The Impact of Defect Size on Bone Healing in Critical-Size Bone Defects Investigated on a Rat Femur Defect Model Comparing Two Treatment Methods

Critical-size bone defects up to 25 cm can be treated successfully using the induced membrane technique established by Masquelet. To shorten this procedure, human acellular dermis (HAD) has had success in replacing this membrane in rat models. The aim of this study was to compare bone healing for smaller and larger defects using an induced membrane and HAD in a rat model. Using our established femoral defect model in rats, the animals were placed into four groups and defects of 5 mm or 10 mm size were set, either filling them with autologous spongiosa and surrounding the defect with HAD or waiting for the induced membrane to form around a cement spacer and filling this cavity in a second operation with a cancellous bone graft. Healing was assessed eight weeks after the operation using µ-CT, histological staining, and an assessment of the progress of bone formation using an established bone healing score. The α-smooth muscle actin used as a signal of blood vessel formation was stained and counted. The 5 mm defects showed significantly better bone union and a higher bone healing score than the 10 mm defects. HAD being used for the smaller defects resulted in a significantly higher bone healing score even than for the induced membrane and significantly higher blood vessel formation, corroborating the good results achieved by using HAD in previous studies. In comparison, same-sized groups showed significant differences in bone healing as well as blood vessel formation, suggesting that 5 mm defects are large enough to show different results in healing depending on treatment; therefore, 5 mm is a viable size for further studies on bone healing.

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.

Management of wounds with exposed bone structures using an induced-membrane followed by polymethyl methacrylate and second-stage skin grafting in the elderly with a 3-year follow-up

The treatment of traumatic wounds with exposed bone or tendons is often challenging. An induced membrane (IM) is used to reconstruct bone defects, as it provides an effective and sufficient blood supply for bone and soft-tissue reconstruction. This study explored a novel two-stage strategy for wound management, consisting of initial wound coverage with polymethyl methacrylate (PMMA) and an autologous split-thickness skin graft under the IM. Fifty inpatients were enrolled from December 2016 to December 2019. Each patient underwent reconstruction according to a two-stage process. In the first stage, the defect area was thoroughly debrided, and the freshly treated wound was then covered using PMMA cement. After 4-6 weeks, during the second stage, the PMMA cement was removed to reveal an IM covering the exposed bone and tendon. An autologous split-thickness skin graft was then performed. Haematoxylin and eosin (H&E) staining and immunohistochemical analysis of vascular endothelial growth factor (VEGF), CD31 and CD34 were used to evaluate the IM and compare it with the normal periosteal membrane (PM). The psychological status and the Lower Extremity Function Scale (LEFS) as well as any complications were recorded at follow-up. We found that all skin grafts survived and evidenced no necrosis or infection. H&E staining revealed vascularised tissue in the IM, and immunohistochemistry showed a larger number of VEGF-, CD31- and CD34-positive cells in the IM than in the normal PM. The duration of healing in the group was 5.40 ± 1.32 months with a mean number of debridement procedures of 1.92 ± 0.60. There were two patients with reulceration in the group. The self-rating anxiety scale scores ranged from 35 to 60 (mean 48.02 ± 8.12). Postoperatively, the LEFS score was 50.10 ± 9.77. Finally, our strategy for the management of a non-healing wound in the lower extremities, consisting of an IM in combination with skin grafting, was effective, especially in cases in which bony structures were exposed in the elderly. The morbidity rate was low.

Induced Membrane Technique for the Treatment of Infected Forearm Nonunion: A Retrospective Study

PURPOSE

Infected forearm nonunion remains a challenge for the hand surgeon. Autologous bone grafting within an induced membrane following implantation of a cement spacer, also known as the Masquelet technique, is a procedure used for addressing segmental bone defects. This report summarized our experience using this technique to treat the infected forearm nonunion.

METHODS

We retrospectively reviewed a series of 32 patients treated for infected forearm nonunion by the 2-stage Masquelet technique between 2009 and 2018. There was an infected nonunion of the ulna in 28 patients and an infected nonunion of the radius in 4 patients. All patients had undergone an average of 2.7 procedures before presenting at our institution. Treatment involved a staged procedure in which an antibiotic-impregnated cement spacer was implanted into the bone defect following debridement without internal fixation. It was left in place for 4-6 weeks, during which time a membrane formed around the cement spacer. In the second stage, the induced membrane was incised, and the cement spacer was removed. The defect was then filled with cancellous autograft with the addition of internal fixation. Postoperative radiographs were taken for the evaluation of bone healing. The functional results of the affected forearm were evaluated for motion loss of elbow or wrist and rotation loss of forearm.

RESULTS

All nonunions healed without recurrent infection or loosening of internal fixation at the time of final follow-up. All the patients showed substantial functional improvement, with excellent results in 14 patients, satisfactory results in 13, and unsatisfactory results in 5.

