Induced membrane for treatment of critical sized bone defect: a review of experimental and clinical experiences

The Masquelet induced membrane technique with PRP-FG-nHA/PA66 scaffold can heal a rat large femoral bone defect

BACKGROUND

Masquelet membrane induction technology is one of the treatment strategies for large bone defect (LBD). However, the angiogenesis ability of induced membrane decreases with time and autologous bone grafting is associated with donor site morbidity. This study investigates if the PRP-FG-nHA/PA66 scaffold can be used as a spacer instead of PMMA to improve the angiogenesis ability of induced membrane and reduce the amount of autologous bone graft.

METHODS

Platelet rich plasma (PRP) was prepared and PRP-FG-nHA/PA66 scaffold was synthesized and observed. The sustained release of VEGFA and porosity of the scaffold were analyzed. We established a femur LBD model in male SD rats. 55 rats were randomly divided into four groups depending on the spacer filled in the defect area. "Defect only" group (n = 10), "PMMA" group (n = 15), "PRP-nHA/PA66" group (n = 15) and "PRP-FG-nHA/PA66" group (n = 15 ). At 6 weeks, the spacers were removed and the defects were grafted. The induced membrane and bone were collected and stained. The bone formation was detected by micro-CT and the callus union was scored on a three point system.

RESULTS

The PRP-FG-nHA/PA66 scaffold was porosity and could maintain a high concentration of VEGFA after 30 days of preparation. The induced membrane in PRP-FG-nHA/PA66 group was thinner than PMMA, but the vessel density was higher.The weight of autogenous bone grafted in PRP-FG-nHA/PA66 group was significantly smaller than that of PMMA group. In PRP-FG-nHA/PA66 group, the bone defect was morphologically repaired.

CONCLUSION

The study showed that PRP-FG-nHA/PA66 scaffold can significantly reduce the amount of autologous bone graft, and can achieve similar bone defect repair effect as PMMA. Our findings provide some reference and theoretical support for the treatment of large segmental bone defects in humans.

Application of double plate fixation combined with Masquelet technique for large segmental bone defects of distal tibia: a retrospective study and literature review

BACKGROUND

There is no effective consensus on the choice of internal fixation method for the Masquelet technique in the treatment of large segmental bone defects of the distal tibia. Thus, the study aimed to investigate the outcomes of the Masquelet technique combined with double plate fixation in the treatment of large segmental bone defects.

METHODS

This was a retrospective study involving 21 patients with large segmental bone defects of the distal tibia who were treated between June 2017 and June 2020. The length of bone defect ranged from 6.0 cm to 11 cm (mean, 8.19 cm). In the first stage of treatment, following complete debridement, a cement spacer was placed to induce membrane formation. In the second stage, double plate fixation and autologous cancellous bone grafting were employed for bone reconstruction. Each patient's full weight-bearing time, bone healing time, and Iowa ankle score were recorded, and the occurrence of any complications was noted.

RESULTS

All patients were followed up for 16 to 26 months (mean, 19.48 months). The group mean full weight-bearing time and bone healing time after bone grafting were 2.41 (± 0.37) months and 6.29 (± 0.66) months, respectively. During the treatment, one patient had a wound infection on the medial side of the leg, so the medial plate was removed. The wound completely healed after debridement without any recurrence. After extraction of iliac bone for grafting, one patient had a severe iliac bone defect, which was managed by filling the gap with a cement spacer. Most patients reported mild pain in the left bone extraction area after surgery. The postoperative Iowa ankle score range was 84-94 (P < 0.05). In this cohort, 15 cases were rated as "excellent", and 6 cases as "good" on the Iowa ankle scoring system.

CONCLUSION

The Masquelet technique combined with double plate fixation is a safe and effective method for the treatment of large segmental bone defects of the distal tibia.

Surgical repair of large segmental bone loss with the induced membrane technique: patient reported outcomes are comparable to nonunions without bone loss

OBJECTIVE

To compare the outcomes of patients with segmental bone loss who underwent repair with the induced membrane technique (IMT) with a matched cohort of nonunion fractures without bone loss.

DESIGN

Retrospective analysis on prospectively collected data.

SETTING

Academic medical center.

PATIENTS

Two cohorts of patients, those with upper and lower extremity diaphyseal large segmental bone loss and those with ununited fractures, were enrolled prospectively between 2013 and 2020. Sixteen patients who underwent repair of 17 extremities with segmental diaphyseal or meta-diaphyseal bone defects treated with the induced membrane technique were identified, and matched with 17 patients who were treated for 17 fracture nonunions treated without an induced membrane. Sixteen of the bone defects treated with the induced membrane technique were due to acute bone loss, and the other was a chronic aseptic nonunion.

MAIN OUTCOME MEASUREMENTS

Healing rate, time to union, functional outcome scores using the Short Musculoskeletal Functional Assessment (SMFA) and pain assessed by the Visual Analog Scale (VAS).

RESULTS

The initial average defect size for patients treated with the induced membrane technique was 8.85 cm. Mean follow-up times were similar with 17.06 ± 10.13 months for patients treated with the IMT, and 20.35 ± 16.68. months for patients treated without the technique. Complete union was achieved in 15/17 (88.2%) of segmental bone loss cases treated with the IMT and 17/17 (100%) of cases repaired without the technique at the latest follow up visit. The average time to union for patients treated with the induced membrane technique was 13.0 ± 8.4 months and 9.64 ± 4.7 months for the matched cohort. There were no significant differences in reported outcomes measured by the SMFA or VAS. Patients treated with the induced membrane technique required more revision surgeries than those not treated with an induced membrane.

CONCLUSION

Outcomes following treatment of acute bone loss from the diaphysis of long bones with the induced membrane technique produces clinical and radiographic outcomes similar to those of long bone fracture nonunions without bone loss that go on to heal.

LEVEL OF EVIDENCE

III.

Influence of polylactide coating stereochemistry on mechanical and in vitro degradation properties of porous bioactive glass scaffolds for bone regeneration

The mechanical properties of polylactide stereocomplexes (PLA SC) have been primarily studied through tensile testing, with inconsistent results, and the compressive properties of PLA SC compared to homocrystalline or amorphous PLA remain poorly understood. In this study, we coated porous bioactive glass 13-93 scaffolds with amorphous, homocrystalline, or stereocomplex PLA to investigate their mechanical and degradation properties before and after immersion in simulated body fluid. The glass scaffolds had interconnected pores and an average porosity of 76%. The PLA coatings, which were 10-100 μm thick and approximately 3% of the glass scaffold mass, covered the glass to a large extent. The compressive strength and toughness of all PLA-coated scaffolds were significantly higher than those of uncoated scaffolds, with approximately a fourfold increase before immersion and a twofold increase after immersion. The compressive strength and toughness of PLA SC-coated scaffolds were similar to those of scaffolds with homocrystalline PLA coating, and significantly higher than for scaffolds with amorphous PLA coating. All PLA coatings moderated the initial pH increase caused by the glass, which could benefit surrounding cells and bone tissue in vivo after implantation.

Treatment of infected bone defects with the induced membrane technique

Aims

This study aimed to evaluate the effectiveness of the induced membrane technique for treating infected bone defects, and to explore the factors that might affect patient outcomes.

Methods

A comprehensive search was performed in PubMed, Embase, and the Cochrane Central Register of Controlled Trials databases between 1 January 2000 and 31 October 2021. Studies with a minimum sample size of five patients with infected bone defects treated with the induced membrane technique were included. Factors associated with nonunion, infection recurrence, and additional procedures were identified using logistic regression analysis on individual patient data.

Results

After the screening, 44 studies were included with 1,079 patients and 1,083 segments of infected bone defects treated with the induced membrane technique. The mean defect size was 6.8 cm (0.5 to 30). After the index second stage procedure, 85% (797/942) of segments achieved union, and 92% (999/1,083) of segments achieved final healing. The multivariate analysis with data from 296 patients suggested that older age was associated with higher nonunion risk. Patients with external fixation in the second stage had a significantly higher risk of developing nonunion, increasing the need for additional procedures. The autografts harvested from the femur reamer-irrigator-aspirator increased nonunion, infection recurrence, and additional procedure rates.

Conclusion

The induced membrane technique is an effective technique for treating infected bone defects. Internal fixation during the second stage might effectively promote bone healing and reduce additional procedures without increasing infection recurrence. Future studies should standardize individual patient data prospectively to facilitate research on the affected patient outcomes.

