% and 17%). The overall new-onset postoperative infection rate was significantly lower in the autograft group (12.4%), compared to the allograft cohort (26.3%) (P < 0.05).

CONCLUSION

Autologous bone grafting appears to represent the bone grafting modality of choice with regard to safety and efficiency in the surgical management of long bone fracture nonunions.

Monotherapy vs. polytherapy in the treatment of forearm non-unions and bone defects

OBJECTIVE

To determinate the efficacy of "polytherapy", a surgical technique that utilize all the components of the diamond concept (mesenchymal stem cells, bone morphogenetic proteins and scaffold) versus a "monotherapy", a surgical technique that utilize only one component of the diamond conceptin the treatment of severe forearm non-unions.

METHODS

We studied a database of 52 patients with 52 forearm non-unions; we classified the patients with the NUSS SCORE and we divided the patients in two group according to the treatment received. So we distinguished a group of patients treated according to the principles of "monotherapy" (33 patients) and a group of patients treated according to the principles of "polytherapy" (19 patients). The minimum follow up was 12 months.

RESULTS

In the monotherapy group 21/33 non-unions (63.64%) went on to develop a radiographic and clinical healing within a period of 12 months, the calculated DASH SCORE showed a mean value of 55.15 points. In the polytherapy group 17/19 (89.47%) nonunions went on to develop clinical and radiographic healing within 12 months, and the average DASH score showed a mean value of 45.47 points.

CONCLUSION

The polytherapy technique with the use of recombinant morphogenetic proteins, autologous MSCs and scaffold in the same surgical time appears to be an effective treatment for patients with severe forearm non-unions.

BMP-2 but not VEGF or PDGF in fibrin matrix supports bone healing in a delayed-union rat model

Treatment of delayed bone healing and non-unions after fractures, osteotomies or arthrodesis still is a relevant clinical challenge. Artificially applied growth factors can increase bone healing and progressively gain importance in clinical routine. The aim of this study was to determine the effects of rhPDGF-BB, rhVEGF-165, and rhBMP-2 in fibrin matrix on bone healing in a delayed-union rat model. Thirty-seven rats underwent a first operation where a standardized femoral critical size defect was created. A silicone spacer was implanted to impair vascularization within the defect. At 4 weeks the spacer was removed in a second operation and rhPDGF-BB, rhVEGF-165, or rhBMP-2 were applied in a fibrin clot. Animals in a fourth group received a fibrin clot without growth factors. At 8 weeks fibrin bound rhBMP-2 treated animals showed a significantly increased union rate and bone volume within the defect compared to the other groups. Single application of fibrin bound rhPDGF-BB and rhVEGF-165 failed to increase bone healing in our atrophic non-union model.

Systemically delivered insulin-like growth factor-I enhances mesenchymal stem cell-dependent fracture healing

In this study, we examined the effectiveness of systemic subcutaneous delivery of recombinant Insulin-like growth factor (IGF)-I concurrently with primary cultured bone marrow-derived mesenchymal stem cell (MSC) transplant on fracture repair. We found that the fracture callus volume increased in mice with a stabilized tibia fracture that received IGF-I+MSC when compared with that in either untreated or MSC alone treated mice. In evaluating the callus tissue components, we found that the soft and new bone tissue volumes were significantly increased in IGF-I+MSC recipients. Histological and in-situ hybridization analyses confirmed a characteristic increase of newly forming bone in IGF-I+MSC recipients and that healing progressed mostly through endochondral ossification. The increase in soft and new bone tissue volumes correlated with increased force and toughness as determined by biomechanical testing. In conclusion, MSC transplant concurrent with systemic delivery of IGF-I improves fracture repair suggesting that IGF-I+MSC could be a novel therapeutic approach in patients who have inadequate fracture repair.

Pulsed electromagnetic fields for the treatment of tibial delayed unions and nonunions. A prospective clinical study and review of the literature

BACKGROUND

Pulsed electromagnetic fields (PEMF) stimulation for the treatment of bone nonunion or delayed union have been in use for several years, but on a limited basis. The aim of this study was to assess the overall efficacy of the method in tibial delayed unions and nonunions and identify factors that could affect the final outcome.

METHODS

We prospectively reviewed 44 patients (27 men) with a mean age of 49.6 ± 18.4 years that received PEMF therapy due to tibial shaft delayed union or nonunion. In all cases, fracture gap was less than 1 cm and infection or soft tissue defects were absent.