CONCLUSIONS

The induced membrane technique is an effective solution for infected forearm nonunion.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Probing the role of methyl methacrylate release from spacer materials in induced membrane bone healing

In the induced membrane (IM) technique for bone reconstruction, a poly(methyl methacrylate) (PMMA) spacer is implanted to induce formation of a foreign body membrane around the defect site. Membrane development is essential for later bone grafting success, yet the mechanism by which the IM promotes bone regeneration remains unknown, as are the ways that spacer composition plays a role in the membrane's healing potential. This study investigated the impact of leached methyl methacrylate (MMA)-the major monomeric component of PMMA-on IM development. In vitro cell culture found that MMA elution did not impact endothelial cell or mesenchymal stem cell proliferation. For in vivo analysis, we advanced a streamlined rat femoral model to efficiently study the influence of spacer properties on IM characteristics. Comparison of membrane formation around polycaprolactone (PCL), MMA-eluting PCL (high-dose PCL-MMA and low-dose PCL-MMA), and surgical PMMA revealed robust membranes enveloped all groups after 4 weeks in vivo, with elevated expression of osteogenic bone morphogenetic protein-2 and angiogenic vascular endothelial growth factor compared with the surrounding muscle and bone tissues. Growth factor quantitation in IM tissue found no statistically significant difference between groups. New bone growth, vascularization, and CD163+ macrophage populations surrounding the polymer implants were also quantified; and blood vessel formation around high-dose PCL-MMA was found to be significantly decreased compared with PCL alone. To the best of our knowledge, these findings represent the first time that results have been obtained about the characteristics of membranes formed around PCL in the IM setting.

Use of Tantalum Trabecular Metal Cones for Management of Nonunion of the Distal Femur with Segmental Bone Defects: Technique and Case Series

Introduction:

Segmental bone loss in the distal femur presents a challenge for reconstruction regardless of etiology. Use of tantalum trabecular metal cones with intramedullary fixation and autologous bone graft may be used as a salvage technique in difficult situations where other options have either been exhausted or are unavailable.

Case Report:

Surgical planning and technique for this approach to reconstruction are described. A retrospective review of five cases with >1 year of follow-up was performed to provide radiographic and clinical outcomes. All five patients had satisfactory outcomes with clinical union and retention of implants at final follow-up (average >4 years).

Conclusions:

Use of tantalum metal cones for reconstruction of distal femur nonunion with segmental bone defects can be a successful technique in a complex group of patients.

Corrigendum: Total Flavonoids of Rhizoma Drynariae Promotes Differentiation of Osteoblasts and Growth of Bone Graft in Induced Membrane Partly by Activating Wnt/β-Catenin Signaling Pathway

[This corrects the article DOI: 10.3389/fphar.2021.675470.].

Total Flavonoids of Rhizoma Drynariae Promotes Differentiation of Osteoblasts and Growth of Bone Graft in Induced Membrane Partly by Activating Wnt/β-Catenin Signaling Pathway

Total flavonoids of Rhizoma drynariae (TFRD), a Chinese medicine, is widely used in the treatment of fracture, bone defect, osteoporosis and other orthopedic diseases, and has achieved good effects. Purpose of this trial was to explore efficacy of TFRD on bone graft’s mineralization and osteoblasts’ differentiation in Masquelet induced membrane technique in rats. Forty male Sprague-Dawley rats were randomly divided into high dose group (H-TFRD), middle dose group (M-TFRD), low dose group (L-TFRD) and control group (control). The critical size bone defect model of rats was established with 10 rats in each group. Polymethyl methacrylate (PMMA) spacer was implanted into the defect of right femur in rats. After the formation of the induced membrane, autogenous bone was implanted into the induced membrane. After 12 weeks of bone graft, bone tissues in the area of bone graft were examined by X-ray, Micro-CT, hematoxylin-eosin (HE) and Masson trichrome staining to evaluate the growth of the bone graft. The β-catenin, c-myc, COL1A1, BMP-2 and OPN in bone graft were quantitatively analyzed by Western blot and Immunohistostaining. Osteoblasts were cultured in the medium containing TFRD. Cell Counting Kit-8 (CCK-8) method, Alkaline phosphatase (ALP) and Alizarin Red S (ARS) staining, Western blot, RT-PCR and other methods were used to detect the effects of TFRD on the proliferation of osteoblasts and the regulation of Wnt/β-catenin signaling pathway. In vivo experiments showed that the growth and mineralization of bone graft in TFRD group was better. Moreover, the expression of Wnt/β-catenin and osteogenesis-related proteins in bone tissue of TFRD group was more than that in other groups. In vitro experiments indicated that osteoblasts proliferated faster, activity of ALP was higher, number of mineralized nodules and proteins related to osteogenesis were more in TFRD group. But blocking Wnt/β-catenin signaling pathway could limit these effects. Therefore, TFRD could promote mineralization of bone graft and differentiation of osteoblasts in a dose-dependent manner during growing period of the bone graft of induced membrane technique, which is partly related to the activation of Wnt/β-catenin signaling pathway.