Nacre-mimetic cerium-doped nano-hydroxyapatite/chitosan layered composite scaffolds regulate bone regeneration via OPG/RANKL signaling pathway

Autogenous bone grafting has long been considered the gold standard for treating critical bone defects. However, its use is plagued by numerous drawbacks, such as limited supply, donor site morbidity, and restricted use for giant-sized defects. For this reason, there is an increasing need for effective bone substitutes to treat these defects. Mollusk nacre is a natural structure with outstanding mechanical property due to its notable "brick-and-mortar" architecture. Inspired by the nacre architecture, our team designed and fabricated a nacre-mimetic cerium-doped layered nano-hydroxyapatite/chitosan layered composite scaffold (CeHA/CS). Hydroxyapatite can provide a certain strength to the material like a brick. And as a polymer material, chitosan can slow down the force when the material is impacted, like an adhesive. As seen in natural nacre, the combination of these inorganic and organic components results in remarkable tensile strength and fracture toughness. Cerium ions have been demonstrated exceptional anti-osteoclastogenesis capabilities. Our scaffold featured a distinct layered HA/CS composite structure with intervals ranging from 50 to 200 μm, which provided a conducive environment for human bone marrow mesenchymal stem cell (hBMSC) adhesion and proliferation, allowing for in situ growth of newly formed bone tissue. In vitro, Western-blot and qPCR analyses showed that the CeHA/CS layered composite scaffolds significantly promoted the osteogenic process by upregulating the expressions of osteogenic-related genes such as RUNX2, OCN, and COL1, while inhibiting osteoclast differentiation, as indicated by reduced TRAP-positive osteoclasts and decreased bone resorption. In vivo, calvarial defects in rats demonstrated that the layered CeHA/CS scaffolds significantly accelerated bone regeneration at the defect site, and immunofluorescence indicated a lowered RANKL/OPG ratio. Overall, our results demonstrate that CeHA/CS scaffolds offer a promising platform for bone regeneration in critical defect management, as they promote osteogenesis and inhibit osteoclast activation.

Questions about Using the Induced Membrane Technique to Manage Cases of Congenital Tibial Pseudarthrosis

The induced membrane technique is an innovative approach for repairing critical bone defects and has been applied recently in patients with congenital pseudarthrosis of the tibia (CPT). CPT is frequently associated with neurofibromatosis type 1 (NF1). Here, we briefly describe the clinical results of the induced membrane technique in NF1-deficient patients with CPT and in an animal model of CPT. Furthermore, we discuss the hypotheses used to explain inconsistent outcomes for the induced membrane technique in CPT-especially when associated with NF1.

A review of the Masquelet technique in the treatment of lower limb critical-size bone defects

The need for bone tissue to heal effectively is paramount given its role in the mechanical support of tissues. Bone has a very good natural healing potential in comparison with most other tissue types, largely regenerating to its pre-injury state in the vast majority of cases. Certain factors such as high energy trauma, tumour resection, revision surgery, developmental deformities and infection can lead to the formation of bone defects, where the intrinsic healing potential of bone is diminished owing to bone loss. Various approaches to resolving bone defects exist in current practice, each with their respective benefits and drawbacks. These include bone grafting, free tissue transfer, Ilizarov bone transport and the Masquelet induced membrane technique. This review focuses on evaluating the Masquelet technique, discussing its method and underlying mechanisms, the effectiveness of certain modifications, and its potential future directions.

3D-Printed Bioactive Scaffold Loaded with GW9508 Promotes Critical-Size Bone Defect Repair by Regulating Intracellular Metabolism

The process of bone regeneration is complicated, and it is still a major clinical challenge to regenerate critical-size bone defects caused by severe trauma, infection, and tumor resection. Intracellular metabolism has been found to play an important role in the cell fate decision of skeletal progenitor cells. GW9508, a potent agonist of the free fatty acid receptors GPR40 and GPR120, appears to have a dual effect of inhibiting osteoclastogenesis and promoting osteogenesis by regulating intracellular metabolism. Hence, in this study, GW9508 was loaded on a scaffold based on biomimetic construction principles to facilitate the bone regeneration process. Through 3D printing and ion crosslinking, hybrid inorganic-organic implantation scaffolds were obtained after integrating 3D-printed β-TCP/CaSiO₃ scaffolds with a Col/Alg/HA hydrogel. The 3D-printed β-TCP/CaSiO₃ scaffolds had an interconnected porous structure that simulated the porous structure and mineral microenvironment of bone, and the hydrogel network shared similar physicochemical properties with the extracellular matrix. The final osteogenic complex was obtained after GW9508 was loaded into the hybrid inorganic-organic scaffold. To investigate the biological effects of the obtained osteogenic complex, in vitro studies and a rat cranial critical-size bone defect model were utilized. Metabolomics analysis was conducted to explore the preliminary mechanism. The results showed that 50 μM GW9508 facilitated osteogenic differentiation by upregulating osteogenic genes, including Alp, Runx2, Osterix, and Spp1 in vitro. The GW9508-loaded osteogenic complex enhanced osteogenic protein secretion and facilitated new bone formation in vivo. Finally, the results from metabolomics analysis suggested that GW9508 promoted stem cell differentiation and bone formation through multiple intracellular metabolism pathways, including purine and pyrimidine metabolism, amino acid metabolism, glutathione metabolism, and taurine and hypotaurine metabolism. This study provides a new approach to address the challenge of critical-size bone defects.

Modified Masquelet technique in children

Masquelet technique is one of the modalities for the treatment of long bone defect. Using cancellous bone graft to fill the bone defect is always a concern in children due to the small size of their iliac crest and open growth plate. We reported a case of 13-year-old male who presented with gap non-union of middle third of tibia. We applied a modified Masquelet technique by using only the cortical fibular graft instead of cancellous bone to fill the space surrounded by induced membrane. Fibula was used as a nonvascularized strut graft and matched stick graft to achieve complete union. We concluded that nonvascularized fibula grafting is an easy and effective option to fill the bone defect in children in the second stage of Masquelet technique.

Surface Modification of Carbon Fiber-Reinforced Polyetheretherketone with MXene Nanosheets for Enhanced Photothermal Antibacterial Activity and Osteogenicity

Ideal bone implant materials need to provide multiple functions such as biocompatibility, non-cytotoxicity, and bone tissue regeneration guidance. To tackle this challenge, according to our previous work, carbon fiber (40 mm)-reinforced polyetheretherketone (CFPEEK) composites were developed by using 3D needle-punched CFPEEK preform molding technology. Because of the excellent mechanical properties, the CFPEEK needled felt matrix composites have a broad application prospect in orthopedic internal fixation and implant materials. In order to expand the application range of composite materials, it is very necessary to improve the surface bioactivity of composite materials. The surface modification of CFPEEK with 2D titanium carbide (MXene) nanosheets (sulfonated CFPEEK (SCFPEEK)-polydopamine (PDA)-Ti₃C₂T_x) for enhanced photothermal antibacterial activity and osteogenicity was explored in this study. Here, the new composites we constructed are composed of Ti₃C₂T_x nanosheets, PDA, and biologically inert SCFPEEK, which gave the bio-inert composites bimodal therapeutic features: photothermal antibacterial activity and in vivo osseointegration. To our knowledge, this is the first time that a CFPEEK implant with a bioactive surface modified by Ti₃C₂T_x nanosheets was demonstrated. Due to the synergistic photothermal therapy (PTT) treatment of Ti₃C₂T_x/PDA, SCFPEEK-PDA-Ti₃C₂T_x (SCP-PDA-Ti) absorbed heat and the temperature increased to 40.8-59.6 °C─the high temperature led to bacterial apoptosis. The SCP-PDA-Ti materials could effectively kill bacteria after 10 min of near-infrared (NIR) irradiation at 808 nm. SCP-PDA-Ti (2.5) and SCP-PDA-Ti (3.0) achieved a 100% bacteriostasis rate. More importantly, the multifunctional implant SCP-PDA-Ti shows good cytocompatibility and an excellent ability to promote bone formation in terms of cytotoxicity, diffusion, alkaline phosphatase activity, alizarin red activity, real-time polymerase chain reaction analysis, and in vivo bone defect osteogenesis experiments. This provides a more extendable development idea for the application of carbon fiber-reinforced composites as orthopedic implants.

The induced membrane technique: Optimization of bone grafting in a rat model of segmental bone defect

INTRODUCTION

The induced membrane technique (IMT) is a two-stage surgical procedure used to treat fracture nonunion and bone defects. Although there is an increasing number of animal studies investigating the IMT, few have examined the outcomes of bone healing after a second stage grafting procedure. This study aimed at comparing two bone grafting procedures, as part of the IMT, in order to establish a rat model providing consistent healing outcomes.

METHODS

In male Fischer 344 rats, we created a 5 mm defect in the right femur, stabilized the bone with a plate and screws, and inserted a polymethylmethacrylate spacer into the defect. Four weeks later, the spacer was removed. Bone graft was harvested from a donor rat and placed into the defect, followed by membrane and wound closure. Experiments were conducted in two groups. In group 1 (n = 11), the bone graft contained a variable amount of cortical and cancellous bone, the time from donor euthanasia to grafting was up to 240 min, and one donor rat provided graft for 5-6 recipients. In group 2 (n = 12), we reduced the contribution of cortical bone to the graft, included bone marrow, and kept donor euthanasia to grafting time under 150 min. One donor was used per 3-4 recipients. The volume of graft per recipient and all other elements of the protocol were the same across groups. Bone healing at 12 weeks post grafting was compared radiographically by two orthopaedic surgeons in a blinded fashion, based on union status and a modified Lane & Sandhu score.

RESULTS

Healing rates improved from 36.4% in Group 1 to 91.6% in Group 2. There was a significant relationship between the methods and resulting union status (p = 0.004). The odds of achieving full union were significantly higher in group 2 compared to group 1 (odds ratio=19.25, 95% confidence interval [1.77-209.55]; p = 0.009). The average radiographic score was also significantly higher in group 2 (p = 0.005).

