Reconstruction of large segmental bone defects in rabbit using the Masquelet technique with α-calcium sulfate hemihydrate

Mechanisms of the Masquelet technique to promote bone defect repair and its influencing factors

The Masquelet technique, also known as the induced membrane technique, is a surgical technique for repairing large bone defects based on the use of a membrane generated by a foreign body reaction for bone grafting. This technique is not only simple to perform, with few complications and quick recovery, but also has excellent clinical results. To better understand the mechanisms by which this technique promotes bone defect repair and the factors that require special attention in practice, we examined and summarized the relevant research advances in this technique by searching, reading, and analysing the literature. Literature show that the Masquelet technique may promote the repair of bone defects through the physical septum and molecular barrier, vascular network, enrichment of mesenchymal stem cells, and high expression of bone-related growth factors, and the repair process is affected by the properties of spacers, the timing of bone graft, mechanical environment, intramembrane filling materials, artificial membrane, and pharmaceutical/biological agents/physical stimulation.

Comparative bone healing with induced membrane technique (IMT) versus empty defects in septic and aseptic conditions in a novel rabbit humerus model

BACKGROUND

Long bone defects resulting from primary trauma or secondary to debridement of fracture-related infection (FRI) remain a major clinical challenge. One approach often used is the induced membrane technique (IMT). The effectiveness of the IMT in infected versus non-infected settings remains to be definitively established. In this study we present a new rabbit humerus model and compare the IMT approach between animals with prior infection and non-infected equivalents.

METHODS

A 5 mm defect was created in the humerus of New Zealand White rabbits (n = 53) and fixed with a 2.5 mm stainless steel plate. In the non-infected groups, the defect was either left empty (n = 6) or treated using the IMT procedure (PMMA spacer for 3 weeks, n = 6). Additionally, both approaches were applied in animals that were inoculated with Staphylococcus aureus 4 weeks prior to defect creation (n = 5 and n = 6, respectively). At the first and second revision surgeries, infected and necrotic tissues were debrided and processed for bacteriological quantification. In the IMT groups, the PMMA spacer was removed 3 weeks post implantation and replaced with a beta-tricalcium phosphate scaffold and bone healing observed for a further 10 weeks. Infected groups also received systemic antibiotic therapy. The differences in bone healing between the groups were evaluated radiographically using a modification of the radiographic union score for tibial fractures (RUST) and by semiquantitative histopathology on Giemsa-Eosin-stained sections.

RESULTS

The presence of S. aureus infection at revision surgery was required for inclusion to the second stage. At the second revision surgery all collected samples were culture negative confirming successful treatment. In the empty defect group, bone healing was increased in the previously infected animals compared with non-infected controls as revealed by radiography with significantly higher RUST values at 6 weeks (p = 0.0281) and at the end of the study (p = 0.0411) and by histopathology with increased cortical bridging (80% and 100% in cis and trans cortical bridging in infected animals compared to 17% and 67% in the non-infected animals). With the IMT approach, both infected and non-infected animals had positive healing assessments.

CONCLUSION

We successfully developed an in vivo model of bone defect healing with IMT with and without infection. Bone defects can heal after an infection with even better outcomes compared to the non-infected setting, although in both cases, the IMT achieved better healing.

The antibiotics supplemented bone cement improved the masquelet's induced membrane in a rat femur critical size defect model

BACKGROUND

Masquelet technique is a two-stage surgical procedure used in the treatment of critical-size bone defects (CSD). Adding antibiotics to polymethylmethacrylate (PMMA) is still questionable to create higher quality induced membrane (IM). The aim of the study was to evaluate the effects of three antibiotic-supplemented cement, fusidic acid, teicoplanin, and gentamicin, on osteogenesis and IM progression applied to rat femur CSD model by comparing histopathological, biochemical, and immunohistochemical findings.