Masquelet's induced membrane technique: Review of current concepts and future directions

Masquelet's induced membrane technique (MIMT) is a relatively new, two-stage surgical procedure to reconstruct segmental bone defects. First performed by Dr. Masquelet in the mid-1980s, MIMT has shown great promise to revolutionize critical-sized bone defect repair and has several advantages over its alternative, distraction osteogenesis (DO). Also, its success in extremely challenging cases (defects > 15 cm) suggests that its study could lead to discovery of novel biological mechanisms that might be at play during segmental defect healing and fracture non-union. MIMT's advantages over DO have led to a world-wide increase in MIMT procedures over the past decades. However, MIMT often needs to be repeated and so the average initial success rate in adults lags significantly behind that of DO (86% vs 95%, respectively). The autologous foreign-body membrane created during the first stage by the immune system's response to a polymethyl methacrylate bone cement spacer is critical to supporting the morselized bone graft implanted in the second stage. However, the biological and/or physical mechanisms by which the membrane supports graft to bone union are unclear. This lack of knowledge makes refining MIMT and improving the success rates through technique improvements and patient selection a significant challenge and hinders wider adoption. In this review, current knowledge from basic, translational, and clinical studies is summarized. The dynamics of both stages under normal conditions as well as with drug or material perturbations is discussed along with perspectives on high-priority future research directions.

Induced membrane by silver-coated knee megaprosthesis: keep or toss?

In the orthopaedic field the foreign body reaction is well known for therapeutic purposes in the alleged Masquelet technique consisting of segmental bone loss two-stage reconstruction. The induced membrane creates advantageous local conditions that promote bone graft remodeling and osteointegration. The aim of our study was to describe the first two cases in Literature of induced membrane observed following silver-coated knee megaprosthesis reconstruction. In addition, it was our interest to evaluate their histological features.

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.

Salvage Reconstruction With the Masquelet Technique Following Wide Resection for Chondrosarcoma of the Proximal Femoral Metaphysis: A Case Report

BACKGROUND

Bone reconstruction following a wide resection for a malignant musculoskeletal tumor remains challenging, especially for an intercalary defect following the resection of a metaphyseal lesion.

CASE REPORT

Here, we describe a surgical procedure using the Masquelet technique for the biological reconstruction of a huge subtrochanteric bone defect following failed pasteurized autologous bone grafting for a conventional chondrosarcoma of the proximal femoral metaphysis with a subtrochanteric pathological fracture. The patient, a 43-year-old Japanese male, was able to walk without a cane or a brace at 15 months after the final operation (International Society of Limb Salvage score, 86.7%).

CONCLUSION

This procedure should be considered as one of the reconstruction options following the wide resection of malignant bone tumors located in the metaphysis.

Induced Periosteum-Mimicking Membrane with Cell Barrier and Multipotential Stromal Cell (MSC) Homing Functionalities

The current management of critical size bone defects (CSBDs) remains challenging and requires multiple surgeries. To reduce the number of surgeries, wrapping a biodegradable fibrous membrane around the defect to contain the graft and carry biological stimulants for repair is highly desirable. Poly(ε-caprolactone) (PCL) can be utilised to realise nonwoven fibrous barrier-like structures through free surface electrospinning (FSE). Human periosteum and induced membrane (IM) samples informed the development of an FSE membrane to support platelet lysate (PL) absorption, multipotential stromal cells (MSC) growth, and the prevention of cell migration. Although thinner than IM, periosteum presented a more mature vascular system with a significantly larger blood vessel diameter. The electrospun membrane (PCL3%-E) exhibited randomly configured nanoscale fibres that were successfully customised to introduce pores of increased diameter, without compromising tensile properties. Additional to the PL absorption and release capabilities needed for MSC attraction and growth, PCL3%-E also provided a favourable surface for the proliferation and alignment of periosteum- and bone marrow derived-MSCs, whilst possessing a barrier function to cell migration. These results demonstrate the development of a promising biodegradable barrier membrane enabling PL release and MSC colonisation, two key functionalities needed for the in situ formation of a transitional periosteum-like structure, enabling movement towards single-surgery CSBD reconstruction.

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.

Introduction of a New Surgical Method to Improve Bone Healing in a Large Bone Defect by Replacement of the Induced Membrane by a Human Decellularized Dermis Repopulated with Bone Marrow Mononuclear Cells in Rat

The Masquelet technique for the treatment of large bone defects is a two-stage procedure based on an induced membrane. We eliminate the first surgical step by using a decellularized dermal skin graft (Epiflex^®) populated with bone marrow mononuclear cells (BMC), as a replacement for the induced membrane. The aim of this study was to demonstrate the feasibility of this technology and provide evidence of equivalent bone healing in comparison to the induced membrane-technique. Therefore, 112 male Sprague–Dawley rats were allocated in six groups and received a 10 mm femoral defect. Defects were treated with either the induced membrane or decellularized dermis, with or without the addition of BMC. Defects were then filled with a scaffold (β-TCP), with or without BMC. After a healing time of eight weeks, femurs were taken for histological, radiological and biomechanical analysis. Defects treated with Epiflex^® showed increased mineralization and bone formation predominantly in the transplanted dermis surrounding the defect. No significant decrease of biomechanical properties was found. Vascularization of the defect could be enhanced by addition of BMC. Considering the dramatic reduction of a patient’s burden by the reduced surgical stress and shortened time of treatment, this technique could have a great impact on clinical practice.

