Vascularized bone grafts for the management of skeletal defects in orthopaedic trauma and reconstructive surgery

Bone Regeneration Facilitated by Autologous Bioscaffold Material: Liquid Phase of Concentrated Growth Factor with Dental Follicle Stem Cell Loading

The application of bioengineering techniques for achieving bone regeneration in the oral environment is an increasingly prominent field. However, the clinical use of synthetic materials carries certain risks. The liquid phase of concentrated growth factor (LPCGF), as a biologically derived material, exhibits superior biocompatibility. In this study, LPCGF was employed as a tissue engineering scaffold, hosting dental follicle cells (DFCs) to facilitate bone regeneration. Both in vivo and in vitro experimental results demonstrate that this platform significantly enhances the expression of osteogenic markers in DFCs, such as alkaline phosphatase (ALP), runt-related transcription factor 2 (Runx2), and type I collagen (Col1a1). Simultaneously, it reduces the expression of inflammation-related genes, particularly interleukin-6 (IL-6) and interleukin-8 (IL-8), thereby alleviating the negative impact of the inflammatory microenvironment on DFCs. Further investigation into potential mechanisms reveals that this process is regulated over time by the WNT pathway. Our research results demonstrate that LPCGF, with its favorable physical characteristics, holds great potential as a scaffold. It can effectively carry DFCs, thereby providing an optimal initial environment for bone regeneration. Furthermore, LPCGF endeavors to closely mimic the mechanisms of bone healing post-trauma to facilitate bone formation. This offers new perspectives and insights into bone regeneration engineering.

Clinical, Radiologic, and Functional Outcomes following Bone Grafting for Metacarpal Non-Unions: A Systematic Review

Objectives: Metacarpal non-unions are complex hand defects that can lead to severe hand impairment. Treatment may require the use of artificial or autologous bone grafts. This systematic review aims to describe the outcomes of bone grafting following metacarpal non-union in an attempt to establish an optimal therapeutic protocol for this complication. Methods: A systematic review was conducted in adherence with PRISMA guidelines. Data collection and analysis were performed in duplicate and confirmed by a third investigator. Our primary outcomes focused on radiological time to bone fusion and rates of non-union. Additionally, functional outcomes and complications were analyzed as means of central tendency. Results: Eighteen studies were included in the systematic review, accounting for a total of 47 patients. The average follow-up time was 12.4 months. Fourteen studies analyzed radiological outcomes, with atrophic non-union representing the most common type. The time to bone fusion, assessed radiologically, following bone graft was an average of 6.9 months (n = 14), with a 100% rate of union in 42 patients. Regarding patient-reported pain improvement, 76% of patients experienced pain relief. Moreover, all patients reported a complete subjective return to baseline hand function. Adverse events, limited to hematoma and seroma, were seen in three patients, representing a complication rate of 11.8% in the examined population. Conclusions: Metacarpal non-union can be treated successfully via vascularized and non-vascularized bone grafting. Based on the available evidence, bone grafts demonstrate favorable union rates, post-operative pain reduction, hand function recovery, earlier bone fusion times, and minimal complications in the context of metacarpal non-union management.

Vascularized Bone Grafting Versus the 2-Stage Masquelet Technique for Upper-Extremity Bone Reconstruction: A Meta-Analysis

PURPOSE

Vascularized bone grafting (VBG) has been described as the technique of choice for larger bone defects in bone reconstruction, yielding excellent results at the traditional threshold of 6 cm as described in the literature. However, we hypothesize that the 2-stage Masquelet technique provides equivalent union rates for upper-extremity bone defects regardless of size, while having no increase in the rate of patient complications.

METHODS

A systematic literature review was conducted using PubMed and Scopus for outcomes after VBG and the Masquelet technique for upper-extremity bone defects of the humerus, radius, ulna, metacarpal, or phalanx (carpal defects were excluded). A meta-analysis was performed to compare outcomes following VBG and the Masquelet technique at varying defect sizes.

RESULTS

There were 77 VBG (295 patients) and 25 Masquelet (119 patients) studies that met inclusion criteria. Patients undergoing the Masquelet technique had defect sizes ranging from 0-15 cm (average 4.5 cm), while patients undergoing VBG had defect sizes ranging from 0-24 cm (average 5.9 cm). The union rate for Masquelet patients was 94.1% with an average time to union of 5.8 months, compared to 94.9% and 4.4 months, respectively, for VBG patients. We did not identify a defect size threshold at which VBG demonstrated a significantly higher union rate. No statistically significant difference was found in union rates between techniques when using multivariable logistic regression analysis.

