Treatments, cost and healthcare utilization of patients with segmental bone defects

Modern Management of Severe Open Fractures of the Extremities: The Role of the Induced Membrane Technique

➢ The administration of antibiotics, revascularization, effective initial debridement, stabilization, and dead-space management are important time-dependent, acute actions.➢ Following the adequate resuscitation of the patient and the local soft tissues, the first stage of the Masquelet technique is performed together with the definitive coverage of the soft-tissue defect.➢ The optimal time for the second stage (grafting of the bone defect) depends on the progress of the soft-tissue reconstruction and the overall state of the patient. It is usually at 6 to 14 weeks.➢ Bone graft involves cancellous autograft; depending on the volume of the defect, it can be acquired using different donor sites and methods and can be combined with cancellous allograft, bone substitutes, bone marrow aspirate, and inductive molecules.➢ Bone healing is independent of the size of the defect, assuming that revascularization of the graft material has not been disturbed.➢ The development of signs of a fracture-related infection in the clinical setting of a severe open fracture dictates surgical treatment and pathogen-specific antibiotics, debridement of the membrane and the surrounding soft tissues, and reinitiation of the staged process of limb salvage.➢ The results of staged management of severe open fractures with bone defects are reproducible and good.

Incorporating Bone-Derived ECM into Macroporous Microribbon Scaffolds Accelerates Bone Regeneration

Tissue-derived extracellular matrix (tdECM) hydrogels serve as effective scaffolds for tissue regeneration by promoting a regenerative immune response. While most tdECM hydrogels are nanoporous and tailored for soft tissue, macroporosity is crucial for bone regeneration. Yet, there's a shortage of macroporous ECM-based hydrogels for this purpose. The study aims to address this gap by developing a co-spinning technique to integrate bone-derived ECM (bECM) into gelatin-based, macroporous microribbon (µRB) scaffolds. The effect of varying doses of bECM on scaffold properties was characterized. In vitro studies revealed 15% bECM as optimal for promoting MSC osteogenesis and macrophage (Mφ) polarization. When implanted in a mouse critical-sized cranial bone defect model, 15% bECM with tricalcium phosphate (TCP) microparticles significantly accelerated bone regeneration and vascularization, filling over 55% of the void by week 2. Increasing bECM to 25% enhanced mesenchymal stem cell (MSC) recruitment and decreased M1 Mφ polarization but reduced overall bone formation and vascularization. The findings demonstrate co-spun gelatin/bECM hydrogels as promising macroporous scaffolds for robust endogenous bone regeneration, without the need for exogenous cells or growth factors. While this study focused on bone regeneration, this platform holds the potential for incorporating various tdECM into macroporous scaffolds for diverse tissue regeneration applications.

Regional Gene Therapy for Bone Tissue Engineering: A Current Concepts Review

The management of segmental bone defects presents a complex reconstruction challenge for orthopedic surgeons. Current treatment options are limited by efficacy across the spectrum of injury, morbidity, and cost. Regional gene therapy is a promising tissue engineering strategy for bone repair, as it allows for local implantation of nucleic acids or genetically modified cells to direct specific protein expression. In cell-based gene therapy approaches, a variety of different cell types have been described including mesenchymal stem cells (MSCs) derived from multiple sources-bone marrow, adipose, skeletal muscle, and umbilical cord tissue, among others. MSCs, in particular, have been well studied, as they serve as a source of osteoprogenitor cells in addition to providing a vehicle for transgene delivery. Furthermore, MSCs possess immunomodulatory properties, which may support the development of an allogeneic "off-the-shelf" gene therapy product. Identifying an optimal cell type is paramount to the successful clinical translation of cell-based gene therapy approaches. Here, we review current strategies for the management of segmental bone loss in orthopedic surgery, including bone grafting, bone graft substitutes, and operative techniques. We also highlight regional gene therapy as a tissue engineering strategy for bone repair, with a focus on cell types and cell sources suitable for this application.