Towards Understanding Therapeutic Failures in Masquelet Surgery: First Evidence that Defective Induced Membrane Properties are Associated with Clinical Failures

The two-stage Masquelet induced-membrane technique (IMT) consists of cement spacer-driven membrane induction followed by an autologous cancellous bone implantation in this membrane to promote large bone defect repairs. For the first time, this study aims at correlating IMT failures with physiological alterations of the induced membrane (IM) in patients. For this purpose, we compared various histological, immunohistochemical and gene expression parameters obtained from IM collected in patients categorized lately as successfully (Responders; n = 8) or unsuccessfully (Non-responders; n = 3) treated with the Masquelet technique (6 month clinical and radiologic post-surgery follow-up). While angiogenesis or macrophage distribution pattern remained unmodified in non-responder IM as compared to responder IM, we evidenced an absence of mesenchymal stem cells and reduced density of fibroblast-like cells in non-responder IM. Furthermore, non-responder IM exhibited altered extracellular matrix (ECM) remodeling parameters such as a lower expression ratio of metalloproteinase-9 (MMP-9)/tissue inhibitor of metalloproteinases (TIMP-1) mRNA as well as an important collagen overexpression as shown by picrosirius red staining. In summary, this study is the first to report evidence that IMT failure can be related to defective IM properties while underlining the importance of ECM remodeling parameters, particularly the MMP-9/TIMP-1 gene expression ratio, as early predictive biomarkers of the IMT outcome regardless of the type of bone, fracture or patient characteristics.

Size matters: Effect of granule size of the bone graft substitute (Herafill®) on bone healing using Masquelet's induced membrane in a critical size defect model in the rat's femur

The Masquelet technique for the treatment of large bone defects is a two-stage procedure based on an induced membrane. The size of a scaffold is reported to be a critical factor for bone healing response. We therefore aimed to investigate the influence of the granule size of a bone graft substitute on bone marrow derived mononuclear cells (BMC) supported bone healing in combination with the induced membrane. We compared three different sizes of Herafill® granules (Heraeus Medical GmbH, Wehrheim) with or without BMC in vivo in a rat femoral critical size defect. A 10 mm defect was made in 126 rats and a membrane induced by a PMMA-spacer. After 3 weeks, the spacer was taken out and membrane filled with different granule sizes. After 8 weeks femurs were taken for radiological, biomechanical, histological, and immunohistochemical analysis. Further, whole blood of the rat was incubated with granules and expression of 29 peptide mediators was assessed. Smallest granules showed significantly improved bone healing compared to larger granules, which however did not lead to an increased biomechanical stability in the defect zone. Small granules lead to an increased accumulation of macrophages in situ which could be assigned to the inflammatory subtype M1 by majority. Increased release of chemotactic respectively proangiogenic active factors in vitro compared to syngenic bone and beta-TCP was observed. Granule size of the bone graft substitute Herafill® has significant impact on bone healing of a critical size defect in combination with Masquelet's technique in terms of bone formation and inflammatory potential.

[Masquelet technique combined with artificial dermis for the treatment of bone and soft tissue defects in rabbits]

Objective

To investigate the effect of Masquelet technique combined with artificial dermis on repairing bone and soft tissue defects in rabbits, and to observe the microstructure and vascularization of induced membrane, so as to guide the clinical treatment of Gustilo-Anderson type Ⅲ open fracture with large bone defect and soft tissue defect.

Methods

Eighty male rabbits, weighing 2.03-2.27 kg (mean, 2.11 kg), were selected. The bilateral thighs of 64 rabbits were randomly divided into experimental group and control group, the remaining 16 rabbits were sham operation group. Bone and soft tissue defect models of femur were made in all rabbits. In the experimental group, the first stage of Masquelet technique was used [polymethyl methacrylate bone cement was filled in bone defect area] combined with artificial dermis treatment; in the control group, the first stage of Masquelet technique was used only; in the sham operation group, the wound was sutured directly without any treatment. Four rabbits in sham operation group and 16 rabbits in the experimental group and control group were sacrificed at 2, 4, 6, and 8 weeks after operation, respectively. The induced membranes and conjunctive membranes were observed on both sides of the femur. The membrane structure was observed by HE staining, and the microvessel density (MVD) was counted by CD34 immunohistochemical staining.

Results

Gross observation showed that the spongy layer of collagen in the artificial dermis of the experimental group disappeared completely at 4 weeks after operation, and the induced membrane structure of the experimental group and the control group was complete; the membrane structure of the control group was translucent, and the membrane structure of the experimental group was thicker, light red opaque, accompanied by small vessel proliferation. The membrane structure of the experimental group and the control group increased gradually from 6 to 8 weeks after operation. In the sham operation group, only scar tissue proliferation was observed over time. HE staining showed that a large number of muscle fibers and a small amount of collagen fibers proliferation with inflammatory cell infiltration could be seen in the experimental group and the control group at 2 weeks after operation; most of the sham operation group were muscle fibers with a small amount of interfibrous vessels. At 4 weeks after operation, collagen fibers increased and some blood vessels formed in the experimental group. The nuclei of collagen fibers in the control group were round-like, while those in the experimental group were flat-round. At 6 and 8 weeks after operation, the collagen fibers in the experimental group and the control group increased. The nuclei of the collagen fibers in the control group were still round-like. The nuclei of the collagen fibers in the experimental group were fusiformis and deeply stained compared with those in the control group. The proliferation of blood vessels was observed in both groups, and the number of proliferation vessels in the experimental group was increased compared with that in the control group. In the sham operation group, a large number of fibroblasts still appeared, but no significant proliferation of blood vessels with time was observed. CD34 immunohistochemical staining showed that MVD in each group increased gradually with the prolongation of time after operation. MVD in the sham operation group was significantly higher than that in the experimental group and the control group at 2 weeks after operation, and significantly smaller than that in the experimental group and the control group at 4, 6, and 8 weeks after operation ( P<0.05). MVD in the experimental group was significantly higher than that in the control group at 4 and 6 weeks after operation ( P<0.05), but there was no significant difference in MVD between the two groups at 2 and 8 weeks ( P>0.05).