CONCLUSION

There was no statistically significant difference in union rates between VBG and the Masquelet technique in upper-extremity bone defects regardless of defect size. Surgeons may consider the Masquelet technique as an alternative to VBG in large bone defects of the upper extremity.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Self-healing hydrogels for bone defect repair

Severe bone defects can be caused by various factors, such as tumor resection, severe trauma, and infection. However, bone regeneration capacity is limited up to a critical-size defect, and further intervention is required. Currently, the most common clinical method to repair bone defects is bone grafting, where autografts are the "gold standard." However, the disadvantages of autografts, including inflammation, secondary trauma and chronic disease, limit their application. Bone tissue engineering (BTE) is an attractive strategy for repairing bone defects and has been widely researched. In particular, hydrogels with a three-dimensional network can be used as scaffolds for BTE owing to their hydrophilicity, biocompatibility, and large porosity. Self-healing hydrogels respond rapidly, autonomously, and repeatedly to induced damage and can maintain their original properties (i.e., mechanical properties, fluidity, and biocompatibility) following self-healing. This review focuses on self-healing hydrogels and their applications in bone defect repair. Moreover, we discussed the recent progress in this research field. Despite the significant existing research achievements, there are still challenges that need to be addressed to promote clinical research of self-healing hydrogels in bone defect repair and increase the market penetration.

Multifactorial Analysis of Treatment of Long-Bone Nonunion with Vascularized and Nonvascularized Bone Grafts

Introduction  The purpose of the study was to evaluate the results of treatment of the nonunion of long bones using nonvascularized iliac crest grafts (ICGs) or vascularized bone grafts (VBGs), such as medial femoral condyle corticoperiosteal flaps (MFCFs) and fibula flaps (FFs). Although some studies have examined the results of these techniques, there are no reports that compare these treatments and perform a multifactorial analysis. Methods  The study retrospectively examined 28 patients comprising 9 women and 19 men with an average age of 49.8 years (range: 16-72 years) who were treated for nonunion of long bones between April 2007 and November 2018. The patients were divided into two cohorts: group A had 17 patients treated with VBGs (9 patients treated with MFCF and 8 with FF), while group B had 11 patients treated with ICG. The following parameters were analyzed: radiographic patterns of nonunion, trauma energy, fracture exposure, associated fractures, previous surgeries, diabetes, smoking, age, and donor-site morbidity. Results  VBGs improved the healing rate (HR) by 9.42 times more than the nonvascularized grafts. Treatment with VBGs showed a 25% decrease in healing time. Diabetes increased the infection rate by 4.25 times. Upper limbs showed 70% lower infection rate. Smoking among VBG patients was associated with a 75% decrease in the HR, and diabetes was associated with an 80% decrease. Conclusion  This study reports the highest success rates in VBGs. The MFCFs seem to allow better clinical and radiological outcomes with less donor-site morbidity than FFs.

Development of Neovasculature in Axially Vascularized Calcium Phosphate Cement Scaffolds

Augmenting the vascular supply to generate new tissues, a crucial aspect in regenerative medicine, has been challenging. Recently, our group showed that calcium phosphate can induce the formation of a functional neo-angiosome without the need for microsurgical arterial anastomosis. This was a preclinical proof of concept for biomaterial-induced luminal sprouting of large-diameter vessels. In this study, we investigated if sprouting was a general response to surgical injury or placement of an inorganic construct around the vessel. Cylindrical biocement scaffolds of differing chemistries were placed around the femoral vein. A contrast agent was used to visualize vessel ingrowth into the scaffolds. Cell populations in the scaffold were mapped using immunohistochemistry. Calcium phosphate scaffolds induced 2.7-3 times greater volume of blood vessels than calcium sulphate or magnesium phosphate scaffolds. Macrophage and vSMC populations were identified that changed spatially and temporally within the scaffold during implantation. NLRP3 inflammasome activation peaked at weeks 2 and 4 and then declined; however, IL-1β expression was sustained over the course of the experiment. IL-8, a promoter of angiogenesis, was also detected, and together, these responses suggest a role of sterile inflammation. Unexpectedly, the effect was distinct from an injury response as a result of surgical placement and also was not simply a foreign body reaction as a result of placing a rigid bioceramic next to a vein, since, while the materials tested had similar microstructures, only the calcium phosphates tested elicited an angiogenic response. This finding then reveals a potential path towards a new strategy for creating better pro-regenerative biomaterials.

Supine harvest of vascularised scapular bone grafts-Anatomical study and clinical application

BACKGROUND

We report our findings from an anatomical study on harvest of a vascularized scapular bone graft from a supine position. A clinical case is presented to illustrate the operative approach.

METHODS

Twenty cadaveric hemibody specimens were dissected in the supine position. Outcomes of interest included the characterization of anatomical variants and measurements of pedicle length. Specific measurements included distance from the origin of the subscapular artery (at the axillary artery) to the branch point of the angular artery from the thoracodorsal artery or serratus branch and the length of the angular branch proper.

RESULTS

There are five reported anatomic variations regarding the origin of the angular branch of the thoracodorsal artery. In our cadaveric cohort only four known types were seen, and an entirely new variant was encountered. Six cadaveric dissections exhibited a type 3 configuration, six were type 1, four were type 2, three were type 4, and one was a previously unreported variant we termed a type 6, with multiple angular artery branches originating from the posterior branch of the thoracodorsal. The mean distance between the origin of the subscapular artery and the takeoff of the angular branch was 6.3 ± 2.0 cm. The mean length of the angular branch was 3.7 ± 1.4 cm.

