Critical-sized defect in the tibia: is it critical? Results from the SPRINT trial

Tunable mechanical properties of chitosan-based biocomposite scaffolds for bone tissue engineering applications: A review

Bone tissue engineering (BTE) aims to develop implantable bone replacements for severe skeletal abnormalities that do not heal. In the field of BTE, chitosan (CS) has become a leading polysaccharide in the development of bone scaffolds. Although CS has several excellent properties, such as biodegradability, biocompatibility, and antibacterial properties, it has limitations for use in BTE because of its poor mechanical properties, increased degradation, and minimal bioactivity. To address these issues, researchers have explored other biomaterials, such as synthetic polymers, ceramics, and CS coatings on metals, to produce CS-based biocomposite scaffolds for BTE applications. These CS-based biocomposite scaffolds demonstrate superior properties, including mechanical characteristics, such as compressive strength, Young's modulus, and tensile strength. In addition, they are compatible with neighboring tissues, exhibit a controlled rate of degradation, and promote cell adhesion, proliferation, and osteoblast differentiation. This review provides a brief outline of the recent progress in making different CS-based biocomposite scaffolds and how to characterize them so that their mechanical properties can be tuned using crosslinkers for bone regeneration.

Fracture related infection in open tibial fractures

Open tibia fractures frequently occur following high-energy trauma. Contamination of the fracture site combined with limited soft tissue coverage and blood supply means that these open fractures are associated with a high rate of complications, including fracture related infection (FRI). FRI is associated with lowered patient outcomes and requires early recognition and appropriate surgical and medical management. The current evidence on FRI after open tibial fractures largely is limited to case series, small retrospective cohort studies and expert opinion. Recent expert consensus has produced guidelines with the aim of standardising care for these patients. This review summarises the current management strategies employed in treating FRI following open tibial fractures and where possible the evidence behind them.

Critical Bone Defect Affecting the Outcome of Management in Anatomical Type IV Chronic Osteomyelitis

Background

The Cierny and Mader classification assists with decision-making by stratifying host status and the pathoanatomy of the disease. However, the anatomical type IV represents a heterogenous group with regard to treatment requirements and outcomes. We propose that modification of the Cierny and Mader anatomical classification with an additional type V classifier (diffuse corticomedullary involvement with an associated critical bone defect) will allow more accurate stratification of patients and tailoring of treatment strategies.

Methods

A retrospective review of 83 patients undergoing treatment for Cierny and Mader anatomical type IV osteomyelitis of the appendicular skeleton at a single centre was performed.

Results

Risk factors for the presence of a critical bone defect were female patients [OR 3.1 (95% CI, 1.08-8.92)] and requirement for soft tissue reconstruction [OR 3.35 (95% CI, 1.35-8.31)]; osteomyelitis of the femur was negatively associated with the presence of a critical bone defect [OR 0.13 (95% CI, 0.03-0.66)]. There was no statistically significant risk of adverse outcomes (failure to eradicate infection or achieve bone union) associated with the presence of a critical-sized bone defect. The median time to the bone union was ten months (95% CI, 7.9-12.1 months). There was a statistically significant difference in the median time to bone union between cases with a critical bone defect [12.0 months (95% CI, 10.2-13.7 months)] and those without [6.0 months (95% CI, 4.8-7.1 months)].

Conclusion

This study provided evidence to support the introduction of a new subgroup of the Cierny and Mader anatomical classification (Type V). Using a standardised approach to management, comparable early outcomes can be achieved in patients with Cierny and Mader anatomical type V osteomyelitis. However, to achieve a successful outcome, there is a requirement for additional bone and soft tissue reconstruction procedures with an associated increase in treatment time.

How to cite this article

Tsang STJ, Epstein GZ, Ferreira N. Critical Bone Defect Affecting the Outcome of Management in Anatomical Type IV Chronic Osteomyelitis. Strategies Trauma Limb Reconstr 2024;19(1):26-31.

Predicting Union, Osteomyelitis, and Amputation Outcomes of Gustilo IIIC Open Tibial Fractures: A Retrospective Study

OBJECTIVE

Open tibial fractures are frequently encountered in high-energy traumas and can result in significant complications such as nonunion, osteomyelitis, and even amputation. Among open tibial fractures, Gustilo type IIIC cases are particularly challenging due to the concomitant occurrence of neurovascular injuries and soft tissue defects. This study aimed to assess factors that affect union time and complications in Gustilo IIIC tibial fractures.

METHODS

Patients who presented at our center with IIIC open tibial fractures from January 2000 to October 2020 were eligible for this retrospective analysis. Patient demographics, fracture characteristics, and the timing, number, and type of surgical intervention were documented. Outcomes of interest included union time, occurrence of osteomyelitis, and amputation. We performed univariate analyses including chi-squared test, Fischer's exact test, analysis of variance, and Kruskal-Wallis test based on the normality of the data and multivariate analyses including Cox proportional hazards model and logistic regression analyses.

RESULTS

Fifty-eight patients were enrolled and grouped by fracture healing time; eight had timely union (13.8%); 27 had late union (46.6%); eight had delayed union (13.8%); three had nonunion (5.2%); and 12 underwent amputation (20.7%). Nine fractures (15.5%) were complicated by osteomyelitis. Union time was prolonged in cases of triple arterial injury, distal third fractures, multiple trauma with injury severity score (ISS) ≥ 16 points, and increased bone defect length. Additionally, a bone gap >50 mm, diabetes mellitus, low body mass index, and triple arterial injury in the lower leg were significant risk factors for amputation. A time from injury to definitive soft tissue coverage of more than 22 days was the major risk factor for osteomyelitis. A scoring system to predict union time was devised and the predicted probability of union within 2 years was stratified based on this score.

CONCLUSION

IIIC tibial fractures involving the distal third of the tibia, fractures with bone defects, triple arterial injury, and multiple trauma with ISS ≥16 points demonstrated delayed union, and an effective prediction system for union time was introduced in this study. Early soft tissue coverage can reduce the risk of osteomyelitis. Finally, diabetes and severe bone and soft tissue defects pose a higher risk of amputation.

Non-vascularised corticocancellous (tricortical) iliac bone graft longer than 3 cm for non-union after failed surgical treatment

PURPOSE

We hypothesised that traditional iliac tricortical bone grafts (no vascularised) still have a reasonable role in promoting satisfactory bony healing in non-union defects of certain sizes. Here, we report the clinical/radiological outcomes through a retrospective case series.

METHODS

We screened 74 patients with definitive non-union in the long bones of the upper extremities who visited the outpatient department from 2008 to 2018. Among these patients, 25 who met our inclusion/exclusion criteria were investigated.

RESULTS

The mean age was 51.92 years, and there were 12, 9, 1, and 3 lesions of the radius, ulna, clavicle, and humerus, respectively. The tools for primary fixations were plate and intramedullary nails in 24 and 1 patients, respectively. Six patients presented with atrophic non-union. The mean period from a previous surgery was 6.84 months. The mean defective bone sizes were 1.81 and 3.50 cm pre-debridement and post-debridement, respectively. All devices had locking plates longer than the previous plate, and the graft was concurrently fixed by screws in three patients. At a mean of 15.92 weeks after the revision surgery, all patients experienced union. At the final follow-up, the clinical outcomes were satisfactory. No significant differences in clinical outcomes were found according to the lesion, type of non-union, period from the previous surgery, or harvest length of the iliac bone.

CONCLUSIONS

If the proper indications and some technical aspects are considered, a non-vascularised iliac bone graft longer than 3 cm could still be a reasonable option for treating diaphyseal non-union of the upper extremities.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Comparison of the 3D-microstructure of human alveolar and fibula bone in microvascular autologous bone transplantation: a synchrotron radiation μ-CT study

Introduction: Autologous bone transplantation is successfully used in reconstructive surgery of large/critical-sized bone defects, whereby the microvascular free fibula flap is still regarded as the gold standard for the reconstruction of such defects in the head and neck region. Here, we report the morphological and lacunar properties of patient-paired bone samples from eight patients from the jaw (AB; recipient site) and the fibula (FB; donor site) on the micron length-scale using Synchrotron µ-CT. Insights into differences and similarities between these bone structures could offer a better understanding of the underlying mechanism for successful surgical outcomes and might clear the path for optimized, nature-inspired bone scaffold designs. Methods: Spatial vessel-pore arrangements, bone morphology, fluid-simulation derived permeability tensor, osteocyte lacunar density, and lacunar morphology are compared. Results: The orientation of the vessel system indicates a homogenous vessel orientation for AB and FB. The average mineral distance (50%) to the closest vessel boundary is higher in AB than in FB (the mean is 96 μm for AB vs. 76 μm for FB; p = 0.021). Average osteocyte lacunar density is found to be higher in AB than in FB (mean 22,874 mm3 vs. 19,376 mm3 for FB; p = 0.038), which might compensate for the high distance from the mineral to the nearest vessel. No significant differences in lacunar volume are found between paired AB and FB. Discussion: A comparable vessel network and similar distribution of vessel porosity between AB and FB may allow the FB graft to exhibit a high regeneration potential when connected to AB, and this might correlate with a high osteoinductive and osteoconductive potential of FB when connected to AB. Since widely used and potent synthetic bone grafts exist, new insight into the bone structure of well-established autologous bone grafts, such as the free fibula flap, could help to improve the performance of such materials and therefore the design of 3D scaffolds.

