Treatment of presumed aseptic non-union of the humeral shaft by osteosynthesis combining intramedullary nailing and screw plate

In 2020, the most common treatment for presumed aseptic non-union of the humeral shaft seems to be decortication, often associated with bone autografting, and stabilized by a screw plate. We propose to evaluate an original technique of rigid osteosynthesis combining intramedullary nailing and screw plate. Between January 2004 and January 2020, 45 patients underwent treatment of presumed aseptic non-union of the humeral shaft by osteosynthesis combining intramedullary nailing and a screw plate. The minimum radio-clinical follow-up was one year postoperatively. The series included 19 men and 26 women with a mean age of 53 years (range 19-84 years). Bone consolidation was achieved in 43 patients, a rate of 95.5%. Comparing patients who achieved bone consolidation with the two failed consolidations did not reveal any statistically significant factor. Interobserver agreement was almost perfect (k=0.93) for the use of the RUST for humeral shaft fractures treated with intramedullary nailing and screw plate. In our study, the treatment of presumed aseptic non- union of the humeral shaft with an osteosynthesis combining intramedullary nailing and screw plate gives, with 95.5% of bone consolidation, results equal to or even superior to the different treatments currently described in the literature.

The critical impact of traumatic muscle loss on fracture healing: Basic science and clinical aspects

Musculoskeletal trauma, specifically fractures, is a leading cause of patient morbidity and disability worldwide. In approximately 20% of cases with fracture and related traumatic muscle loss, bone healing is impaired leading to fracture nonunion. Over the past few years, several studies have demonstrated that bone and the surrounding muscle tissue interact not only anatomically and mechanically but also through biochemical pathways and mediators. Severe damage to the surrounding musculature at the fracture site causes an insufficiency in muscle-derived osteoprogenitor cells that are crucial for fracture healing. As an endocrine tissue, skeletal muscle produces many myokines that act on different bone cells, such as osteoblasts, osteoclasts, osteocytes, and mesenchymal stem cells. Investigating how muscle influences fracture healing at cellular, molecular, and hormonal levels provides translational therapeutic solutions to this clinical challenge. This review provides an overview about the contributions of surrounding muscle tissue in directing fracture healing. The focus of the review is on describing the interactions between bone and muscle in both healthy and fractured environments. We discuss current progress in identifying the bone-muscle molecular pathways and strategies to harness these pathways as cues for accelerating fracture healing. In addition, we review the existing challenges and research opportunities in the field.

Risk factors and healthcare costs associated with long bone fracture non-union: a retrospective US claims database analysis

BACKGROUND

Few contemporary US-based long bone non-union analyses have recently been published. Our study was designed to provide a current understanding of non-union risks and costs, from the payers' perspective.

METHODS

The Merative™ MarketScan® Commercial Claims and Encounters database was used. Patients with surgically treated long bone (femur, tibia, or humerus) fractures in the inpatient setting, from Q4 2015 to most recent, were identified. Exclusion criteria included polytrauma and amputation at index. The primary outcome was a diagnosis of non-union in the 12 and 24 months post-index. Additional outcomes included concurrent infection, reoperation, and total healthcare costs. Age, gender, comorbidities, fracture characteristics, and severity were identified for all patients. Descriptive analyses were performed. Crude and adjusted rates of non-union (using Poisson regressions with log link) were calculated. Marginal incremental cost of care associated with non-union and infected non-union and reoperation were estimated using a generalized linear model with log link and gamma distribution.

RESULTS

A total of 12,770, 13,504, and 4,805 patients with femoral, tibial, or humeral surgically treated fractures were identified, 74-89% were displaced, and 18-27% were comminuted. Two-year rates of non-union reached 8.5% (8.0%-9.1%), 9.1% (8.6%-9.7%), and 7.2% (6.4%-8.1%) in the femoral, tibial, and humeral fracture cohorts, respectively. Shaft fractures were at increased risk of non-union versus fractures in other sites (risk ratio (RR) in shaft fractures of the femur: 2.36 (1.81-3.04); tibia: 1.95 (1.47-2.57); humerus: 2.02 (1.42-2.87)). Fractures with severe soft tissue trauma (open vs. closed, Gustilo III vs. Gustilo I-II) were also at increased risk for non-union (RR for Gustilo III fracture (vs. closed) for femur: R = 1.96 (1.45-2.58), for tibia: 3.33 (2.85-3.87), RR for open (vs. closed) for humerus: 1.74 (1.30-2.32)). For all fractures, younger patients had a reduced risk of non-union compared to older patients. For tibial fractures, increasing comorbidity (Elixhauser Index 5 or greater) was associated with an increased risk of non-union. The two-year marginal cost of non-union ranged from $33K-$45K. Non-union reoperation added $16K-$34K in incremental costs. Concurrent infection further increased costs by $46K-$86K.

CONCLUSIONS

Non-union affects 7-10% of surgically treated long bone fracture cases. Shaft and complex fractures were at increased risk for non-union.

Factors Informing the Development of a Clinical Pathway and Patients' Quality of Life after a Non-Union Fracture of the Lower Limb

Patients with non-union fractures spend extended periods of time in the hospital following poor healing. Patients have to make several follow-up visits for medical and rehabilitation purposes. However, the clinical pathways and quality of life of these patients are unknown. This prospective study aimed to identify the clinical pathways (CPs) of 22 patients with lower-limb non-union fractures whilst determining their quality of life. Data were collected from hospital records from admission to discharge, utilizing a CP questionnaire. We used the same questionnaire to track patients' follow-up frequency, involvement in activities of daily living, and final outcomes at six months. We used the Short Form-36 questionnaire to assess patients' initial quality of life. The Kruskal-Wallis test compared the quality of life domains across different fracture sites. We examined CPs using medians and inter-quantile ranges. During the six-month follow-up period, 12 patients with lower-limb non-union fractures were readmitted. All of the patients had impairments, limited activity, and participation restrictions. Lower-limb fractures can have a substantial impact on emotional and physical health, and lower-limb non-union fractures may have an even greater effect on the emotional and physical health of patients, necessitating a more holistic approach to patient care.