CONCLUSIONS

Supine positioning for harvest of a vascularized bone graft obviates the need for an intraoperative position change and allows reconstruction of bone defects in the hand and upper extremity within a single surgical field.

Non-vascularized fibular autograft for resistant humeral diaphyseal nonunion: Retrospective case series

INTRODUCTION

There is a great surgical challenge when humeral diaphyseal fractures are initially open, complex, or associated with segmental bone loss. The challenge becomes even greater with previous multiple unsuccessful surgeries. The question of this study was: Does combining locked compression plating with non-vascularized fibular autograft in cases of resistant humeral diaphyseal nonunion yield reliable bony union and satisfactory functional outcome?

HYPOTHESIS

The use of non-vascularized fibular autograft in conjunction with locked compression plating will provide stable construct, enhance bony union and improve functional outcome in cases of resistant humeral diaphyseal nonunion.

MATERIALS AND METHODS

Thirty-three patients with resistant humeral diaphyseal nonunion who were surgically managed combining non-vascularized fibular autograft fixed with locked compression plating in the period from January 2011 to June 2017, were retrospectively studied. All patients were followed-up for a minimum of 24 months. The time to union, the postoperative disability of arm, shoulder and hand (DASH) score, in addition to the possible complications including infection or nonunion were reported and analyzed.

RESULTS

Twenty-nine patients have achieved union at the final follow-up with a mean time to radiological union of 7.5±2.6 months (range: 3-12). The mean postoperative DASH score was 7.7±8.9 (range: 0-38.8) which was significantly better than the preoperative value (p<0.001) and superior in the patients of aseptic nonunion (p=0.04). Eight patients showed complications in the form of infection (four), nonunion (two cases), transient radial nerve palsy (one case) and one case of septic nonunion that was managed by two-stage reconstruction using vascularized fibular autograft. There were comparable results in patients with either open or closed fractures. However, patients with septic nonunion experienced more significant complications (p=0.02).

DISCUSSION

The use of non-vascularized fibula autograft in cases of resistant humeral diaphyseal nonunion provides adequate fracture stability, quadrilateral screw purchase, enhances bony union in addition to promoting satisfactory functional outcome particularly in aseptic nonunion.

LEVEL OF EVIDENCE

IV; retrospective case series.

Outcomes of free vascularized fibular graft for post-traumatic osteonecrosis of the femoral head

INTRODUCTION

Osteonecrosis of the femoral head (ONFH) can occur after traumatic injuries of the hip. Surgical treatment with total hip arthroplasty (THA) may not produce lifelong viability in younger patients. Free vascularized fibular graft (FVFG) has become a reliable method to delay or even avoid THA in this patient population by aiming to correct loss of viable bone through vascularized autologous bone transfer. The purpose of this study was to evaluate the longevity and outcomes of FVFG for traumatic hip injuries resulting in ONFH.

METHODS

We performed a retrospective review of our institutional database of patients who had undergone FVFG from 1980-2006 for post-traumatic ONFH and had a minimum follow-up of 5 years. Data collected included demographics, pre-operative Urbaniak ONFH staging, Harris Hip scores (HHS), SF-12 scores, and conversion to THA.

RESULTS

Seventy-two hips in 68 patients met inclusion criteria. Mean follow-up was 11.6 years (range 5.1-33.2 years). Etiology included femoral neck fracture in 36 patients (61%), hip dislocation in 7 (12%), trauma without fracture or dislocation in 11 (19%), and femoral neck nonunion in 5 (8%). The most common stage at presentation was stage IV (48 patients). Graft survival at final follow-up (mean 10.9 years) was 64%, with mean time to conversion to THA of 8.4 years in those that did not survive (36%). There was no difference between THA conversion rates in hips with pre-collapse (Stage I and II) versus impending or post-collapse (Stage III or IV) lesions (p = 0.227). In hips with surviving grafts at final follow-up, mean HHS improved from 56.7 to 77.3 (SD 24.57, range 69-93), a mean improvement of 20.6 (p < 0.001).

CONCLUSIONS

Our study reveals improvement in HHS in surviving FVFG and an acceptable overall THA conversion rate at mid to long term follow-up in Urbaniak stage I through IV hips. FVFG remains a viable option for treatment in younger patients with pre- and post-collapse (stage IV) ONFH lesions secondary to hip trauma.

