Reconstruction Of Segmental Bone Defects Research Articles

Reconstruction of Segmental Bone Defect in Canine Tibia Model Utilizing Bi-Phasic Scaffold: Pilot Study.

The reunion and restoration of large segmental bone defects pose significant clinical challenges. Conventional strategies primarily involve the combination of bone scaffolds with seeded cells and/or growth factors to regulate osteogenesis and angiogenesis. However, these therapies face inherent issues related to immunogenicity, tumorigenesis, bioactivity, and off-the-shelf transplantation. The biogenic micro-environment created by implanted bone grafts plays a crucial role in initiating the bone regeneration cascade. To address this, a highly porous bi-phasic ceramic synthetic bone graft, composed of hydroxyapatite (HA) and alumina (Al), was developed. This graft was employed to repair critical segmental defects, involving the creation of a 2 cm segmental defect in a canine tibia. The assessment of bone regeneration within the synthetic bone graft post-healing was conducted using scintigraphy, micro-CT, histology, and dynamic histomorphometry. The technique yielded pore sizes in the range of 230-430 μm as primary pores, 40-70 μm as secondary inner microchannels, and 200-400 nm as tertiary submicron surface holes. These three components are designed to mimic trabecular bone networks and to provide body fluid adsorption, diffusion, a nutritional supply, communication around the cells, and cell anchorage. The overall porosity was measured at 82.61 ± 1.28%. Both micro-CT imaging and histological analysis provided substantial evidence of robust bone formation and the successful reunion of the critical defect. Furthermore, an histology revealed the presence of vascularization within the newly formed bone area, clearly demonstrating trabecular and cortical bone formation at the 8-week mark post-implantation.

Reconstruction of Intercalary Bone Defects After Tumour Resection with the Use of a Free Vascularised Fibular Graft: the Concealed Advantages of the External Fixator.

The free vascularised fibular graft represents the mainstay of intercalary bone defect reconstruction after tumour resection. Different reconstruction techniques are described, favouring internal fixation and possibly overlooking potential advantages of external fixation. This series is a description of the technique performed at our institution using an external fixator for the reconstruction of segmental bone defects which enables to maintain limb length and rotational alignment after large segmental bone resection. Data collected were demographic, surgical and histological data, perioperative complications and postoperative data. Eighteen different complications were encountered in seven patients. Mean reoperation rate was 1.3 per patient but no patient required further interventions in order to correct limb length or rotational alignment. Pin-track infection rate was 6%. The limb salvage rate was 100%. Solid final bone healing was obtained in all patients. External fixation for the reconstruction of intercalary bone defects after tumour resection is a safe technique which might offer the advantage of limb length and alignment preservation.

Safety of free fibula flap harvest in IIIA and IIIB tibio-peroneal trunk variations

In head and neck cancer malignancies, free fibula flap is the gold standard for reconstruction of segmental bone defects owing to its predictable anatomy, long bone length, and feasibility for multiple osteotomies. However, sometimes because of variations in anatomy of tibio-peroneal trunk, it is a dilemma for the surgeons to use free fibula flap for reconstruction. This case series aimed to evaluate the safety of harvest of fibula in such cases in terms of acute and chronic donor-site complications. A retrospective study was conducted from January 2018 to May 2021. All the patients with tibio-peroneal trunk anomaly, diagnosed during surgery, who underwent successful harvest of the free fibula were included in the study and analyzed for the early major and minor donor wound complications, long-term donor complications, and late functional deficit using the Foot and Ankle Disability Index (FADI). Out of 714 free fibulae operated, 26 patients (3.6%) had such tibio-peroneal trunk variations: 22 (2.9%) cases of type III A and B anomalies and 4 (0.56%) cases of type III C anomalies. The average FADI score was 95.3%. No one had any difficulty in personal care and activity of daily living. The free fibula flap can be safely harvested in patients with type III A and B anomalies if vascularity of foot after clamping of peroneal vessels is good and anterior tibial vessels are normal.