Evaluation of the time-dependent osteogenic activity of glycerol incorporated magnesium oxide nanoparticles in induced calvarial defects

Introduction

Magnesium-based biomaterials have been explored for their potential as bone healing materials, as a result of their outstanding biodegradability and biocompatibility. These characteristics make magnesium oxide nanoparticles (MgO NPs) a promising material for treating bone disorders. The purpose of this investigation is to assess the osteogenic activity of newly-developed locally administered glycerol-incorporated MgO NPs (GIMgO NPs) in rabbits' calvarial defects.

Materials and methods

Characterization of GIMgO was done by X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). Bilateral calvarial defects were created in eighteen New Zealand Rabbits, of which they were divided into 3 groups with time points corresponding to 2, 4, and 6 weeks postoperatively (n = 6). One defect was implanted with absorbable gel foam impregnated with GIMgO NPs while the other was implanted with gel foam soaked with glycerol (the control). The defects were assessed using histological, Micro-Computed Tomography (Micro-CT), and histometric evaluation.

Results

The characterization of the GIMgO nanogel revealed the presence of MgO NPs and glycerol as well as the formation of the crystalline phase of the MgO NPs within the nanogel sample. The histological and micro-CT analysis showed time-dependent improvement of healing activity in the calvarial defects implanted with GIMgO NPs when compared to the control. Furthermore, the histometric analysis demonstrated a marked increase in the total area of new bone, connective tissue, new bone area and volume in the GIMgO NPs implanted site. Statistically, the amount of new bone formation was more significant at 6 weeks than at 2 and 4 weeks postoperatively in the calvarial defects implanted with GIMgO NPs as compared to the control.

Conclusion

The locally applied GIMgO NPs demonstrated efficacy in promoting bone formation, with more significant effects observed over an extended period. These findings suggest its suitability for clinical use as a therapeutic alternative to enhance bone healing.

Current concepts of bone grafting in trauma surgery

Bone graft in trauma surgery is commonly used in managing bone defects, non-union, fracture related infections, arthrodesis or to provide structural support in fractures. A variety of bone grafts are made available to the treating physician, which includes autograft, allograft and bone graft substitutes. The future of bone grafting in trauma surgery is exciting with the incorporation of technological advancement such as gene therapy, 3D-printing and tissue engineering. Regardless, there are still limitations to what we understand regarding current bone grafting techniques with conflicting literature on their clinical utility and indication. The aim of this review article therefore is to take a step back and critically evaluate the current concepts of bone grafting in trauma surgery, with special emphasis made on reviewing the types of bone graft, biology of bone graft incorporation and indication for its use in various clinical scenarios.

Functional Outcomes of Tibia Fractures Treated With Intramedullary Interlocking Nails by Suprapatellar Approach: A Prospective Study

Background Tibia fractures are the most common lower extremity fractures. The subcutaneous anatomy of this long bone predisposes it to high fracture frequency in a high-energy trauma. The tibia is a major weight-bearing, long tubular bone that is axially and rotationally unstable when fractured, which ideally necessitates its surgical fixation in adults. Tibia fractures can be treated with a variety of choice of implants and surgical approaches. This study aims to assess the clinical and functional outcomes of a tibia fracture treated with intramedullary interlocking nails by a suprapatellar approach. Methodology A total of 32 patients were selected from patients admitted at Shri B. M. Patil Medical College and Research Centre with tibia fractures between January 2021 and May 2022. All the patients were treated with closed reduction and internal fixation with intramedullary interlocking nails by suprapatellar approach with a semi-extended knee position. All patients were followed up clinically and radiologically at regular intervals of six weeks, three months, six months, and one year. All functional outcomes were assessed based on modified Lysholm knee scores. Results A total of 31 patients showed union at the fracture site. One patient had nonunion and implant failure at the distal locking site, and two patients had persistent anterior knee pain at the end of one year. Functional outcome assessment based on modified Lysholm scores had excellent results, with a mean score of 95. Patients were followed up for a mean of 11.5 months. The mean time of union was observed as 12.5 months. Conclusions Suprapatellar tibia nailing is an effective alternative approach with ease of reduction and decreased intraoperative fluoroscopy time. The entry is in line with the medullary cavity preventing malreduction of proximal and distal tibia fractures. The additional proximal locking option also increases the stability of implant fixation.

Additive Manufacturing of Polymer/Bioactive Glass Scaffolds for Regenerative Medicine: A Review

Tissue engineering (TE) is a branch of regenerative medicine with enormous potential to regenerate damaged tissues using synthetic grafts such as scaffolds. Polymers and bioactive glasses (BGs) are popular materials for scaffold production because of their tunable properties and ability to interact with the body for effective tissue regeneration. Due to their composition and amorphous structure, BGs possess a significant affinity with the recipient's tissue. Additive manufacturing (AM), a method that allows the creation of complex shapes and internal structures, is a promising approach for scaffold production. However, despite the promising results obtained so far, several challenges remain in the field of TE. One critical area for improvement is tailoring the mechanical properties of scaffolds to meet specific tissue requirements. In addition, achieving improved cell viability and controlled degradation of scaffolds is necessary to ensure successful tissue regeneration. This review provides a critical summary of the potential and limitations of polymer/BG scaffold production via AM covering extrusion-, lithography-, and laser-based 3D-printing techniques. The review highlights the importance of addressing the current challenges in TE to develop effective and reliable strategies for tissue regeneration.

Fibula pro tibia and cancellous allograft vitalised with autologous bone for non-union of the distal tibia diaphysis: Surgical technique

Background

The management of medium-sized osseous defects and pseudoarthrosis of the tibia is challenging. This surgical technique aims to bridge medium-sized tibial defects using the fibula as a lead structure. The fibula and cancellous bone graft fuse with the tibia leading to synostosis.

Methods

Cortico-cancellous bone is harvested from the anterior iliac crest. The bone is shredded into small pieces of about 5 mm and mixed with stem cell-rich blood from the situs. Additionally, cancellous allografts can be used for expansion. The approach is extended along the interosseous membrane to reach the tibial defect. The pseudarthrosis is debrided and the tibial bone adjacent to the defect is decorticated. A 3.5 mm 1/3 tube plate is positioned to the fibula and fixed. Four quadricortical screws are positioned. Autograft is secured into the tibial bone defect and between the fibula and the tibia directly on the anterior surface of the interosseous membrane.

Results

15 patients were followed up for a mean of 17 months. Osseous consolidation was achieved in 73.3% of all cases. On average, bone healing has occurred 17 weeks postoperatively. These patients did not have any pain walking with full weight bearing and without any walking aids at the last follow-up.

Conclusion

The fibula pro tibia procedure is a sufficient tool for treating non-unions of the mid and distal third of the tibia diaphysis in cases with a bony defect size of 1 cm-6 cm.

Bone Healing of Critical-Sized Femoral Defects in Rats Treated with Erythropoietin Alone or in Combination with Xenograft

Critical-size bone defect models are the standard in studies of the osteogenic potential of biomaterials. The present investigation aimed to evaluate the ability of recombinant human erythropoietin (EPO) to induce trabecular bone healing either alone or combined with a xenograft in a rat femoral critical-size defect model. Five-mm bone defects were created in the femoral diaphysis of fifty-six skeletally mature male Wistar albino rats. The animals were divided into six groups: one control group and five experimental groups. The defects in the control group were left empty, whereas an absorbable collagen cone soaked either with saline or erythropoietin (alone or in combination with xenograft) was placed in locally treated groups. The systemic treatment group received EPO subcutaneously. Bone formation was objectively evaluated through radiography, osteodensitometry and histological examination on post-operative days 30 and 90. The results demonstrate that EPO, locally applied on a collagen scaffold, was capable of inducing bone healing, whereas the single systemically administered high EPO dose had only an insignificant effect on bone formation. The combination of EPO with a bone substitute under the form of cancellous granules resulted in more rapid integration between the xenograft and host bone.