Conclusion

Masquelet technique combined with artificial dermis in the treatment of femoral bone defect and soft tissue defect in rabbits can significantly promote the vascularization of membrane structure at 4-6 weeks after operation. The combination of these two methods has guiding significance for the treatment of Gustilo-Anderson type Ⅲ open fracture with bone and soft tissue defects.

Use of the induced membrane technique for long bone reconstruction in low-resource settings

The induced membrane technique is a simple and effective method for reconstructing bone defects in limbs. It is suited to low resource settings, if sufficient care is taken in preparing and performing the technique. Key points for the success of this procedure are described here. In austere environments, its use is mostly limited by possibilities for treatment of bone infection, but also by access to surgical cement and available bone stock. Alternatives for overcoming these last two obstacles are presented.

Reconstruction of Carpal Bone Loss of Septic Wrist Arthritis Using Induced Membrane Technique

The induced membrane technique has been widely used for the reconstruction of the segmental bone defect. The technique requires two-stage surgery. The first surgery is debridement of the affected bone and replacement of the defect by cement spacer. The spacer is removed at the second surgery, and the defect is filled with cancellous bone. The use of the technique for septic wrist arthritis treatment has not been reported. We report two cases of septic wrist arthritis treated by the induced membrane technique. Radical debridement including the carpal bones was performed as a first surgery. The cement spacer was placed into the bone defect after first surgery; then cancellous bone was transplanted into the induced membrane several weeks later. External fixator or plate fixation was performed simultaneously. Bone formation was observed in both cases at several months after the reconstruction surgery. There was no pain or recurrence of infection in both cases. We consider this technique is a possible method for reconstruction, especially in a difficult case.

Type III open tibia fractures in low-resources setting. Part 3: achievement of bone union and treatment of segmental bone defects

After presentations of the principles of limb salvage and soft-tissue coverage for Gustilo III open tibia fractures, this third part is dedicated to management of tibial non-unions in low-resource settings. Inter-tibiofibular grafting and the induced membrane technique are preferred because they make it possible to deal with almost all situations. Key technical points of these methods are presented, followed by treatment guidelines based on Catagni's classification and bone defect size.

Masquelet's induced membrane promotes the osteogenic differentiation of bone marrow mesenchymal stem cells by activating the Smad and MAPK pathways

The Masquelet's induced membrane (IM) technique is widely used to treat large segmental bone defects due to its physical priority and biological function. However, the underlying molecular mechanism of the IM on bone formation remains unknown. In the present study, rat bone marrow-derived mesenchymal stem cells (BMSCs) were used as an in vitro model and bone morphogenetic protein 2 (BMP-2) was used as a positive control to evaluate the effects of the IM on the osteogenic differentiation of BMSCs. Although the IM group did not exhibit a significant increase in the expression of Runt-related transcription factor 2 (Runx2), Collagen I (Col I), osteocalcin (OCN) and alkaline phosphatase (ALP) relative to the BMP-2 administration, the IM was considerably effective compared with the untreated group. Mechanistically, we found that the IM activated the Smad and mitogen-activated protein kinase (MAPK) pathways, which was further confirmed by application of specific inhibitors of Smad1/5/8 (LDN-193189) and ERK1/2 (U0126). After the combined treatment of the IM and LDN-193189 as well as U0126, the IM-induced increase in Runx2, Col I, and OCN expression was significantly inhibited. These results suggest that IM promotes the osteogenic differentiation of rat BMSCs by activating the Smad1/5/8 and MAPK pathways.

Circular external fixation and cemented PMMA spacers for the treatment of complex tibial fractures and infected nonunions with segmental bone loss

PURPOSE

The purpose of this study was to compare the outcome of combined circular external fixation and cemented polymethylmethacrylate (PMMA) spacer application between a cohort of patients with grade 3 open fractures and infected tibial nonunions and concomitant segmental bone loss.

METHODS

The study was designed as a retrospective cohort study. All patients who were treated for complex tibial fractures or infected nonunions with segmental bone loss between 2009 and 2013 were included if they were aged between 16 years and 60 years, sustained acute traumatic grade 3 open tibial fractures, presented with infected nonunion, and were followed up for a minimum of 12 months. Patients with a history of ipsilateral tibial fractures, contralateral lower extremity fractures, polytrauma, chest, or abdominal trauma and patients with head injuries were excluded. Both groups were treated with aggressive debridement, circular external fixation, and antibiotic-impregnated PMMA spacer. Outcome measures were the time in the external fixator (EFT) and the external fixation index (EFI).