Reconstruction of Load-Bearing Segmental Bone Defects Using Carbonate Apatite Honeycomb Blocks

In a globally aging society, synthetic bone blocks are in increasing demand. An ideal synthetic bone block fuses early with bone and is replaced with new bone at a suitable speed while withstanding the weight load. Herein, we report carbonate apatite honeycomb (HC) blocks with superior mechanical strength, osteoconductivity, and bioresorbability compared to a clinically used synthetic porous block (control block). Three types of HC blocks were fabricated via the debinding of HC green bodies at 600, 650, and 700 °C and subsequent phosphatization, designated as HC-600, HC-650, and HC-700, respectively. The macropores in these HC blocks uniaxially penetrated the blocks, whereas those in the control block were not interconnected. Consequently, the HC blocks exhibited higher open macroporosities (18%–20%) than the control block (2.3%). In contrast, the microporosity of the control block (46.4%) was higher than those of the HC blocks (19%–30%). The compressive strengths of the HC-600, HC-650, HC-700, and control blocks were 24.7, 43.7, 103.8, and 38.9 MPa, respectively. The HC and control blocks were implanted into load-bearing segmental bone defects of rabbit ulnae. Uniaxial HC macropores enabled faster bone ingrowth than the poorly interconnected macropores in the control block. Microporosity in the HC blocks affected bone formation and osteoclastic resorption over a period of 24 weeks. The resorption of HC-650 corresponded to new bone formation; therefore, new bone with strength equal to that of the original bone bridged the separated bones. Thus, the HC blocks achieved the reconstruction of segmental bone defects while withstanding the weight load. The findings of this study contribute to the design and development of synthetic bone blocks for reconstructing segmental defects.

A multifunctional nanocomposite hydrogel with controllable release behavior enhances bone regeneration.

Autologous and allogeneic bone grafts remain the gold standard for repairing bone defects. However, donor shortages and postoperative infections contribute to unsatisfactory treatment outcomes. Tissue engineering technology that utilizes biologically active composites to accelerate the healing and reconstruction of segmental bone defects has led to new ideas for in situ bone repair. Multifunctional nanocomposite hydrogels were constructed by covalently binding silver (Ag+) core-embedded mesoporous silica nanoparticles (Ag@MSN) to bone morphogenetic protein-2 (BMP-2), which was encapsulated into silk fibroin methacryloyl (SilMA) and photo-crosslinked to form an Ag@MSN-BMP-2/SilMA hydrogel to preserve the biological activity of BMP-2 and slow its release. More importantly, multifunctional Ag+-containing nanocomposite hydrogels showed antibacterial properties. These hydrogels possessed synergistic osteogenic and antibacterial effects to promote bone defect repair. Ag@MSN-BMP-2/SilMA exhibited good biocompatibility in vitro and in vivo owing to its interconnected porosity and improved hydrophilicity. Furthermore, the multifunctional nanocomposite hydrogel showed controllable sustained-release activity that promoted bone regeneration in repairing rat skull defects by inducing osteogenic differentiation and neovascularization. Overall, Ag@MSN-BMP-2/SilMA hydrogels enrich bone regeneration strategies and show great potential for bone regeneration.

Reconstruction of ametadiaphyseal bone defect after open comminuted fracture of the proximal femur using amodified Masquelet technique

The reconstruction of segmental bone defects after surgical treatment of infected delayed unions as well as nonunions, places the highest demands on the surgical technical implementation. After treating the fracture-related infection, guaranteeing biomechanical stability is crucial for the success of the treatment. The presented case describes the successful treatment of an infected delayed union after an open metadiaphyseal comminuted fracture of the proximal femur using amodified Masquelet technique. Asolid allogeneic bone graft in combination with autologous cancellous bone were inserted into a7 cm subtrochanteric defect zone and stabilized with acombined plate and nail osteosynthesis.

The induced membrane technique: A therapeutic option for managing bone defects in the upper extremity: Case series for 7 patients

IntroductionThe reconstruction of bone defects of tumoral, infectious or traumatic origin of the limbs remains a major therapeutic challenge for the orthopedic surgeon and the patient, in terms of anatomical and functional results. Cases presentationWe report the case of 7 patients who underwent induced membrane bone reconstruction of the upper extremity, 5 patients with initial injury to the forearm, and 2 of our patients, to the humerus. In terms of function, the range of prono-supination was 125°, the range of wrist flexion-extension was 165°, and the range of elbow mobility was 170°. All patients achieved union at the time of the last follow-up. Two patients achieved union at 6 months, one patient at 5 months, one patient at 4 months, and three patients at 3 months. DiscussionThe induced membrane (IM) technique has been used for more than 30 years, and it's more and more widely accepted all over the world, as a simple and effective technique for reconstruction of segmental bone defects. The technique comprises 2 surgical stages, The first step involves the total excision of infected and non-viable lesions both bone and soft tissue until tissue with optimal vascularization "Paprika sign", then the strict instrumental stabilization of the skeleton and the realization of a covering flap if necessary, depending on the site of the initial injury initial lesion and the extent of the resection. ConclusionThe technique of induced membrane has proven its effectiveness in the management of bone loss.