Low intensity near-infrared light promotes bone regeneration via circadian clock protein cryptochrome 1

Bone regeneration remains a great clinical challenge. Low intensity near-infrared (NIR) light showed strong potential to promote tissue regeneration, offering a promising strategy for bone defect regeneration. However, the effect and underlying mechanism of NIR on bone regeneration remain unclear. We demonstrated that bone regeneration in the rat skull defect model was significantly accelerated with low-intensity NIR stimulation. In vitro studies showed that NIR stimulation could promote the osteoblast differentiation in bone mesenchymal stem cells (BMSCs) and MC3T3-E1 cells, which was associated with increased ubiquitination of the core circadian clock protein Cryptochrome 1 (CRY1) in the nucleus. We found that the reduction of CRY1 induced by NIR light activated the bone morphogenetic protein (BMP) signaling pathways, promoting SMAD1/5/9 phosphorylation and increasing the expression levels of Runx2 and Osterix. NIR light treatment may act through sodium voltage-gated channel Scn4a, which may be a potential responder of NIR light to accelerate bone regeneration. Together, these findings suggest that low-intensity NIR light may promote in situ bone regeneration in a CRY1-dependent manner, providing a novel, efficient and non-invasive strategy to promote bone regeneration for clinical bone defects.

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.

Diagnostic and Therapeutic Roles of the “Omics” in Hypoxic–Ischemic Encephalopathy in Neonates

Perinatal asphyxia and neonatal encephalopathy remain major causes of neonatal mortality, despite the improved availability of diagnostic and therapeutic tools, contributing to neurological and intellectual disabilities worldwide. An approach using a combination of clinical data, neuroimaging, and biochemical parameters is the current strategy towards the improved diagnosis and prognosis of the outcome in neonatal hypoxic–ischemic encephalopathy (HIE) using bioengineering methods. Traditional biomarkers are of little use in this multifactorial and variable phenotype-presenting clinical condition. Novel systems of biology-based “omics” approaches (genomics, transcriptome proteomics, and metabolomics) may help to identify biomarkers associated with brain and other tissue injuries, predicting the disease severity in HIE. Biomarker studies using omics technologies will likely be a key feature of future neuroprotective treatment methods and will help to assess the successful treatment and long-term efficacy of the intervention. This article reviews the roles of different omics as biomarkers of HIE and outlines the existing knowledge of our current understanding of the clinical use of different omics molecules as novel neonatal brain injury biomarkers, which may lead to improved interventions related to the diagnostic and therapeutic aspects of HIE.

CGF-HLC-I repaired the bone defect repair of the rabbits mandible through tight junction pathway

Background: The human-like collagen I (HLC-I) combined concentrated growth factors was used to construct CGF-HLC-I composite biomaterials to repair the critical bone defect disease model of rabbit mandible. This study aimed to research the repair mechanism of CGF-HLC-I/Bio-Oss in rabbit mandibular critical bone defect, to provide a new treatment direction for clinical bone defect repair.

Methods: The optimal concentration of HLC-I (0.75%) was selected in this study. Nine New Zealand white rabbits were randomly divided into 3 groups, normal control group, Bio-Gide/Bio-Oss and CGF-0.75%HLC-I/Bio-Oss group (n = 3, each group). CGF-0.75%HLC-I/Bio-Oss and Bio-Gide/Bio-Oss were implanted into rabbit mandibles, then X-ray, Micro-CT, HE and Masson staining, immunohistochemical staining and biomechanical testing were performed with the bone continuity or maturity at 4, 8 and 12 weeks after surgery. The repair mechanism was studied by bioinformatics experiments.

Results: As the material degraded, the rate of new bone formation in the CGF-0.75% HLC-I/Bio-Oss group was better than that the control group by micro-CT. The biomechanical test showed that the compressive strength and elastic modulus of the CGF-0.75%HLC-I/Bio-Oss group were higher than those of the control group. HE and Masson staining showed that the bone continuity or maturity of the CGF-0.75%HLC-I/Bio-Oss group was better than that of the control group. Immunohistochemical staining showed significantly higher bone morphogenetic protein 2 (BMP2) and Runt-related transcription factor 2 (RUNX2) in the CGF-0.75%HLC-I/Bio-Oss group than the control group at 8 and 12 W and the difference gradually decreased with time. There were 131 differentially expressed proteins (DEPs) in the Bio-Gide/Bio-Oss and CGF-0.75%HLC-I/Bio-Oss groups, containing 95 up-regulated proteins and 36 down-regulated proteins. KEGG database enrichment analysis showed actinin alpha 1 (ACTN1) and myosin heavy-Chain 9 (MYH9) are the main potential differential proteins related to osteogenesis, and they are enriched in the TJs pathway.

Conclusion: CGF-0.75%HLC-I/Bio-Oss materials are good biomaterials for bone regeneration which have strong osteoinductive activity. CGF-0.75%HLC-I/Bio-Oss materials can promote new bone formation, providing new ideas for the application of bone tissue engineering scaffold materials in oral clinics.

Short term outcomes and complications of distal ulnar ostectomy in 23 juvenile dogs with carpal valgus secondary to discordant radial-ulnar physeal growth

Objective

The goal of this study was to report short term clinical and radiographic outcomes after distal ulnar ostectomy in dogs with carpal valgus due to discordant radial-ulnar growth.

Study design

Retrospective case study.

Sample group

Client owned dogs under 1 year of age with carpal valgus and open distal radial physes pre-operatively.

Methods

Medical records from four veterinary referral centers were searched from January 1, 2015 to January 1, 2022 for juvenile dogs that had been treated with distal ulnar ostectomy for carpal valgus due to premature closure of the distal ulnar physis. Patients were excluded if they were skeletally mature at the time of ostectomy; medical records were incomplete; radial physis was closed at surgery; or definitive corrective osteotomy was performed. Radiographs were evaluated pre-operatively and for short term follow up at ~8 weeks. Complications and short term clinical outcomes were evaluated also.

Results

31 limbs from 23 dogs were evaluated. Patients ranged from 4 to 10.8 months of age. All dogs presented for visible carpal valgus and varying degrees of thoracic limb lameness. Sixty-four percent of patients showed resolution of lameness while an additional 13% showed an improvement in clinical lameness without complete resolution. Complications were seen in 32% of patients with 70% percent of those being minor, bandage related complications. Radiographically, 38% of limbs showed bridging callus formation of the ostectomy at an average of 7.5 weeks post operatively and 75% percent of patients with elbow incongruity improved radiographically. There was no significant difference in radial joint angles pre-operatively and at the time of follow up.

Conclusion

Distal ulnar ostectomy ameliorates lameness in juvenile dogs with premature distal ulnar physeal closure and shows lack of progression of distal carpal valgus deformity, but does not improve joint angulation.

Clinical significance

Distal ulnar ostectomy is associated with mild bandage-related complications and halting of progressive limb deformity within the time frame evaluated, and should therefore be considered a treatment for premature closure of the distal ulnar physis. It does not lead to deformity correction at 8 weeks following surgery but is associated with improved elbow congruity.

Outcomes of Patients With Large Versus Small Bone Defects in Open Tibia Fractures Treated With an Intramedullary Nail: A Descriptive Analysis of a Multicenter Retrospective Study

OBJECTIVES

To compare outcomes in patients with open tibia shaft fractures based on defect size.

DESIGN

Retrospective review.

SETTING

Eighteen trauma centers.

POPULATION

The study included 132 patients with diaphyseal tibia bone defects >1 cm and ≥50% cortical loss treated with intramedullary nail.

OUTCOMES

The primary outcome was number of secondary surgeries to promote healing (bone graft, revision fixation, or bone transport). Additional outcomes included occurrence of secondary surgeries (bone graft, infection, amputation, and flap failure) and proportion healed at one year. Results are compared by "radiographic apparent bone gap" of <2.5 or ≥2.5 cm.

RESULTS

The estimated conditional probability of bone grafting within one year given graft-free at 90 days was 44% and 47% in the <2.5 cm and ≥2.5 cm groups, respectively. An estimated infection risk of 14% was observed in both groups [adjusted hazard ratio (HR) 0.98, 95% confidence interval (CI): 0.33-2.92], estimated amputation risk was 9% (<2.5 cm) and 4% (≥2.5 cm) (unadjusted HR 0.66, 95% CI: 0.13-3.29), and estimated flap failure risk (among those with flaps) was 10% and 13%, respectively (unadjusted HR 1.71, 95% CI: 0.24-12.25). There was no appreciable difference in the proportion healed at one year between defect sizes [adjusted HR: 1.07 (95% CI, 0.63-1.82)].