CONCLUSION

The revised bone grafting method significantly improved the healing outcomes and contributed to establishing a consistent rat model of the IMT. This model can benefit preclinical investigations by allowing for reliable and clinically-relevant comparisons.

Effects of PMMA spacer loaded with varying vancomycin concentrations on bone regeneration in the Masquelet technique

Whether antibiotics should be included remains greatly debated in Masquelet technique. This study intended to determine the effect of polymethyl methacrylate (PMMA) spacer loaded with different vancomycin concentrations on bone defect repair. Hollow cylindrical spacers consisting of PMMA and varying vancomycin concentrations (0, 1, 2, 4, 6, 8, and 10 g) were prepared. Critical bone defects of rabbits were created at the radial shaft, and spacers were implanted and subsequently intramedullary fixed with retrograde Kirschner’s wires (n = 4 for each vancomycin concentration). After 4 weeks, the induced membranes were opened and cancellous allografts were implanted into the defects. Eight weeks post-operatively, the results of X-ray, histology, and micro-CT revealed that some cortical bone was formed to bridge the gap and the bone marrow cavity was formed over time. Quantitatively, there was more new bone formation in the groups with a relatively lower vancomycin concentration (1–4 g) compared with that in the groups with a higher vancomycin concentration (6–10 g). Our findings suggested that PMMA spacers loaded with relatively lower vancomycin concentrations (1–4 g) did not interfere with new bone formation, whereas spacers loaded with relatively higher vancomycin concentrations (6–10 g) had negative effects on bone formation.

Masquelet technique in post-traumatic infected femoral and tibial segmental bone defects. Union and reoperation rates with high proportions (up to 64%) of allograft in the second stage

Introduction The aim of this study was to describe union, reoperation and failure rates after using the induced membrane (IM) technique with ≥50% allograft over autograft to treat infected femoral and tibial segmental bone defects (SBD). Materials and methods We retrospectively analyzed patients with femoral and tibial SBD treated in our center between 2012 and 2019 using ≥50% allograft over autograft during the second stage of the Masquelet technique. We analyzed the affected bone, defect size, osteosynthesis technique used, time elapsed between the first and second stage of the technique, graft proportions, union time, reoperations, and non-union rates. Results We included 21 patients (61.90% men) with a median age of 41 (range 18-68) years. The tibia was affected in 61.90% (n:13) and the femur in 38.09% (n:8) of the cases. SBD length was 4.5 (range 3.5-14) cm. The median interval between both stages of the technique was 10 (range 6-28) weeks. The proportion of allograft used was 50 % in 10 patients, 51 to 55% in 5 patients, 56 to 59% in 4 patients, and 60 to 64% in 2. The union rate was 95.23% over a median time of 7 (range 6-12) months. There were 3 (14.28%) reoperations: 2 for relapse of infection and 1 for mechanical instability. There was one failure (4.76%). One patient presented non-union and nail break. The median follow-up after the second stage of the technique was 26 (range 13-54) months. Conclusion The use of the induced membrane technique and a high proportion of allograft (up to 64%) achieved similar union and failure rates than those reported for similar series that relied on lower allograft proportions.

Complications in the Treatment of Delayed Union and Underlying Chronic Osteomyelitis After Right Crural Fracture Treated With Anterolateral Thigh Flap and Double-Barrelled Vascularized Fibula Graft

Background: Segmental bone defects pose a major, unsolved clinical challenge and may be the result of high-energy trauma, infection, and tumour resection or revision surgery. Several options exist to reconstruct, including Ilizarov bone transport, Masquelet technique, cylindrical mesh technique, allografts, and vascularized bone autografts. We present a patient with a delayed union of the tibia with concomitant chronic osteomyelitis treated with anterolateral thigh (ALT) flap and double-barrelled vascularized fibula graft.

Case presentation:A 60-year-old male with a chronic pretibial wound with underlying osteomyelitis of the right leg presented himself at the emergency department and was admitted to the surgical ward. He had complex chronic osteomyelitis of a tibial non-union after an earlier right crural fracture (a previous work-related accident). He was treated with an ALT flap and double-barrelled vascularized fibula graft, which was complicated with an additional fracture and breakage of osteosynthesis material.

Conclusion: Segmental bone defects pose a major, unsolved clinical challenge in orthopaedic, trauma-surgical, and plastic surgical practice. Concomitant infections and fractures can be part of the postoperative course. Patients with complex segmental bone defects need to be treated by a multidisciplinary team including at least an (orthopaedic) trauma surgeon, a plastic surgeon, and an infectiologist.

Locking Compression Plate as an External Fixator for the Treatment of Tibia Infected Bone Defects

PURPOSE

This study was designed to observe the medium-term efficacy of an induced membrane technique combined with a locking compression plate as an external fixator for the treatment of tibia infected bone defects.

METHODS

Patients with a tibial infection were admitted to our department between January 2013 and November 2014. All patients were treated with the induced membrane technique. In the first stage, polymethyl methacrylate (PMMA) cement was implanted in the defects after debridement and then fixed with a locking compression plate (LCP) as an external fixator. In the second stage, bone grafts were implanted to rebuild the defects. The external plates were replaced with nails in 57 patients (internal group), and the remaining 30 patients were not exchanged with fixation (external group). The infection control rate, bone union rate, and complications of the two groups were compared.

RESULTS

Eighty-seven patients were enrolled in this study, and all patients had a minimum follow-up of 5 years (average 62.8 months) after grafting. Eighty-three patients (95.4%) achieved bone union, and the average union time was 6.77 months. Five patients (5.7%) experienced recurrence of infection. Complications included pin tract infection, fixation loosening, deformity connection, and limitation of joint range of motion (ROM). No significant differences in the infection control rate or bone defect union rate were noted between the two groups. The overall rate of complications in the external group was 50%, which was greater than that noted in the internal group (21.1%).

CONCLUSIONS

Locking compression plates are external fixators with smaller sizes that are easier to operate than conventional annular fixators or assembled external fixators. The use of locking compression plates in combination with the induced membrane technique in the treatment of tibia infected bone defects can achieve good clinical efficacy after medium-term follow-up.

The Basic Science Behind the Clinical Success of the Induced Membrane Technique for Critical-Sized Bone Defects

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The induced membrane technique (IMT) takes advantage of an osteoinductive environment that is created by the placement of a cement spacer into a bone defect.

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Most commonly, a polymethylmethacrylate (PMMA) spacer has been used, but spacers made from other materials have emerged and achieved good clinical outcomes.

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The IMT has demonstrated good results for long-bone repair; however, more research is required in order to optimize union rates as well as delineate more precise indications and surgical timing.

S53P4 bioactive glass scaffolds induce BMP expression and integrative bone formation in a critical-sized diaphysis defect treated with a single-staged induced membrane technique

Critical-sized diaphysis defects are complicated by inherent sub-optimal healing conditions. The two-staged induced membrane technique has been used to treat these challenging defects since the 1980's. It involves temporary implantation of a membrane-inducing spacer and subsequent bone graft defect filling. A single-staged, graft-independent technique would reduce both socio-economic costs and patient morbidity. Our aim was to enable such single-staged approach through development of a strong bioactive glass scaffold that could replace both the spacer and the graft filling. We constructed amorphous porous scaffolds of the clinically used bioactive glass S53P4 and evaluated them in vivo using a critical-sized defect model in the weight-bearing femur diaphysis of New Zealand White rabbits. S53P4 scaffolds and standard polymethylmethacrylate spacers were implanted for 2, 4, and 8 weeks. Induced membranes were confirmed histologically, and their osteostimulative activity was evaluated through RT-qPCR of bone morphogenic protein 2, 4, and 7 (BMPs). Bone formation and osseointegration were examined using histology, scanning electron microscopy, energy-dispersive X-ray analysis, and micro-computed tomography imaging. Scaffold integration, defect union and osteosynthesis were assessed manually and with X-ray projections. We demonstrated that S53P4 scaffolds induce osteostimulative membranes and produce osseointegrative new bone formation throughout the scaffolds. We also demonstrated successful stable scaffold integration with early defect union at 8 weeks postoperative in critical-sized segmental diaphyseal defects with implanted sintered amorphous S53P4 scaffolds. This study presents important considerations for future research and the potential of the S53P4 bioactive glass as a bone substitute in large diaphyseal defects. STATEMENT OF SIGNIFICANCE: Surgical management of critical-sized diaphyseal defects involves multiple challenges, and up to 10% result in delayed or non-union. The two-staged induced membrane technique is successfully used to treat these defects, but it is limited by the need of several procedures and bone graft. Repeated procedures increase costs and morbidity, while grafts are subject to donor-site complications and scarce availability. To transform this two-staged technique into one graft-independent procedure, we developed amorphous porous scaffolds sintered from the clinically used bioactive glass S53P4. This work constitutes the first evaluation of such scaffolds in vivo in a critical-sized diaphyseal defect in the weight-bearing rabbit femur. We provide important knowledge and prospects for future development of sintered S53P4 scaffolds as a bone substitute.