Reconstruction of traumatic tubular bone defects using vascularized fibular graft

Large segmental bone defects due to major trauma constitute a major challenge for the orthopaedic surgeon, especially when combined with poor or lost soft tissue envelope. Vascularized fibular transfer is considered as the gold standard for the reconstruction of such defects of the extremities due to its predictable vascular pedicle, long cylindrical shape, and tendency to hypertrophy, and resistance to infection. Vascularized bone grafts remain viable throughout the healing period and are capable of inducing rapid graft union without prolonged creeping substitution, osteogenesis and hypertrophy at the reconstruction site, and fight with infection. The fibular graft can be transferred solely, or as a composite flap including muscle, subcutaneous tissue, skin and even a nerve segment in order to reconstruct both bone and soft tissue components of the injury at single stage operation. Such a reconstruction can even be performed in the presence of local infection, since vascularized bone and adjacent soft tissue components enhances the blood flow at the traumatized zone, allowing for the delivery of antibiotics and immune components to the infection site. In an effort to preserve growth potential in pediatric patients; the fibular head and proximal growth plate can be included to the graft. This practice also enables to reconstruct the articular ends of various bones, including distal radius and proximal ulna. Apart from defect reconstruction, vascularized fibular grafts also proved to be a reliable in treating atrophic nonunions, reconstruction of osteomyelitic bone segments. These grafts are superior to alternative reconstructive techniques, as bone grafts with intrinsic blood supply lead to higher success rates in reconstruction and accelerate the repair process at the injury site in cases where blood supply to the injury zone is defective, poor soft tissue envelope, and local infection at the trauma zone.

miRNA induced co-differentiation and cross-talk of adipose tissue-derived progenitor cells for 3D heterotypic pre-vascularized bone formation

Engineered bone grafts require a vascular network to supply cells with oxygen, nutrients and remove waste. Using heterotypic mature cells to create these graftsin vivohas resulted in limited cell density, ectopic tissue formation and disorganized tissue. Despite evidence that progenitor cell aggregates, such as progenitor spheroids, are a potential candidate for fabrication of native-like pre-vascularized bone tissue, the factors dictating progenitor co-differentiation to create heterotypic pre-vascularized bone tissue remains poorly understood. In this study, we examined a three-dimensional heterotypic pre-vascularized bone tissue model, using osteogenic and endotheliogenic progenitor spheroids induced by miR-148b and miR-210 mimic transfection, respectively. Spheroids made of transfected cells were assembled into heterotypic structures to determine the impact on co-differentiation as a function of micro-RNA (miRNA) mimic treatment group and induction time. Our results demonstrated that miRNAs supported the differentiation in heterotypic structures, and that developing heterotypic structures is determined in part by progenitor maturity, as confirmed by gene and protein markers of osteogenic and endotheliogenic differentiation and the mineralization assay. As a proof of concept, miRNA-transfected spheroids were also bioprinted using aspiration-assisted bioprinting and organized into hollow structures to mimic the Haversian canal. Overall, the presented approach could be useful in fabrication of vascularized bone tissue using spheroids as building blocks.

Combining a Vascular Bundle and 3D Printed Scaffold with BMP-2 Improves Bone Repair and Angiogenesis

Vascularization is currently considered the biggest challenge in bone tissue engineering due to necrosis in the center of large scaffolds. We established a new expendable vascular bundle model to vascularize a three-dimensional printed channeled scaffold with and without bone morphogenetic protein-2 (BMP-2) for improved healing of large segmental bone defects. Bone formation and angiogenesis in an 8 mm critical-sized bone defect in the rat femur were significantly promoted by inserting a bundle consisting of the superficial epigastric artery and vein into the central channel of a large porous polycaprolactone scaffold. Vessels were observed sprouting from the vascular bundle inserted in the central tunnel. Although the regenerated bone volume in the group receiving the scaffold and vascular bundle was similar to that of the healthy femur, the rate of union of the group was not satisfactory (25% at 8 weeks). BMP-2 delivery was found to promote not only bone formation but also angiogenesis in the critical-sized bone defects. Both insertion of the vascular bundle alone and BMP-2 loading alone induced comparable levels of angiogenesis and when used in combination, significantly greater vascular volume was observed. These findings suggest a promising new modality of treatment in large bone defects. Level of Evidence: Therapeutic level I.

Vascularized Bone Grafts in Spinal Reconstruction: An Overview of Nomenclature and Indications

Several vascularized bone grafts (VBGs) have been introduced for reconstruction and augmenting fusion of the spine. The expanding use of VBGs in the field of spinoplastic reconstruction, however, has highlighted the need to clarify the nomenclature for bony reconstruction as well as establish the position of VBGs on the bony reconstructive algorithm. In the current literature, the terms "flap" and "graft" are often applied inconsistently when describing vascularized bone transfer. Such inconsistency creates barriers in communication between physicians, confusion in interpreting the existing studies, and difficulty in comparing surgical techniques. VBGs are defined as bone segments transferred on their corresponding muscular attachments without a named major feeding vessel. The bone is directly vascularized by the muscle attachments and unnamed periosteal feeding vessels. VBGs are best positioned as a separate entity in the bony reconstruction algorithm between nonvascularized bone grafts (N-VBGs) and bone flaps. VBGs offer numerous advantages as they supply fully vascularized bone to the recipient site without the microsurgical techniques or pedicle dissection required for raising bone flaps. Multiple VBGs have been introduced in recent years to optimize these benefits for spinoplastic reconstruction.