CONCLUSIONS

Larger size bone defects were not associated with higher number of secondary procedures to promote healing or a lower overall one-year healing rate.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Current Perspectives on the Management of Bone Fragments in Open Tibial Fractures: New Developments and Future Directions

Open tibial fractures may be associated with bone loss at the time of the injury or following surgical debridement of the fracture. This article discusses the various treatment options available and the latest developments surrounding the management of free bone fragments in open tibial fractures.

Regenerative matching axial vascularisation of absorbable 3D-printed scaffold for large bone defects: A first in human series

BACKGROUND

We describe the first clinical series of a novel bone replacement technique based on regenerative matching axial vascularisation (RMAV). This was used in four cases: a tibial defect after treatment of osteomyelitis; a calvarial defect after trauma and failed titanium cranioplasty; a paediatric tibial defect after neoadjuvant chemotherapy and resection of Ewing sarcoma; and a paediatric mandibular deficiency resulting from congenital hemifacial microsomia.

METHOD

All patients underwent reconstruction with three-dimensional (3D)-printed medical-grade polycaprolactone and tricalcium phosphate (mPCL-TCP) scaffolds wrapped in vascularised free corticoperiosteal flaps.

OUTCOME

Functional volumes of load-sharing regenerate bone have formed in all cases after a moderate duration of follow-up. At 36 cm, case 1 remains the longest segment of load bearing bone ever successfully reconstructed. This technique offers an alternative to existing methods of large volume bone defect reconstruction that may be safe, reliable, and give predictable outcomes in challenging situations. It achieves this by using a bioresorbable scaffold to support and direct the growth of regenerate bone, driven by RMAV.

CONCLUSION

This technique may facilitate the reconstruction of bone defects previously thought unreconstructable, reduce the risk of long-term implant-related complications and achieve these outcomes in a hostile environment. These potential benefits must now be formally tested in prospective clinical trials.

Nano-Hydroxyapatite Bone Scaffolds with Different Porous Structures Processed by Digital Light Processing 3D Printing

The morphologies and structures of the scaffold have a significant influence on their mechanical and biological properties. In this work, different types of porous structures: Triply periodic minimal surface-Schwarz primitive (P), body-centered cubic, and cubic pore-shaped (CPS) hydroxyapatite scaffolds with ~70% porosity were fabricated through digital light processing (DLP) 3D printing technology. The compressive properties and in vitro cell evaluations such as cell proliferation and attachment morphology of these scaffolds were systematically compared. The results showed that the CPS scaffolds exhibited the highest compressive strength (~22.5 MPa) and modulus (~400 MPa). In addition, the CPS scaffolds also performed the most active cell metabolisms as compared to other two structures, which may account for the larger pore size and smaller curvature of the substrate. This study provides a general guidance for the fabrication and selection of porous bone scaffolds processed by DLP 3D printing.

[Fracture-related infections after intramedullary nailing : Diagnostics and treatment]

Intramedullary nailing is the treatment of choice for a large number of fractures requiring surgery. In cases of fracture-related infections (FRI) the treatment of nail infections requires special attention due to the closed situation of the osteosynthesis material in the intramedullary canal. This article gives an overview of the general principles and diagnostic criteria for FRI after nail fixation and discusses the treatment recommendations based on three case examples. In cases of acute implant infections, an implant-retaining procedure is principally possible for both periprosthetic joint infections and FRI; however, after intramedullary nailing the nail should also be exchanged in cases of acute nail infections as a sufficient debridement of the nail is impossible due to its intramedullary location. In chronic FRI after intramedullary nailing a one-stage or two-stage procedure can be followed. In cases of adequate soft tissue coverage, good fracture reduction and an expected bone healing without critical bony substance defects, a one-stage procedure with nail exchange should be preferred. If a chronic infection with soft tissue and bone defects develops after intramedullary nailing, a two-stage procedure analogous to the treatment of osteomyelitis should be considered. In this case a multidisciplinary team approach with specialists in plastic surgery, microbiology and infectious diseases is necessary. The use of local antibiotics and antimicrobial-coated implants is deemed to be advantageous.

Osteocalcin biomarker level evaluation on fracture healing with bone defect after stromal vascular fraction application in murine model

Introduction

Bone defect (3 mm in murine model) is a condition when the bone tissue cannot undergo a natural healing process caused by severe trauma, tumor, or irradiation. A bone defect is a challenge even for experienced Orthopaedic surgeons. Stromal vascular fraction (SVF) is a heterogeneous cell population derived from adipose tissue that results from minimal manipulation of the adipose tissue itself. Several studies have elucidated the effect of either SVF on bone defect healing. However, to the author's knowledge, there is no study evaluating the effect of SVF application on fracture healing, which was measured with osteocalcin biomarker. This study aims to evaluate the effect of SVF application on bone defect healing measured with osteocalcin as a biomarker of bone healing.

Materials and methods

This was an animal study involving twelve Wistar strain Rattus norvegivus. They were divided into three groups: negative group (normal rats), positive group (rats with bone defect and treated without SVF application), and SVF group (rats with bone defect and treated with SVF application). After 30 days, the rats were sacrificed, the osteocalcin biomarkers were evaluated. This biomarker was quantified using ELISA.

Results

Osteocalcin biomarker expressions were higher in the group treated with SVF application than those without using SVF. All comparisons of the SVF group and positive control group showed significant differences (p < 0.05).

Conclusion

SVF application could aid the healing process in a murine model with bone defect, marked by increased osteocalcin levels.

•

A study evaluating the effect of SVF application on fracture healing, measured with osteocalcin biomarker.

•

Osteocalcin is useful in the evaluation of bone turnover and the clinical setting of bone loss.

•

SVF could aid the healing process in a murine model with bone defect.

•

A bone defect is a challenge even for experienced Orthopaedic surgeons.

A Machine Learning Algorithm to Identify Patients at Risk of Unplanned Subsequent Surgery After Intramedullary Nailing for Tibial Shaft Fractures

OBJECTIVES

In the SPRINT trial, 18% of patients with a tibial shaft fracture (TSF) treated with intramedullary nailing (IMN) had one or more unplanned subsequent surgical procedures. It is clinically relevant for surgeon and patient to anticipate unplanned secondary procedures, other than operations that can be readily expected such as reconstructive procedures for soft tissue defects. Therefore, the objective of this study was to develop a machine learning (ML) prediction model using the SPRINT data that can give individual patients and their care team an estimate of their particular probability of an unplanned second surgery.

METHODS

Patients from the SPRINT trial with unilateral TSFs were randomly divided into a training set (80%) and test set (20%). Five ML algorithms were trained in recognizing patterns associated with subsequent surgery in the training set based on a subset of variables identified by random forest algorithms. Performance of each ML algorithm was evaluated and compared based on (1) area under the ROC curve, (2) calibration slope and intercept, and (3) the Brier score.

RESULTS

Total data set comprised 1198 patients, of whom 214 patients (18%) underwent subsequent surgery. Seven variables were used to train ML algorithms: (1) Gustilo-Anderson classification, (2) Tscherne classification, (3) fracture location, (4) fracture gap, (5) polytrauma, (6) injury mechanism, and (7) OTA/AO classification. The best-performing ML algorithm had an area under the ROC curve, calibration slope, calibration intercept, and the Brier score of 0.766, 0.954, -0.002, and 0.120 in the training set and 0.773, 0.922, 0, and 0.119 in the test set, respectively.

CONCLUSIONS

An ML algorithm was developed to predict the probability of subsequent surgery after IMN for TSFs. This ML algorithm may assist surgeons to inform patients about the probability of subsequent surgery and might help to identify patients who need a different perioperative plan or a more intensive approach.