Rational design and fabrication of monophasic bioceramic microspheres with enhanced mechanical and biological performances in reconstruction of segmental bone defect.

Over the past decades, there has been extensive study on the design of porous bioceramic scaffolds with controlled bioactivity and biodegradation in bone tissue repair. A variety of suggestive models and concepts have been proposed with regard to the role of microstructure and composition of biomaterials which affect new bone tissue growth. However, it is a challenge to fabricate functional scaffolds with the desired physiological properties and osteogenic potentials that is comparable to the bone's natural healing time scale. We demonstrate a one-step versatile fabrication of a single-phase and homogenously mixed bioactive load-bearing scaffolds (Sr-CS, CaSiO3/Ca2SiO4, and CaP) with superior biological properties in a critical size bone defect (Ø ~ 6.0 × 8.0mm). In vivo study revealed the CaSiO3/Ca2SiO4 scaffold had the best amount of new bone growth and osteogenic repair. The Sr-CS exhibited an adequate pore network for rapid inorganic exchange and moderate mechanical stability; however, the CaSiO3/Ca2SiO4 saw over-fast resorption and mass loss compared to the Sr-CS and CaP. On the other hand, the CaP scaffold saw mechanically outstanding elastroplastine and stability but had limited biodegradation of its constructs which retarded new cancellous bone growth. The CaSiO3/Ca2SiO4 group saw superior acceleration and formation of mineralized new bone tissues in the defect. Moreover, the CaSiO3/Ca2SiO4 showed appreciable decay of the biomaterials beneficial for osteogenic cell activity. The dramatic stimulation of bone repair and angiogenesis with the CaSiO3/Ca2SiO4 suggests a promising application of this novel bioactive scaffold in the repair of skeletal defects. Systemic representation of the fabricated microspheres with in vivo and in vitro study analysis.

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.

Implant Survival, Clinical Outcome and Complications of Megaprosthetic Reconstructions Following Sarcoma Resection.

Simple SummaryMalignant bone and soft tissue tumors are usually surgically removed with an envelope of healthy tissue as a barrier. If located in the long bones of the upper and lower extremity, this approach leads to a large bone defect commonly affecting a joint. One way to rebuild the bone defect and the neighboring joint is the use of a megaprosthesis that is anchored in the remaining bone comparable to a conventional joint replacement. In general this approach is popular as it provides early stability and allows the affected patient to begin rehabilitation early on. However, complications leading to long-term unplanned reoperation are common. This article provides an overview of current implant survival, types of complication and long-term outcomes of megaprostheses used following tumor resection.Megaprosthetic reconstruction of segmental bone defects following sarcoma resection is a frequently chosen surgical approach in orthopedic oncology. While the use of megaprostheses has gained popularity over the last decades and such implants are increasingly used for metastatic reconstructions and in non-tumor cases, there still is a high risk of long-term complications leading to revision surgery. This article investigates current implant survivorship, frequency and types of complications as well as functional outcomes of upper and lower limb megaprosthetic reconstructions.

Is the Capanna Technique a Reliable Method for Revision Surgery after Failure of Previous Limb-Salvage Surgery?

Reconstruction of a massive bone defect caused by previous failed limb-salvage surgery in patients with bone sarcoma is challenging. Many procedures have been used, but they all have their inherent disadvantages. The Capanna technique has demonstrated good functional outcomes and a low incidence of complications in primary reconstructive surgery of massive bone defect. However, few studies have focused on its usage in revision surgery after failed primary limb-salvage surgery. Between June 2011 and January 2017, 13 patients underwent revision surgery with the Capanna technique for reconstruction of a secondary segmental bone defect caused by a previous failed surgical procedure. The demographics, operating procedures, graft union, functional outcomes, oncologic outcomes, and postoperative complications of each patient were recorded. The current study investigated 13 patients. The rate of limb salvage was 100 %. Bone union was achieved for all patients during a mean time of 8.54 ± 2.15 months (range 4-11 months) at the fibula-host bone junction and 14.92 ± 2.33 months (range 12-21 months) at the allograft-host bone junction. The postoperative complications included wound healing issues and internal fixation loosening. Allograft fracture, nonunion, and infection were not observed. All the patients achieved good functional outcomes, with a Musculoskeletal Tumor Society (MSTS) score of 0.86 ± 0.03 at the latest follow-up visit. The Capanna technique is a reliable alternative method for revision reconstruction of a segmental bone defect caused by a previous failed surgical procedure. Level IV, therapeutic study.