Preliminary osteogenic and antibacterial investigations of wood derived antibiotic-loaded bone substitute for the treatment of infected bone defects

Introduction: The development of reliable treatments for infected or potentially infected bone loss resulting from open fractures and non-unions is extremely urgent, especially to reduce the prolonged courses of antimicrobial therapy to which affected patients are subjected. Numerous bone graft substitutes have been used over the years, but there are currently no effective solutions to treat critical bone loss, especially in the presence of infection. The present study evaluated the use of the biomorphic calcium phosphate bone scaffold b. Bone™, based on a next-generation resorbable biomimetic biomaterial, in bone reconstruction surgery in cases of infection. Methods: Using an "in vitro 3D bone fracture model" to predict the behavior of this drug delivery system during critical bone loss at an infected (or potentially infected) site, the effects of scaffolds loaded with gentamicin or vancomycin on the viability and differentiation capacity of human mesenchymal stem cells (hMSCs) were evaluated. Results: This scaffold, when loaded with gentamicin or vancomycin, exhibits a typical drug release curve that determines the inhibitory effects on the growth of Staphylococcus aureus, Enterococcus faecalis, and Escherichia coli, as well as relative biofilm formation. Discussion: The study demonstrates that b.bone scaffolds can effectively address key challenges in orthopedic surgery and patient care by inhibiting bacterial growth and biofilm formation through rapid, potent antibiotic release, reducing the risk of treatment failure due to resistance, and providing a promising solution for bone infections and improved patient outcomes. Future studies could explore the combination of different antibiotics on these scaffolds for more tailored and effective treatments against post-traumatic osteomyelitis pathogens.

Vascular restoration through local delivery of angiogenic factors stimulates bone regeneration in critical size defects

Critical size bone defects represent a significant challenge worldwide, often leading to persistent pain and physical disability that profoundly impact patients' quality of life and mental well-being. To address the intricate and complex repair processes involved in these defects, we performed single-cell RNA sequencing and revealed notable shifts in cellular populations within regenerative tissue. Specifically, we observed a decrease in progenitor lineage cells and endothelial cells, coupled with an increase in fibrotic lineage cells and pro-inflammatory cells within regenerative tissue. Furthermore, our analysis of differentially expressed genes and associated signaling pathway at the single-cell level highlighted impaired angiogenesis as a central pathway in critical size bone defects, notably influenced by reduction of Spp1 and Cxcl12 expression. This deficiency was particularly pronounced in progenitor lineage cells and myeloid lineage cells, underscoring its significance in the regeneration process. In response to these findings, we developed an innovative approach to enhance bone regeneration in critical size bone defects. Our fabrication process involves the integration of electrospun PCL fibers with electrosprayed PLGA microspheres carrying Spp1 and Cxcl12. This design allows for the gradual release of Spp1 and Cxcl12 in vitro and in vivo. To evaluate the efficacy of our approach, we locally applied PCL scaffolds loaded with Spp1 and Cxcl12 in a murine model of critical size bone defects. Our results demonstrated restored angiogenesis, accelerated bone regeneration, alleviated pain responses and improved mobility in treated mice.

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.

The polymicrobial infection affects the infection recurrence rate (not failure) in treating femoral and tibial bone defects with the Masquelet technique-a comparative retrospective analysis of 54 patients with mono- and polymicrobial infections

INTRODUCTION

This study evaluated whether polymicrobial infection affects reoperation rates due to infection recurrence and treatment failure with the Masquelet technique in infected posttraumatic segmental bone defects of the femur and tibia.

METHODS

 We retrospectively analyzed patients treated between 2012 and 2021 in two trauma referral centers. We evaluated demographic data, injury, treatment, infection recurrence, failures, and bone healing rates according to whether the infection was mono- or polymicrobial. After uni-bivariate analysis between patients with polymicrobial and monomicrobial infection, we identified the variables associated with infection recurrence and failure through multivariate analysis.