Exogenously delivered iPSCs disrupt the natural repair response of endogenous MPCs after bone injury

Promoting bone healing including fracture non-unions are promising targets for bone tissue engineering due to the limited success of current clinical treatment methods. There has been significant research on the use of stem cells with and without biomaterial scaffolds to treat bone fractures due to their promising regenerative capabilities. However, the relative roles of exogenous vs. endogenous stem cells and their overall contribution to in vivo fracture repair is not well understood. The purpose of this study was to determine the interaction between exogenous and endogenous stem cells during bone healing. This study was conducted using a standardized burr-hole bone injury model in a mesenchymal progenitor cell (MPC) lineage-tracing mouse under normal homeostatic and osteoporotic conditions. Burr-hole injuries were treated with a collagen-I biomaterial loaded with and without labelled induced pluripotent stem cells (iPSCs). Using lineage-tracing, the roles of exogenous and endogenous stem cells during bone healing were examined. It was observed that treatment with iPSCs resulted in muted healing compared to untreated controls in intact mice post-injury. When the cell populations were examined histologically, iPSC-treated burr-hole defects presented with a dramatic reduction in endogenous MPCs and cell proliferation throughout the injury site. However, when the ovaries were removed and an osteoporotic-like phenotype induced in the mice, iPSCs treatment resulted in increased bone formation relative to untreated controls. In the absence of iPSCs, endogenous MPCs demonstrated robust proliferative and osteogenic capacity to undertake repair and this behaviour was disrupted in the presence of iPSCs which instead took on an osteoblast fate but with little proliferation. This study clearly demonstrates that exogenously delivered cell populations can impact the normal function of endogenous stem/progenitor populations during the normal healing cascade. These interactions need to be better understood to inform cell and biomaterial therapies to treat fractures.

A comprehensive molecular profiling approach reveals metabolic alterations that steer bone tissue regeneration

Bone regeneration after fracture is a complex process with high and dynamic energy demands. The impact of metabolism on bone healing progression and outcome, however, is so far understudied. Our comprehensive molecular profiling reveals that central metabolic pathways, such as glycolysis and the citric acid cycle, are differentially activated between rats with successful or compromised bone regeneration (young versus aged female Sprague-Dawley rats) early in the inflammatory phase of bone healing. We also found that the citric acid cycle intermediate succinate mediates individual cellular responses and plays a central role in successful bone healing. Succinate induces IL-1β in macrophages, enhances vessel formation, increases mesenchymal stromal cell migration, and potentiates osteogenic differentiation and matrix formation in vitro. Taken together, metabolites-here particularly succinate-are shown to play central roles as signaling molecules during the onset of healing and in steering bone tissue regeneration.

Incidence and nonunion rates of tibial fractures in adults with osteogenesis imperfecta: a retrospective cohort study of 402 patients with 42 fractures at an expert clinic

BACKGROUND

Tibial fractures are the most common fractures seen in adults and lead to the most nonunions. Osteogenesis imperfecta (OI) is characterized by increased bone fragility and higher risk of fractures. No studies have been published on the incidence of tibial fractures and nonunions in adults with OI. This study aims to summarize the incidence of tibial fractures and nonunions in this population.

METHODS

A retrospective, descriptive study. All medical charts of adult patients in the OI database of our OI expert clinic were analyzed for tibial fractures between 2008 and 2020. Tibial fracture incidence, nonunion rate, treatment modality and potential risk factors were determined.

RESULTS

The database consisted of 402 patients, 34 of whom had suffered one or more tibial fractures, resulting in 42 fractures. The incidence of tibial fractures in adults with OI is 870 per 100,000 person-years. Two out of 42 fractures led to nonunion (5%). It was not possible to adjust for risk factors or type of treatment.

CONCLUSION

There is a higher incidence of tibial fractures in patients with OI, but a nonunion rate comparable to the general population. With only two nonunions it is not possible to draw conclusions on the influence of risk factors or treatment of tibial fractures on OI.

The perceptions of clinicians using low-intensity pulsed ultrasound (LIPUS) for orthopaedic pathology: A national qualitative study

INTRODUCTION

Low-intensity pulsed ultrasound (LIPUS) is a non-invasive treatment modality for delayed union or non-union of acute fractures. We aimed to assess the current use of LIPUS at a national level in the United Kingdom, why and how clinicians use it, what treatment protocols are followed, and what the current perceptions are on this technology.

METHODOLOGY

Using a detailed online survey compromised of 20 questions delivered to known LIPUS users, we were able to collect qualitative data on indication of use, type of machine used, personal views on the technology, frequency of usage, and treatment protocols. Each question was peer-reviewed to exclude bias.

RESULTS

A total of 70 respondents completed the survey. LIPUS was used by most clinicians for cases of non-union (N = 55, 78.5%) and delayed union (N = 51, 72.8%). The majority of respondents personally used a LIPUS device between 1 and 5 times in 12 months (N = 38, 54.3%). Most considered LIPUS a failure after three to six months of treatment without clinical improvement (N = 39, 55.7%). A total of 32 respondents (45.7%) mentioned the need for funding approval before accessing LIPUS technology. Poor revision surgery candidates (N = 48, 68.6%) and atrophic non-union (N = 46, 65.7%) were the most frequently cited reasons for using LIPUS technology as treatment. Most participants (N = 48, 68.6%) considered LIPUS to be cost-effective. Despite most clinicians being comfortable with the use of LIPUS, some respondents did not understand the basic science underpinning the technology nor could explain the need for LIPUS to patients comfortably.