Clinical and radiological assessment of the induced membrane technique using beta-tricalcium phosphate in reconstructive surgery for lower extremity long bone defects.

To clarify the effectiveness of the induced membrane technique (IMT) using beta-tricalcium phosphate (β-TCP) for reconstruction of segmental bone defects by evaluating clinical and radiological outcomes, and the effect of defect size and operated site on surgical outcomes. A review of the medical records was conducted of consecutive 35 lower limbs (30 males and five females; median age 46 years (interquartile range (IQR) 40 to 61)) treated with IMT using β-TCP between 2014 and 2018. Lower Extremity Functional Score (LEFS) was examined preoperatively and at final follow-up to clarify patient-centered outcomes. Bone healing was assessed radiologically, and time from the second stage to bone healing was also evaluated. Patients were divided into ≥ 50 mm and < 50 mm defect groups and into femoral reconstruction, tibial reconstruction, and ankle arthrodesis groups. There were ten and 25 defects in the femur and tibia, respectively. Median LEFS improved significantly from 8 (IQR 1.5 to 19.3) preoperatively to 63.5 (IQR 57 to 73.3) at final follow-up (p < 0.001). Bone healing was achieved in all limbs, and median time from the second stage to bone healing was six months (IQR 5 to 10). Median time to bone healing, preoperative LEFS, or postoperative LEFS did not differ significantly between the defect size groups or among the treatment groups. IMT using β-TCP provided satisfactory clinical and radiological outcomes for segmental bone defects in the lower limbs; surgical outcomes were not influenced by bone defect size or operated part. Cite this article: Bone Joint J2021;103-B(3):456-461.

Guided bone regeneration with osteoconductive grafts and PDGF: A tissue engineering option for segmental bone defect reconstruction.

Regeneration and reconstruction of segmental bone defects (SBD) is a clinical challenge in maxillofacial surgery and orthopedics. The present study evaluated efficacy of guided bone-regeneration (GBR) of rat femoral SBD using osteoconductive equine-bone (EB) and beta-tricalcium phosphate (beta-TCP) grafts, either with or without platelet-derived growth-factor (PDGF). Following ethical-approval, 50 male Wistar-Albino rats (aged ~12-15 months and weighing ~450-500 g) were included. A 5 mm femoral critical-size SBD was created and animals were divided into five groups depending on the graft material used for GBR (EB, EB + PDGF, Autograft, beta-TCP, beta-TCP + PDGF; n = 10/group). Following 12-weeks of healing, animals were sacrificed and femur specimens were analyzed through qualitative histology and quantitative histomorphometry. There was new bone bridging femoral SBD in all groups and qualitatively, better bone formation was seen in autograft and EB + PDGF groups. Histomorphometric bone-area (BA %) was significantly high in autograft group, followed by EB + PDGF, beta-TCP + PDGF, EB, and beta-TCP groups. Addition of PDGF to EB and beta-TCP during GBR resulted in significantly higher BA%. After 12-weeks of healing, EB + PDGF for GBR of rat femoral segmental defects resulted in new bone formation similar to that of autograft. Based on this study, GBR with EB and adjunct PDGF could be a potential clinical alternative for reconstruction and regeneration of segmental bone defects.

Current overview on masquelet technique

Masquelet technique or induced membrane technique has gained wide popularity and is now widely accepted as a simple and effective technique for the reconstruction of segmental bone defects. The technique is founded on the concept that the enclosed foreign body induces a tissue response, which leads to the formation of a surrounding biological active membrane termed as “induced membrane.” The technique was initially described for bone loss resulting from septic nonunion of the leg, and it has been extended to all long bone segments, including the clavicle, whatever may be the etiology of the bone defect. In this review, we describe the current overview of the Masquelet technique over the last decade.