A novel biocomposite scaffold with antibacterial potential and the ability to promote bone repair

Clinical treatment of bone defects caused by trauma, tumor resection and other bone diseases, especially bone defects that can lead to infection, remains a major challenge. Currently, autologous bone implantation is the gold standard for treatment of bone defects, but it is limited by secondary trauma and insufficient autologous material. Moreover, postoperative infection is an important factor affecting bone healing.AcN-RADARADARADARADA-CONH2 (RADA) is a new type of self-assembling peptide(SAP) composed of Arg,Ala,Asp and other amino acids was designed and prepared. The "RADA" self-assembling peptide hydrogels has excellent biological activity and it's completely biodegradable and non-toxic.It is also have been confirmed to promote cell proliferation, wound healing, tissue repair, and drug delivery. To promote bone regeneration and simultaneously prevent bacterial infection, we designed biocomposite scaffolds comprising RADA and calcium phosphate cement (CPC), termed RADA-CPC. The morphological features of the scaffold were characterized by scanning electron microscopy (SEM). In vitro studies demonstrated that RADA-CPC enhances osteoblast proliferation, differentiation and mineralization. In addition, the scaffold was used as a drug delivery system to treat postoperative infections by sustained release of ciprofloxacin (CIP). The RADA-CPC scaffold may have potential application prospects in orthopedics field because of its role in promoting bone repair and as a sustained-release drug carrier to prevent infections.

Graphene-Based Biomaterials for Bone Regenerative Engineering: A Comprehensive Review of the Field and Considerations Regarding Biocompatibility and Biodegradation

Graphene and its derivatives have continued to garner worldwide interest due to their unique characteristics. Having expanded into biomedical applications, there have been efforts to employ their exceptional properties for the regeneration of different tissues, particularly bone. This article presents a comprehensive review on the usage of graphene-based materials for bone regenerative engineering. The graphene family of materials (GFMs) are used either alone or in combination with other biomaterials in the form of fillers in composites, coatings for both scaffolds and implants, or vehicles for the delivery of various signaling and therapeutic agents. The applications of the GFMs in each of these diverse areas are discussed and emphasis is placed on the characteristics of the GFMs that have implications in this regard. In tandem and of importance, this article evaluates the safety and biocompatibility of the GFMs and carefully elucidates how various factors influence the biocompatibility and biodegradability of this new class of nanomaterials. In conclusion, the challenges and opportunities regarding the use of the GFMs in regenerative engineering applications are discussed, and future perspectives for the developments in this field are proposed.

Treatment of acute bone defects in severe lower limb Trauma

PURPOSE

To present our experience in the management of acute large bone defects treated with the use of vascularized fibular grafts supported by Ilizarov circular external frames.

PATIENTS AND METHODS

During a period of 6 years (from 2007 to 2013) 8 patients with acute large bone defects (IVB according to Winquist modified classification) were treated at our institution with early bone reconstruction by means of microvascular fibular grafts. All patients were evaluated by the use of the following parameters: X-ray consolidation, discharge time, duration of treatment, malalignment of the lower limb and final leg length discrepancy, knee and ankle mobility (ROM), pain (VAS), number of eventual additive treatments (plastic surgery, etc.), walking independence (use of crutches), possibility to get back to work, subjective evaluation about the treatment and the result (SF-36, personal feelings about circular external fixator dressing) RESULTS: The mean treatment time, often connected to the mean consolidation time, was 61 weeks and the mean number of operations was 7.6. Six of the eight patients got back to their previous daily activities and work, without any further issues.

DISCUSSION

based on our experience, Ilizarov and fibular vascular grafts are not alternatives, as often reported in literature. Their combined use, especially in lesions as those classified as Winquist IV B, can represent an effective tool in the surgeon's hands to solve the most difficult cases of acute bone loss caused by severe high-energy traumas.

Microsurgical reconstruction of complex oromandibular defects: An update

Free flaps are the gold standard for reconstruction of the mandible, tongue and floor of the mouth. Free fibular flaps are the most preferable option for reconstruction of complex mandibular defects, as well as for tongue and mouth floor reconstruction, since they are harvested easily, present excellent sculptability and good functional outcomes. Alternative options for bone reconstruction include the fibular and iliac crest free flap, and for soft tissue reconstruction include the anterolateral thigh, the radial forearm free flap, and the nasolabial island flap. The principles of the surgical approach include resection of the mandibular segment, intraoperative evaluation of the defect, and various surgical manipulations of the flap on site to reconstruct the defect. Advances in computerized preoperative planning have allowed virtual simulation of the defect and fabrication of an individualized stereolithic mandibular model. This short review discusses the current trends of bone and soft tissue flaps for complex oromandibular reconstructions aiming to present a comprehensive review that the readers would find interesting and informative.

