Managing large bone defects in children: a systematic review of the 'induced membrane technique'

Improvements in Pediatric Bone Loss Reconstruction With the Induced Membrane Technique

BACKGROUND

The induced membrane technique is now widely used for pediatric diaphyseal bone loss due to various etiologies. Although consolidation rates remain satisfactory, complications, and healing delays may occur requiring additional procedures. We studied a series of induced membrane bone reconstructions in which the second stage included an embedded endomembranous non vascularized fibular shaft, in addition to iliac bone grafts. The purpose of this study was to analyze the results in terms of bone consolidation and complications.

METHODS

This is a retrospective comparative and multicentric study of 32 children with large bone loss treated with the induced membrane reconstruction technique. Patients were divided into 2 groups according to the graft used during the second stage. The first group (G1) of 16 patients had a nonvascularized fibula embedded inside the membrane in addition with the corticocancellous grafts from the iliac crest. The second group (G2) of 16 patients underwent reconstruction using the original technique, with iliac crest graft only.

RESULTS

The 2 groups were similar in terms of etiologies of bone loss and follow-up (mean: 44 mo for G1 and 49 mo for G2). Mean bone losses were 15.4 cm (range: 2 to 25; SD: 5.6) for G1 and 10.6 cm (range: 3 to 19; SD: 5.2) for G2. In the first group, all patients healed primarily, with a mean time of 5.9 months (range: 4 to 8; SD: 1.6). In the second group, 2 of 16 patients did not healed; for the others 14, healing mean time was 6.9 months (range: 3 to 12; SD: 2.7). The short-term and long-term complications rates were 38% to 19% for G1 and 50% to 31% for G2, respectively. Regarding the donor site, the fibulas reconstructed spontaneously with a mean time of 4.8 months (range: 3 to 6; SD: 1.2).

CONCLUSIONS

The integration of a nonvascularized fibula during the second stage of the induced membrane technique appears to improve the consolidation rate in the pediatric population.

LEVEL OF EVIDENCE

Level III-Retrospective comparative study.

Sequestration and Involucrum: Understanding Bone Necrosis and Revascularization in Pediatric Orthopedics

Sequestration, a condition where a section of bone becomes necrotic due to a loss of vascularity or thrombosis, can be a challenging complication of osteomyelitis. This review explores the pathophysiology of sequestration, highlighting the role of the periosteum in forming involucrum and creeping substitution which facilitate revascularization and bone formation. The authors also discuss the induced membrane technique, a two-stage surgical procedure for cases of failed healing of sequestration. Future directions include the potential use of prophylactic anticoagulation and novel drugs targeting immunocoagulopathy, as well as the development of advanced imaging techniques and single-stage surgical procedures.

Treatment of a Ballistic Radius Fracture with Segmental Bone Loss Using the Masquelet Technique in a Child: A Case Report

CASE

A 4-year-old boy sustained an accidental self-inflicted gunshot wound to the left forearm. Radiographs revealed a comminuted mid-diaphyseal ballistic radius fracture with a critical-sized bone defect. The fracture was treated with the placement of a flexible intramedullary nail and antibiotic cement spacer, followed by second-stage bone grafting and open reduction and internal fixation of the radius 6 weeks later. Four months after the second-stage procedure, the radial defect healed appropriately without complications.

CONCLUSION

In this case of a pediatric comminuted mid-diaphyseal radius fracture with bone loss, the induced membrane technique resulted in healing across a critical-sized bone defect.

Masquelet Technique for the Tibia: A Systematic Review and Meta-Analysis of Contemporary Outcomes

OBJECTIVE

To systematically review outcomes of the Masquelet "induced membrane" technique (MT) in treatment of tibial segmental bone loss and to assess the impact of defect size on union rate when using this procedure.

DATA SOURCES

PubMed, EBSCO, Cochrane, and SCOPUS were searched for English language studies from January 1, 2010, through December 31, 2019.

STUDY SELECTION

Studies describing the MT procedure performed in tibiae of 5 or more adult patients were included. Pseudo-arthrosis, nonhuman, pediatric, technique, nontibial bone defect, and non-English studies were excluded, along with studies with less than 5 patients. Selection adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria.

DATA EXTRACTION

A total of 30 studies with 643 tibiae were included in this meta-analysis. Two reviewers systematically screened titles or abstracts, followed by full texts, to ensure quality, accuracy, and consensus among authors for inclusion or exclusion criteria of the studies. In case of disagreement, articles were read in full to assess their eligibility by the senior author. Study quality was assessed using previously reported criteria.

DATA SYNTHESIS

Meta-analysis was performed with random-effects models and meta-regression. A meta-analytic estimate of union rate independent of defect size when using the MT in the tibia was 84% (95% CI, 79%-88%). There was no statistically significant association between defect size and union rate ( P = 0.11).