Bidirectional differentiation of BMSCs induced by a biomimetic procallus based on a gelatin-reduced graphene oxide reinforced hydrogel for rapid bone regeneration

Developmental engineering strategy needs the biomimetic composites that can integrate the progenitor cells, biomaterial matrices and bioactive signals to mimic the natural bone healing process for faster healing and reconstruction of segmental bone defects. We prepared the gelatin-reduced graphene oxide (GOG) and constructed the composites that mimicked the procallus by combining the GOG with the photo-crosslinked gelatin hydrogel. The biological effects of the GOG-reinforced composites could induce the bi-differentiation of bone marrow stromal cells (BMSCs) for rapid bone repair. The proper ratio of GOG in the composites regulated the composites' mechanical properties to a suitable range for the adhesion and proliferation of BMSCs. Besides, the GOG-mediated bidirectional differentiation of BMSCs, including osteogenesis and angiogenesis, could be activated through Erk1/2 and AKT pathway. The methyl vanillate (MV) delivered by GOG also contributed to the bioactive signals of the biomimetic procallus through priming the osteogenesis of BMSCs. During the repair of the calvarial defect in vivo, the initial hypoxic condition due to GOG in the composites gradually transformed into a well-vasculature robust situation with the bi-differentiation of BMSCs, which mimicked the process of bone healing resulting in the rapid bone regeneration. As an inorganic constituent, GOG reinforced the organic photo-crosslinked gelatin hydrogel to form a double-phase biomimetic procallus, which provided the porous extracellular matrix microenvironment and bioactive signals for the bi-directional differentiation of BMSCs. These show a promised application of the bio-reduced graphene oxide in biomedicine with a developmental engineering strategy.

Treatment of infected tibial non-unions using a BMAC and S53P4 BAG combination for reconstruction of segmental bone defects: A clinical case series.

Treatment of infected non-unions of the tibia is a challenging problem. The cornerstones of optimal infected non-union treatment consist of extensive debridement, fracture fixation, antimicrobial therapy and creation of an optimal local biological bone healing environment. The combination of S53P4 bioactive glass (BAG), as osteostimulative antibacterial bone graft substitute, and bone marrow aspirate concentrate (BMAC) for the implantation of mesenchymal stem cells and growth factors might be a promising combination. In this paper, preliminary results of a new treatment algorithm for infected non-unions of the tibia is presented. In this retrospective case series patients with infected non-unions of the tibia are treated according to a new treatment algorithm. Patients are treated with extensive debridement surgery, replacement of the osteosynthesis and implantation of S53P4 BAG and BMAC in a one-stage or two-stage procedure based on non-union severity. Subsequently patients are treated with culture based antibiotic therapy and followed until union and infection eradication. Five patients with an infected non-union were treated, mean age was 55, average NUSS-score was 44 and the average segmental bone defect was 4.6cm. One patient was treated in a one-stage procedure and four patients in a two-stage induced membrane-, or "Masquelet"-procedure. On average, 23 ml S53P4 BAG and 6.2 ml BMAC was implanted. The mean follow-up period was 13.6 months and at the end of follow-up all patients had clinical consolidation with an average RUST-score of 7.8 and complete eradication of infection. These early data on the combined implantation of S53P4 BAG and BMAC in treatment of infected non-unions shows promising results. These fracture healing results and eradication rates resulted in promising functional recovery of the patients. To substantiate these results, larger and higher quality studies should be performed.

Use of a Reverse Metacarpal Bone Flap for the Treatment of Segmental Bone Defects of the Proximal Phalanges

The purpose of this retrospective study was to report the results of reconstruction of segmental bone defects of the proximal phalanges using a reverse metacarpal vascularized bone flap harvested from the third metacarpal bone. From August 2012 to May 2017, 17 patients with segmental osteomyelitis or necrotic bone of the proximal phalanges were treated. There were 15 male and 3 female patients, with a mean age of 36 years (range, 19-65 years). The mean size of bone defects was 26× 9× 9 mm (range, 16× 6× 7 mm to 35× 10× 7 mm); and the mean size of bone flaps was 27× 8× 7 mm (range, 15× 7× 4 mm to 40× 8× 7 mm). The mean follow-up period was 26 months. The mean motion arc of the metacarpophalangeal joints was 56° (range, 22°-90°). The mean pinch strength of the injured fingers was 3.1 kg (range, 2-3.6 kg), and the mean pinch strength of the normal contralateral side was 6.9 kg (range, 4.2- 8.5 kg). The reverse metacarpal bone flap may promote osseous healing in reconstructing segmental defects of the proximal phalanges. Therapeutic IV.