One-Barrel Microsurgical Fibula Flap for Reconstruction of Large Defects of the Femur

Various methods for reconstructing large femur bone defects after tumor resection have been introduced. In this study, we reviewed the clinical outcomes of using a 1-barrel free vascularized fibular graft (FVFG) protected by a lateral locking plate for large femoral defects not involving the knee joint.Between August 2007 and August 2013, we treated 7 patients with large femoral bone defects after tumor resection. The mean age of the patients was 19 years (range, 12-36 years), and 3 were women. All defects were free of infection before the procedure. Femoral bone defects were reconstructed using a 1-barrel FVFG protected by a lateral locking plate. The mean bone defect size was 10.5 cm (range, 6-16 cm). We reviewed clinical outcomes at the last follow-up.All patients survived beyond the last follow-up; the mean follow-up period was 54 months (range, 26-100 months). Two patients sustained stress fractures of the FVFG, but the lateral locking plate protected the fractured graft until in situ bone healing obtained. Mean time to bone union of both host-graft junctions was 24 months (range, 18-31 months). The mean Musculoskeletal Tumor Society score (%) was 85.8% (range, 80-95%).A 1-barrel FVFG protected by a lateral locking plate maintained a stable graft-host bone construct, successfully leading to bone healing, even in cases of stress fractures of the graft, and appears to be a good option for large femur bone defects.

The role of the periosteal sleeve in the reconstruction of bone defects using a non-vascularised fibula graft in the pediatric population

BACKGROUND

Following resection of large benign bone tumors surgeons are confronted with bone defects severely affecting the stability of a limb. To restore the mechanical continuity of the bone different treatment methods using bone grafts have been described. In pediatric patients the thick periosteal sleeve is thought to contribute to bone formation.

HYPOTHESIS

An intact periosteal sleeve is crucial in bone remodelling around a non-vascularised fibular graft used to bridge large bone defects.

METHODS

We present a treatment technique applied in 6 cases comprising of subperiosteal tumor resection at the diaphyseal or metaphyseal level of long bones followed by defect bridging with a non-vascularised fibula graft inserted into the periosteal sleeve of the resection zone. Elastic intramedullary nails or plates were used for stabilisation.

RESULTS

Due to the intact periosteum at the resection site bone integration occurred quickly and full remodelling was seen in all but one case. Tumor location in this case was at the metaphyseal level resulting in tumor resection at the growth plate. Although bone healing at the distal resection site was seen after a few weeks proximal consolidation was only partial. Full reconstitution of the fibula in the remaining periosteal sleeve was seen in 5 cases, partial reconstitution in 1 case.

DISCUSSION

In the pediatric patient, the described technique is an effective and reliable treatment method for large benign bone tumors requiring resection. However, great diameter discrepancy of the donor and recipient site and a thin periosteum can be a limiting factor for its application.

LEVEL OF EVIDENCE

Level IV clinical study.

Treatment of critical-sized bone defects: clinical and tissue engineering perspectives

Critical-sized bone defects are defined as those that will not heal spontaneously within a patient's lifetime. Current treatment options include vascularized bone grafts, distraction osteogenesis, and the induced membrane technique. The induced membrane technique is an increasingly utilized method with favorable results including high rates of union. Tissue engineering holds promise in the treatment of large bone defects due to advancement of stem cell biology, novel biomaterials, and 3D bioprinting. In this review, we provide an overview of the current operative treatment strategies of critical-sized bone defects as well as the current state of tissue engineering for such defects.

Bone-strengthening pill (BSP) promotes bone cell and chondrocyte repair, and the clinical and experimental study of BSP in the treatment of osteonecrosis of the femoral head

About 1 in 3 people suffer from bone and joint disease, which is a disease of bone and cartilage cells. Osteonecrosis of the femoral head (ONFH) is a typical example of bone and joint disease involving bone cell necrosis. Osteonecrosis of the femoral head leads to the occurrence of premature osteoarthritis of the hip and collapse of the cartilage cells, and there is currently no effective drug treatment available. In order to study the effects of "bone-strengthening pill" (BSP) on the repair of bone and cartilage cells, we investigated the potential effects of the herbal mixture BSP in an animal model of avascular necrosis of the femoral head and in patients. Results showed that 90% of rats injected with prednisone developed ONFH, whereas BSP administration prevented ONFH development in 70% of prednisone-injected rats. We evaluated the constituents of BSP by HPLC fingerprinting. We also evaluated the clinical efficacy of BSP in a double-blind, randomized, controlled trial of 300 patients with ONFH. The response rate was found to be higher in the treatment group than in the control group, with a response rate of 82% in the treatment group. Treatment with BSP also significantly reduced pain, improved hip function, reduced lameness, and improved pathology by X-ray and MRI analysis, compared with patients who did not receive BSP. These results suggest that BSP treatment inhibits and reverses necrosis of the femoral head bone cells and cartilage cells to repair the femoral head, promote the repair of bone and cartilage diseases.