CONCLUSIONS

The MT is an effective method for the treatment of segmental bone loss in the tibia and can be successful even for large defects. Future work is needed to better understand the patient-specific factors most strongly associated with MT success and complications.

LEVEL OF EVIDENCE

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

Induced Membrane Technique for the Management of Segmental Femoral Defects: A Systematic Review and Meta-Analysis of Individual Participant Data

Several modifications of the induced membrane technique (IMT) have been reported, but there is no consensus regarding their results and prognosis. Moreover, most studies have focused on tibial defects; no meta-analysis of the treatment of femoral defects using the IMT has been reported. This systematic review and meta-analysis aimed to identify the potential risk factors of post-procedural complications following the treatment of segmental femoral defects using the IMT. A comprehensive search was performed on the Cochrane Library, EBSCO, EMBASE, Ovid, PubMed, Scopus, and Web of Science databases, using the keywords "femur," "Masquelet technique," and "induced membrane technique." Original articles composed in English, having accessible individual patient data, and reporting more than two cases of bony defect or nonunion of femur or more than five cases of any body part were included. Post-procedural bone graft infections, final union status, and union time after second-stage operation were analyzed. Fourteen reports, including 90 patients, were used in this study. External fixation in second-stage surgery had an odds ratio of 9.267 for post-procedural bone graft infection (p = 0.047). The odds ratio of post-procedural bone graft infection and age >65 years for final non-union status was 51.05 (p = 0.003) and 9.18 (p = 0.042). Shorter union time was related to impregnated antibiotics in the spacer (p = 0.005), transplanting all-autologous grafts (p = 0.042), and the application of intramedullary nails as the second-stage fixation method (p = 0.050). The IMT appears to be reasonable and reproducible for femoral segmental bone defects. Several preoperative and surgical factors may affect post-procedural complications and union time.

Modified Masquelet technique in children

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

Dual Magnetically Expandable Intramedullary Nails for Treatment of a Large Bony Defect in a Patient with Sarcoma: A Case Report

Aim

To describe the surgical technique of performing an all-internal lengthening to address a large diaphyseal femur defect in the sarcoma patient.

Background

Various strategies exist to address large intercalary bone defects with various biomechanical and biological implications.

Case description

A 23-year-old female with high-grade osteosarcoma of her left femur underwent wide resection and an internal reconstruction of a 12.5-cm femoral defect using dual magnetic lengthening intramedullary nails resulting in restoration of leg lengths, and pre-resection function with minimal residual disability.

Conclusion

Preoperative chemotherapy, wide resection and post-operative chemotherapy for osteosarcoma are the current standard of care. Resection often leads to large bone defects requiring complex reconstruction. Following intercalary bone resection, biological reconstruction is a consideration. An all-inside technique was developed in an effort to minimise complications of long-term external fixation for distraction osteogenesis, or extensile secondary grafting procedures for induced membrane strategy.

Clinical significance

This previously unreported surgical technique allows for an all-internal lengthening of large diaphyseal bone defects. While specifically used in an oncologic post-resection setting, this technique is applicable to the broader limb reconstruction and lengthening practice and overcomes some inherent limitations to previously described techniques.

How to cite this article

Copp J, Magister S, Napora J, et al. Dual Magnetically Expandable Intramedullary Nails for Treatment of a Large Bony Defect in a Patient with Sarcoma: A Case Report. Strategies Trauma Limb Reconstr 2022;17(3):189-194.

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.

Vascularized Pedicled Fibula for Pediatric Tibia Reconstruction

This video reviews the technique of a vascularized fibula flap for pediatric tibia reconstruction. A 4-year-old boy with a history of a left tibial infected nonunion status after multiple debridements presented with segmental bone loss and difficulty with ambulation. An ipsilateral vascularized fibula flap was used for reconstruction. The patient proceeded to union and was independently ambulatory with bracing.

Forearm reconstruction by induced-membrane technique after sarcoma resection in children: technique and functional outcome in three cases

Forearm sarcoma is rare in children. Here, we report three cases. One child presented undifferentiated soft-tissue sarcoma involving the ulna, another had Ewing's sarcoma of the ulna, and the third had Ewing's sarcoma of the proximal radius. In the first case, there were episodes of iterative aseptic nonunion, treated surgically. At last follow-up (respectively 11, 9 and 8 years postoperatively), the mean Musculoskeletal Tumor Society (MSTS) score was 80%, 90% and 77% respectively, and all cases were in remission. The induced membrane technique to reconstruct bone defect after sarcoma resection in children is a possible limb-salvage strategy.