SDF-1 mediates mesenchymal stem cell recruitment and migration via the SDF-1/CXCR4 axis in bone defect

INTRODUCTION

Recent studies have indicated the potential of stem cell therapy in combination with cytokines to restore the bone repair via migration and homing of stem cells to the defected area. The present study aimed to investigate the mobilization and recruitment of mesenchymal stem cells (MSCs) in response to SDF-1.

MATERIALS AND METHODS

Herein, the knockout rat model of the bone defect (BD) was treated with the induced membrane technique. Then, wild type Wistar rats and SDF-1-knockout rats were selected for the establishment of BD-induced membrane (BD-IM) models and bone-graft (BG) models. The number of MSCs was evaluated by flow cytometry, along with the expression pattern of the SDF-1/CXCR4 axis as well as osteogenic factors was identified by RT-qPCR and Western blot analyses. Finally, the MSC migration ability was assessed by the Transwell assay.

RESULTS

Our data illustrated that in the induced membrane tissues, the number of MSCs among the BD-IM modeled rats was increased, whereas, a lower number was documented among BG modeled rats. Besides, we found that lentivirus-mediated over-expression of SDF-1 in BG modeled rats could activate the SDF-1/CXCR4 axis, mobilize MSCs into the defect area, and up-regulate the osteogenic proteins.

CONCLUSIONS

Collectively, our study speculated that up-regulation of SDF-1 promotes the mobilization and migration of MSCs through the activation of the SDF-1/CXCR4 signal pathway.

Expression of VEGF in Peripheral Serum Is a Possible Prognostic Factor in Bone-Regeneration via Masquelet-Technique-A Pilot Study

Two-step Masquelet-technique established a new procedure in the treatment of osseous defects, addressing prerequisites postulated by the “diamond concept”. Increase in blood perfusion and growth factors are enhanced by the “Masquelet-membrane”. To describe this, we measured serum levels of Vascular Endothelial Growth Factor (VEGF) of patients with atrophic non-unions of long bones undergoing Masquelet-technique. From over 500 non-union patients undergoing Masquelet-technique with prospective follow-up we randomly selected 30 patients. 23 were included, 7 lost to follow-up or excluded because of incomplete data. Serum was drawn at specified intervals before and after surgery. Patients were followed for at least 6 months after step 2. Classification into both groups was performed according to radiological results and clinical outcome 6 months after step 2. Concentration of VEGF in patients’ serum was performed via ELISA. 14 achieved osseous consolidation (responder group), 9 cases did not (non-responder). Responders showed a significant increase of serum-VEGF in the first and second week when compared to the preoperative values of step 1. Non-responders showed a significant increase of VEGF in the second week after Steps 1 and 2. Comparison of groups showed significantly higher increase of serum-VEGF week2 after step 1 and preoperative to step 2 for responders. Results show one possibility of illustrating therapeutic progress by monitoring growth factors and possibly allowing prognostic conclusions thereof. This might lead to a more targeted treatment protocol.

Membrane-Induced Technique for the Management of Combined Soft Tissue and Osseous Defects

The induced membrane technique is a simple, effective, and reproducible treatment method for segmental bone defects. It is a 2-stage approach that requires eventual autologous bone graft to manage the deficit. The first stage requires debridement of all nonviable tissue while preserving a healthy soft tissue envelope. A polymethylmethacrylate is implanted between the osseous segments to maintain length. The osseous defect can be stabilized internally or externally. During the second stage, a vascularized induced membrane is formed and produces multiple growth factors. The induced membrane technique is a valuable option for limb salvage in cases of segmental bone defects.

"Primary free-flap tibial open fracture reconstruction with the Masquelet technique" and internal fixation

BACKGROUND

Grade III open fractures of the lower extremity are serious injuries and are difficult to reconstruct. The optimal treatment for such injuries is unclear. We aimed to determine the safety and efficacy of orthoplastic reconstruction, using a primary free anterolateral thigh flap combined with the Masquelet technique and internal fixation for Gustilo grade IIIB/C open tibial fractures.

METHODS

From April 2018 to April 2019, 15 patients, ranging from 19 to 72 years old, with Gustilo grade IIIB/C open fractures were treated using a primary free anterolateral thigh flap combined with the Masquelet technique and internal fixation. This involved wound debridement and removal of free bone fragments, followed by bone cement packing of the defect, external fixation, and vacuum sealing drainage treatment. The final stage involved switching from external to internal fixation and wound repair using a free anterolateral thigh flap. Repair time ranged from 2 to 7 days. Flap size ranged from 25 × 15 cm² to 13 × 7cm². Hospital stay ranged from 11 to 50 days (mean, approximately 33.3 days). Bone cement was removed after 6-19 weeks and replaced with autogenic cancellous bone.

RESULTS

All flaps survived without incident. One patient experienced a wound infection, but there were no deep infections. For all patients, bone union was achieved after 4 to 7 months.

CONCLUSION

The use of a primary free anterolateral thigh flap combined with the Masquelet technique and internal fixation is a safe and effective procedure for reconstruction of Gustilo grade IIIB/C open fractures.

Nb-Ti-Zr alloys for orthopedic implants

Niobium (Nb), Titanium (Ti), and Zirconium (Zr) have attracted much attention as implant materials due to it's excellent mechanical properties and biocompatibility. However, little attention has been paid to high Nb-containing biomedical alloys. Here, the 50 wt.%Nb-XTi-Zr ternary alloy(x = 20wt.%, 30 wt.%, 40 wt.%) with relative density over 90% was prepared by powder metallurgy method. The massive α(Zr) distributed along the grain boundaries and lamellar β(Zr) appeared in the grains of β(Nb) in the 50 wt.%Nb-20wt.%Ti-Zr alloy. The acicular α phase is mainly distributed in the β-grain of 50 wt.%Nb-30wt.%Ti-Zr alloy. And α(Ti)-colonies in the β-grains and continuous α(Ti)_GB at β-grain boundary can be observed in the 50 wt.%Nb-40wt.%Ti-Zr alloy. Comparing with Nb-20wt.%Ti-Zr alloy and 50 wt.%Nb-40wt.%Ti-Zr alloy, the 50 wt.%Nb-30wt.%Ti-Zr alloy showed lower Vickers hardness and elastic modulus. Furthermore, the as-sintered 50 wt.%Nb-XTi-Zr alloy promoted the cell proliferation and cell adhesion of MG-63 cells on the surface of alloys. In conclusion, the 50 wt.%Nb-XTi-Zr alloy combines excellent mechanical and biological properties, and the 50 wt.%Nb-30wt.%Ti-Zr alloy with lower elastic modulus (close to the bone) is a more promising candidate for bone implant material.

A cell-based combination product for the repair of large bone defects

Regenerative cell-based implants using periosteum-derived stem cells were developed for the treatment of large 3 cm fresh and 4.5 centimeter biological compromised bone gaps in a tibial sheep model and compared with an acellular ceramic-collagen void filler. It was hypothesized that the latter is insufficient to heal large skeletal defects due to reduced endogenous biological potency. To this purpose a comparison was made between the ceramic dicalciumphosphate scaffold (CopiOs®) as such, the same ceramic coated with clinical grade Bone Morphogenetic Protein 2 and 6 (BMP) only or a BMP coated cell-seeded combination product. These implants were evaluated in 2 sheep models, a fresh 3 cm critical size tibial defect and a 4.5 cm biologically exhausted tibial defect. For the groups in which growth factors were applied, BMP-6 was chosen at a dose of 344 μg for 3 cm and 1.500 μg or 3.800 μg for 4.5 cm defects. An additional group in the 4.5 cm defect was tested using BMP-2 in a dose of 1.500 μg. For all the cell based implants autologous periosteum-derived cells were used which were cultured in monolayer during 6 weeks. For the fresh defect 408 million cells and for the biologically exhausted tibial defect 612 million cells were drop-seeded on the BMP coated scaffolds. Bone healing was studied during 16 weeks postimplantation, using standard radiographs. While fresh defects responded to all treatments, regardless the use of cells, the biologically hampered defects responded in half of the cases and only if the BMP-cell combination product was used, supporting the concept that cell-based therapies may become attractive in treating defects with a compromised biological status.

Outcome of Induced Membrane Technique in Treatment of failed previously operated Congenital Pseudarthrosis of the Tibia

BACKGROUND

Although a remarkable success in the treatment of congenital pseudarthrosis tibia (CPT) had been achieved, failure rate is still high and the likelihood of amputation is still considerable. The current study evaluates the outcome of induced membrane technique in the treatment of failed previously operated patients of congenital pseudarthrosis of the tibia. We hypothesized that induced membrane technique will improve union rates in CPT with failed previous multiple operations.

PATIENTS AND METHODS

Nineteen consecutive patients of failed previously operated CPT were prospectively included in the study. All patients were treated by induced membrane technique with autogenous free non-vascularized fibular strut graft augmented by autogenous iliac graft and fixed by intramedullary K-Wire as well as Ilizarov external fixator.