La technique de la membrane induite « engainante » pour le traitement des pseudarthroses rebelles sans perte de substance osseuse et le renforcement des reconstructions osseuses segmentaires fragiles. Rapport préliminaire

The induced membrane technique is now well accepted for reconstruction of segmental bone defect. On the other hand, some cases of aseptic non-union are unsuccessfully treated by several surgical attempts for obtaining bone healing. The two stages wrapping induced membrane technique was developed initially for treating atrophic and recalcitrant aseptic non union without bone loss. At the first stage, the site of non-union was firmly fixed and tiles of cement were placed close to the bone on two or three aspects of the bone. At the second stage, after removing the spacers, the induced cavities were filled with cancellous bone autograft. In the two reported cases bone healing was acquired in 4 months. One case was a recalcitrant atrophic non-union of the humeral shaft, the other case concerned the enhancement of an insufficient segmental reconstruction of the femur. The follow up were respectively 3 years and 2 years without complication. The membrane induced by the cement tiles prevents the bone graft resorption and improves the osteogenicity through its biological properties.

Reconstruction osseuse métacarpienne par membrane induite sans ciment

Hand ballistics traumas often produce complex limb injuries and large segmental bone defects. The induced membrane (IM) technique is a simple and effective procedure for reconstruction of segmental bone defects. Usually polymethylmethacrylate (PMMA) cement is required for the first stage of the surgery. We describe four metacarpal bone reconstructions with the IM technique but without PMMA cement after ballistic trauma in a low-resources setting. Two patients were treated in a forward surgical unit for gunshot wounds of the hand. A 33 years old man presented a 4th and 5th metarcarpal bone fracture with critical bone defect and a 25 years old man presented a 2nd and 3rd metacarpal bone and soft tissue defect. In addition to the surgical initial management, we performed the IM technique with a syringe's body in polypropylene (PP) instead of PMMA cement that was not available in this situation. A thick membrane was observable six weeks after the spacer implantation. We performed the bone graft in one case with an iliac crest and in the other with a tibial cortical and cancelous graft. Bone union was achieved in the two cases for the four metacarpal bones. We report cases treated in an austere environment where PMMA cement was not available. This PP induced membrane technique as first been described in a public communication at the SICOT congress by Mozumder et al. It involved critical bone defects from the lower limb. The IM technique has proven its efficiency in hand and wrist bone defect reconstruction but its success is based on strict compliance with technical execution. Our plastic spacers met the requirements of surgical technique. After six weeks, an IM membrane macroscopically similar to cement's IM was found in all cases. The PP spacer shows interesting characteristics: it does not contain antibiotics, it does not heat the surrounding tissues and it is not expensive and easily available. The use of a PP spacer allowed us to achieve bone union in four critical metacarpal bone defects related to ballistic trauma. This procedure respects the technical execution of the IM technique. It is achievable in very low-resources settings. Further biomolecular studies are necessary to assess the PP IM biological properties.

Endoprosthetic replacement following intercalary resection

Endoprosthetic replacement is avaluable treatment option following intercalary resection of bone tumours in the diaphysis. To identify indication, operative technique, implants currently available, literature results and alternative procedures for the alloplastic reconstruction of segmental bone defects. This review article summarizes the authors' own experiences and relevant clinical studies focussing on this topic. According to the literature, 10-year-survival rates of intercalary endoprostheses range between 64 and 80%. Yet, comparisons between different publications are difficult due to the limited number of cases, different implants, follow-up periods and the heterogeneous patient populations. Biological alternatives for reconstruction are autologous bone transplantation, distraction osteogenesis and bone transport, allogenic bone transplantation, and the induced membrane technique. Innovative tissue engineering approaches are still limited to preclinical testing. Short- to mid-term results for segmental endoprostheses following intercalary resections are satisfactory and may be regarded as superior to those of biological reconstructions due to the immediate full weight-bearing capability. However, they are mainly applied for elderly patients and in palliative situations because of potential long-term complications.