Role of Huntington procedure as a limb salvage surgery for complex gap nonunion of tibia in children

BACK GROUND

Complex gap nonunion of tibia following open fractures and osteomyelitis with pathological fractures in children is a treatment challenge with unpredictable outcome. Treatment options available are bone transport, bone grafting, induced membrane technique, allograft reconstruction and Huntington procedure (ipsilateral transposition of vascularized fibula). There is no consensus in the literature about which technique is optimal in the given situation. The purpose of the present study is to evaluate the role of Huntington procedure in the management of complex gap nonunion of tibia in paediatric patients.

MATERIAL AND METHOD

Eighteen patients (11 males and 7 females) with a mean age of 8.4 years (range 3-12 years) having complex gap nonunion of tibia with an average bone defect of 6.6 cm (range 5-17 cm) were treated with Huntington procedure between June 2008 to December 2016. The mean follow-up was 4.3years (range 3.5-6 years).

RESULT

Union was seen in all except one, with an average time to union being 11.5 weeks and13.8 weeks at proximal and distal tibio-fibular synostosis respectively. Revision plating was done in one patient with nonunion. Hypertrophy of fibula was seen in all patients. One patient developed 15° ankle varus and required corrective osteotomy. Ankle was fixed in equinus in three patients with a mean value of 13.3° (range 5°-25°). Lambrinaudi procedure was done to correct 25° fixed ankle equinus in one patient. Fixed flexion deformity of knee was seen in nine patients with a mean value of 9.7° (range 5°-20°). Two patients had iatrogenic foot drop; one recovered completely and one had only partial recovery. Shortening was seen in eight patients with a mean value of 3.5 cm (range 1-5 cm). At final evaluation 9 patients were very satisfied, 8 satisfied and 1 was dissatisfied.

CONCLUSION

Huntington procedure is a useful limb salvage surgery for complex gap nonunion of tibia in children. However; further improvements in the surgical technique are needed to increase the patient satisfaction by reducing the risk of complications.

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 Membranes for Segmental Mandibular Reconstruction: Case Series and Technique Review

PURPOSE

This article describes the induced membrane technique (IMT) and presents 10 cases in which the technique was applied for segmental mandibular reconstruction.

METHODS

Ten patients requiring segmental mandibular resection were reconstructed using the staged IMT. Mandibular resection, placement of a reconstruction plate and polymethylmethacrylate spacer, was performed. At the second procedure, the spacer was removed through a small incision and particulate autograft from the ilium was placed, in some cases with bone morphogenic protein.

RESULTS

Nine of the 10 patients achieved bony continuity with the IMT. Spacers were designed to optimize mandibular form and future implant-based restoration. All patients have either had implants placed or have adequate bone for implant placement. The average hospital length of stay for both surgeries combined was 3.1 nights.

CONCLUSIONS

The IMT can be successfully used to reconstruct segmental mandibular defects, allowing surgeons to create a neomandible with optimal form both for facial contour and for dental implant-based reconstruction.

Radiological and clinical outcomes using induced membrane technique combined with bone marrow concentrate in the treatment of chronic osteomyelitis of immature patients

Aims

Treatment of chronic osteomyelitis (COM) for young patients remains a challenge. Large bone deficiencies secondary to COM can be treated using induced membrane technique (IMT). However, it is unclear which type of bone graft is optimal. The goal of the study was to determine the clinical effectiveness of bone marrow concentrator modified allograft (BMCA) versus bone marrow aspirate mixed allograft (BMAA) for children with COM of long bones.

Methods

Between January 2013 and December 2017, 26 young patients with COM were enrolled. Different bone grafts were applied to repair bone defects secondary to IMT procedure for infection eradication. Group BMCA was administered BMCA while Group BMAA was given BMAA. The results of this case-control study were retrospectively analyzed.

Results

Patient infection in both groups was eradicated after IMT surgery. As for reconstruction surgery, no substantial changes in the operative period (p = 0.852), intraoperative blood loss (p = 0.573), or length of hospital stay (p = 0.362) were found between the two groups. All patients were monitored for 12 to 60 months. The median time to bone healing was 4.0 months (interquartile range (IQR) 3.0 to 5.0; range 3 to 7) and 5.0 months (IQR 4.0 to 7.0; range 3 to 10) in Groups BMCA and BMAA, respectively. The time to heal in Group BMCA versus Group BMAA was substantially lower (p = 0.024).

Conclusion

IMT with BMCA or BMAA may attain healing in large bone defects secondary to COM in children. The bone healing time was significantly shorter for BMCA, indicating that this could be considered as a new strategy for bone defect after COM treatment.

Cite this article: Bone Joint Res 2021;10(1):31–40.

The induced membrane technique for the management of long bone defects

AIMS

The purpose of this study was to: review the efficacy of the induced membrane technique (IMT), also known as the Masquelet technique; and investigate the relationship between patient factors and technique variations on the outcomes of the IMT.