RESULTS

The mean interval between the 1^st and 2^nd stages of the procedure was 4.9 weeks. Sound union was achieved in all cases in a mean time of 25.3 weeks. The mean follow up period was 5.02 years (range, 2.4-6.5). No refracture was documented till last follow up.

CONCLUSION

Induced membrane technique had proved as a successful method in the treatment of failed previously operated CPT with a satisfactory outcome and low complication rates.

LEVEL OF EVIDENCE

IV.

Comparing the outcomes of the induced membrane technique between the tibia and femur: Retrospective single-center study of 33 patients

INTRODUCTION

Bone defects are challenging to treat surgically. The primary objective of our study was to compare the union rate and time to union between the tibia and femur when using the induced membrane technique. The secondary objective was to document how failures were managed.

MATERIAL AND METHODS

This retrospective, single-center study involved 33 patients (23 men, 10 women) who were older than 18 years of age. They were treated surgically for a leg fracture or long bone nonunion (22 tibia, 11 femur) using the induced membrane technique between January 2011 and December 2016 and had a complete follow-up. The minimum follow-up was 1 year for fractures and 2 years for non-union cases. Bone union was defined as the presence of at least two cortices with bridging on two radiographic views and return to full weight bearing.

RESULTS

The mean patient age was 38.3±15.5 years (18-72). The mean bone defect size was 7.9±5.0cm (2.3-18.0). The mean follow-up was 3.3±1.8 years (1-7.2). The union rate was 61% (20 patients). The mean time to union was 10±6.4 months (3-23). The time to union was significantly longer in the tibia (11.6±6.9 months [3-23]) than in the femur (6.3±2.9 months [3.4-10.3]) (p=0.025). The failure rate did not differ between the tibia and femur. Nine of the 13 patients (69%) in which the treatment failed were reoperated; 7 of them underwent nonunion treatment (78%) and 2 underwent amputation (22%). The other 4 patients were waiting for an infection to resolve before being reoperated.

CONCLUSION

The induced membrane technique is an effective surgical procedure for large bone defects in both the tibia and femur. However, the time to union was shorter in the femur than the tibia in our cohort.

LEVEL OF EVIDENCE

IV, retrospective study.

The Masquelet technique: Current concepts, animal models, and perspectives

Bone reconstruction within a critical-sized defect remains a real challenge in orthopedic surgery. The Masquelet technique is an innovative, two-step therapeutic approach for bone reconstruction in which the placement of a poly (methylmethacrylate) spacer into the bone defect induces the neo-formation of a tissue called "induced membrane." This surgical technique has many advantages and is often preferred to a vascularized bone flap or Ilizarov's technique. Although the Masquelet technique has achieved high clinical success rates since its development by Alain-Charles Masquelet in the early 2000s, very little is known about how the process works, and few animal models of membrane induction have been developed. Our successful use of this technique in the clinic and our interest in the mechanisms of tissue regeneration (notably bone regeneration) prompted us to develop a surgical model of the Masquelet technique in rats. Here, we provide a comprehensive review of the literature on animal models of membrane induction, encompassing the defect site, the surgical procedure, and the histologic and osteogenic properties of the induced membrane. We also discuss the advantages and disadvantages of those models to facilitate efforts in characterizing the complex biological mechanisms that underlie membrane induction.

Cambridge experience in spontaneous bone regeneration after traumatic segmental bone defect: a case series and review of literature

High-energy traumatic long bone defects are some of the most challenging to reconstruct. Although cases of spontaneous bone regeneration in these defects have been reported, we are aware of no management guidelines or recommendations for when spontaneous bone regeneration should be considered a viable management option. We aim to identify how certain patient characteristics and surgical factors may help predict spontaneous bone regeneration. A total of 26 cases with traumatic segmental defects were treated at our institution, with eight cases (30.8%) undergoing spontaneous regeneration. We discuss four in detail. Six (75%) reported a degree of periosteal preservation, four (50%) were associated with traumatic brain injury and none were complicated by infection. The average time to spontaneous bone regeneration was 2.06 months. According to our cases, patients with favourable characteristics may benefit from delaying surgical treatment by 6 weeks to monitor for any signs of spontaneous bone formation.

Three-Dimensional Coating of SF/PLGA Coaxial Nanofiber Membranes on Surfaces of Calcium Phosphate Cement for Enhanced Bone Regeneration

Calcium phosphate cements (CPCs) have been widely used for the study of bone regeneration because of their excellent physical and chemical properties, but poor biocompatibility and lack of osteoinductivity limit potential clinical applications. To overcome these limitations, and based on our previous research, CPC scaffolds were prepared with CPC as the principal material and polyethylene glycol (PEG) as a porogen to introduce interconnected macropores. Using a bespoke electrospinning auxiliary receiver, silk fibroin (SF)/poly(lactide-co-glycolide) (PLGA) coaxial nanofibers containing dexamethasone (DXM) and recombinant human bone morphogenetic protein-2 (rhBMP2) were fabricated which were coated on the surface of the CPC. By comparing the surface morphology by SEM, hydrophilicity, results of FTIR spectroscopy, and mechanical properties of the composite materials fabricated using different electrospinning times (20, 40, 60 min), the CPC surface constructed by electrospinning for 40 min was found to exhibit the most appropriate physical and chemical properties. Therefore, composite materials were built for further study by electrospinning for 40 min. The osteogenic capacity of the SF/PLGA/CPC, SF-DXM/PLGA/CPC, and SF-DXM/PLGA-rhBMP2/CPC scaffolds was evaluated by in vitro cell culture with rat bone marrow mesenchymal stem cells (BMSCs) and using a rat cranial defect repair model. ALP activity, calcium deposition levels, upregulation of osteogenic genes, and bone regeneration in skull defects in rats with SF-DXM/PLGA-rhBMP2/CPC implants were significantly higher than in rats implanted with the other scaffolds. These results suggest that drug-loaded coaxial nanofiber coatings prepared on a CPC surface can continuously and effectively release bioactive drugs and further stimulate osteogenesis. Therefore, the SF-DXM/PLGA-rhBMP2/CPC scaffolds prepared in this study demonstrated the most significant potential for the treatment of bone defects.

Management of Infected Bone Defects of the Lower Extremities by Three-Stage Induced Membrane Technique

BACKGROUND Infected bone defects are therapeutic challenges. Although the induced membrane technique has been used for this problem, there is a 3% to 20.7% failure to eradicate infection, and there have been few reports about its use in tuberculous infection. We present our three-stage induced membrane technique (TSIMT) for treating infected bone defects of the lower extremity. MATERIAL AND METHODS Forty-one adult patients with infected bone defects of the lower extremities treated by TSIMT were included in a retrospective case-series study between January 2013 and June 2018. The clinical, imaging and laboratory assessment outcomes were analyzed. RESULTS In the first stage, 3 patients had ankle tuberculous bone defects and 17 patients underwent 2-4 debridements. In the second stage, the average bone defect was 6.0 cm; 1 patient needed an anterolateral thigh flap to cover the wound. In the third stage, 10 patients underwent autograft mixed allograft, and 18 cases used internal fixation. The mean follow-up period was 23.3 months. All patients achieved bone union and clinical eradication of infection. Changes in Lower Extremity Functional Scale (LEFS) scores after 1 year of TSIMT and bone union time are associated with advanced age, longer duration of infected bone defects, active smoking, and external fixation (p<0.05), but are not dependent on bone defect size, debridement times, type of bone graft, or spacer-placing time (p>0.05). CONCLUSIONS TSIMT is effective in treating infected bone defects of the lower extremities. Advanced age, longer duration of infected bone defects, active smoking, and external fixation adversely affect bone union and recovery of infected extremities in a limited time span.

Studies of Superb Microvascular Imaging and Contrast-Enhanced Ultrasonography in the Evaluation of Vascularization in Early Bone Regeneration

OBJECTIVE

The aim of this study was to investigate value of superb microvascular imaging (SMI) and contrast-enhanced ultrasonography (CEUS) in evaluating the neovascularization of early bone regeneration.

METHODS

Twenty-five Sprague-Dawley male rats were implanted with recombinant human bone morphogenetic protein-2/calcium phosphate cement (rhBMP-2/) in the muscle space of the left hind limb near the femoral head to establish the rat model of intramuscular ectopic osteogenesis. Ultrasonography and pathologic analysis were performed on the 3rd, 7th, 14th, 21st, and 28th days after modeling. Two-dimensional ultrasonography, SMI, and CEUS were used to assess neovascularization and bone formation.

RESULTS

Pathologic examination showed that different levels of neovascularization were observed in the graft bone over time after modeling, which increased significantly from the 3rd to 14th day, and then gradually decreased. CEUS and SMI showed no obvious microvessels inside the graft bone on the 3rd day. On the 7th day after modeling, a small number of neovascular vessels were observed around the graft bone. On the 14th day, neovascularization was observed in both the peripheral and inner parts of the graft bone. The number of neovascular vessels inside the graft bone had decreased gradually by the 21st and 28th days. The results of SMI and CEUS indexes showed that the vascular index, peak intensity, enhancement intensity, and enhancement rate first increased and then decreased with time. Their peak points were found on the 14th day. Arrival time, time to peak, and enhancement time decreased gradually over time (P < .05).