RESULTS

Fracture union was confirmed in 34 cases (77.3%). No relationship was found between union rate and age (p = 0.819), fracture side (left or right) (p = 0.734), fracture type (simple or comminuted, open or closed) (p = 0.111), smoking (p = 0.245), diabetes (p = 0.68) and initial treatment method applied (plates, nail, plaster of paris) (p = 0.395). The time of treatment onset didn't affect the incidence of fracture healing (p = 0.841). Although statistical significance was not demonstrated, longer treatment duration showed a trend of increased probability of union (p = 0.081).

CONCLUSION

PEMF stimulation is an effective non-invasive method for addressing non-infected tibial union abnormalities. Its success is not associated with specific fracture or patient related variables and it couldn't be clearly considered a time-dependent phenomenon.

Rap system of stress stimulation can promote bone union after lower tibial bone fracture: a clinical research

BACKGROUND

Lower tibial bone fracture may easily cause bone delayed union or nonunion because of lacking of dynamic mechanical load.

OBJECTIVE

Research Group would design a new instrument as Rap System of Stress Stimulation (RSSS) to provide dynamic mechanical load which would promote lower tibial bone union postoperatively.

METHODS

This clinical research was conducted from January 2008 to December 2010, 92 patients(male 61/female 31, age 16-70 years, mean 36.3 years) who suffered lower tibial bone closed fracture were given intramedullary nail fixation and randomly averagely separated into experimental group and control group(according to the successively order when patients went for the admission procedure). Then researchers analysed the clinical healing time, full weight bearing time, VAS (Visual Analogue Scales) score and callus growth score of Lane-Sandhu in 3,6,12 months postoperatively. The delayed union and nonunion rates were compared at 6 and 12 months separately.

RESULTS

All the 92 patients had been followed up (mean 14 months). Clinical bone healing time in experimental group was 88.78±8.80 days but control group was 107.91±9.03 days. Full weight bearing time in experimental group was 94.07±9.81 days but control group was 113.24±13.37 days respectively (P<0.05). The delayed union rate in 6 months was 4.3% in experimental group but 10.9% in control group(P<0.05). The nonunion rate in 12 months was 6.5% in experimental group but 19.6% in control group(P<0.05). In 3, 6, 12 months postoperatively, VAS score and Lane-Sandhu score in experimental group had more significantly difference than them in control group.

CONCLUSIONS

RSSS can intermittently provide dynamic mechanical load and stimulate callus formation, promote lower tibial bone union, reduce bone delayed union or nonunion rate. It is an adjuvant therapy for promoting bone union after lower tibial bone fracture.

Judet decortication and compression plate fixation of long bone non-union: Is bone graft necessary?

Non-union occurs in 5-10% of all fractures and is caused by a variety of mechanical and biological factors. Stable fixation is essential and many authors recommend the addition of bone graft. Our aim was to evaluate the results of internal fixation using Judet decortication and compression plating for long bone fractures and assess the impact of bone grafting on union rates. Our study group comprised all the patients undergoing compression plate fixation under a single surgeon over a fourteen year period (n=96). AO principles were used and the standard technique involved Judet decortication, compression plating and lag screws. Autologous bone graft was harvested from the iliac crest. The mean age was 45 years and 62% were male. The fracture site was the clavicle (n=20); humerus (n=23); radius and ulna (n=5); femur (n=31) and tibia (n=17). The primary fracture treatment was non-operative (n=41); IM nail (n=22); plate fixation (n=28) and external fixation (n=5). Deep infection was present in 6 cases. Bone graft was used in 40 cases. 91/96 non-unions treated with compression plating healed (95%). Bone grafting was used in all cases for the initial part of the series but its use declined as the surgeon became more confident that the non-unions would heal without the use of bone graft. The case mix and complexity remained constant throughout the study period and the union rate also remained constant. The mean time to radiological union was 6.4 months. In those treated with a compression plate without bone graft the union rate was 94.6% whilst the addition of bone graft resulted in a union rate of 95% (p=0.67). From our study we concluded that the routine use of autologous bone graft may not be necessary and, based upon the union rates observed in this study, a prospective randomised study to evaluate the use of bone graft in non-union surgery would need a sample size of 194,000 to detect a significant increase in union with 80% power. In terms of Numbers Needed Treat (NNT), we would need to give 1179 patients a bone graft to prevent one additional failure of healing.