CONCLUSION

LIPUS technology may have a significant role to play in the treatment of orthopaedic fracture related pathology. Regular users perceived the technology to be cost-effective and efficacious. Further research should standardize treatment protocols and aim to establish a national LIPUS registry.

Monitoring the Progress of Treatment in Fracture Non-Union: The Role of Alkaline Phosphatase and Ultrasonography

Objective  To evaluate the role of serum alkaline phosphatase (ALP) and ultrasonography (USG) in monitoring the progress of treatment in diaphyseal non-unions. Methods  This prospective observational cohort study included adult patients with diaphyseal fractures of major long bones previously treated with internal fixation and eventually resulting in non-union. Following the definitive treatment for non-union, the patients were followed-up periodically for six months, and serial monitoring of the levels of ALP and USG were performed along with radiographs (X-rays) to ascertain the status of the union. Results  After an initial rise at seven weeks, ALP levels declined to normal values in fractures which united, whereas they remained high in cases of persistent non-union. Similarly, after an elevation of the vascular resistive index (RI) at around 12 weeks in all the patients, it decreased in cases progressing to union, while it remained persistently high even at 24 weeks in fractures failing to unite. Cases of persistent non-union continued to show hypoechogenic callus at 24 weeks instead of converting into hyperechogenic callus, as observed in cases which progressed to union. Conclusion  Significant changes suggestive of union appeared simultaneously on the X-rays, USG and ALP levels during the follow-up. However, a serial examination of the ALP levels and USG during the follow-up gave a hint of the direction of progress in the healing process of fracture non-union. Their role in monitoring the outcome of non-union is more complimentary than supplementary to the X-rays.

3D GelMA ICC Scaffolds Combined with SW033291 for Bone Regeneration by Modulating Macrophage Polarization

Despite the interaction between bone marrow mesenchymal stem cells (BMSCs) and macrophages has been found to play a critical role in repairing bone defects, it remains a challenge to develop a desirable tissue engineering scaffold for synchronous regulation of osteogenic differentiation and macrophage polarization. Herein, this study proposed a novel strategy to treat bone defects based on three-dimensional Gelatin Methacryloyl Inverted Colloidal Crystal (3D GelMA ICC) scaffold and an active 15-hydroxyprostaglandin dehydrogenase (15-PGDH) inhibitor SW033291. Specifically, the 3D GelMA ICC scaffolds were firstly prepared by colloidal templating method, which displayed good cell attachment and promoted intercellular interaction among macrophage and BMSCs due to its uniform pore interconnectivity. By combined use of SW033291, the release of Prostaglandin E2 (PGE2) from BMSCs on the GelMA ICC scaffold was significantly upregulated and macrophages M2 polarization was markedly increased. In turn, BMSCs proliferation and osteogenic differentiation was further enhanced by paracrine regulation of M2 macrophage, and thus finally caused more in vivo new bone formation by shaping up a pro-regenerative local immune microenvironment surrounding GelMA ICC scaffold. Our findings demonstrate the potential of 3D GelMA ICC scaffolds combined with SW033291 to become an effective tissue engineering strategy for bone regeneration.

High-energy extracorporeal shockwave therapy in humeral delayed and non-unions

INTRODUCTION

Within the last few decades, focused high-energy extracorporeal shockwave therapy (ESWT) has proven to be an effective alternative to standard of care revision surgery in delayed healing fractures or manifest non-unions in various anatomical regions.

MATERIALS AND METHODS

A retrospective multi-variant analysis of an open prospective, single-armed clinical study was conducted. Patients receiving focused high-energy ESWT for a delayed healing or an apparent non-union of a humeral fracture between January 1999 and December 2015 at a single trauma center were included in the study. Bony healing was defined as cortical continuity in three of four cortices and pain-free force loading and evaluated using CT scans and clinical examination at three- and six-month follow-ups after ESWT.

RESULTS

A total of 236 patients were included. N = 93 (43.8%) showed bony consolidation three months after ESWT and n = 105 (52.5%) after six months. Sub-group analysis showed significantly better healing for the proximal metaphyseal humerus (66.7% after six months, n = 42) compared to the diaphyseal region (48.1%, n = 133) and distal metaphyseal humerus (48.1%, n = 25). Regression analysis indicated significantly increased healing rates for patients of younger ages (p = 0.001) and a fracture diastasis of less than 5 mm (p = 0.002).

CONCLUSION

The findings of this study indicate that ESWT can be considered as a treatment option for a well-selected patient population despite the lower healing rates compared to other anatomical regions.

Insights into the Cellular and Molecular Mechanisms That Govern the Fracture-Healing Process: A Narrative Review

Fracture-healing is a complex multi-stage process that usually progresses flawlessly, resulting in restoration of bone architecture and function. Regrettably, however, a considerable number of fractures fail to heal, resulting in delayed unions or non-unions. This may significantly impact several aspects of a patient’s life. Not surprisingly, in the past few years, a substantial amount of research and number of clinical studies have been designed, aiming at shedding light into the cellular and molecular mechanisms that regulate fracture-healing. Herein, we present the current knowledge on the pathobiology of the fracture-healing process. In addition, the role of skeletal cells and the impact of marrow adipose tissue on bone repair is discussed. Unveiling the pathogenetic mechanisms that govern the fracture-healing process may lead to the development of novel, smarter, and more effective therapeutic strategies for the treatment of fractures, especially of those with large bone defects.