CONCLUSION

The combined application of SMI and CEUS may be useful in evaluating the neovascularization of early osteoanagenesis.

Induced membrane technique in the treatment of infectious bone defect: A clinical analysis

BACKGROUND

At present, it is still a challenge for repairing a wide range of bone defect caused by various reasons. We aimed to investigate the effect of induced membrane technique in the treatment of infectious bone defect.

PATIENTS AND METHODS

The clinical data of twenty-one patients with infectious bone defect that received induced membrane technique treatment from January 2008 to August 2017 were collected for this study. The complications were recorded, and the bone defect healing and the recovery of joint function were evaluated by Paley method. The adjacent joint activities were also evaluated.

RESULTS

One month after the first stage of surgery, one case had wound dehiscence, and others healed well without infection. Six cases had induced membrane injury during the second stage of surgery, and 4 of them received induced membrane wrapping reconstruction. At the last follow-up, bone defect healing was excellent, the joint function was restored (the rate of excellent and good was 90.5%). The joint range of motion recovered well and the rate of excellent and good was 81.0%.

CONCLUSION

Induction membrane technique in the treatment of infectious bone defect has advantages of simple operation, rapid healing of bone defects, and low recurrence rate of infection.

Results of the Induced Membrane Technique in the Management of Traumatic Bone Loss in the Lower Limb: A Cohort Study

OBJECTIVE

To present our technique and early results using the Masquelet technique.

DESIGN

Retrospective cohort study.

PATIENTS/PARTICIPANTS

Thirteen patients with 14 open fractures of the femur and tibia were included between November 2013 and December 2014.

INTERVENTION

A Masquelet technique was used to manage the open fractures.

MAIN OUTCOME MEASURE

Infection and union rate.

RESULTS

The mean follow-up was 17 months. The mean bone defect was 56.6 mm. Eight fractures (57.1%) progressed to union at an average of 42.1 weeks. Infection developed in 3 fractures (21.4%). Overall, the induced membrane technique was abandoned in 5 (35.7%) cases.

CONCLUSIONS

The induced membrane technique showed a substantial rate of failure in the acute trauma setting in the lower limb. In the absence of sound published evidence, the authors now use the technique in selected cases only.

LEVEL OF EVIDENCE

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

Masquelet Technique: Effects of Spacer Material and Micro-topography on Factor Expression and Bone Regeneration

We and others have shown that changing surface characteristics of the spacer implanted during the first Masquelet stage alters some aspects of membrane development. Previously we demonstrated that titanium (TI) spacers create membranes that are better barriers to movement of solutes > 70 kDa in size than polymethyl methacrylate (PMMA) induced-membranes, and roughening creates more mechanically compliant membranes. However, it is unclear if these alterations affect the membrane's biochemical environment or bone regeneration during the second stage. Ten-week-old, male Sprague-Dawley rats underwent an initial surgery to create an externally stabilized 6 mm femoral defect. PMMA or TI spacers with smooth (~ 1 μm) or roughened (~ 8 μm) surfaces were implanted. Four weeks later, rats were either euthanized for membrane harvest or underwent the second Masquelet surgery. TI spacers induced thicker membranes that were similar in structure and biochemical expression. All membranes were bilayered with the inner layer having increased factor expression [bone morphogenetic protein 2 (BMP2), transforming growth factor beta (TGFβ), interleukin 6 (IL6), and vascular endothelial growth factor (VEGF)]. Roughening increased overall IL6 levels. Ten-weeks post-engraftment, PMMA-smooth induced membranes better supported bone regeneration (60% union). The other groups only had 1 or 2 that united (9-22%). There were no significant differences in any micro computed tomography or dynamic histology outcome. In conclusion, this study suggests that the membrane's important function in the Masquelet technique is not simply as a barrier. There is likely a critical biochemical, cellular, or vascular component as well.

[Treatment of severe distal humeral bone defects with three-dimensional printing technology]

Objective

To explore the application of three-dimensional (3D) printing technology in precise and individualized surgical treatment of severe distal humeral bone defect.

Methods

Five patients with severe distal humeral bone defects were treated with customized 3D printing prostheses between December 2010 and December 2015. There were 4 males and 1 female, with an age of 23-57 years (mean, 35 years); and the length of the bone defect was 5-12 cm (mean, 8 cm). The cause of injury was mechanical injury in 2 cases and strangulation in 3 cases. All of them were the open fracture of Gustilo type Ⅲ. There were 2 cases of radial fracture, 1 case of cubital nerve injury, and 3 cases of radial nerve injury. The time from injury to one-stage operation was 6-18 hours (mean, 10 hours). The operation time, intraoperative blood loss, and intraoperative fluoroscopy were recorded. During follow-up, the anteroposterior and lateral X-ray films of the elbow joints were performed to identify whether there was prosthesis loosening; Mayo Elbow Performance Score (MEPS) and upper extremity Enneking score were used to evaluate limb function.

Results

The operation time was 140-190 minutes (mean, 165 minutes). The intraoperative blood loss was 310-490 mL (mean, 415 mL). The intraoperative fluoroscopy was 1-3 times (mean, 1.6 times). Five patients were followed up 14-38 months (mean, 21 months). The wound exudate occurred in 1 case and cured after anti-inflammatory local dressing change; the subcutaneous hematoma occurred in 1 case, and improved after color Doppler ultrasound guided puncture and drainage. The MEPS scores and the Enneking scores were all significantly improved when compared with preoperative ones ( P<0.05). Except MEPS score between 6 and 12 months after operation had no significant difference ( P>0.05), there were significant differences in MEPS scores and Enneking scores between the other time points ( P<0.05). During the follow-up, no prosthetic loosening or joint dislocation occurred.

Conclusion

3D printing technology can achieve personalized treatment of severe distal humeral bone defects, obtain relatively good elbow joint function, and has less postoperative complications and satisfactory effectiveness.

Recombinant Human Bone Morphogenetic Protein 6 Delivered Within Autologous Blood Coagulum Restores Critical Size Segmental Defects of Ulna in Rabbits

BMP2 and BMP7, which use bovine Achilles tendon-derived absorbable collagen sponge and bovine bone collagen as scaffold, respectively, have been approved as bone graft substitutes for orthopedic and dental indications. Here, we describe an osteoinductive autologous bone graft substitute (ABGS) that contains recombinant human BMP6 (rhBMP6) dispersed within autologous blood coagulum (ABC) scaffold. The ABGS is created as an injectable or implantable coagulum gel with rhBMP6 binding tightly to plasma proteins within fibrin meshwork, as examined by dot-blot assays, and is released slowly as an intact protein over 6 to 8 days, as assessed by ELISA. The biological activity of ABGS was examined in vivo in rats (Rattus norvegicus) and rabbits (Oryctolagus cuniculus). In a rat subcutaneous implant assay, ABGS induced endochondral bone formation, as observed by histology and micro-CT analyses. In the rabbit ulna segmental defect model, a reproducible and robust bone formation with complete bridging and restoration of the defect was observed, which is dose dependent, as determined by radiographs, micro-CT, and histological analyses. In ABGS, ABC scaffold provides a permissive environment for bone induction and contributes to the use of lower doses of rhBMP6 compared with BMP7 in bovine bone collagen as scaffold. The newly formed bone undergoes remodeling and establishes cortices uniformly that is restricted to implant site by bridging with host bone. In summary, ABC carrier containing rhBMP6 may serve as an osteoinductive autologous bone graft substitute for several orthopedic applications that include delayed and nonunion fractures, anterior and posterior lumbar interbody fusion, trauma, and nonunions associated with neurofibromatosis type I.

Induced membrane technique for the treatment of severe acute tibial bone loss: preliminary experience at medium-term follow-up

PURPOSE

Management of acute open tibial fractures with critical bone defect remains a challenge in trauma surgery. Few and heterogeneous cases have been reported about the treatment with the induced membrane technique.

METHODS

We prospectively evaluated three patients treated with the induced membrane technique for acute Gustilo IIIB tibial fractures with critical bone defect. Success treatment was defined by bone union with patient pain free. Clinical and radiological evaluations were performed regularly until healing, then annually and with a minimum follow-up of five years.

RESULTS

In all patients but one, a success was recorded, respectively, at four and six months. These two patients were pain free until the final follow-up, and no graft resorption or secondary complications related to the index surgery were observed. The third case was managed successfully with a bone transport technique.

CONCLUSION

The induced membrane technique is an alternative good option for the treatment of these severe lesions.

Masquelet technique: The effect of altering implant material and topography on membrane matrix composition, mechanical and barrier properties in a rat defect model

The Masquelet technique is a surgical procedure to regenerate segmental bone defects. The two-phase treatment relies on the production of a vascularized foreign-body membrane to support bone grafts over three times larger than the traditional maximum. Historically, the procedure has always utilized a bone cement spacer to evoke membrane production. However, membrane formation can easily be effected by implant surface properties such as material and topology. This study sought to determine if the membrane's mechanical or barrier properties are affected by changing the spacer material to titanium or roughening the surface finish. Ten-week-old, male Sprague Dawley rats were given an externally stabilized, 6 mm femur defect which was filled with a pre-made spacer of bone cement (PMMA) or titanium (TI) with a smooth (∼1 μm) or roughened (∼8 μm) finish. After 4 weeks of implantation, the membranes were harvested, and the matrix composition, tensile mechanics, shrinkage, and barrier function was assessed. Roughening the spacers resulted in significantly more compliant membranes. TI spacers created membranes that inhibited solute transport more. There were no differences between groups in collagen or elastin distribution. This suggests that different membrane characteristics can be created by altering the spacer surface properties. Surgeons may unknowingly effecting membrane formation via bone cement preparation techniques.