3D printed scaffolds of calcium silicate-doped β-TCP synergize with co-cultured endothelial and stromal cells to promote vascularization and bone formation

Synthetic bone scaffolds have potential application in repairing large bone defects, however, inefficient vascularization after implantation remains the major issue of graft failure. Herein, porous β-tricalcium phosphate (β-TCP) scaffolds with calcium silicate (CS) were 3D printed, and pre-seeded with co-cultured human umbilical cord vein endothelial cells (HUVECs) and human bone marrow stromal cells (hBMSCs) to construct tissue engineering scaffolds with accelerated vascularization and better bone formation. Results showed that in vitro β-TCP scaffolds doped with 5% CS (5%CS/β-TCP) were biocompatible, and stimulated angiogenesis and osteogenesis. The results also showed that 5%CS/β-TCP scaffolds not only stimulated co-cultured cells angiogenesis on Matrigel, but also stimulated co-cultured cells to form microcapillary-like structures on scaffolds, and promoted migration of BMSCs by stimulating co-cultured cells to secrete PDGF-BB and CXCL12 into the surrounding environment. Moreover, 5%CS/β-TCP scaffolds enhanced vascularization and osteoinduction in comparison with β-TCP, and synergized with co-cultured cells to further increase early vessel formation, which was accompanied by earlier and better ectopic bone formation when implanted subcutaneously in nude mice. Thus, our findings suggest that porous 5%CS/β-TCP scaffolds seeded with co-cultured cells provide new strategy for accelerating tissue engineering scaffolds vascularization and osteogenesis, and show potential as treatment for large bone defects.

Outcomes and Complications of Reconstruction with Use of Free Vascularized Fibular Graft for Spinal and Pelvic Defects Following Resection of a Malignant Tumor

BACKGROUND

Following resection of malignant tumors of the spine and pelvis, reconstructive surgeons often face large structural defects. Unlike reconstruction in the extremities, wherein a free vascularized fibular graft (FVFG) is a highly utilized option for segmental osseous reconstruction, there are limited data on the use of an FVFG in the spine and pelvis. The aim of this study was to review our institution's experience with reconstruction with use of an FVFG following oncological resection in the spine and pelvis.

METHODS

We reviewed 24 cases involving the use of an FVFG in reconstruction of segmental osseous defects of the spine and pelvis following oncological resection from 2000 to 2015. The cohort consisted of 12 male and 12 female patients with a mean age of 37 years and a mean follow-up of 5 years. Fifty-four percent of the reconstructions were spinopelvic or sacropelvic.

RESULTS

The overall 2, 5, and 10-year rate of survival was 76%, 55%, and 37%, respectively. With regard to disease-free survival, the overall 2, 5, and 10-year rate was 81%, 72%, and 48%. The overall rate of union was 86%, with a mean time to union of 7 months. Complications were common, with 83% of the patients sustaining at least 1 postoperative complication. Following the procedure, the mean Musculoskeletal Tumor Society rating was 53%.

CONCLUSIONS

An FVFG provides a durable means of reconstruction of osseous defects in the spine and pelvis. Although patient function was acceptable following these large reconstructions, the rate of postoperative complications was high.

LEVEL OF EVIDENCE

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

Warning About the Use of Critical-Size Defects for the Translational Study of Bone Repair: Analysis of a Sheep Tibial Model

The repair of large long bone defects requires complex surgical procedures as the bone loss cannot simply be replaced by autologous grafts due to an insufficient bone stock of the human body. Tissue engineering strategies and the use of Advanced Therapy Medicinal Products (ATMPs) for these reconstructions remain a considerable challenge, in particular since robust outcomes in well-defined large animal models are lacking. To be suitable as a model for treatment of human sized bone defects, we developed a large animal model in both skeletally immature and mature sheep and made close observations on the spontaneous healing of defects. We warn for the spontaneous repair of large defects in immature animals, which can mask the (in)effectiveness of ATMP therapies, and propose the use of large 4.5 cm defects that are pretreated with a polymethylmethacrylate (PMMA) spacer in skeletally mature animals.

Vascularized versus Nonvascularized Bone Grafts: What Is the Evidence?

BACKGROUND

There is a general perception in practice that a vascular supply should be used when large pieces of bone graft are used, particularly those greater than 6 cm in length for long-bone and large-joint reconstructions. However, the scientific source of this recommendation is not clear.

QUESTIONS/PURPOSES

We wished to perform a systematic review to (1) investigate the origin of evidence for this 6-cm rule, and (2) to identify whether there is strong evidence to support the importance of vascularization for longer grafts and/or the lack of vascularization for shorter grafts.

METHODS

Two systematic reviews were performed using SCOPUS and Medline, one for each research question. For the first research purpose, a review of studies from 1975 to 1983 matching article title ("bone" and "graft") revealed 725 articles, none of which compared graft length. To address the second purpose, a review of articles before 2014 that matched "bone graft" AND ("vascularised" OR "vascularized") AND ("non-vascularised" OR "non-vascularized") revealed 633 articles, four met prespecified inclusion criteria and were evaluated qualitatively. MINORS ratings ranged from 16 to 18 of 24, and National Health and Medical Research Council [NHMRC] Evidence Hierarchy ratings ranged from III-2 (comparative studies without concurrent controls) to III-3 (comparative studies with concurrent controls).