Percutaneous management of ununited femoral fracture

We describe a percutaneous technique used for the management of non-union in a complex diaphyseal femoral fracture treated initially with intramedullary nailing. Seven months after the initial fixation, a proximal fracture gap failed to progress to union. A percutaneous procedure involving fracture gap freshening and supplementation with bone morphogenetic protein and demineralised bone matrix resulted in a satisfactory progression to union. The percutaneous procedure allowed less soft tissue insult around the fracture site, a short hospital stay, a fast return to the preoperative level of mobility and fracture union.

The use of bone-graft substitutes in large bone defects: any specific needs?

INTRODUCTION

The gold standard for restoring bone defects is still considered to be autologous bone grafting. However, clinical benefits are not guaranteed and donor-site complications and morbidity is not infrequent. Research is on-going for the development of alternative bone substitutes of both biological and synthetic origin. The purpose of this study was to evaluate the type of materials used and their efficacy for the treatment of large bone defects in traumatology and orthopaedic surgery.

MATERIALS AND METHOD

A literature review was carried out of Embase and PubMed databases. Inclusion criteria were articles in English language focusing on the use of bone substitutes in trauma and orthopaedic surgery for the treatment of bone defects and included details on the structural, biological or biomechanical properties of the pure product. Furthermore, based on two clinical challenges, fracture non-union and impaction grafting we elaborated on the use of polytherapy for large bone defects as guided by the diamond concept.

RESULTS

All the products indicated in this manuscript possess osteoconductive activities but have different resorption times and biomechanical properties. Bone graft substitute materials are used for a wide range of clinical applications even when the level of clinical evidence is low. The size and location of the defect and the local biological and mechanical environment as well as the biomechanical characteristics of the material determine the type of device that can be implanted in a bone defect.

CONCLUSION

Proper assessment of the biological and mechanical environment and accurate patient selection are necessary to judge the extent of therapy the injury warrants. A sound understanding of various aspects of biomaterial properties and their relation and influence towards bone healing is of utmost importance. We suggest the application of polytherapy for the treatment of large bone defects and advocate the use of the diamond concept as a guideline.

Skeletal tissue regeneration: current approaches, challenges, and novel reconstructive strategies for an aging population

Loss of skeletal tissue as a consequence of trauma, injury, or disease is a significant cause of morbidity with often wide-ranging socioeconomic impacts. Current approaches to replace or restore significant quantities of lost bone come with substantial limitations and inherent disadvantages that may in themselves cause further disability. In addition, the spontaneous repair capacity of articular cartilage is limited; thus, investigation into new cartilage replacement and regeneration techniques are warranted. Along with the challenges of an increasingly aging demographic, changing clinical scenarios and rising functional expectations provide the imperative for new, more reliable skeletal regeneration strategies. The science of tissue engineering has expanded dramatically in recent years, notably in orthopedic applications, and it is clear that new approaches for de novo skeletal tissue formation offer exciting opportunities to improve the quality of life for many, particularly in the face of increasing patient expectations. However, significant scientific, financial, industrial, and regulatory challenges should be overcome before the successful development of an emergent tissue engineering strategy can be realized. We outline current practice for replacement of lost skeletal tissue and the innovative approaches in tissue regeneration that have so far been translated to clinical use, along with a discussion of the significant hurdles that are presented in the process of translating research strategies to the clinic.

Treatment of long bone non-unions with polytherapy: indications and clinical results

The incidence of long bone non-unions has been estimated to range between 5 and 10%. Autologous bone graft usually harvested from the iliac crest continues to be the gold standard for biological enhancement of atrophic non-unions. However, its use has been hampered by minor and major donor site complications. Moreover despite possessing the properties of osteogenecity, osteoconductivity and some osteoinductivity the overall results of treatment have not been consistent with disappointing success rates at times. The concept of polytherapy for the treatment of non-unions, namely the simultaneous application of the three fundamental elements of the diamond concept, osteoprogenitor cells, growth factor and osteoconductive scaffold, appears to be an attractive alternative but more studies are desirable to validate this strategy.