RESULTS

 We analyzed 54 patients, 30 (55.55%) with tibial and 24 (44.44%) femoral segmental bone defects, with a mean follow-up of 41.7 ± 15.0 months. Forty-four (81.48%) presented monomicrobial, and 10 (18.51%) polymicrobial infections. Comparatively, the need for soft tissue reconstruction and the infection recurrence rate was significantly higher in patients with polymicrobial infections. There was no significant difference in the failure rate (20 vs. 6.81% p = 0.23). Multivariable logistic regression analysis identified the polymicrobial infection as the only independent variable associated with infection recurrence (Odds Ratio = 11.07; p = 0.0017).

CONCLUSION

 Our analysis suggests that polymicrobial infection is associated with a higher risk of infection recurrence in treating the femur and tibia segmental bone defects with the Masquelet technique. This information can help surgeons to inform patients about this and give them a realistic expectation of the outcome and the possibility of reoperation.

3D-Printed Osteoinductive Polymeric Scaffolds with Optimized Architecture to Repair a Sheep Metatarsal Critical-Size Bone Defect

The reconstruction of critical-size bone defects in long bones remains a challenge for clinicians. A new osteoinductive medical device is developed here for long bone repair by combining a 3D-printed architectured cylindrical scaffold made of clinical-grade polylactic acid (PLA) with a polyelectrolyte film coating delivering the osteogenic bone morphogenetic protein 2 (BMP-2). This film-coated scaffold is used to repair a sheep metatarsal 25-mm long critical-size bone defect. In vitro and in vivo biocompatibility of the film-coated PLA material is proved according to ISO standards. Scaffold geometry is found to influence BMP-2 incorporation. Bone regeneration is followed using X-ray scans, µCT scans, and histology. It is shown that scaffold internal geometry, notably pore shape, influenced bone regeneration, which is homogenous longitudinally. Scaffolds with cubic pores of ≈870 µm and a low BMP-2 dose of ≈120 µg cm-3 induce the best bone regeneration without any adverse effects. The visual score given by clinicians during animal follow-up is found to be an easy way to predict bone regeneration. This work opens perspectives for a clinical application in personalized bone regeneration.

Intelligent Vascularized 3D/4D/5D/6D-Printed Tissue Scaffolds

Blood vessels are essential for nutrient and oxygen delivery and waste removal. Scaffold-repairing materials with functional vascular networks are widely used in bone tissue engineering. Additive manufacturing is a manufacturing technology that creates three-dimensional solids by stacking substances layer by layer, mainly including but not limited to 3D printing, but also 4D printing, 5D printing and 6D printing. It can be effectively combined with vascularization to meet the needs of vascularized tissue scaffolds by precisely tuning the mechanical structure and biological properties of smart vascular scaffolds. Herein, the development of neovascularization to vascularization to bone tissue engineering is systematically discussed in terms of the importance of vascularization to the tissue. Additionally, the research progress and future prospects of vascularized 3D printed scaffold materials are highlighted and presented in four categories: functional vascularized 3D printed scaffolds, cell-based vascularized 3D printed scaffolds, vascularized 3D printed scaffolds loaded with specific carriers and bionic vascularized 3D printed scaffolds. Finally, a brief review of vascularized additive manufacturing-tissue scaffolds in related tissues such as the vascular tissue engineering, cardiovascular system, skeletal muscle, soft tissue and a discussion of the challenges and development efforts leading to significant advances in intelligent vascularized tissue regeneration is presented.

Matched-Pair Analysis: Large-Sized Defects in Surgery of Lower Limb Nonunions

BACKGROUND

The treatment of large-sized bone defects remains a major challenge in trauma and orthopaedic surgery. Although there are many treatment options, there is still no clear guidance on surgical management, and the influence of defect size on radiological and clinical outcome remains unclear due to the small number of affected patients. The aim of the present study was to determine the influence of defect size on the outcome of atrophic and infected nonunions of the tibia or the femur based on the diamond concept in order to provide recommendations for treatment guidance.