Development of a tibial experimental non-union model in rats

BACKGROUND

Many non-union animal models have been developed to explore the problems surrounding fracture healing. However, the existing models are not perfect and cannot satisfy all non-union studies. This study aimed to make a non-union model of the tibia in rats by cauterization of the posterior of 2 mm on both sides of the fracture end after open osteotomy of the tibia and fixing the fractured tibia with a Kirschner wire 0.8 mm in diameter.

METHODS

For this study, 96 female adult Sprague-Dawley (SD) rats were used. The rats underwent surgery to produce a tibial open fracture and were fixed with a 0.8-mm diameter Kirschner wire. In 48 of the rats, the periosteum proximal and distal to the fracture end was cauterized.

RESULTS

At 2, 4, 6, and 8 weeks after surgery, radiological and histological analysis showed typical physiological healing in the control group, and the healing rate was 100% at 6 weeks. But the non-union group was characterized by resorption of the fracture ends with few callus formations and no bridging callus formation, and the healing rate was 0% at 8 weeks.

CONCLUSIONS

This method represents a reproducible model to create atrophic non-unions. This model provides a new option for studying the basic healing mechanisms and evaluating new therapies for bone regeneration and treatment of non-unions.

Smoking and the patient with a complex lower limb injury

Smoking is known to increase the risk of peri-operative complications in Orthoplastic surgery by impairing bone and wound healing. The effects of nicotine replacement therapies (NRTs) and electronic cigarettes (e-cigarettes) has been less well established. Previous reviews have examined the relationship between smoking and bone and wound healing separately. This review provides surgeons with a comprehensive and contemporaneous account of how smoking in all forms interacts with all aspects of complex lower limb trauma. We provide a guide for surgeons to refer to during the consent process to enable them to tailor information towards smokers in such a way that the patient may understand the risks involved with their surgical treatment. We update the literature with recently discovered methods of monitoring and treating the troublesome complications that occur more commonly in smokers effected by trauma.

The epidemiology and orthopaedic burden of civilian gunshot injuries over a four-year period at a level one trauma unit in Cape Town, South Africa

PURPOSE

The aim of this study was to quantify the overall burden of orthopaedic gunshot-related injuries at our institution over a four year period. Secondary aims included identifying complications from gunshot-related injuries and the additional burden it places on healthcare services.

METHODS

A retrospective review was conducted on all patients with gunshot injuries presenting to our hospital's trauma unit between January 2014 and December 2017. Patient data was recorded, and demographic data, number and type of implants, blood products used, duration of hospital admission, duration of ICU admission, radiological studies performed, and prevalence of complications were analysed.

RESULTS

A total of 1449 patients with a mean age of 28.2 ± 9.7 years (range 2.0-71.0) were included in this study. The majority of these gunshot-related orthopaedic injuries were sustained to the lower extremities and were treated non-operatively. The median duration of hospital stay was 7.0 (IQR 4.0-12.0). The most common complications identified were nerve injury (8.3%), vascular injury (6.5%), fracture-related infection (3.2%), non-union (3.1%), and compartment syndrome (1.6%). The total cost of care was ZAR 53,568,537 (USD 4,320,043) with an average cost per patient of ZAR 37,031 (USD 2986).

CONCLUSION

This study highlighted the burden of gunshot injuries presenting to our hospital and the strain it places on its healthcare resources. The prevalence of complications was comparable to international studies on the subject. With improved understanding of this burden, more healthcare resources can be allocated to this problem and better prevention strategies can be planned.

Time Course of Immune Response and Immunomodulation During Normal and Delayed Healing of Musculoskeletal Wounds

Single trauma injuries or isolated fractures are often manageable and generally heal without complications. In contrast, high-energy trauma results in multi/poly-trauma injury patterns presenting imbalanced pro- and anti- inflammatory responses often leading to immune dysfunction. These injuries often exhibit delayed healing, leading to fibrosis of injury sites and delayed healing of fractures depending on the intensity of the compounding traumas. Immune dysfunction is accompanied by a temporal shift in the innate and adaptive immune cells distribution, triggered by the overwhelming release of an arsenal of inflammatory mediators such as complements, cytokines and damage associated molecular patterns (DAMPs) from necrotic cells. Recent studies have implicated this dysregulated inflammation in the poor prognosis of polytraumatic injuries, however, interventions focusing on immunomodulating inflammatory cellular composition and activation, if administered incorrectly, can result in immune suppression and unintended outcomes. Immunomodulation therapy is promising but should be conducted with consideration for the spatial and temporal distribution of the immune cells during impaired healing. This review describes the current state of knowledge in the spatiotemporal distribution patterns of immune cells at various stages during musculoskeletal wound healing, with a focus on recent advances in the field of Osteoimmunology, a study of the interface between the immune and skeletal systems, in long bone fractures. The goals of this review are to (1) discuss wound and fracture healing processes of normal and delayed healing in skeletal muscles and long bones; (2) provide a balanced perspective on temporal distributions of immune cells and skeletal cells during healing; and (3) highlight recent therapeutic interventions used to improve fracture healing. This review is intended to promote an understanding of the importance of inflammation during normal and delayed wound and fracture healing. Knowledge gained will be instrumental in developing novel immunomodulatory approaches for impaired healing.