LEVEL OF EVIDENCE

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Clinical and Radiographic Predictors of Nonunion in Open Tibial Shaft Fractures

Open fracture is a risk factor for nonunion of diaphyseal tibia fractures. Compared with closed injuries, there is a relative lack of scientific knowledge regarding the healing of open tibia fractures. The objective of this study was to investigate which patient, injury, and surgeon-related factors predict nonunion in open tibial shaft fractures. A cohort of 98 patients with 104 extra-articular open tibial shaft fractures (OTA/AO 41A2-3, 42A-C, and 43A) were treated surgically between 2007 and 2018 at a single level 1 trauma center and were retrospectively reviewed. Patients underwent irrigation and debridement followed by definitive intramedullary nailing or plate fixation. Patient, injury, and perioperative prognostic factors were analyzed as predictors of nonunion based on anteroposterior and lateral radiographs. The nonunion rate was 27.9% (n=29). There were 12 occurrences of deep infection (11.5%). The median follow-up was 14 months. High-energy mechanism of injury (hazard ratio [HR], 5.76), Gustilo-Anderson class IIIA injury (HR, 3.66), postoperative cortical continuity of 0% to 25% (HR, 2.90), early postoperative complication (HR, 4.20), and deep infection (HR, 2.25) were significant predictors of nonunion on univariable analysis (P<.05). On multivariable assessment, only high-energy mechanism of injury, Gustilo-Anderson class IIIA injury, and early postoperative complication reached significance as predictors of nonunion. These data also indicate that lack of cortical continuity is a significant univariable radiographic predictor of nonunion. This is potentially modifiable, may guide surgeons in selecting patients for early bone grafting procedures, and should be assessed carefully in this high-risk population. [Orthopedics. 2021;44(3):142-147.].

3D Printing of Micro- and Nanoscale Bone Substitutes: A Review on Technical and Translational Perspectives

Recent developments in three-dimensional (3D) printing technology offer immense potential in fabricating scaffolds and implants for various biomedical applications, especially for bone repair and regeneration. As the availability of autologous bone sources and commercial products is limited and surgical methods do not help in complete regeneration, it is necessary to develop alternative approaches for repairing large segmental bone defects. The 3D printing technology can effectively integrate different types of living cells within a 3D construct made up of conventional micro- or nanoscale biomaterials to create an artificial bone graft capable of regenerating the damaged tissues. This article reviews the developments and applications of 3D printing in bone tissue engineering and highlights the numerous conventional biomaterials and nanomaterials that have been used in the production of 3D-printed scaffolds. A comprehensive overview of the 3D printing methods such as stereolithography (SLA), selective laser sintering (SLS), fused deposition modeling (FDM), and ink-jet 3D printing, and their technical and clinical applications in bone repair and regeneration has been provided. The review is expected to be useful for readers to gain an insight into the state-of-the-art of 3D printing of bone substitutes and their translational perspectives.

Decompression strategy for critical-sized lesions: A case series and literature review

Critical-sized lesions are defined as the smallest sized intraosseous wound in a particular bone that will not heal spontaneously during the lifetime of that animal. These critical-sized entities pose a unique challenge in endodontics, where these lesions are most likely cystic, with dimensions extending over 10 mm. This paper describes a structured methodology to treat such cases whilst also highlighting inconsistencies and variability between practitioners regarding management of critical-sized lesions. The case series demonstrates that non-surgical root canal therapy followed by surgical decompression may be the treatment of choice for such pathosis. A 16 gauge nasogastric tube was used as a decompression device and sutured to surrounding mucosa. Healing was evaluated using both two- and three-dimensional radiographs. Decompression of critical-sized lesions would appear to be a reliable, conservative and an altogether complete procedure that may not warrant second-stage surgery.

NURD 2.0: Prediction of tibial nonunion after intramedullary nail fixation at any time within 3 months after injury

Introduction Nonunion after fixation of long bones negatively impacts outcomes and requires additional surgery. The ability to predict likelihood of nonunion after tibial shaft fracture would be helpful to clinicians and patients. The goal of this work was to combine three previous models of tibial shaft nonunion at different time points into one overall model that incorporates time as a continuous variable. Methods We conducted a retrospective review at a Level I academic trauma center. The study cohort consisted of patients with tibial shaft fractures treated with nail insertion from 2007 through 2014, excluding patients who did not have contact between bone ends, those who had planned bone grafting for acute bone defects, and those who lacked adequate follow-up. Three previous models were combined: 382 patients at time 0, 323 at 6 weeks, and 240 at 12 weeks. The primary outcome variable was surgery for nonunion. Bivariate and multivariate regression analyses determined which of 42 clinical and radiographic variables were significantly associated with nonunion. Predictive power was evaluated using area under the curve (AUC). Results The original nonunion risk determination (NURD) score was significantly improved through addition of 6- and 12-week radiographic union scores for tibial fractures, infection and complications, smoking status, and need for flaps. Overall, over the course of 12 weeks, the NURD-based model produced an AUC of 0.87 at initial time of fixation that improved to >0.9 at 6 and 12 weeks. Data were used to bin patients into five clinically important risk strata (p < 0.001). Patients in the lowest risk strata had 0% probability of nonunion (0 of 97 patients); in the second lowest risk strata, 4% (three of 73 patients); and in the highest risk strata, 48% (38 of 80 patients). Conclusions We created a NURD 2.0 score that predicts nonunion at various time points during the first 3 months after fracture. The new model is a notable improvement over previous models. A computerized version allows surgeons and patients to use the score when making treatment decisions regarding need for nonunion surgery.

Three-dimensional printed poly (L-lactide) and hydroxyapatite composite for reconstruction of critical bone defect in rabbits

PURPOSE

To use a 3D printed poly (L-lactide) acid (PLLA) and hydroxyapatite (HA) composite as a bone substitute for reconstruction of a critical bone defect in the radius of rabbits.

METHODS

A 1.5 cm ostectomy was performed in the radial diaphysis of 60 New Zealand white rabbits. The rabbits were divided into three groups according to surgical treatment of the bone defect (group I - control, group II - bone graft, group III - 3D PLLA). Each group was divided into four subgroups with different radiographic and histopathologic evaluation times (T1 - 15 days, T2 - 30 days, T3 - 60 days, T4 - 90 days).

RESULTS

The implant group had greater clinically lameness (p = 0.02), edema (p = 0.007), pain (p = 0.04) and more complications at the surgical site (p = 0.03). Histologically, this group showed greater congestion (p = 0.04), hemorrhage (p = 0.04) and inflammation. Osteogenesis was microscopically similar between days (p = 0.54) and treatments (p = 0.17), even though radiographically, more effective bone healing occurred in the graft group (II), with more callus and bone bridge formation.

CONCLUSIONS

The customization of a 3D PLLA/HA scaffold was successful. However, in animals receiving the polymer-ceramic composite less bone callus and bone bridge was formed compared to the graft group.

The induced membrane technique for bone defects: Basic science, clinical evidence, and technical tips

The clinical management of large bone defects continues to be a difficult clinical problem to manage for treating surgeons. The induced membrane technique is a commonly employed strategy to manage these complex injuries and achieve bone union. Basic science and clinical evidence continue to expand to address questions related to the biology of the membrane and how interventions may impact clinical outcomes. In this review, we discuss the basic science and clinical evidence for the induced membrane technique as well as provide indications for the procedure and technical tips for performing the induced membrane technique.

Systematic Review of the Preclinical Technology Readiness of Orthopedic Gene Therapy and Outlook for Clinical Translation

Bone defects and improper healing of fractures are an increasing public health burden, and there is an unmet clinical need in their successful repair. Gene therapy has been proposed as a possible approach to improve or augment bone healing with the potential to provide true functional regeneration. While large numbers of studies have been performed in vitro or in vivo in small animal models that support the use of gene therapy for bone repair, these systems do not recapitulate several key features of a critical or complex fracture environment. Larger animal models are therefore a key step on the path to clinical translation of the technology. Herein, the current state of orthopedic gene therapy research in preclinical large animal models was investigated based on performed large animal studies. A summary and an outlook regarding current clinical studies in this sector are provided. It was found that the results found in the current research literature were generally positive but highly methodologically inconsistent, rendering a comparison difficult. Additionally, factors vital for translation have not been thoroughly addressed in these model systems, and the risk of bias was high in all reviewed publications. These limitations directly impact clinical translation of gene therapeutic approaches due to lack of comparability, inability to demonstrate non-inferiority or equivalence compared with current clinical standards, and lack of safety data. This review therefore aims to provide a current overview of ongoing preclinical and clinical work, potential bottlenecks in preclinical studies and for translation, and recommendations to overcome these to enable future deployment of this promising technology to the clinical setting.

Classification of Bone Defects: An Extension of the Orthopaedic Trauma Association Open Fracture Classification

OBJECTIVES

To develop a post-traumatic bone defect classification scheme and complete a preliminary assessment of its reliability.

DESIGN

Retrospective classification.

SETTING

Tertiary referral trauma center.

PATIENTS/PARTICIPANTS

Twenty open fractures with bone loss.

INTERVENTION

Assignment of a bone defect classification grade.