PATIENTS AND METHODS

All medical records, surgical reports, laboratory data and radiological images of patients treated surgically for atrophic or infected nonunions of the lower limbs (femur or tibia) between 1 January 2010 and 31 December 2020 were examined. Patients with proximal, diaphyseal or distal nonunions of the femur or tibia who were surgically treated at our institution according to the "diamond concept" and attended our standardised follow-up program were included in a database. Surgical treatment was performed as a one- or two-step procedure, depending on the type of nonunion. Patients with a segmental bone defect ≥5 cm were matched with patients suffering a bone defect <5 cm based on five established criteria. According to our inclusion and exclusion criteria, 70 patients with a bone defect ≥5 cm were suitable for analysis. Two groups were formed by matching: the study group (bone defect ≥5 cm; n = 39) and control group (bone defect <5 cm; n = 39). The study was approved by the local ethics committee (S-262/2017).

RESULTS

The mean defect size was 7.13 cm in the study and 2.09 cm in the control group. The chi-square test showed equal consolidation rates between the groups (SG: 53.8%; CG: 66.7%). However, the Kaplan-Meier curve and log-rank test showed a significant difference regarding the mean duration until consolidation was achieved, with an average of 15.95 months in the study and 9.24 months in the control group (α = 0.05, p = 0.001). Linear regression showed a significant increase in consolidation duration with increasing defect size (R² = 0.121, p = 0.021). Logistic regression modelling showed a significant negative correlation between consolidation rate and revision performance, as well as an increasing number of revisions, prior surgeries and total number of surgeries performed on the limb. Clinical outcomes showed equal full weight bearing of the lower extremity after 5.54 months in the study vs. 4.86 months in the control group (p = 0.267).

CONCLUSION

Surprisingly, defect size does not seem to have a significant effect on the consolidation rate and should not be seen as a risk factor. However, for the treatment of large-sized nonunions, the follow-up period should be prolonged up to 24 months, due to the extended time until consolidation will be achieved. This period should also pass before a premature revision with new bone augmentation is performed. In addition, it should be kept in mind that as the number of previous surgeries and revisions increases, the prospects for consolidation decrease and a change in therapeutic approach may be required.

Definitive fixation in the first stage of the induced membrane technique for septic segmental bone defects. Why not?

Background

Infected segmental bone defects (I-SBD) are challenging and complex to manage. This study aimed to show the outcomes achieved in I-SBD of the femur and tibia, treated with the induced membrane technique performing a definitive bone stabilization in the first stage.

Methods

We retrospectively reviewed 30 patients with infected non-articular segmental bone defects of the femur (n = 11) and tibia (n = 19), operated consecutively between January 2015 and May 2021. The need for fixation exchange, bone defect length, allo/autograft ratio used, bone healing, reoperation (discriminating between mechanical and infection-related causes), and failure rates (graft resorption or nonunion) were recorded.

Results

Fixation in the first stage was performed with 28 (93.33%) intramedullary nails, ten coated with antibiotic cement, and 2 (6.67%) locked plates. None were removed during the second stage of the technique. The mean length of the bone defects was 5cm (range 3.5-12). The most commonly used allo-/autograft ratio was 50-50. The bone healing rate was 93.33% (n = 28), with a median follow-up of 7 months (range 3-12). The reoperation rate due to mechanical instability was 3.33% (n = 1) and for recurrence of infection was 10.0% (n = 3). The overall failure rate was 6.67% (n = 2). The median follow-up was 42 months (range 12-85).

Conclusion

Masquelet technique appears feasible and effective in treating infected segmental bone defects of the femur and tibia. Definitive fixation at the first stage showed a success rate of 93.33%, with a re-operation rate of 10.0% related to infection.