METHODS

A systematic search was performed in CINAHL, The Cochrane Library, Embase, Ovid MEDLINE, and PubMed. We included articles from 1 January 1980 to 30 September 2019. Studies with a minimum sample size of five cases, where the IMT was performed primarily in adult patients (≥ 18 years old), in a long bone were included. Multivariate regression models were performed on patient-level data to determine variables associated with nonunion, postoperative infection, and the need for additional procedures.

RESULTS

A total of 48 studies were included, with 1,386 cases treated with the IMT. Patients had a mean age of 40.7 years (4 to 88), and the mean defect size was 5.9 cm (0.5 to 26). In total, 82.3% of cases achieved union after the index second stage procedure. The mean time to union was 6.6 months (1.4 to 58.7) after the second stage. Our multivariate analysis of 450 individual patients showed that the odds of developing a nonunion were significantly increased in those with preoperative infection. Patients with tibial defects, and those with larger defects, were at significantly higher odds of developing a postoperative infection. Our analysis also demonstrated a trend towards the inclusion of antibiotics in the cement spacer having a protective effect against the need for additional procedures.

CONCLUSION

The IMT is an effective management strategy for complex segmental bone defects. Standardized reporting of individual patient data or larger prospective trials is required to determine the optimal implementation of this technique. This is the most comprehensive review of the IMT, and the first to compile individual patient data and use regression models to determine predictors of outcomes. Cite this article: Bone Joint J 2020;102-B(12):1723-1734.

Adding a Fibular Strut Allograft to Intramedullary Nail and Cancellous Autograft During Stage II of the Masquelet Technique for Segmental Femur Defects: A Technique Tip

Reconstruction of segmental diaphyseal bone defects has been a major challenge in limb salvage surgery. Staged reconstruction as first described by Masquelet is a common strategy to deal with this problem in limb salvage surgery. One consequence of this technique is a time period of prolonged limited weightbearing while the segmental defect heals. The purpose of this study was to describe an adjunctive technique for stage II of the Masquelet procedure and retrospectively analyze the outcome and weight bearing progression of 3 patients who sustained femur fractures with significant bone loss and underwent this technique. A retrospective chart review was performed. The patients (2 males, 1 female with an average age of 36.6 years) all sustained segmental femur fractures which resulted in significant bone loss. Induced membrane technique with adjunct use of a fibular strut allograft was performed after initial stabilization and PMMA spacer placement. All three patients went on to union and full weight bearing after being treated by the described technique. All the patients were allowed toe-touch weight bearing immediately after surgery and all progressed to weight bearing as tolerated at an average of 3.6 months. Using a fibular strut allograft as an adjunct to the induced membrane technique serves as a biologic and mechanical scaffold and may allow earlier weightbearing.

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

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

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

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

Chronic infection and infected non-union of the long bones in paediatric patients: preliminary results of bone versus beta-tricalcium phosphate grafting after induced membrane formation

PURPOSE

Chronic infection (CO) and infected non-union of the long bones are relatively rare conditions in paediatric patients. Large bone defects secondary to these conditions can be managed with the induced membrane technique. The technique requires grafting of the bone void, although it is not yet established what bone substitute is the best option. The aim of this work was to evaluate the outcome and efficacy of treatment in children with CO and infected non-union of the long bones using the induced membrane technique and bone (BG) versus beta-tricalcium phosphate (BTP) grafting.

METHODS

Eight skeletally immature patients with CO and infected non-union of the long bones were treated surgically between 2010 and 2017 by a combination of resection of necrotic infected bone, debridement of surrounding soft tissue, osteosynthesis using a stable internal fixation when needed, and application of antibiotic-laden cement (ALC) spacer inducing new membrane before final bone reconstruction with bone substitutes: BTP in five cases, BG (allograft and/or autologous graft) in three cases. A second surgical step, once inflammatory markers had normalized, consisted of ALC spacer removal, application of BG or BTP graft and concomitant stable osteosynthesis, if needed, if this had not been done during the first surgical stage. All the patients underwent clinical, laboratory and imaging evaluation before and after surgery. Antibiotics were adjusted according to culture and sensitivity.

RESULTS

Mean patient age at time of diagnosis was 13 ± four years (range, 4-16) and all had at least a 12-month follow-up (range 12-60). Estimated time for induced membrane formation was significantly shorter in patients treated with BTP compared with BG: 3±1 vs. 10±2 (p = 0.02). This result was confirmed by multivariate analysis (p = 0.044) taking into account adjustment for age of patients and time after initial surgery. Time of final union was about 5.5 ± 4.1 months (range 2-66). At the last follow-up visit, bone had healed and all the patients had resumed daily living and sports activities.

CONCLUSION

The induced membrane technique with BG or BTP graft can achieve bone healing in large bone defects secondary to CO and infected non-union in children and adolescents. The choice of bone substitute is important. Our preliminary results show graft integration and bone healing can be expected sooner if BTP is used as bone void filler.