METHODS

Twenty-eight male rats were divided into four groups control, gentamicin (G), teicoplanin (T), and fusidic acid (FA). A 10 mm CSD was created in rat femurs. In the postoperative 4th week, intracardiac blood samples were collected for biochemical analysis of bone alkaline phosphatase (BALP), osteocalcin (OC), and tumor necrosis factor-alpha (TNF-α) levels. IMs obtained in secondary operation were fixed and prepared for histopathological scoring of membrane progression and immunohistochemical evaluation of rat-specific Transforming Growth Factor-Beta (TGF-β), Runt-related Transcription Factor 2 (Runx2), and Vascular Endothelial Growth Factor (VEGF) expressions.

RESULTS

Levels of BALP and OC in serum didn't change among groups significantly while serum TNF-α levels significantly decreased in all antibiotic groups compared to the control group (P = 0.017). Histological scores of groups FA and T were significantly higher than those of groups Control and G (P = 0.0007). IMs of groups T and FA showed good progression while those of groups Control and G were also moderately progressed. A significant increase in TGF-β expression was observed in group G and FA (P = 0.001) while a significant increase in the expression of VEGF was observed in groups G and T compared to the control group (P = 0.036).

CONCLUSIONS

The bone cement impregnated with thermostable and safe antibiotics, gentamicin, fusidic acid, and teicoplanin can increase osteogenesis and support IM progression by increasing the expressions of TGF-β and VEGF. Anabolic effects of induced membranes used in the treatment of critical-size bone defects can be enhanced by antibiotic-supplemented PMMAs applied by altering the original technique.

New bone formation using antibiotic-loaded calcium sulfate beads in bone transports for the treatment of long-bone osteomyelitis

PURPOSE

Bone transport is one of the most frequently used techniques for critical-sized bone defects due to trauma or infection. To fill the defect area and avoid the collapse of soft tissues during transport, some authors have described the use of polymethylmethacrylate or absorbable antibiotic carriers in the form of cylindrical blocks.

METHODS

In this article, we present our experience in the treatment of post-traumatic osteomyelitis of the lower and upper limbs, using a bone transport technique with antibiotic-loaded calcium sulfate in the form of beads. Results With the progressive absorption of calcium sulfate, we observed the formation of a bone-like tissue envelope at the periphery of the defect area. Histological analysis and direct visualization during open revision surgery of the docking site in all patients confirmed the presence of newly formed bone tissue with a high presence of osteoblasts and few osteoclasts; no areas of necrosis or signs of infection were observed. This bone envelope maintained the mechanical protective function of the transport path and docking site, and also provided a biological stimulus to avoid the development of necrotic areas and optimize the consolidation phase. Conclusion Bone transport with calcium sulfate beads improves biological and mechanical support and reduces the number of surgeries required.

Effect of Locally Administered Denosumab on Bone Graft Healing in Rabbit Critical-Size Calvarial Defects

BACKGROUND/AIM

Denosumab is a human monoclonal immunoglobulin G2 antibody developed from the ovarian cells of Chinese hamsters. We aimed to histomorphometrically and radiologically evaluate the effects of xenografts used with local denosumab on the healing of defect sites using rabbit skulls.

MATERIALS AND METHODS

Two 10-mm diameter critical-size defects were created in 16 rabbits. The defect areas were filled with xenografts and xenograft + 3 mg denosumab in the control and denosumab groups (DEN), respectively. We evaluated new bone, residual graft, soft tissue areas, and bone volume in 4- and 8-week study groups.

RESULTS

Histomorphometrically, there were no statistically significant differences between groups at both 4 and 8 weeks regarding residual graft, new bone, and soft tissue area (p > 0.05). The 4-week residual graft control group values were significantly higher than the 8-week values (p < 0.05). The soft tissue area was significantly greater in the 4-week compared with the 8-week DEN group (p < 0.05). The radiologically measured total bone volume was significantly greater in the 8-week specimens than in the 4-week specimens (p < 0.05).

CONCLUSION

In this study, denosumab used locally with bone grafts, showed no direct effect on new and total bone volume.