Cell-free and cytokine-free self-assembling peptide hydrogel-polycaprolactone composite scaffolds for segmental bone defects

Segmental bone defects over the self-healing threshold are a major challenge for orthopedics. Despite the advancements in clinical practice, traditional tissue engineering methods are limited by the addition of heterogeneous cells and cytokines, leading to carcinoma or other adverse effects. Here, we present a cell-free and cytokine-free strategy using an ECM-mimetic self-assembling peptide hydrogel (SAPH)- polycaprolactone (PCL) composite scaffold. The hydrophilic SAPH endows the rigid PCL scaffold with excellent biocompatibility and preference for osteogenesis induction. The autologous cells around the bone defect site immediately grew, proliferated, and secreted ECM and cytokines after contacting the implanted SAPH-PCL composite scaffold, and the bone repair of rabbit ulnar segmental bone defect was achieved in just six months. Quantitative proteomic analysis reveals that the SAPH-PCL composite scaffold accelerates osteoblastogenesis, osteoclastogenesis, and angiogenesis with moderate immune responses and negligible effects on pathological fibrosis. These findings have important implications for the potential clinical applications of the SAPH-PCL composite scaffold in patients with segmental bone defects and identify the mechanisms of action for accelerated segmental bone defect repair.

Treatment of tibial bone defects: pilot analysis of direct medical costs between distraction osteogenesis with an Ilizarov frame and the Masquelet technique

Purpose

The cost implications of limb reconstruction techniques have not been adequately investigated. Aim of this pilot study was to compare the direct medical cost of tibial bone defects managed with distraction osteogenesis–Ilizarov method (ILF), or with Masquelet technique (MIF).

Methods

Data of 20 random patients treated in a single centre were analysed. Inclusion criteria included acute tibial defects, or post-debridement of nonunions with complete follow-up and successful union. The endpoint of clinical efficacy was the time-to-defect union. Comparisons were made between equally sized subgroups (ILF vs. MIF).

Results

The average defect length was 5.6 cm (2.6–9.6 cm). The overall cost of 20 cases reached £452,974 (mean £22,339, range £13,459–£36,274). Statistically significant differences favoring the MIF were found regarding the average time-to-union; number of surgeries, of admissions and follow-up visits, as well as the mean intraoperative cost (£8857 vs. £14,087). These differences lead to significant differences of the mean cost of the overall treatment (MIF £18,131 vs. ILF £26,126). Power analysis based on these data indicated that 35 patients on each group would allow detection of a 25% difference, with an alpha value of 0.05 and probability (power) of 0.9.

Conclusions

The results and analysis presented highlight factors affecting the high financial burden, even in a best-case scenario, this type of surgery entails. Larger pivotal studies should follow to improve the cost efficiency of clinical practice.

3D-Printing for Critical Sized Bone Defects: Current Concepts and Future Directions

The management and definitive treatment of segmental bone defects in the setting of acute trauma, fracture non-union, revision joint arthroplasty, and tumor surgery are challenging clinical problems with no consistently satisfactory solution. Orthopaedic surgeons are developing novel strategies to treat these problems, including three-dimensional (3D) printing combined with growth factors and/or cells. This article reviews the current strategies for management of segmental bone loss in orthopaedic surgery, including graft selection, bone graft substitutes, and operative techniques. Furthermore, we highlight 3D printing as a technology that may serve a major role in the management of segmental defects. The optimization of a 3D-printed scaffold design through printing technique, material selection, and scaffold geometry, as well as biologic additives to enhance bone regeneration and incorporation could change the treatment paradigm for these difficult bone repair problems.

[Augmentation in surgical sepsis : Chances and limitations in the treatment of osteitis with calcium hydroxyapatite containing antibiotics]

BACKGROUND

The surgical treatment of osteitis or fracture-related infections (FRI) is often associated with large bone defects. The treatment of these defects remains a major challenge in trauma surgery. Within the concept of tissue engineering, the development of various hybrid bone graft substitutes, such as calcium hydroxyapatite with added antibiotics, is continuously progressing.