RESULTS

Twenty-four patients with a mean age of 32 ± 14.7 years were included. Twelve patients with a mean age of 32 + 14 years and a mean bone defect of 82 + 36 mm were treated for acute complex grade 3 open tibial fractures, and 12 patients with a mean age of 35.1 + 15.7 years and a mean bone defect of 50 + 26 mm were treated for infected nonunions. There was no significant difference ( p = 0.44) between the groups for EFT (249 ± 99 days-tibial fractures; 255 ± 142 days-infected nonunion). There were significant between group differences ( p = 0.027) for EFI (37.3 ± 9.1 cm/days-tibial fractures; 56 ± 14.5 cm/days-infected nonunion).

CONCLUSION

The findings of this study suggest that patients were treated for infected nonunion with segmental bone loss using circular external fixation, distraction osteogenesis, and antibiotic-impregnated PMMA spacers, and the spacers may not offer any advantage over a conventional approach using the principles of osteogenesis only. In contrast, antibiotic-impregnated spacers for open tibial trauma were advantageous and reduced the EFI considerably.

Salvage of mangled upper extremity using the Masquelet technique in a child: A case report

Aim

To report our experience with the Masquelet concept in a pediatric upper extremity following an open injury to the elbow.

Methods

A case report and literature review.

Results

An 11-year-old boy was transferred to our institution after a motor vehicle collision. There was a primary loss of the ulnohumeral articulation and the surrounding soft tissues as well as the ulnar nerve. Reconstruction used the Masquelet-induced membrane technique and a soft tissue flap. At the 30-month follow-up, the extremity was pain free and functional.

Conclusion

This case highlights the value of the Masquelet technique in pediatric extremity injuries, where there is a loss of a major articular segment, as well as significant soft tissue compromise.

Influence of External Beam Radiotherapy on the Properties of Polymethyl Methacrylate-Versus Silicone-Induced Membranes in a Bilateral Segmental Bone Defect in Rats

INTRODUCTION

Standard care for malignant tumors arising next to a bone structure is surgical removal with safety margins, followed by external beam radiotherapy (EBRT). Complete tumor removal can result in large bone defects. A two-step bone reconstruction technique using the induced membrane (IM) technique has proven its efficacy to bridge gap nonunion. During the first step, a spacer is placed in the bone gap. The spacer then is removed and the IM around it is filled with autologous cancellous bone graft. However, the feasibility of this technique with the addition of adjuvant EBRT between the two reconstruction steps has not yet been studied. Polymethyl methacrylate (PMMA) used to be the standard spacer material for the first step. Silicone spacers could replace them owing to their good behavior when submitted to EBRT and their easier removal from the surgical site during the second step. The aim of this study was to evaluate the influence of EBRT on the histological and biochemical properties of IM induced using PMMA or silicone as spacer.

MATERIALS AND METHODS

The analyses were performed on PMMA- or silicone-IM with and without EBRT in a 6-mm bilateral femoral defect in 32 rats. Thickness and vessel content were measured in both groups. Bone morphogenetic protein 2 (BMP2) and vascular endothelial growth factor (VEGF) content in lysates of the crushed membranes were measured by enzyme immunoassay. Finally, alkaline phosphatase activity was analyzed in human bone marrow stromal cell cultures in contact with the same lysates.

RESULTS

EBRT did not change the histological structure of the cellular internal layer or the fibrous outer layer. The nature of the spacer only influenced IM thickness, PMMA-IM with external radiotherapy being significantly thicker. EBRT decreased the vascular density of IM but was less effective on VEGF/BMP2 production. In vitro, IM could have an osteoinductive potential on human bone marrow stem cells.

CONCLUSION

EBRT did not modify the histological properties of IMs but decreased their vascular density. VEGF and BMP2 production within IMs was not affected by EBRT. Silicone spacers are able to induce membranes with similar histological characteristics to PMMA-IM.

Reconstruction of traumatic bone loss using the induced membrane technique: preliminary results about 11 cases

INTRODUCTION

The use of Masquelet technique is a serious option to consider for biologic reconstruction of severe bone loss. Here is exposed a continuous and prospective study on bone loss management using that technique. The aims of this study were to assess epidemiology of bone loss due either to trauma or to non-unions and to give preliminary results.

PATIENTS AND METHODS

It was a prospective study from April 2015 to december 2016 involving patients treated using the induced membrane technique for a diaphyseal bone defect due either to trauma or non-unions. AO plates or Orthofix external fixators were used for osteosynthesis. Bone healing was radiologically assessed and any complications were listed.

RESULTS

During the study period, 11 patients were treated using the induced membrane technique. There were 8 males and 3 females. Their mean age was 40.45 years (21-59). The skeletal segments concerned were 2 humerus, 6 femurs and 3 tibias with a mean bone defect length of 4,45 cm (2.5-8). The delay between reconstruction and trauma was 8 months (20 days - 3 years). After a mean follow-up of 6.54 months (3-11) six patients presented a good radiological healing (4 femurs, 2 humerus) whereas in four patients, autograft osteointegration was still ongoing (2 femurs, 2 tibias). A tibia secondary infection was observed in a patient with the graft partial resorption. In another patient, an initial gangrene lead to a leg amputation.

CONCLUSION

The induced membrane technique is an excellent option for bone defect reconstruction compared to other usual bone graft techniques. It helped us to manage large bone loss in various skeletal segments.