The biology and treatment of acute long-bones diaphyseal fractures: Overview of the current options for bone healing enhancement

Diaphyseal fractures represent a complex biological entity that could often end into impaired bone-healing, with delayed union and non-union occurring up to 10% of cases. The role of the modern orthopaedic surgeon is to optimize the fracture healing environment, recognize and eliminate possible interfering factors, and choose the best suited surgical fixation technique. The impaired reparative process after surgical intervention can be modulated with different surgical techniques, such as dynamization or exchange nailing after failed intramedullary nailing. Moreover, the mechanical stability of a nail can be improved through augmentation plating, bone grafting or external fixation techniques with satisfactory results. According to the "diamond concept", local therapies, such as osteoconductive scaffolds, bone growth factors, and osteogenic cells can be successfully applied in "polytherapy" for the enhancement of delayed union and non-union of long bones diaphyseal fractures. Moreover, systemic anti-osteoporosis anabolic drugs, such as teriparatide, have been proposed as off-label treatment for bone healing enhancement both in fresh complex shaft fractures and impaired unions, especially for fragility fractures. The article aims to review the biological and mechanical principles of failed reparative osteogenesis of diaphyseal fractures after surgical treatment. Moreover, the evidence about the modern non-surgical and pharmacological options for bone healing enhancement will discussed.

Nanocomposites drug delivery systems for the healing of bone fractures

The skeletal system is fundamental for the structure and support of the body consisting of bones, cartilage, and connective tissues. Poor fracture healing is a chief clinical problem leading to disability, extended hospital stays and huge financial liability. Even though most fractures are cured using standard clinical methods, about 10% of fractures are delayed or non-union. Despite decades of progress, the bone-targeted delivery system is still restricted due to the distinctive anatomical bone features. Recently, various novel nanocomposite systems have been designed for the cell-specific targeting of bone, enhancing drug solubility, improving drug stability and inhibiting drug degradation so that it can reach its target site without being removed in the systemic circulation. Such targeting systems could consist of biological compounds i.e. bone marrow stem cells (BMSc), growth factors, RNAi, parathyroid hormone or synthetic compounds, i.e. bisphosphonates (BPs) and calcium phosphate cement. Hydrogels and nanoparticles are also being employed for fracture healing. In this review, we discussed the normal mechanism of bone healing and all the possible drug delivery systems being employed for the healing of the bone fracture.

Results of advanced core decompression in patients with osteonecrosis of the femoral head depending on age and sex-a prospective cohort study

Background

Core decompression is a common surgical technique to treat osteonecrosis of the femoral head. The aim of this study is to evaluate the effect of the parameters “age” and “sex” on the outcome of this type of treatment.

Methods

A prospective cohort study was performed. Eighty-six osteonecrotic hips with a mean follow-up of 32.5 months (± 24.8) after advanced core decompression were analysed regarding age- and sex-dependent treatment failure. Additionally, the modified Harris Hip Score and Numeric Rating Scale were compared regarding the parameters age and sex.

Results

The mean hip survival of the male participants was 51.3 months (39.4% treatment failure), whereas females presented a longer, thus not significant, mean survival of 61.4 months (30% therapy failure; p = 0.48). The further evaluation revealed significantly better survival in the patients aged < 40 years (mean survival 66.09 months, 16% treatment failure) in comparison to those aged ≥ 40 years (mean survival 50.14 months, 46% therapy failure; p = 0.03). The modified Harris Hip Score and Numeric Rating Scale results of patients whose treatment did not fail during the study period were similar, irrespective of the patient’s sex or age.

Conclusions

The study shows that the number of therapy failures is significantly higher in older patients, with 40 years of age marking the borderline. Patients’ sex does not seem to affect the outcome of treatment, and postoperative clinical scores appear to be identical with individuals not affected by therapy failure. Since age and sex are unalterable parameters, the study helps to provide valuable predictions regarding the chances of long-term hip survival after treatment of osteonecrosis.

The Treatment of Acute Diaphyseal Long-bones Fractures with Orthobiologics and Pharmacological Interventions for Bone Healing Enhancement: A Systematic Review of Clinical Evidence

BACKGROUND

The healing of long bones diaphyseal fractures can be often impaired and eventually end into delayed union and non-union. A number of therapeutic strategies have been proposed in combination with surgical treatment in order to enhance the healing process, such as scaffolds, growth factors, cell therapies and systemic pharmacological treatments. Our aim was to investigate the current evidence of bone healing enhancement of acute long bone diaphyseal fractures.

METHODS

A systematic review was conducted by using Pubmed/MEDLINE; Embase and Ovid databases. The combination of the search terms "long-bones; diaphyseal fracture; bone healing; growth factors; cell therapies; scaffolds; graft; bone substitutes; orthobiologics; teriparatide".

RESULTS

The initial search resulted in 4156 articles of which 37 papers fulfilled the inclusion criteria and were the subject of this review. The studies included 1350 patients (837 males and 513 females) with a mean age of 65.3 years old.

CONCLUSIONS

General lack of high-quality studies exists on the use of adjuvant strategies for bone healing enhancement in acute shaft fractures. Strong evidence supports the use of bone grafts, while only moderate evidence demineralized bone matrix and synthetic ceramics. Conflicting results partially supported the use of growth factors and cell therapies in acute fractures. Teriparatide showed promising results, particularly for atypical femoral fractures and periprosthetic femoral fractures.

Design, Fabrication and Validation of a Precursor Pulsed Electromagnetic Field Device for Bone Fracture Repair

Pulsed electromagnetic field (PEMF) stimulation has been utilized in the medical field since the early 20th century. A number of therapeutic devices have been developed for the treatment of bone fractures and other medical applications. Most of these devices are backed by limited quantitative evidence. In this paper we present the development of a PEMF device for the purposes of determining, through in vitro experimentation, the exposure parameters required to give the most optimal fracture repair. Following electromagnetic field characterization, the device was shown to match well with computational field simulations. The exposure system has been validated through adipose-derived stem cell viability studies with an exposure frequency of 5 Hz and an intensity of 1.1 mT, for a duration of seven days at 30 minutes per day. Under the specific field characteristics chosen, the fatty-tissue derived stem cell proliferation was not hindered and in fact was stimulated $( 0. 025 < P < 0.01)$ by the PEMF exposure. With continued experimentation of numerous exposure conditions at the cellular scale, it will be possible to quantitatively determine the optimal exposure conditions required to produce the most rapid fresh fracture repair. Following this, there is significant potential for development of an optimized wearable device suitable for enhancing repair of all types of bone fractures.