The induced membrane technique in animal models: a systematic review

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Is induced membrane technique effective in reconstruction of mandibular segmental bone defects? An experimental study

This study aimed to compare the effectiveness of different graft materials using induced membrane technique for reconstruction of mandibular segmental bone defects. New Zealand rabbits were used as the experimental animal. As first-stage surgical procedure, segmental bone defects were created at the lower border of the mandibula in all groups. Polymethylmethacrylate (PMMA) cement was inserted into the defects. After 6 weeks, PMMA cement was removed in all groups. In the Control group, defect areas were left empty. Defects were filled with autogenous graft in the Autograft group, xenograft in the Xenograft group, and a mixture of autogenous graft and xenograft in the Autograft + Xenograft group. Histopathological, stereological, and immunohistochemical analyses were performed. A total of 40 New Zealand rabbits were used. Rabbits were randomly divided into four subgroups as Control, Autograft, Xenograft and Autograft + Xenograft groups (n = 10). When the groups were compared in terms of newly formed bone tissue volumes, significant difference was found between the Control group and Autograft group, Xenograft group and Autograft + Xenograft group (p < 0.001, p < 0.001, p = 0.003). The results of immunohistochemical examination were consistent with this finding. Stereological and immunohistochemical results can be used as a justification to adopt the induced membrane technique on an experimental basis in humans when it comes to the reconstruction of small segmental mandibular defects.

Effectiveness of treating segmental bone defects with a synergistic co-delivery approach with platelet-rich fibrin and tricalcium phosphate

Several studies have applied tricalcium phosphate (TCP) or autografts in bone tissue engineering to enhance the clinical regeneration of bone. Unfortunately, there are several drawbacks related to the use of autografts, including a risk of infection, blood loss, limited quantities, and donor-site morbidities. Platelet-rich fibrin (PRF) is a natural extracellular matrix (ECM) biomaterial that possesses bioactive factors, which can generally be used in regenerative medicine. The goal of the present investigation was to develop osteoconductive TCP incorporated with bioactive PRF for bio-synergistic bone regeneration and examine the potential biological mechanisms and applications. Our in vitro results showed that PRF plus TCP had excellent biosafety and was favorable for initiating osteoblast cell attachment, slow release of bioactive factors, cell proliferation, cell migration, and ECM formation that potentially impacted bone repair. In a rabbit femoral segmental bone defect model, regeneration of bone was considerably augmented in defects locally implanted by PRF plus TCP according to radiographic and histologic examinations. Notably, the outcomes of this investigation suggest that the combination of PRF and TCP possesses novel synergistic and bio-inspired functions that facilitate bone regeneration.

Asprin-loaded strontium-containing α-calcium sulphate hemihydrate/nano-hydroxyapatite composite promotes regeneration of critical bone defects

Our laboratory originally synthesized strontium(Sr)‐containing α‐calcium sulphate hemihydrate/nano‐hydroxyapatite composite (Sr‐α‐CSH/n‐HA) and demonstrated its ability to repair critical bone defects. This study attempted to incorporate aspirin into it to produce a better bone graft material for critical bone defects. After 5% Sr‐α‐CSH was prepared by coprecipitation and hydrothermal methods, it was mixed with aspirin solution of different concentrations (50 μg/ml, 200 μg/ml, 800 μg/ml and 3200 μg/ml) at a fixed liquid‐solid ratio (0.54 v/w) to obtain aspirin‐loaded Sr‐α‐CSH/n‐HA composite. In vitro experiments were performed on the composite extracts. The tibial defects (3 mm*5 mm) in SD rat model were filled with the composite for 4 weeks and 12 weeks to evaluate its osteogenic capacity in vivo. Our results showed its capability of proliferation, migration and osteogenesis of BMSCs in vitro got improved. In vivo treatment with 800 μg/ml aspirin–loaded Sr‐α‐CSH/n‐HA composite led to significantly more new bone formation in the defects compared with Sr‐α‐CSH/n‐HA composite and significantly promoted the expression of osteogenic‐related genes and inhibited osteoclast activity. In general, our research suggests that aspirin‐loaded Sr‐α‐CSH/n‐HA composite may have a greater capacity of repairing tibial defects in SD rats than simple Sr‐α‐CSH/n‐HA composite.