Inhibition of Dll4/Notch1 pathway promotes angiogenesis of Masquelet's induced membrane in rats

The Masquelet’s induced membrane technique for repairing bone defects has been demonstrated to be a promising treatment strategy. Previous studies have shown that the vessel density of induced membrane is decreased in the late stage of membrane formation, which consequently disrupts the bone healing process. However, relatively little is known about certain mechanisms of vessel degeneration in the induced membrane tissue and whether promotion of angiogenesis in induced membranes can improve bone regeneration. Here, we showed that the Delta-like ligand 4/ Notch homolog 1 (Dll4/Notch1) pathway was relatively activated in the late stage of induced membrane, especially at the subcutaneous site. Then, DAPT, a classical γ-secretase inhibitor, was applied to specifically inhibit Notch1 activation, followed by up-regulation of vascular endothelial growth factor receptor 2 (VEGFR2) and CD31 expression. DAPT-modified induced membranes were further confirmed to contribute to bone regeneration after autogenous bone grafting. Finally, in vitro experiments revealed that knocking down Notch1 contributed to the functional improvement of endothelial progenitor cells (EPCs) and that DAPT-treated induced membrane tissue was more favorable for angiogenesis of EPCs compared with the vehicle group. In conclusion, the present findings demonstrate that Dll4/Notch1 signaling is negatively associated with the vessel density of induced membrane. Pharmacological inhibition of Notch1 attenuated the vessel degeneration of induced membrane both in vitro and in vivo, which consequently improved bone formation at the bone defect site and graft resorption at the subcutaneous site.

Repairs to serious bone injuries may be improved by blocking a signaling pathway that causes newly forming membranes to fail. Masquelet’s technique involves placing acrylic spacers in areas of bone damage, inducing the formation of vascularised membranes which encourage the body to accept bone grafts. However, sometimes Masquelet’s membranes do not form correctly, leading to weaknesses in bone repairs and potential graft rejection. In experiments on rats, Qian Tang from Wenzhou Medical University, China, and coworkers found that a particular signaling pathway, D114/Notch1, was upregulated around 6 weeks post-operation, reducing blood vessel density and limiting new vessel growth, weakening the membranes. The team inhibited this pathway using an existing therapy that prevents blood clots. This treatment improved bone repairs by promoting the formation and function of blood vessels in membranes.

Use of Masquelet's technique for treating the first metatarsophalangeal joint in cases of gout combined with a massive bone defect

BACKGROUND

To examine the safety and efficacy of Masquelet's technique as a surgical method for treating the first metatarsophalangeal joint in cases of gout accompanied by a massive bone defect.

METHODS

From January 2010 to January 2016, eleven patients (7 males and 4 females; mean age 33.1 years; range, 23-43 years) received surgical treatment for a first metatarsophalangeal joint tophus which caused a serious bone defect. The first metatarsophalangeal bone defects ranged from 3-6cm, or nearly 50% of the length of normal bone. During the first stage of Masquelet's technique, we removed the tophus and infused that area with bone cement that contained antibiotics. Two months later, we performed the second stage, in which the prosthesis was replaced with iliac cancellous bone, and the operated area was stabilized via locking plate fixation.

RESULTS

All of the surgeries were successful, and the 11 patients were followed up for an average of 10.9 months. Postoperative evaluations showed that 10 of the 11 patients healed between 9 and 14 days after the initial surgery. Bone fusion occurred between 2.3 and 3.6 months after the operation, and the average healing time was 3.0 months. One foot wound became infected, but healed after vacuum aspiration. When the American Association of Foot and Ankle Surgery Maryland Foot scoring system was used to evaluate the foot function of the 11 patients prior to surgery, all 11 patients were graded as "failures." Following surgery, 2 patients were graded excellent, 5 were good, 3 were fair, and only 1 patient failed. The total combined excellent and good rate was 63.6%. The total mean Maryland scores pre- and post-surgery were 27.8 points and 74.1 points, respectively; thus the average patient score increased by 46.3 points.

CONCLUSIONS

Joints with advanced tophus nodules develop segmental bone defects. Masquelet's technique is an effective method for treating such nodules and their associated bone defects.

Altering spacer material affects bone regeneration in the Masquelet technique in a rat femoral defect

The Masquelet technique depends on pre-development of a foreign-body membrane to support bone regeneration with grafts over three times larger than the traditional maximum. To date, the procedure has always used spacers made of bone cement, which is the polymer polymethyl methacrylate (PMMA), to induce the foreign-body membrane. This study sought to compare (i) morphology, factor expression, and cellularity in membranes formed by PMMA, titanium, and polyvinyl alcohol sponge (PVA) spacers in the Masquelet milieu and (ii) subsequent bone regeneration in the same groups. Ten-week-old, male Sprague-Dawley rats were given an externally stabilized, 6 mm femur defect, and a pre-made spacer of PMMA, titanium, or PVA was implanted. All animals were given 4 weeks to form a membrane, and those receiving an isograft were given 10 weeks post-implantation to union. All samples were scanned with microCT to measure phase 1 and phase 2 bone formation. Membrane samples were processed for histology to measure membrane morphology, cellularity, and expression of the factors BMP2, TGFβ, VEGF, and IL6. PMMA and titanium spacers created almost identical membranes and phase 1 bone. PVA spacers were uniformly infiltrated with tissue and cells and did not form a distinct membrane. There were no quantitative differences in phase 2 bone formation. However, PMMA induced membranes supported functional union in 6 of 7 samples while a majority of titanium and PVA groups failed to achieve the same. Spacer material can alter the membrane enough to disrupt phase 2 bone formation. The membrane's role in bone regeneration is likely more than just as a physical barrier. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Marrow compartment contribution to cortical defect healing

Background and purpose - Healing of shaft fractures is commonly described as regards external callus. We wanted to clarify the role of the bone marrow compartment in the healing of stable shaft fractures. Patients and methods - A longitudinal furrow was milled along the longitudinal axis of the femoral shaft in mice. The exposed bone marrow under the furrow was scooped out. The mice were then randomized to no further treatment, or to receiving 2 silicone plugs in the medullary canal distal and proximal to the defect. The plugs isolated the remaining marrow from contact with the defect. Results were studied with histology and flow cytometry. Results - Without silicone plugs, the marrow defect was filled with new bone marrow-like tissue by day 5, and new bone was seen already on day 10. The new bone was seen only at the level of the cortical injury, where it seemed to form simultaneously in the entire region of the removed cortex. The new bone seemed not to invade the marrow compartment, and there was a sharp edge between new bone and marrow. The regenerated marrow was similar to uninjured marrow, but contained considerably more cells. In the specimens with plugs, the marrow compartment was either filled with loose scar tissue, or empty, and there was only minimal bone formation, mainly located around the edges of the cortical injury. Interpretation - Marrow regeneration in the defect seemed to be a prerequisite for normal cortical healing. Shaft fracture treatment should perhaps pay more attention to the local bone marrow.

The Effect of Surgical Technique and Spacer Texture on Bone Regeneration: A Caprine Study Using the Masquelet Technique

BACKGROUND

The Masquelet-induced-membrane technique is a commonly used method for treating segmental bone defects. However, there are no established clinical standards for management of the induced membrane before grafting.

QUESTIONS/PURPOSES

Two clinically based theories were tested in a chronic caprine tibial defect model: (1) a textured spacer that increases the induced-membrane surface area will increase bone regeneration; and (2) surgical scraping to remove a thin tissue layer of the inner induced-membrane surface will enhance bone formation.

METHODS

Thirty-two skeletally mature female goats were assigned to four groups: smooth spacer with or without membrane scraping and textured spacer with or without membrane scraping. During an initial surgical procedure (unilateral, left tibia), a defect was created excising bone (5 cm), periosteum (9 cm), and muscle (10 g). Segments initially were stabilized with an intramedullary rod and an antibiotic-impregnated polymethylmethacrylate spacer with a smooth or textured surface. Four weeks later, the spacer was removed and the induced-membrane was either scraped or left intact before bone grafting. Bone formation was assessed using micro-CT (total bone volume in 2.5-cm central defect region) as the primary outcome; radiographs and histologic analysis as secondary outcomes, with the reviewer blinded to the treatment groups of the samples being assessed 12 weeks after grafting. All statistical tests were performed using a linear mixed effects model approach.