Polytherapy in Bone Regeneration: Clinical Applications and Preliminary Considerations

Polytherapy, namely the simultaneous application of three fundamental elements necessary for bone regeneration (growth factors, osteogenic cells and osteocnductive scaffolds) seems to lead to a very high success rate in the treatment of complex non-union (NU) cases and critical bone defects. NU are reported in 5–10% of long bone fractures. The use of autologous bone grafts has been long-considered the gold standard for the treatment of these cases. However the harvesting procedure from the iliac crest increases surgery time and presents some donor site complications which may be elevated. In recent years, surgeons have some alternatives to autologous grafting such as: application of organic or synthetic bone substitute, application of mesenchymal stromal cells (MSC) or growth factors (GF). In the literature there are many studies available about their application in monotherapy, but unfortunately the healing rate doesn't exceed 90%. Polytherapy seems to be a logical option to improve the healing rate, nevertheless, there are not still extensive studies that validate this strategy and moreover, some questions are not resolved.

Treatment of femoral diaphyseal non-unions: our experience

Despite the continuous advances of surgical solutions, still 1-7% of fractures develop non-unions. The delays in fracture healing increase the period of incapacity of the patient with major consequences, on the psychological and functional recovery, but also on the direct and indirect health-related costs. In particular, femoral diaphyseal non-unions are often characterised by a challenging and long-lasting period of healing. The clinician treating these complex cases has to consider amongst other parameters, the condition of the soft tissue envelope, the adequacy of any pre-existing fixation, the alignment and length of the affected limb, the potential presence of an infection, as well as the general condition of the patient. Open reduction and plate fixation of femoral diaphyseal non-unions offers a valid alternative of stabilisation and if applied to carefully selected cases, can give optimal results.

Arachidonic acid, eicosanoids, and fracture repair

Not all fractures heal well or rapidly in the adult skeleton, and basic scientists and clinicians continue to search for ways to make fractures heal more predictably. It is a fundamental tenet of orthopaedics that skeletal injury is followed by inflammation and that this inflammatory response is the first stage in a sequence of events that culminate in skeletal repair. Modulating this response can affect the inflammatory stage and in turn subsequent stages that are required for healing. Literally dozens of studies in animals dating back to the 1970s have investigated the effects of commonly used anti-inflammatory medications on prostaglandin synthesis and fracture repair with strikingly uniform results. More recently, investigators have begun examining other means of modulating the early inflammatory stages after fracture in an effort to enhance fracture healing. This article reviews recent investigations into the potential role of leukotrienes as negative regulators of fracture healing and potential pharmacologic use of medications that block this effect.

Stimulation of osteogenic differentiation in human osteoprogenitor cells by pulsed electromagnetic fields: an in vitro study

BACKGROUND

Although pulsed electromagnetic field (PEMF) stimulation may be clinically beneficial during fracture healing and for a wide range of bone disorders, there is still debate on its working mechanism. Mesenchymal stem cells are likely mediators facilitating the observed clinical effects of PEMF. Here, we performed in vitro experiments to investigate the effect of PEMF stimulation on human bone marrow-derived stromal cell (BMSC) metabolism and, specifically, whether PEMF can stimulate their osteogenic differentiation.

METHODS

BMSCs derived from four different donors were cultured in osteogenic medium, with the PEMF treated group being continuously exposed to a 15 Hz, 1 Gauss EM field, consisting of 5-millisecond bursts with 5-microsecond pulses. On culture day 1, 5, 9, and 14, cells were collected for biochemical analysis (DNA amount, alkaline phosphatase activity, calcium deposition), expression of various osteoblast-relevant genes and activation of extracellular signal-regulated kinase (ERK) signaling. Differences between treated and control groups were analyzed using the Wilcoxon signed rank test, and considered significant when p < 0.05.

RESULTS

Biochemical analysis revealed significant, differentiation stage-dependent, PEMF-induced differences: PEMF increased mineralization at day 9 and 14, without altering alkaline phosphatase activity. Cell proliferation, as measured by DNA amounts, was not affected by PEMF until day 14. Here, DNA content stagnated in PEMF treated group, resulting in less DNA compared to control.Quantitative RT-PCR revealed that during early culture, up to day 9, PEMF treatment increased mRNA levels of bone morphogenetic protein 2, transforming growth factor-beta 1, osteoprotegerin, matrix metalloproteinase-1 and -3, osteocalcin, and bone sialoprotein. In contrast, receptor activator of NF-κB ligand expression was primarily stimulated on day 14. ERK1/2 phosphorylation was not affected by PEMF stimulation.