MAIN OUTCOME MEASUREMENTS

Open fractures were classified based on orthogonal radiographs, assessing the extent and local geometry of bone loss, including D1-incomplete defects, D2-minor/subcritical (complete) defects (<2 cm), and D3-segmental/critical-sized defects (≥2 cm). Incomplete defects (D1) include D1A-<25% cortical loss, D1B-25%-75% cortical loss, and D1C->75% cortical loss. Minor/subcritical (complete) defects (<2 cm) (D2) include D2A-2 oblique ends allowing for possible overlap, D2B-one end oblique/one end transverse, and D2C-2 transverse ends. Segmental/critical-sized Defects (≥2 cm) include D3A-moderate defects, 2 to <4 cm; D3B-major defects, 4 to <8 cm; and D3C-massive defects, ≥8 cm. Reliability was assessed among 3 independent observers using Fleiss' kappa tests.

RESULTS

Interobserver reliability demonstrated the classification scheme has very good agreement, κ = 0.8371, P < 0.0005. Intraobserver reliability was excellent, κ = 1.000 (standard error 0.1478-0.1634), P < 0.00001. Interobserver reliability for the distinction between categories alone (D1, D2, or D3) was also excellent, κ = 1.000 (standard error 0.1421-0.1679), P < 0.00001.

CONCLUSIONS

This classification scheme provides a robust guide to bone defect assessment that can potentially facilitate selection of the most appropriate treatment strategy to optimize clinical outcomes.

Management of critical-sized bone defects in the treatment of fracture-related infection: a systematic review and pooled analysis

PURPOSE

This systematic review determined the reported treatment strategies, their individual success rates, and other outcome parameters in the management of critical-sized bone defects in fracture-related infection (FRI) patients between 1990 and 2018.

METHODS

A systematic literature search on treatment and outcome of critical-sized bone defects in FRI was performed. Treatment strategies identified were, autologous cancellous grafts, autologous cancellous grafts combined with local antibiotics, the induced membrane technique, vascularized grafts, Ilizarov bone transport, and bone transport combined with local antibiotics. Outcomes were bone healing and infection eradication after primary surgical protocol and recurrence of FRI and amputations at the end of study period.

RESULTS

Fifty studies were included, describing 1530 patients, the tibia was affected in 82%. Mean age was 40 years (range 6-80), with predominantly male subjects (79%). Mean duration of infection was 17 months (range 1-624) and mean follow-up 51 months (range 6-126). After initial protocolized treatment, FRI was cured in 83% (95% CI 79-87) of all cases, increasing to 94% (95% CI 92-96) at the end of each individual study. Recurrence of infection was seen in 8% (95% CI 6-11) and amputation in 3% (95% CI 2-3). Final outcomes overlapped across treatment strategies.

CONCLUSION

Results should be interpreted with caution due to the retrospective and observational design of most studies, the lack of clear classification systems, incomplete data reports, potential underreporting of adverse outcomes, and heterogeneity in patient series. A consensus on classification, treatment protocols, and outcome is needed to improve reliability of future studies.

3D Hybrid Nanofiber Aerogels Combining with Nanoparticles Made of a Biocleavable and Targeting Polycation and MiR-26a for Bone Repair

The healing of large bone defects represents a clinical challenge, often requiring some form of grafting. Three-dimensional (3D) nanofiber aerogels could be a promising bone graft due to their biomimetic morphology and controlled porous structures and composition. miR-26a has been reported to induce the differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) and facilitate bone formation. Introducing miR-26a with a suitable polymeric vector targeting BMSCs could improve and enhance the functions of 3D nanofiber aerogels for bone regeneration. Herein, we first developed the comb-shaped polycation (HA-SS-PGEA) carrying a targeting component, biocleavable groups and short ethanolamine (EA)-decorated poly(glycidyl methacrylate) (PGMA) (abbreviated as PGEA) arms as miR-26a delivery vector. We then assessed the cytotoxicity and transfection efficiency of this polycation and cellular response to miR-26a-incorporated nanoparticles (NPs) in vitro. HA-SS-PGEA exhibited a stronger ability to transport miR-26a and exert its functions than the gold standard polyethyleneimine (PEI) and low-molecular-weight linear PGEA. We finally examined the efficacy of HA-SS-PGEA/miR-26a NPs loaded 3D hybrid nanofiber aerogels showing a positive effect on the cranial bone defect healing. Together, the combination of 3D nanofiber aerogels and functional NPs consisting of a biodegradable and targeting polycation and therapeutic miRNA could be a promising approach for bone regeneration.

Free vascularised medial femoral condyle periosteal flaps in recalcitrant long bone non-union: a systematic review

INTRODUCTION

In adults, treatment of recalcitrant long bone non-union is extremely challenging, with poorly vascularised and atrophic defects unresponsive to standard non-vascularised bone graft treatment. Recent studies have documented the use of free vascularised periosteal flaps to achieve union in refractory long bone fracture non-union, yet its use is not well established. This systematic review aims to assess the evidence for free vascularised periosteal flaps in recalcitrant long bone non-union.

MATERIALS AND METHODS

The MEDLINE®/PubMed^® and Embase databases were searched for the Medical Subject Heading (MeSH) terms periosteal flap/vascularised flap/long bone/non-union/non united fracture in accordance with the PRISMA guidelines. Bibliographies were scrutinised for additional articles.

RESULTS

Pooled data from 14 studies met the inclusions criteria, comprising 137 cases of non-union, with 117 relating to long bone non-union. Pooled data indicated an overall 99% (116/117) successful union rate. All studies were of mid- to low-level evidence (Level III, IV and V). Only one study directly compared vascularised periosteal flaps to non-vascularised bone grafts, showing union rates of 100% versus 80% and faster time to union (2 versus 5.5 months).

CONCLUSIONS

Free vascularised periosteal flaps are promising with pooled data showing a 99% success rate in achieving union in refractory long bone non-union. This compares favourably with standard orthopaedic care consisting of revision fixation and non-vascularised bone graft union rates of approximately 80%. However, study design flaws should be addressed by validated outcome measures plus adequate blinding, and further comparative studies with greater patient numbers are required.

Does muscle improve validated outcome measures in open tibial fractures? New insights from a cohort study of the anterolateral thigh flap (ALT) versus ALT-Vastus lateralis flaps

The benefits of the muscle in open lower limb fractures remain to be determined. This study compared statistically equivalent groups of open tibial fractures treated by free anterolateral thigh (ALT) flaps or ALT flaps incorporating muscle (ALT-Vastus lateralis/ALT- VL). Method and Results: Chang Gung Memorial Hospital, Taiwan, 2004-2008, 49 free flaps in open lower limb fractures (38 open tibial) were specifically reconstructed with free ALT or ALT-VL flaps. Risk factors for non-union: equivalent between the two groups, with no differences in smoking, steroids, diabetes, time to flap and the AO classification of soft tissue and bone injury. Comparison of union rates: no difference was noted between groups in the Radiographic Union Score in Tibial Fractures (RUST) at 3, 6, 9 and 12 months. The only factor significantly associated with non-union was presence of a SPRINT trial defined 'critical' bone defect with odds ratio 14.4 (95% CI 1.36 - 131.5), with no association with AO bone classification, flap type, comorbidity or flap size. Patient-reported outcomes: the ALT-VL group showed improved patient satisfaction (p = 0.01, Cohen's d = 1.1). Functional outcomes (Enneking score) were not statistically significant, but the ALT-VL group trended towards significance in function and skin quality domains. Conclusions: Based on the results of this study, one can conclude that the degree of bone injury (specifically a 'critical' defect) is of greater relevance than flap choice with regard to fracture consolidation. Muscle does not result in improvements to union, the speed of union or deep infection. However, better PROMs may be related to the inclusion of the muscle around the fracture site.

Systematic Approach to the Management of Post-traumatic Segmental Diaphyseal Long Bone Defects: Treatment Algorithm and Comprehensive Classification System

BACKGROUND

Bone defects remain challenging to manage. The wide array of treatment options is a testament no single strategy works in every patient. This is more complex if consideration is given to the status of the host and the soft tissues. The choice of treatment should be based on specific patient requirements after taking all variables into account.

MATERIALS AND METHODS

We present a comprehensive classification system and treatment algorithm to assist with decision-making in management. All potential treatment modalities including amputation are discussed with their relevant pearls and pitfalls.

CONCLUSION

The proposed classification system may potentially assists with communication, enable patient stratification for assigning the most appropriate treatment modality and guide reporting of treatment outcomes.

HOW TO CITE THIS ARTICLE

Ferreira N, Tanwar YS. Systematic Approach to the Management of Post-traumatic Segmental Diaphyseal Long Bone Defects: Treatment Algorithm and Comprehensive Classification System. Strategies Trauma Limb Reconstr 2020;15(2):106-116.