RESULTS

Micro-CT analysis showed greater bone formation in defects with scraped induced membrane (mean, 3034.5 mm³; median, 1928.0 mm³; quartile [Q]1-Q3, 273.3-2921.1 mm³) compared with defects with intact induced membrane (mean, 1709.5 mm³; median, 473.8 mm³; Q1-Q3, 132.2-1272.3 mm³; p = 0.034). There was no difference in bone formation between textured spacers (mean, 2405.5 mm³; median, 772.7 mm³; Q1-Q3, 195.9-2743.8 mm³) and smooth spacers (mean, 2473.2 mm³; median, 1143.6 mm³; Q1-Q3, 230.2-451.1 mm³; p = 0.917).

CONCLUSIONS

Scraping the induced-membrane surface to remove the innermost layer of the induced-membrane increased bone regeneration. A textured spacer that increased the induced-membrane surface area had no effect on bone regeneration.

CLINICAL RELEVANCE

Scraping the induced membrane during the second stage of the Masquelet technique may be a rapid and simple means of improving healing of segmental bone defects, which needs to be confirmed clinically.

Biological Evaluation of Flexible Polyurethane/Poly l-Lactic Acid Composite Scaffold as a Potential Filler for Bone Regeneration

Degradable bone graft substitute for large-volume bone defects is a continuously developing field in orthopedics. With the advance in biomaterial in past decades, a wide range of new materials has been investigated for their potential in this application. When compared to common biopolymers within the field such as PLA or PCL, elastomers such as polyurethane offer some unique advantages in terms of flexibility. In cases of bone defect treatments, a flexible soft filler can help to establish an intimate contact with surrounding bones to provide a stable bone-material interface for cell proliferation and ingrowth of tissue. In this study, a porous filler based on segmented polyurethane incorporated with poly l-lactic acid was synthesized by a phase inverse salt leaching method. The filler was put through in vitro and in vivo tests to evaluate its potential in acting as a bone graft substitute for critical-sized bone defects. In vitro results indicated there was a major improvement in biological response, including cell attachment, proliferation and alkaline phosphatase expression for osteoblast-like cells when seeded on the composite material compared to unmodified polyurethane. In vivo evaluation on a critical-sized defect model of New Zealand White (NZW) rabbit indicated there was bone ingrowth along the defect area with the introduction of the new filler. A tight interface formed between bone and filler, with osteogenic cells proliferating on the surface. The result suggested polyurethane/poly l-lactic acid composite is a material with the potential to act as a bone graft substitute for orthopedics application.

Management of traumatic bone defects: Metaphyseal versus diaphyseal defects

Although bone defects after trauma appear in different locations and forms, many clinicians have adopted a single strategy to deal with any defect. In this overview, a distinction is made between metaphyseal, or cancellous defects, and diaphyseal, or cortical defects. The treatment goals and background of these two types of defects are discussed in order to describe the difference in strategy and hence the difference in treatment method.

Induced membrane technique for treating tibial defects gives mixed results

Aims

This study describes the use of the Masquelet technique to treat segmental tibial bone loss in 12 patients.

Patients and Methods

This retrospective case series reviewed 12 patients treated between 2010 and 2015 to determine their clinical outcome. Patients were mostly male with a mean age of 36 years (16 to 62). The outcomes recorded included union, infection and amputation. The mean follow-up was 675 days (403 to 952).

Results

The mean tibial defect measured 5.8 cm (2 to 15) in length. Of the 12 patients, 11 had an open fracture. Eight underwent fixation with an intramedullary nail, three with plates and one with a Taylor Spatial Frame. The mean interval between stages was 57 days (35 to 89). Bony union was achieved in only five patients. Five patients experienced infective complications during treatment, with two requiring amputation because of severe infection.

Conclusion

The Masquelet technique was relatively ineffective in achieving union in this series, and was associated with a high rate of infection. Cite this article: Bone Joint J 2017;99-B:680–5.

Modified Masquelet technique using allogeneic umbilical cord-derived mesenchymal stem cells for infected non-union femoral shaft fracture with a 12 cm bone defect: A case report

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A case of infected non-union fracture with critical-sized bone defect.

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Modified Masquelet technique was used to overcome the defect.

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The addition of allogenic UC-MSCs, BMP-2 and hydroxyapatite encourages healing.

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This technique may serve as an effective way to overcome large defects.

Introduction

Non-union due to large bone loss often causes significant long-term morbidity. We incorporate the use of allogeneic umbilical cord-derived mesenchymal stem cells (UC-MSCs) as part of the diamond concept of regenerative medicine in a case of infected non-union fracture.

Presentation of case

We reported a 54-year-old female patient presenting with pain on the right thigh. She was previously diagnosed with a closed fracture of the right femoral shaft and underwent four surgeries before finally being referred to Dr. Cipto Mangunkusumo General Hospital with infected non-union of the right femoral shaft. The patient was treated with a combination of UC-MSCs, bone morphogenetic protein-2 (BMP-2), Hydroxyapatite (HA), and mechanical stabilization using Masquelet Technique. The combination of allogeneic MSCs, BMP2, HA, and Masquelet Technique was successful in creating new bone with no apparent side effects.

Discussion

Bone loss might be caused by external factors (true defects), or structural loss of the existing bone. The combination of allogeneic UC-MSCs, BMP-2, HA and an induced membrane technique pioneered by Masquelet allowed for faster regeneration process and more optimal bone healing. This paper aims to assess and compare the result of such procedures with the previous four surgeries done to the patient, which did not yield satisfactory results.

Conclusion

The application of allogeneic UC-MSC, BMP-2, HA and Masquelet technique as proposed in the diamond concept is a viable method in treating critical-sized bone defect and provides an effective way to overcome non-union caused by large defect.

Two stage management of Cierny-Mader type IV chronic osteomyelitis of the long bones

INTRODUCTION

Cierny-Mader (C-M) type IV chronic osteomyelitis represents a complex clinical challenge with permeation of extensive bone and soft tissue involvement. Aggressive debridement through viable tissue margin includes en bloc resection improves the odds of eradication of infection, which creates large bone and soft tissue loss in treating this type of osteomyelitis. The potentially large defects increase reconstruction problems with traditional reconstruction technique. The newly staged induced membrane technique presents length-independent, potential as an alternative reconstruction method for segmental bone defects due to type IV chronic osteomyelitis. The purpose of this study was to assess the result and related factors of C-M type IV chronic osteomyelitis treated with staged methods of aggressive debridement and induced membrane technique.

METHODS

From January 2012 to January 2014, 36 consecutive adult patients of C-M type IV chronic osteomyelitis were treated by this staged method in our clinical center with a minimum of 2-years follow-up. The clinical and imaging results were retrospectively analyzed.

RESULTS

Five patients had a second debridement and eight needed a local flap transfer to cover the wound in the first stage. Patients formed a mean of 5.5cm (range: 2-10.9) segmental bone defect; Sixteen patients had autograft and twenty had autograft mixed allograft in the second stage. The mean follow-up time was 29.5 months (range: 24-45). No patients required amputation. Bone union was achieved in all patients. Clinical eradication of osteomyelitis was achieved in 35 (97%) patients, 35 (97%) patients were able to walk independently, and 31patients (86%) returned to work. Patients returned to a mean of 82% (46.3%-100%) lower extremity function. Bone union time was not dependent on the length of bone defect, but associated with the infection site (p=0.005) and age (p=0.005).

CONCLUSIONS

Staged methods of aggressive debridement and induced membrane technique seems to be a simple, reliable and effective for the treatment of C-M type IV chronic osteomyelitis. Advanced age and poor soft tissue envelope may have adverse affects and are relative contraindications. The combined assessment and management of such patients with a plastic surgeon are advocated.

Success rate and risk factors of failure of the induced membrane technique in children: a systematic review

The induced membrane technique was designed by Masquelet et al. to address segmental bone defects of critical size in adults. It has been used after bone defects of traumatic, infectious and tumoral origin with satisfactory results. Recently, it has been used in children but, after an initial enthusiasm, several cases of failure have been reported. The purpose of this study was to assess the success rate and the risk factors of failure of the induced membrane for children. We conducted a systematic review of all the studies reporting the results of the induced membrane technique to address bone defects of critical size in children. Our primary outcome was the success rate of the technique defined as a bone union before any iterative surgery. Our secondary outcomes were the complications and the risk factors of failure. We searched Medline via Pubmed, EMBASE and the Cochrane Library. Twelve studies, including 69 patients, met the inclusion criteria. There were 41 boys and 28 girls. Mean age at surgery was 10 years. Mean size of resection was 12.38 cm and the mean time between the two stages was 5.86 months. Mean rate of bone union after the two stages of the induced membrane technique was 58% (40/69) but this rate increased to 87% after revision surgeries (60/69). Main complications were non-unions (19/69), lysis of the graft (6/69) and fractures of the bone graft (6/69). Only 1/69 deep infection was reported. Other non specific complications were regularly reported such limb length discrepancies, joint stiffness and protruding wires. Risk factor of failure that could be suspected comprised the resection of a malignant tumour, a bone defect located at the femur, a wide resection, a long time between the two stages, an unstable osteosynthesis and a bone graft associating autograft to other graft materials. The induced membrane technique is suitable for bone defects of critical size in children. It is a reliable technique with no need of micro vascular surgery. However, we found several risk factors of failure for the use of the induced membrane technique to address segmental bone defect of critical size in children.