CONCLUSIONS

PEMF exposure of differentiating human BMSCs enhanced mineralization and seemed to induce differentiation at the expense of proliferation. The osteogenic stimulus of PEMF was confirmed by the up-regulation of several osteogenic marker genes in the PEMF treated group, which preceded the deposition of mineral itself. These findings indicate that PEMF can directly stimulate osteoprogenitor cells towards osteogenic differentiation. This supports the theory that PEMF treatment may recruit these cells to facilitate an osteogenic response in vivo.

Efficacy of minimally invasive techniques for enhancement of fracture healing: evidence today

The successful treatment of nonunions represents a major challenge for orthopaedic surgeons. Lately, ongoing advances made in the field of molecular medicine and molecular biology have increased our understanding of the pathways and involvement of mediators surrounding the bone healing process. As a result, the surgeon's armamentarium has been increased in terms of options for intervention. This article aims to provide an overview of minimally invasive techniques applicable in the treatment of nonunions of fractures.

Technical tricks when using the reamer irrigator aspirator technique for autologous bone graft harvesting

This report describes technical tricks for using the reamer irrigator aspirator to harvest autologous bone graft from the femur. This device is a focus of interest in orthopaedics because it can be used to harvest bone graft from the femoral canal and medial condyle in voluminous quantities. Moreover, according to some authors, the osteogenic potential of this graft is at least as effective as that of autogenous bone obtained from the iliac crest. The reamer irrigator aspirator device has substantially different design characteristics and technicalities compared with those of a standard reamer. First, a guidewire must be redirected into multiple areas, including the center of the distal femur and into both condyles, to harvest ample bone graft. This is accomplished by prebending the guidewire in a stronger fashion than required for regular reaming in the case of femoral nailing procedures. This bend can increase the risk for eccentric reaming as well as lodging of the suctioning device within the femoral canal. Second, the front and lateral drilling surfaces of this device are very sharp and further cleaned and maintained sharp by the irrigation process to permit the surgeon to obtain significant volumes of graft with a single passage of this device. At the same time, however, this sharp front-end cutting design can increase the risk of iatrogenic fracture if reaming is performed without caution. Third, a powerful suctioning device is connected to the reamer such that the blood loss that can occur during continuous reaming, irrigation, and aspiration must be considered with this technique. We hereby discuss these potential dangers and describe the correct use of this device with technical tricks to minimize the risk of unexpected intraoperative events.

The synergistic effect of autograft and BMP-7 in the treatment of atrophic nonunions

Combining autologous bone graft and recombinant human bone morphogenetic protein-7 (BMP-7) to treat long-bone fracture aseptic atrophic nonunions theoretically could promote bone healing at higher rates than each of these grafting agents separately. We retrospectively reviewed prospectively collected data on patient general characteristics, clinical outcomes, and complications over 3 years to determine the healing rates and the incidence of complications and adverse events of this "graft expansion rationale." There were 45 patients (32 male) with a median age of 43 years (range, 19-76 years). Minimum followup was 12 months (mean, 24.5 months; range, 12-65 months). There were seven humeral, 19 femoral, and 19 tibial nonunions. The median number of prior operations was two (range, 1-7). All fractures united. Clinical and radiographic union occurred within a median of 5 months (range, 3-14 months) and 6 months (range, 4-16 months), respectively. Thirty-nine (87%) patients returned to their preinjury occupation at a mean of 4.2 months (range, 3-6 months). The median visual analog scale pain score was 0.9 (range, 0-2.8; maximum 10), and the median functional score was 86 (range, 67-95; maximum 100) at the final followup. BMP-7 as a bone-stimulating agent combined with conventional autograft resulted in a nonunion healing rate of 100% in these 45 patients.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Application of bone morphogenetic proteins to femoral non-unions: a 4-year multicentre experience

Fracture non-unions often complicate orthopaedic trauma. BMPs (bone morphogenetic proteins) are currently considered the most appealing osteoinductive agents. Applications of BMP-7 since January 2004 were prospectively recorded in a multicentre registry of aseptic femoral non-unions. The study included 30 patients who had undergone a median of 1 revision operation before BMP-7 application and who were followed up for a median 24 months. In 23/30 cases the application of BMP-7 was combined with revision of the fixation, and in 12 it was combined also with autograft. Non-union healing was verified in 26/30 cases in a median period of 6 months. No adverse events were associated with BMP-7 application. Our case series supports the safety and efficacy of BMP-7 in femoral non-unions. Multicentre networks and systematic, long-term follow-up of patients may improve understanding of this promising osteoinductive bone substitute.