OBJECTIVE

Chances and limitations in the treatment of osteitis with calcium hydroxyapatite containing antibiotics.

MATERIAL AND METHODS

Overview of the results of a 2-stage (infection) pseudarthrosis model on rat femurs treated with Cerament® G (Bonesupport, Lund, Schweden). Evaluation of the clinical experiences based on three case examples of osteitis treated with calcium hydroxyapatite containing antibiotics (Cerament® G or Cerament® V).

RESULTS

After establishment of a 2‑stage pseudarthrosis model on the rat femur, the osteoconductive and osteoinductive potential of calcium hydroxyapatite containing antibiotics could be confirmed. In the clinical application, the use of Cerament® G seems to lead to a more favorable outcome in small cavitary defects. The recurrence rates are higher than previously described, especially for larger segmental defects.

CONCLUSION

Taking the clinical and experimental results into consideration, a stricter evaluation of the indications for the use of Cerament® G is necessary to achieve the best possible outcome for patients.

Effects of Channels and Micropores in Honeycomb Scaffolds on the Reconstruction of Segmental Bone Defects

The reconstruction of critical-sized segmental bone defects is a key challenge in orthopedics because of its intractability despite technological advancements. To overcome this challenge, scaffolds that promote rapid bone ingrowth and subsequent bone replacement are necessary. In this study, we fabricated three types of carbonate apatite honeycomb (HC) scaffolds with uniaxial channels bridging the stumps of a host bone. These HC scaffolds possessed different channel and micropore volumes. The HC scaffolds were implanted into the defects of rabbit ulnar shafts to evaluate the effects of channels and micropores on bone reconstruction. Four weeks postoperatively, the HC scaffolds with a larger channel volume promoted bone ingrowth compared to that with a larger micropore volume. In contrast, 12 weeks postoperatively, the HC scaffolds with a larger volume of the micropores rather than the channels promoted the scaffold resorption by osteoclasts and bone formation. Thus, the channels affected bone ingrowth in the early stage, and micropores affected scaffold resorption and bone formation in the middle stage. Furthermore, 12 weeks postoperatively, the HC scaffolds with large volumes of both channels and micropores formed a significantly larger amount of new bone than that attained using HC scaffolds with either large volume of channels or micropores, thereby bridging the host bone stumps. The findings of this study provide guidance for designing the pore structure of scaffolds.

Skeletal regeneration for segmental bone loss: Vascularised grafts, analogues and surrogates

Massive segmental bone defects (SBD) are mostly treated by removing the fibula and transplanting it complete with blood supply. While revolutionary 50 years ago, this remains the standard treatment. This review considers different strategies to repair SBD and emerging potential replacements for this highly invasive procedure. Prior to the technical breakthrough of microsurgery, researchers in the 1960s and 1970s had begun to make considerable progress in developing non autologous routes to repairing SBD. While the breaktthrough of vascularised bone transplantation solved the immediate problem of a lack of reliable repair strategies, much of their prior work is still relevant today. We challenge the assumption that mimicry is necessary or likely to be successful and instead point to the utility of quite crude (from a materials technology perspective), approaches. Together there are quite compelling indications that the body can regenerate entire bone segments with few or no exogenous factors. This is important, as there is a limit to how expensive a bone repair can be and still be widely available to all patients since cost restraints within healthcare systems are not likely to diminish in the near future. STATEMENT OF SIGNIFICANCE: This review is significant because it is a multidisciplinary view of several surgeons and scientists as to what is driving improvement in segmental bone defect repair, why many approaches to date have not succeeded and why some quite basic approaches can be as effective as they are. While there are many reviews of the literature of grafting and bone repair the relative lack of substantial improvement and slow rate of progress in clinical translation is often overlooked and we seek to challenge the reader to consider the issue more broadly.