Free Tissue Transfer with Distraction Osteogenesis and Masquelet Technique Is Effective for Limb Salvage in Patients with Gustilo Type IIIB Open Fractures

Osteocutaneous reconstruction can be challenging because of concomitant injuries and limited donor sites. There is a paucity of data on limb salvage outcomes following combined soft-tissue reconstruction and bone transport or Masquelet procedures. The authors reviewed a consecutive series of open tibia fracture patients undergoing soft-tissue reconstruction with either distraction osteogenesis or Masquelet technique. Endpoints were perioperative flap complications and bone union. Fourteen patients with Gustilo type IIIB open tibia fractures were included. Half of the group received muscle flaps and the remaining half received fasciocutaneous flaps. Ten patients (71.4 percent) underwent distraction osteogenesis and the remaining patients underwent Masquelet technique. Average bone gap length was 65.7 ± 31.3 mm (range, 20 to 120 mm). In the bone transport group, the average external fixation duration was 245 days (range, 47 to 686 days). In the Masquelet group, the average duration of the first stage of this two-stage procedure (i.e., time from cement spacer placement to bone grafting) was 95 days (range, 42 to 181 days). Bone union rate, as determined by radiographic evidence, was 85.7 percent. There was one complete flap failure (7.1 percent). One patient underwent below-knee amputation after failing bone transport and developing chronic osteomyelitis and subsequent infected nonunion. Our case series demonstrates that nonosteocutaneous flap methods of limb reconstruction are a viable option in patients with segmental long bone defects, with a bone union rate of 85 percent and a limb salvage rate over 90 percent in patients with Gustilo type IIIB fractures. CLINICAL QUESTION/LEVEL OF EVIDENCE:: Therapeutic, IV.

Managing bone loss in open fractures

Segmental bone loss continues to pose substantial clinical and technical challenges to orthopaedic surgeons. While several surgical options exist for the treatment of these complex patients, there is not a clear consensus or specific guidelines on the optimal management of these injuries as a whole. Many factors must be taken into consideration when planning surgery for these individuals. In order for these techniques to yield optimal results, each injury must be approached in a step-wise and multidisciplinary fashion to ensure that care is taken in bone and wound bed preparation, that soft tissues are healthy and free of contaminants, and that the patient's medical condition has been optimized. Through this article, we will answer relevant questions and discuss common obstacles and challenges encountered with these complex injuries. We will also review the many treatment options available or in development to address this problem.

Suprapatellar nailing of fractures of the tibia

OBJECTIVE

Intramedullary nailing of tibia fractures via a suprapatellar, transarticular approach with the knee joint in 20-30° of flexion and the use of specific protection tubes to preserve intra-articular structures.

INDICATIONS

Extra-articular fractures of the proximal tibia; simple and comminuted fractures of the tibia diaphysis; segmental diaphyseal fractures of the tibia; extra-articular fractures of the distal tibia and fractures with simple intra-articular distal extension; floating knee injuries.

CONTRAINDICATIONS

Gustilo grade 3C open fractures of the tibia; severe soft tissue laceration, contamination or infection in the suprapatellar area; ipsilateral knee joint prosthesis; knee arthrodesis; implants blocking the nail entry point.

SURGICAL TECHNIQUE

Via a suprapatellar, transarticular approach an intramedullary tibia nail is inserted after anatomical reposition of the tibial fracture with the knee joint in 20-30° of flexion. Use of specific protection tubes to preserve intra-articular structures. The proximal and distal locking configuration depends upon the specific fracture characteristics.

RESULTS

In all, 61 patients underwent suprapatellar tibia nailing and were under follow-up at least until fracture union. Twelve patients suffered from an open fracture. A total of 17 patients had a distal third fracture, 8 sustained a proximal third fracture and 36 had a shaft fracture. Follow-up focused on patients with distal fractures; 6/17 patients sustained open fractures. Average time to union was 9 weeks. One fracture did not heal and required exchange nailing. Two patients complained about anterior knee pain. Functionally, full range of motion was regained in all patients.

Decorating 3D Printed Scaffolds with Electrospun Nanofiber Segments for Tissue Engineering

Repairing large tissue defects often represents a great challenge in clinics due to issues regarding lack of donors, mismatched sizes, irregular shapes, and immune rejection. 3D printed scaffolds are attractive for growing cells and producing tissue constructs because of the intricate control over pore size, porosity, and geometric shape, but the lack of biomimetic surface nanotopography and limited biomolecule presenting capacity render them less efficacious in regulating cell responses. Herein, a facile method for coating 3D printed scaffolds with electrospun nanofiber segments is reported. The surface morphology of modified 3D scaffolds changes dramatically, displaying a biomimetic nanofibrous structure, while the bulk mechanical property, pore size, and porosity are not significantly compromised. The short nanofibers-decorated 3D printed scaffolds significantly promote adhesion and proliferation of pre-osteoblasts and bone marrow mesenchymal stem cells (BMSCs). Further immobilization of bone morphogenetic protein-2 mimicking peptides to nanofiber segments-decorated 3D printed scaffolds show enhanced mRNA expressions of osteogenic markers Runx2, Alp, OCN, and BSP in BMSCs, indicating the enhancement of BMSCs osteogenic differentiation. Together, the combination of 3D printing and electrospinning is a promising approach to greatly expand the functions of 3D printed scaffolds and enhance the efficacy of 3D printed scaffolds for tissue engineering.

Risk Factors for Tibial Plafond Nonunion: Medial Column Fixation May Reduce Nonunion Rates

OBJECTIVES

To identify the incidence and risk factors for development of tibial plafond nonunion.

DESIGN

Retrospective comparative study.

SETTING

Two Level 1 academic trauma centers.

PATIENTS/PARTICIPANTS

Seven hundred forty tibial plafond fractures (OTA/AO 43B3 and 43C) treated January 2006 to December 2015.

INTERVENTION

Open reduction and internal fixation.

MAIN OUTCOME MEASUREMENT

Nonunion.

RESULTS

Five hundred eighteen patients with a mean age of 43 years (range, 18-81 years) and mean follow-up of 27 months (range, 12-115 months) were involved. Seventy-two patients (72/518, 14%) were identified as having a nonunion. Surgical approach was not associated with nonunion in univariate analysis. Multiple regression model 1 identified OTA/AO 43C [odds ratio (OR) = 4.43; 95% confidence interval (CI), 1.01-19.41; P = 0.048], tobacco use (OR = 2.02; 95% CI, 1.10-3.71; P = 0.024), both minimal and substantial bone loss (P = 0.006 and P < 0.001, respectively), and open fracture (OR = 1.96; 95% CI, 1.10-3.48; P = 0.022) as risk factors for tibial plafond nonunion. Model 2 identified locking plate (OR = 1.97; 95% CI, 1.13-3.40; P = 0.016) and failure to treat the medial column (vs. screw P = 0.047, or plate P = 0.038) as risk factors.

CONCLUSIONS

The tibial plafond nonunion rate was 14%. Bone loss, open fracture, failure to treat the medial column, locking plates, and tobacco use were all significant risk factors for developing tibial plafond nonunion. Equally important, surgical approach was not significantly associated with plafond nonunion.

LEVEL OF EVIDENCE

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

Factors Predictive of Blocking Screw Placement in Retrograde Nailing of Distal Femur Fractures

OBJECTIVES

(1) Identify factors that predict blocking screw placement in the treatment of a distal femur fracture with retrograde nail fixation and (2) determine whether acceptable alignment and stability were achieved in fractures that received blocking screws.

DESIGN

Retrospective Comparative Study.

SETTING

Level I Trauma Center.

PATIENTS/PARTICIPANTS

Between 2011 and 2017, we identified 84 patients with distal third femur fractures treated with a retrograde femoral nail. Data were analyzed according to those who did (BLOCK, n = 30) and did not (NO BLOCK, n = 54) receive blocking screws. Patients in both groups were treated by orthopaedic trauma surgeons; postoperative weight-bearing radiographs were obtained of every patient.

INTERVENTION

Fixation using a retrograde femoral nail with or without blocking screws. Blocking screws were placed at the discretion of the treating surgeon to reduce malaligned fractures or improve stability.

MAIN OUTCOME MEASUREMENTS

(1) Demographics, radiographic apparent bone gap (RABG), space available for the nail (SAFN), and distal segment length [as a ratio of bicondylar width (BCW)]; and (2) post-operative alignment and stability (change in alignment over time).