CXCR4 Antagonism to Treat Delayed Fracture Healing

A significant number of fractures develop nonunion. Stem cell homing is regulated through stromal cell-derived factor 1 (SDF1) and its receptor CXCR4. Stem/progenitor cell populations can be endogenously mobilized by administering growth factors with a pharmacological antagonist of CXCR4, AMD3100, which may be a means to improve fracture healing. A 1.5 mm femoral osteotomy in Wistar rats was stabilized with an external fixator. Rats were pretreated with phosphate buffered saline [PBS(P)], vascular endothelial growth factor [VEGF(V)], insulin-like growth factor-1 [IGF1(I)], or granulocyte colony stimulating factor [GCSF(G)] before AMD3100. A control group (C) did not receive growth factors or AMD3100. Bone formation after 5 weeks was analyzed. Group P had a significant increase in total bone volume (BV) (p = 0.01) and group I in percentage bone in the fracture gap (p = 0.035). Group G showed a decrease in BV. All treated groups had an increase in trabecular thickness. Histology showed decreased cartilage tissue associated with increased bone in groups with improved healing, and increased fibrous tissue in poorly performing groups. Antagonism of SDF1-CXCR4 axis can boost impaired fracture healing. AMD3100 given alone was the most effective means to boost healing, whereas pretreatment with GCSF reduced healing. AMD3100 is likely mobilizing stem cells into the blood stream that home to the fracture site enhancing healing.

VEGF with AMD3100 endogenously mobilizes mesenchymal stem cells and improves fracture healing

A significant number of fractures develop non-union. Mesenchymal stem cell (MSC) therapy may be beneficial, however, this requires cell acquisition, culture and delivery. Endogenous mobilization of stem cells offers a non-invasive alternative. The hypothesis was administration of VEGF and the CXCR4 antagonist AMD3100 would increase the circulating pool of available MSCs and improve fracture healing. Ex-breeder female wistar rats received VEGF followed by AMD3100, or sham PBS. Blood prepared for culture and colonies were counted. P3 cells were analyzed by flow cytometry, bi-differentiation. The effect of mobilization on fracture healing was evaluated with 1.5 mm femoral osteotomy stabilized with an external fixator in 12-14 week old female Wistars. The mobilized group had significantly greater number of cfus/ml compared to controls, p = 0.029. The isolated cells expressed 1.8% CD34, 35% CD45, 61% CD29, 78% CD90, and differentiated into osteoblasts but not into adipocytes. The fracture gap in animals treated with VEGF and AMD3100 showed increased bone volume; 5.22 ± 1.7 µm³ and trabecular thickness 0.05 ± 0.01 µm compared with control animals (4.3 ± 3.1 µm³ , 0.04 ± 0.01 µm, respectively). Radiographic scores quantifying fracture healing (RUST) showed that the animals in the mobilization group had a higher healing score compared to controls (9.6 vs. 7.7). Histologically, mobilization resulted in significantly lower group variability in bone formation (p = 0.032) and greater amounts of bone and less fibrous tissue than the control group. Clinical significance: This pre-clinical study demonstrates a beneficial effect of endogenous MSC mobilization on fracture healing, which may have translation potential to prevent or treat clinical fractures at risk of delayed or non-union fractures. © 2018 The Authors. Journal of Orthopaedic Research® Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 37:1294-1302, 2019.

Genomewide Association Study of Fracture Nonunion Using Electronic Health Records

Nonunion is a clinically significant complication of fracture associated with worse outcomes, including increased pain, disability, and higher healthcare costs. The risk for nonunion is likely to be complex and multifactorial, and as such, the biology underlying such risk remains poorly understood. Genetic studies represent one approach to identify implicated biology for further investigation, but to date the lack of large cohorts for study has limited such efforts. We utilized the electronic health records of two large academic medical centers in Boston to identify individuals with fracture nonunion and control individuals with fracture but no evidence of nonunion. We conducted a genomewide association study among 1760 individuals of Northern European ancestry with upper or lower extremity fracture, including 131 with nonunion, to examine whether common variants were associated with nonunion in this cohort. In all, one locus in the Calcyon (CALY) gene exceeded a genomewide threshold for statistical significance (p = 1.95e-8), with eight additional loci associated with p < 5e-7. Previously reported candidate genes were not supported by this analysis. Electronic health records should facilitate identification of common genetic variations associated with adverse orthopedic outcomes. The loci we identified in this small cohort require replication and further study to characterize mechanism of action, but represent a starting point for the investigation of genetic liability for this costly outcome.

Nanoscale Coatings for Ultralow Dose BMP-2-Driven Regeneration of Critical-Sized Bone Defects

While new biomaterials for regenerative therapies are being reported in the literature, clinical translation is slow. Some existing regenerative approaches rely on high doses of growth factors, such as bone morphogenetic protein-2 (BMP-2) in bone regeneration, which can cause serious side effects. An ultralow-dose growth factor technology is described yielding high bioactivity based on a simple polymer, poly(ethyl acrylate) (PEA), and mechanisms to drive stem cell differentiation and bone regeneration in a critical-sized murine defect model with translation to a clinical veterinary setting are reported. This material-based technology triggers spontaneous fibronectin organization and stimulates growth factor signalling, enabling synergistic integrin and BMP-2 receptor activation in mesenchymal stem cells. To translate this technology, plasma-polymerized PEA is used on 2D and 3D substrates to enhance cell signalling in vitro, showing the complete healing of a critical-sized bone injury in mice in vivo. Efficacy is demonstrated in a Münsterländer dog with a nonhealing humerus fracture, establishing the clinical translation of advanced ultralow-dose growth factor treatment.