Effects of Local Antibiotic Delivery from Porous Space Maintainers on Infection Clearance and Induction of an Osteogenic Membrane in an Infected Bone Defect

Reconstruction of large bone defects can be complicated by the presence of both infection and local antibiotic administration. This can be addressed through a two-stage reconstructive approach, called the Masquelet technique, that involves the generation of an induced osteogenic membrane over a temporary poly(methyl methacrylate) (PMMA) space maintainer, followed by definitive reconstruction after the induced membrane is formed. Given that infection and antibiotic delivery each have independent effects on local tissue response, the objective of this study is to evaluate the interaction between local clindamycin release and bacterial contamination with regards to infection prevention and the restoration of pro-osteogenic gene expression in the induced membrane. Porous PMMA space maintainers with or without clindamycin were implanted in an 8 mm rat femoral defect model with or without Staphylococcus aureus inoculation for 28 days in a full-factorial study design (four groups, n = 8/group). Culture results demonstrated that 8/8 animals in the inoculated/no antibiotic group were infected at 4 weeks, which was significantly reduced to 1/8 animals in the inoculated/antibiotic group. Quantitative polymerase chain reaction analysis demonstrated that clindamycin treatment restores inflammatory cytokine and growth factor expression to the same levels as the no inoculation/no antibiotic group, demonstrating that clindamycin can ameliorate the negative effects of bacterial inoculation and does not itself negatively impact the expression of important cytokines. Main effect analysis shows that bacterial inoculation and clindamycin treatment have independent and interacting effects on the gene expression profile of the induced membrane, further highlighting that antibiotics play an important role in the regeneration of infected defects apart from their antimicrobial properties.

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.

Restoration of long bone defects treated with the induced membrane technique: protocol and outcomes

This prospective study was undertaken at a regional tertiary referral centre to evaluate the results of treatment of bone defects managed with the induced membrane (IM) technique. Inclusion criteria were patients with bone defects secondary to septic non-union, chronic osteomyelitis and acute fracture with bone loss. Pathological fractures with bone loss were excluded. Data collection included patient demographics, pathology, previous surgical intervention, size of bone defect, type of graft implanted, time-to-union and complications/reinterventions. The minimum time of follow up was 12 months. Forty-three patients (32 males) met the inclusion criteria with a mean age of 47.9 years (range 18-80 years). 22 patients had an acute traumatic bone loss associated with open fracture and 21 presented with an infected non-union or underlying osteomyelitis requiring bone excision. The most common microorganisms grown were staphylcoccous aureus and coagulase negative staphylococcous. The mean length of the bone defect area was 4.2 cm (range 2-12 cm). All patients were managed with the two stage technique receiving composited grafting (Autologous bone graft (Iliac crest/RIA), graft expander as required, osteoprogenitor cells, growth factor) during the second stage. There was one failure (humeral infected non-union) in a previous background of bone radiation that necessitated reconstruction with a free fibula vascularized graft. One patient had a fall and sustained implant failure (humeral defect) 3 months after reconstruction and following re-plating progressed to union 4 months later. Two patients required re-grafting due to failure of healing in one of the defect sides. One patient presented with a discharging sinus 2 years after successful healing of a tibial defect that was treated successfully with soft tissue and bone debridement without necessitating further interventions. One patient despite union (distal 1/3 tibia) underwent a below knee amputation due to a dysfunctional ankle/foot (previous foot compartment syndrome-regional pain syndrome). Of those patients, with lower limb injuries, 4 patients had leg length discrepancies of 1 cm, 1.5 cm, 2 cm (two patients) respectively. The mean time to radiological union was 5.4 months (range 2-12 months). The average time of healing of 1 cm bone defect was 1.24 months. Patients with upper limb reconstruction recovered earlier than those with lower limb injuries. At the latest follow up all patients were able to mobilize full weight bearing without residual pain. The induced membrane technique appears to be an alternative good option for the management of large bone defects secondary to acute bone loss or infected non-unions. The incidence of re-interventions was low in this challenging cohort of patients. The technique should be considered in the surgeon's armamentarium as it is effective and is associated with a low rate of complications.

Induced membrane technique for the treatment of bone defects due to post-traumatic osteomyelitis

Objectives

Induced membrane technique is a relatively new technique in the reconstruction of large bone defects. It involves the implantation of polymethylmethacrylate (PMMA) cement in the bone defects to induce the formation of membranes after radical debridement and reconstruction of bone defects using an autologous cancellous bone graft in a span of four to eight weeks. The purpose of this study was to explore the clinical outcomes of the induced membrane technique for the treatment of post-traumatic osteomyelitis in 32 patients.

Methods

A total of 32 cases of post-traumatic osteomyelitis were admitted to our department between August 2011 and October 2012. This retrospective study included 22 men and ten women, with a mean age of 40 years (19 to 70). Within this group there were 20 tibias and 12 femurs with a mean defect of 5 cm (1.5 to 12.5). Antibiotic-loaded PMMA cement was inserted into the defects after radical debridement. After approximately eight weeks, the defects were implanted with bone graft.

Results

The patients were followed for 27.5 months (24 to 32). Radiographic bone union occurred at six months for 26 cases (81%) and clinical healing occurred in 29 cases (90%) at ten months. A total of six cases had a second debridement before bone grafting because of recurrence of infection and one patient required a third debridement. No cases of osteomyelitis had recurred at the time of the last follow-up visit.