Effects of topical mechanical stability on the formation of Masquelet membrane in a rabbit radial defect model

The exact mechanism of Masquelet technique is unknown. This study intends to explore the effects of topical mechanical stability on the formation of Masquelet membrane. Segmental radius shaft defect was created in all rabbits, which were filled with polymethylmethacrylate (PMMA) in Non-fixation group, and with PMMA fixed with plates in Fixation group, and subjected to no disposal in control group. The topical stability of PMMA and plates were monitored via X-ray and mechanical test. And the membranes were excised for further Histological, IHC and Western-Blotting analysis 4 and 6 weeks post-operatively. X-ray revealed no sign of plates loosening, or shift of PMMA. Mechanical tests revealed superior topical stability by plates. Pathological examinations suggested that vascularized and osteogenic membranes were formed around PMMA. IHC and Western-Blotting analysis revealed that both Fixation and Non-fixation group exerted significant effects on the expression of Ki67, COL I, and CD31 positive cells, as well as the protein expression of osteogenic (RUNX2, ALP) and angiogenic (VEGFA, TGF-β1) factors. And compared with membrane in Non-fixation group, Fixing PMMA spacer with plates caused a significant increase in osteogenic and angiogenic expression. This study indicates that rigid fixation provided by plate in Masquelet technique positively alters the quality of membrane formed surrounding PMMA, in terms of significantly osteogenic and angiogenic potential.

Bone Healing and Regeneration Potential in Rabbit Cortical Defects Using an Innovative Bioceramic Bone Graft Substitute

This study aimed to elucidate the local effect and micro-computed tomographic (μ-CT) assessment following bone implantation of an innovative bioceramic (α-calcium sulfate hemihydrate; α-CSH) on femur lateral condyle cortical bone of rabbit models. The innovative α-CSH bioceramic was synthesized through a green processing technology (microwave irradiation treatment). The bilateral implantation model was performed among 24 New Zealand White rabbits which were divided into three groups based on the type of filling materials: α-CSH, control, and blank. Treatments were performed in defects with 6 mm diameter and 7 mm depth and observed after 2, 4, 8, and 12 weeks. Material reaction and bone formation after implantation were evaluated radiographically and histopathologically. The μ-CT analysis results showed that the degradation of α-CSH and control material was similar at 4 and 8 weeks. The bone volume in the defects indicated the α-CSH increased most in 8 weeks. In histopathological evaluation, the α-CSH group was repaired with lamellar bone and well-grown bone marrow infiltration similar to the control material. Moreover, the α-CSH revealed a faster degradation rate and better healing progress than the control material under the same conditions. Therefore, the α-CSH was confirmed to be useful in promoting osteoconduction and in controlling the resorption rate in bone defects. Further, the innovative α-CSH could be considered as a promising bone substitute for utilization in bone reconstructive therapy in dental and orthopedic fields.

Strontium Modified Calcium Sulfate Hemihydrate Scaffold Incorporating Ginsenoside Rg1/Gelatin Microspheres for Bone Regeneration

The aim of this study was to prepare a promising biomaterial for bone tissue repair and regeneration. The Strontium - calcium sulfate hemihydrate (Sr-α-CaS) scaffold incorporating gelatin microspheres (GMs) encapsulated with Ginsenoside Rg1 (Rg1) was designed. The scaffolds of Rg1/GMs/Sr-α-CaS showed sustained release of Rg1, good biocompatibility and ability of promoting osteogenic differentiation and angiogenesis in vitro. The scaffolds were implanted into animal model of cranial bone defect to characterize bone tissue repair and regeneration in vivo. From the images of Micro-CT, it was obvious that the most bone tissue was formed in Rg1/GMs/Sr-α-CaS group in 12 weeks. New bone structure, collagen and mineralization were analyzed with staining of HE, Masson and Safranin O-Fast green and showed good distribution. The expression of osteocalcin of Rg1/GMs/Sr-α-CaS indicated new bone formation in defect site. The results revealed that synergy of Rg1 and Sr showed the best effect of bone repair and regeneration, which provided a new candidate for bone defect repair in clinic.