Mathematical and computational models for bone tissue engineering in bioreactor systems

Research into cellular engineered bone grafts offers a promising solution to problems associated with the currently used auto- and allografts. Bioreactor systems can facilitate the development of functional cellular bone grafts by augmenting mass transport through media convection and shear flow-induced mechanical stimulation. Developing successful and reproducible protocols for growing bone tissue in vitro is dependent on tuning the bioreactor operating conditions to the specific cell type and graft design. This process, largely reliant on a trial-and-error approach, is challenging, time-consuming and expensive. Modelling can streamline the process by providing further insight into the effect of the bioreactor environment on the cell culture, and by identifying a beneficial range of operational settings to stimulate tissue production. Models can explore the impact of changing flow speeds, scaffold properties, and nutrient and growth factor concentrations. Aiming to act as an introductory reference for bone tissue engineers looking to direct their experimental work, this article presents a comprehensive framework of mathematical models on various aspects of bioreactor bone cultures and overviews modelling case studies from literature.

Incidence, Costs and Predictors of Non-Union, Delayed Union and Mal-Union Following Long Bone Fracture

Fracture healing complications are common and result in significant healthcare burden. The aim of this study was to determine the rate, costs and predictors of two-year readmission for surgical management of healing complications (delayed, mal, non-union) following fracture of the humerus, tibia or femur. Humeral, tibial and femoral (excluding proximal) fractures registered by the Victorian Orthopaedic Trauma Outcomes Registry over five years (n = 3962) were linked with population-level hospital admissions data to identify two-year readmissions for delayed, mal or non-union. Study outcomes included hospital length-of-stay (LOS) and inpatient costs. Multivariable logistic regression was used to determine demographic and injury-related factors associated with admission for fracture healing complications. Of the 3886 patients linked, 8.1% were readmitted for healing complications within two years post-fracture, with non-union the most common complication and higher rates for femoral and tibial shaft fractures. Admissions for fracture healing complications incurred total costs of $4.9 million AUD, with a median LOS of two days. After adjusting for confounders, patients had higher odds of developing complications if they were older, receiving compensation or had tibial or femoral shaft fractures. Patients who are older, with tibial and femoral shaft fractures should be targeted for future research aimed at preventing complications.

Masquelet technique to treat a septic nonunion after nailing of a femoral open fracture

Septic nonunion is one of the most serious complications after an open fracture because both the infection and the bone defect need to be dealt with. Treatment is always protracted and expensive, and the result is uncertain. In the 1980s, Masquelet first described the technique of the induced membrane and autologous bone grafting to manage critical size bone defects. In septic nonunions, the described approach, characterised by two different surgical steps, allows a radical approach to manage the infection, and gives a significant biological stimulus to bone healing. In this case, we present a 35-year-old male patient with an open grade II femoral shaft fracture (AO / OTA 32C3). The patient was initially treated with an intramedullary nail and the resulting septic nonunion was subsequently managed with the induced membrane technique and a double-plate osteosynthesis to protect the biological chamber.

Development of controlled drug delivery systems for bone fracture-targeted therapeutic delivery: A review

Impaired fracture healing is a major clinical problem that can lead to patient disability, prolonged hospitalization, and significant financial burden. Although the majority of fractures heal using standard clinical practices, approximately 10% suffer from delayed unions or non-unions. A wide range of factors contribute to the risk for nonunions including internal factors, such as patient age, gender, and comorbidities, and external factors, such as the location and extent of injury. Current clinical approaches to treat nonunions include bone grafts and low-intensity pulsed ultrasound (LIPUS), which realizes clinical success only to select patients due to limitations including donor morbidities (grafts) and necessity of fracture reduction (LIPUS), respectively. To date, therapeutic approaches for bone regeneration rely heavily on protein-based growth factors such as INFUSE, an FDA-approved scaffold for delivery of bone morphogenetic protein 2 (BMP-2). Small molecule modulators and RNAi therapeutics are under development to circumvent challenges associated with traditional growth factors. While preclinical studies has shown promise, drug delivery has become a major hurdle stalling clinical translation. Therefore, this review overviews current therapies employed to stimulate fracture healing pre-clinically and clinically, including a focus on drug delivery systems for growth factors, parathyroid hormone (PTH), small molecules, and RNAi therapeutics, as well as recent advances and future promise of fracture-targeted drug delivery.

Bone healing in an aged murine fracture model is characterized by sustained callus inflammation and decreased cell proliferation

Geriatric fractures take longer to heal and heal with more complications than those of younger patients; however, the mechanistic basis for this difference in healing is not well understood. To improve this understanding, we investigated cell and molecular differences in fracture healing between 5-month-old (young adult) and 25-month-old (geriatric) mice healing utilizing high-throughput analysis of gene expression. Mice underwent bilateral tibial fractures and fracture calluses were harvested at 5, 10, and 20 days post-fracture (DPF) for analysis. Global gene expression analysis was performed using Affymetrix MoGene 1.0 ST microarrays. After normalization, data were compared using ANOVA and evaluated using Principal Component Analysis (PCA), CTen, heatmap, and Incromaps analysis. PCA and cross-sectional heatmap analysis demonstrated that DPF followed by age had pronounced effects on changes in gene expression. Both un-fractured and 20 DPF aged mice showed increased expression of immune-associated genes (CXCL8, CCL8, and CCL5) and at 10 DPF, aged mice showed increased expression of matrix-associated genes, (Matn1, Ucma, Scube1, Col9a1, and Col9a3). Cten analysis suggested an enrichment of CD8+ cells and macrophages in old mice relative to young adult mice and, conversely, a greater prevalence of mast cells in young adult mice relative to old. Finally, consistent with the PCA data, the classic bone healing pathways of BMP, Indian Hedgehog, Notch and Wnt clustered according to the time post-fracture first and age second.