Conclusion

The induced membrane technique for the treatment of post-traumatic osteomyelitis is a simple, reliable method, with good early results. However, there are many challenges in determining the scope of the debridement, type of limb fixation and source of bone graft to be used.

Cite this article: Dr Z. Xie. Induced membrane technique for the treatment of bone defects due to post-traumatic osteomyelitis. Bone Joint Res 2016;5:101–105. DOI: 10.1302/2046-3758.53.2000487.

Bone transport through an induced membrane in the management of tibial bone defects resulting from chronic osteomyelitis

Wide resection of infected bone improves the odds of achieving remission of infection in patients with chronic osteomyelitis. Aggressive debridement is followed by the creation of large bone defects. The use of antibiotic-impregnated PMMA spacers, as a customized dead space management tool, has grown in popularity. In addition to certain biological advantages, the spacer offers a therapeutic benefit by serving as a vehicle for delivery of local adjuvant antibiotics. In this study, we investigate the efficacy of physician-directed antibiotic-impregnated PMMA spacers in achieving remission of chronic tibial osteomyelitis. This retrospective case series involves eight patients with chronic osteomyelitis of the tibial diaphysis managed with bone transport through an induced membrane using circular external fixation. All patients were treated according to a standardized treatment protocol. A review of the anatomical nature of the disease, the physiological status of the host and the outcome of treatment in terms of remission of infection, time to union and the complications that occurred was carried out. Seven patients, with a mean bone defect of 7 cm (range 5-8 cm), were included in the study. At a mean follow-up of 28 months (range 18-45 months), clinical eradication of osteomyelitis was achieved in all patients without the need for further reoperation. The mean total external fixation time was 77 weeks (range 52-104 weeks), which equated to a mean external fixation index of 81 days/cm (range 45-107). Failure of the skeletal reconstruction occurred in one patient who was not prepared to continue with further reconstructive surgery and requested amputation. Four major and four minor complications occurred. The temporary insertion of antibiotic-impregnated PMMA appears to be a useful dead space management technique in the treatment of post-infective tibial bone defects. Although the technique does not appear to offer an advantage in terms of the external fixation index, it may serve as a useful adjunct in order to achieve resolution of infection.

The masquelet induced membrane technique with BMP and a synthetic scaffold can heal a rat femoral critical size defect

Long bone defects can be managed by the induced membrane technique together with autologous bone graft. However, graft harvest is associated with donor site morbidity. This study investigates if a tricalcium phosphate hydroxyapatite scaffold can be used alone or in combination with bone active drugs to improve healing. Sprague Dawley rats (n = 40) were randomized into four groups. (A) scaffold, (B) BMP-7, (C) BMP-7 + scaffold, and (D) BMP-7 + scaffold + systemic bisphosphonate at 2 weeks. Locked femoral nailing was followed by 6 mm segment removal and implantation of an epoxy spacer. At 4 weeks, the spacers were removed and the defects grafted. Eleven weeks later, the bones were explanted for evaluation with radiography, manual assessment, micro-CT, histology, and Fourier Transform Infrared spectroscopy (FTIR). Isolated scaffolds (A) did not heal any defects, whereas the other treatments led to healing in 7/10 (B), 10/10 (C), and 9/10 (D) rats. Group D had greater volume of highly mineralized bone (p < 0.01) and higher bone volume fraction (p < 0.01) compared to all other groups. A synthetic scaffold + BMP-7 combined with a bisphosphonate improved the callus properties in a rat femoral critical size defect, compared to both BMP-7 and scaffold alone or the two combined.

Establishment and characterization of the Masquelet induced membrane technique in a rat femur critical-sized defect model

The Masquelet induced membrane technique for reconstructing large diaphyseal defects has been shown to be a promising clinical treatment, yet relatively little is known about the cellular, histological and biochemical make-up of these membranes and how they produce this positive clinical outcome. We compared cellular make-up, histological changes and growth factor expression in membranes induced around femur bone defects and in subcutaneous pockets at 2, 4 and 6 weeks after induction, and to the periosteum. We found that membranes formed around bone defects were similar to those formed in subcutaneous pockets; however, both were significantly different from periosteum with regard to structural characteristics, location of blood vessels and overall thickness. Membranes induced at the femur defect (at 2 weeks) and in periosteum contain mesenchymal stem cells (MSCs; STRO-1⁺ ) which were not found in membranes induced subcutaneously. BMP-2, TGFβ and VEGF were significantly elevated in membranes induced around femur defects in comparison to subcutaneously induced membranes, whereas SDF-1 was not detectable in membranes induced at either site. We found that osteogenic and neovascular activity had mostly subsided by 6 weeks in membranes formed at both sites. It was conclude that cellular composition and growth factor content in induced membranes depends on the location where the membrane is induced and differs from periosteum. Osteogenic and neovascular activity in the membranes is maximal between 2 and 4 weeks and subsides after 6. Based on this, better and quicker bone healing might be achieved if the PMMA cement were replaced with a bone graft earlier in the Masquelet technique. Copyright © 2013 John Wiley & Sons, Ltd.