RESULTS

No evidence was found that clarified grafts longer than 6 cm should be vascularized. The first reference to the 6-cm rule cites articles that do not provide strong evidence for the rule. Of the four articles found in the second systematic review, none examined osseous union of vascularized and nonvascularized grafts with respect to length. One study (III-3, MINORS 18 of 24) of fibular grafts to various limb defects found that vascularization made no difference to union rate or time to union. Vascularized grafts were more likely to require surgical revision for wound breakdown, nonunion, graft fracture, or mechanical problems (hazard ratio [HR], 5.97, p = 0.008) and grafts smaller than 10 cm had fewer complications requiring revision (HR, 0.88; p = 0.03). Three studies (III-2 to III-3, MINORS 16 to 18 of 24) that examined fibular grafts to the femoral head found that vascularized grafts had superior Harris hip and pain scores. Two of the three articles showed that vascularization was associated with superior radiologic measures of collapse progression.

CONCLUSIONS

No compelling evidence was found to illuminate the origin of the 6-cm rule for vascularized bone grafts, or that such a rule is based on published research. The evidence we found for grafts to long-bone defects suggested that vascularization might increase the risk of complications that require a surgical revision without increasing union rates or time to union. For large joints, vascularization may result in better functional scores and pain scores, while the evidence that they improve radiologic measures of progression is mixed. There were no studies of long-bone or large-joint reconstructions that examined the role of length with respect to osseous union. We suggest that future studies should present data for graft lengths quantitatively and with individual data points rather than categories of length ranges.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Functionalized d-form self-assembling peptide hydrogels for bone regeneration

Bone defects are very common in orthopedics, and there is great need to develop suitable bone grafts for transplantation in vivo. However, current bone grafts still encounter some limitations, including limited availability, immune rejection, poor osteoinduction and osteoconduction, poor biocompatibility and degradation properties, etc. Self-assembling peptide nanofiber scaffolds have emerged as an important substrate for cell culture and bone regeneration. We report on the structural features (eg, Congo red staining, circular dichroism spectroscopy, transmission electron microscopy, and rheometry assays) and osteogenic ability of d-RADA16-RGD peptide hydrogels (with or without basic fibroblast growth factor) due to the better stability of peptide bonds formed by these peptides compared with those formed by l-form peptides, and use them to fill the femoral condyle defect of Sprague Dawley rat model. The bone morphology change, two-dimensional reconstructions using microcomputed tomography, quantification of the microcomputed tomography analyses as well as histological analyses have demonstrated that RGD-modified d-form peptide scaffolds are able to enhance extensive bone regeneration.

Tissue engineering strategies for promoting vascularized bone regeneration

This review focuses on current tissue engineering strategies for promoting vascularized bone regeneration. We review the role of angiogenic growth factors in promoting vascularized bone regeneration and discuss the different therapeutic strategies for controlled/sustained growth factor delivery. Next, we address the therapeutic uses of stem cells in vascularized bone regeneration. Specifically, this review addresses the concept of co-culture using osteogenic and vasculogenic stem cells, and how adipose derived stem cells compare to bone marrow derived mesenchymal stem cells in the promotion of angiogenesis. We conclude this review with a discussion of a novel approach to bone regeneration through a cartilage intermediate, and discuss why it has the potential to be more effective than traditional bone grafting methods.

Microstructure Evolution and Mechanical Properties Improvement in Liquid-Phase-Sintered Hydroxyapatite by Laser Sintering

CaO-Al₂O₃-SiO₂ (CAS) as a liquid phase was introduced into hydroxyapatite (HAp) to prepare bone scaffolds. The effects of the CAS content (1, 2, 3, 4 and 5 wt%) on microstructure and mechanical properties of HAp ceramics were investigated. The optimal compression strength, fracture toughness and Vickers hardness reached 22.22 MPa, 1.68 MPa·m1/2 and 4.47 GPa when 3 wt% CAS was added, which were increased by 105%, 63% and 11% compared with those of HAp ceramics without CAS, respectively. The improvement of the mechanical properties was attributed to the improved densification, which was caused by the solid particle to rearrange during liquid phase sintering. Moreover, simulated body fluid (SBF) study indicated the HAp ceramics could maintain the mechanical properties and form a bone-like apatite layer when they were immersed in SBF. Cell culture was used to evaluate biocompatibility of the HAp ceramics. The results demonstrated MG-63 cells adhered and spread well.

Management of traumatic bone loss in the lower extremity

Segmental bone loss represents a difficult clinical entity for the treating orthopedic surgeon. This article discusses the various treatment modalities available for limb reconstruction, with a focus on the indications, potential complications, and the outcomes of available treatment options.

Free vascularised fibular grafts in orthopaedics

Bony defects caused by trauma, tumors, infection or congenital anomalies can present a significant surgical challenge. Free vascularised fibular bone grafts (FVFGs) have proven to be extremely effective in managing larger defects (longer than 6 cm) where other conventional grafts have failed. FVFGs also have a role in the treatment of avascular necrosis (AVN) of the femoral head, failed spinal fusions and complex arthrodeses. Due to the fact that they have their own blood supply, FVFGs are effective even in cases where there is poor vascularity at the recipient site, such as in infection and following radiotherapy. This article discusses the versatility of the FVFG and its successful application to a variety of different pathologies. It also covers the applied anatomy, indications, operative techniques, complications and donor-site morbidity. Though technically challenging and demanding, the FVFG is an extremely useful salvage option and can facilitate limb reconstruction in the most complex of cases.