RESULTS

Patients treated with blocking screws had a higher body mass index (BMI) (BLOCK: 29.0, NO BLOCK 25.7, P = 0.03). In addition, the BLOCK group had larger RABGs (BLOCK: 8.2 mm, NO BLOCK: 3.6 mm, P = 0.02), more SAFN (BLOCK: 51.4 mm, NO BLOCK: 39.8 mm, P = 0.02), and shorter distal segments (BLOCK: 1.7 × BCW, NO BLOCK: 2.0 × BCW, P = 0.01). In a multivariable logistic regression, the combination of these factors was significantly predictive of blocking screw placement with a large effect size (R = 0.36, P < 0.01). A distal segment length ≤ ×2 BCW was 77% sensitive for blocking screw placement, and a BMI ≥25 kg/m was 70% sensitive. Negative predictive values for blocking screw placement were distal segment length > ×2 BCW (79%), BMI <25 kg/m (77%), RABG <4 mm (76%), and SAFN <50 mm (71%). Patients that received blocking screws had acceptable postoperative alignment and stability, similar to fractures that did not receive blocking screws (P > 0.05).

CONCLUSIONS

This retrospective study of distal femur fractures treated with retrograde nails identified several factors that can be used to predict when blocking screw placement may be useful for increasing stability and maintaining alignment in distal third femur fractures treated with retrograde IM nails. Patients treated with blocking screws had a higher BMI, greater cortical bone loss, more SAFN, and shorter distal segments. There was no difference in postoperative alignment or stability between the 2 groups.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Prediction of tibial nonunion at the 6-week time point

INTRODUCTION

Intramedullary (IM) nail fixation is a common operative treatment, yet concerns regarding the frequency of complications, such as nonunion, remain. Treatment of tibial shaft fractures remains a challenge, and little evidence of prognostic factors that increase risk of nonunion is available. The aim of this study was to develop a predictive model of tibial shaft fracture nonunion 6 weeks after reamed intramedullary (IM) nail fixation based on commonly collected clinical variables and the radiographic union score for tibial fractures (RUST).

METHODS

A retrospective case-control study was conducted. All tibial shaft fractures treated at our level I trauma center from 2007 to 2014 were retrospectively reviewed. Only patients with follow-up until fracture healing or secondary operation for nonunion were included. Fracture gaps ≥3 mm were excluded. A total of 323 patients were included for study.

RESULTS

Infection within 6 weeks of operation, standard RUST, and the Nonunion Risk Determination (NURD) score had statistically significant associations with nonunion (odds ratio > or < 1.0; p < 0.01). The NURD score was increasingly predictive of nonunion with decreasing RUST. All patients in the high RUST group (RUST ≥ 10), achieved union regardless of NURD score. In the medium RUST group (RUST 6-9), 25% of patients with a NURD score ≥7 experienced nonunion. In the low RUST group (RUST <6 or infection within 6 weeks), 69% of patients with a NURD score ≥7 experienced nonunion.

CONCLUSION

Three variables predicted nonunion. Based on these variables, we created a clinical prediction tool of nonunion that could aid in clinical decision making and discussing prognosis with patients.

Novel 3D Hybrid Nanofiber Aerogels Coupled with BMP-2 Peptides for Cranial Bone Regeneration

An ideal synthetic bone graft is a combination of the porous and nanofibrous structure presented by natural bone tissue as well as osteoinductive biochemical factors such as bone morphogenetic protein 2 (BMP-2). In this work, ultralight 3D hybrid nanofiber aerogels composed of electrospun PLGA-collagen-gelatin and Sr-Cu codoped bioactive glass fibers with incorporation of heptaglutamate E7 domain specific BMP-2 peptides have been developed and evaluated for their potential in cranial bone defect healing. The nanofiber aerogels are surgically implanted into 8 mm × 1 mm (diameter × thickness) critical-sized defects created in rat calvariae. A sustained release of E7-BMP-2 peptide from the degradable hybrid aerogels significantly enhances bone healing and defect closure over 8 weeks in comparison to unfilled defects. Histomorphometry and X-ray microcomputed tomography (µ-CT) analysis reveal greater bone volume and bone formation area in case of the E7-BMP-2 peptide loaded hybrid nanofiber aerogels. Further, histopathology data divulged a near complete nanofiber aerogel degradation along with enhanced vascularization of the regenerated tissue. Together, this study for the first time demonstrates the fabrication of 3D hybrid nanofiber aerogels from 2D electrospun fibers and their loading with therapeutic osteoinductive BMP-2 mimicking peptide for cranial bone tissue regeneration.

Diagnosis and Management of Polytraumatized Patients With Severe Extremity Trauma

Multiply injured patients with severe extremity trauma are at risk of acute systemic complications and are at high risk of developing longer term orthopaedic complications including soft-tissue infection, osteomyelitis, posttraumatic osteoarthritis, and nonunion. It is becoming increasingly recognized that injury magnitude and response to injury have major jurisdiction pertaining to patient outcomes and complications. The complexities of injury and injury response that affect outcomes present opportunities to apply precision approaches to understand and quantify injury magnitude and injury response on a patient-specific basis. Here, we present novel approaches to measure injury magnitude by adopting methods that quantify both mechanical and ischemic tissue injury specific to each patient. We also present evolving computational approaches that have provided new insight into the complexities of inflammation and immunologic response to injury specific to each patient. These precision approaches are on the forefront of understanding how to stratify individualized injury and injury response in an effort to optimize titrated orthopaedic surgical interventions, which invariably involve most of the multiply injured patients. Finally, we present novel methods directed at mangled limbs with severe soft-tissue injury that comprise severely injured patients. Specifically, methods being developed to treat mangled limbs with volumetric muscle loss have the potential to improve limb outcomes and also mitigate uncompensated inflammation that occurs in these patients.

Critical-Size Bone Defects: Is There a Consensus for Diagnosis and Treatment?

There is a significant burden of disease associated with bone defects, and their management is challenging. These injuries have a profound clinical and economic impact, and outcomes are limited by high rates of complication and reoperation, as well as poor functional outcomes. There remains a lack of consensus around definitions, reliable models, and best practices for the surgical management of bone defects. The current state of the literature on bone defects is reviewed here, with a focus on defining critical-size bone defect, the use of the induced membrane technique, the role of biologics, and the management of infected bone defects.

Risk Factors for Failure of Bone Grafting of Tibia Nonunions and Segmental Bone Defects: A New Preoperative Risk Assessment Score

OBJECTIVE

To develop a clinically useful prediction model of success at the time of surgery to promote bone healing for established tibial nonunion or traumatic bone defects.

DESIGN

Retrospective case controlled.

SETTING

Level 1 trauma center.

PATIENTS

Adult patients treated with surgery for established tibia fracture nonunion or traumatic bone defects from 2007 to 2016. Two hundred three patients met the inclusion criteria and were available for final analysis.

INTERVENTION

Surgery to promote bone healing of established tibia fracture nonunion or segmental defect with plate and screw construct, intramedullary nail fixation, or multiplanar external fixation.

MAIN OUTCOME MEASURES

Failure of the surgery to promote bone healing that was defined as unplanned revision surgery for lack of bone healing or deep infection. No patients were excluded who had a primary outcome event.

RESULTS

Multivariate logistic modeling identified 5 significant (P < 0.05) risk factors for failure of the surgery to promote bone healing: (1) mechanism of injury, (2) Increasing body mass index, (3) cortical defect size (mm), (4) flap size (cm), and (5) insurance status. A prediction model was created based on these factors and awarded 0 points for fall, 17 points for high energy blunt trauma (OR = 17; 95% CI, 1-286, P = 0.05), 22 points for industrial/other (OR = 22; 95% CI, 1-4, P = 0.04), and 28 points for ballistic injuries (OR = 28; 95% CI, 1-605, P = 0.04). One point is given for every 10 cm of flap size (OR = 1; 95% CI, 1-1.1, P < 0.001), 10 mm of mean cortical gap distance (OR = 1; 95% CI, 1-2, P = 0.004), and 10 units BMI, respectively (OR = 1.5; 95% CI, 1-3, P = 0.16). Two points are awarded for Medicaid or no insurance (OR = 2; 95% CI, 1-5, P = 0.035) and 3 points for Medicare (3; 95% CI, 1-9, P = 0.033). Each 1-point increase in risk score was associated with a 6% increased chance of requiring at least 1 revision surgery (P < 0.001).

CONCLUSIONS

This study presents a clinical score that predicts the likelihood of success after surgery for tibia fracture nonunions or traumatic bone defects and may help clinicians better determine which patients are likely to fail these procedures and require further surgery.