CLINICAL SIGNIFICANCE

Greater understanding of age-dependent molecular changes with healing will help form a mechanistic basis for therapies to improve patient outcomes. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:149-158, 2018.

Diaphyseal long bone nonunions - types, aetiology, economics, and treatment recommendations

The intention of the current article is to review the epidemiology with related socioeconomic costs, pathophysiology, and treatment options for diaphyseal long bone delayed unions and nonunions. Diaphyseal nonunions in the tibia and in the femur are estimated to occur 4.6-8% after modern intramedullary nailing of closed fractures with an even much higher risk in open fractures. There is a high socioeconomic burden for long bone nonunions mainly driven by indirect costs, such as productivity losses due to long treatment duration. The classic classification of Weber and Cech of the 1970s is based on the underlying biological aspect of the nonunion differentiating between "vital" (hypertrophic) and "avital" (hypo-/atrophic) nonunions, and can still be considered to represent the basis for basic evaluation of nonunions. The "diamond concept" units biomechanical and biological aspects and provides the pre-requisites for successful bone healing in nonunions. For humeral diaphyseal shaft nonunions, excellent results for augmentation plating were reported. In atrophic humeral shaft nonunions, compression plating with stimulation of bone healing by bone grafting or BMPs seem to be the best option. For femoral and tibial diaphyseal shaft fractures, dynamization of the nail is an atraumatic, effective, and cheap surgical possibility to achieve bony consolidation, particularly in delayed nonunions before 24 weeks after initial surgery. In established hypertrophic nonunions in the tibia and femur, biomechanical stability should be addressed by augmentation plating or exchange nailing. Hypotrophic or atrophic nonunions require additional biological stimulation of bone healing for augmentation plating.

Healing of fracture nonunions treated with low-intensity pulsed ultrasound (LIPUS): A systematic review and meta-analysis

INTRODUCTION

Bone fractures fail to heal and form nonunions in roughly 5% of cases, with little expectation of spontaneous healing thereafter. We present a systematic review and meta-analysis of published papers that describe nonunions treated with low-intensity pulsed ultrasound (LIPUS).

METHODS

Articles in PubMed, Ovid MEDLINE, CINAHL, AMED, EMBASE, Cochrane Library, and Scopus databases were searched, using an approach recommended by the Methodological Index for Non-Randomized Studies (MINORS), with a Level of Evidence rating by two reviewers independently. Studies are included here if they reported fractures older than 3 months, presented new data with a sample N≥12, and reported fracture outcome (Heal/Fail).

RESULTS

Thirteen eligible papers reporting LIPUS treatment of 1441 nonunions were evaluated. The pooled estimate of effect size for heal rate was 82% (95% CI: 77-87%), for any anatomical site and fracture age of at least 3 months, with statistical heterogeneity detected across all primary studies (Q=41.2 (df=12), p<0.001, Tau²=0.006, I²=71). With a stricter definition of nonunion as fracture age of at least 8 months duration, the pooled estimate of effect size was 84% (95% CI: 77%-91.6%; heterogeneity present: Q=21 (df=8), p<0.001, Tau²=0.007, I²=62). Hypertrophic nonunions benefitted more than biologically inactive atrophic nonunions. An interval without surgery of <6months prior to LIPUS was associated with a more favorable result. Stratification of nonunions by anatomical site revealed no statistically significant differences between upper and lower extremity long bone nonunions.

CONCLUSIONS

LIPUS treatment can be an alternative to surgery for established nonunions. Given that no spontaneous healing of established nonunions is expected, and that it is challenging to test the efficacy of LIPUS for nonunion by randomized clinical trial, findings are compelling. LIPUS may be most useful in patients for whom surgery is high risk, including elderly patients at risk of delirium, or patients with dementia, extreme hypertension, extensive soft-tissue trauma, mechanical ventilation, metabolic acidosis, multiple organ failure, or coma. With an overall average success rate for LIPUS >80% this is comparable to the success of surgical treatment of non-infected nonunions.

Changes of Bone Turnover Markers in Long Bone Nonunions Treated with a Regenerative Approach

In this clinical trial, we investigated if biochemical bone turnover markers (BTM) changed according to the progression of bone healing induced by autologous expanded MSC combined with a biphasic calcium phosphate in patients with delayed union or nonunion of long bone fractures. Bone formation markers, bone resorption markers, and osteoclast regulatory proteins were measured by enzymatic immunoassay before surgery and after 6, 12, and 24 weeks. A satisfactory bone healing was obtained in 23 out of 24 patients. Nine subjects reached a good consolidation already at 12 weeks, and they were considered as the “early consolidation” group. We found that bone-specific alkaline phosphatase (BAP), C-terminal propeptide of type I procollagen (PICP), and beta crosslaps collagen (CTX) changed after the regenerative treatment, BAP and CTX correlated to the imaging results collected at 12 and 24 weeks, and BAP variation along the healing course differed in patients who had an “early consolidation.” A remarkable decrease in BAP and PICP was observed at all time points in a single patient who experienced a treatment failure, but the predictive value of BTM changes cannot be determined. Our findings suggest that BTM are promising tools for monitoring cell therapy efficacy in bone nonunions, but studies with larger patient numbers are required to confirm these preliminary results.

Malunion of Long-Bone Fractures in a Conflict Zone in the Democratic Republic of Congo

INTRODUCTION

Malunion is a well-recognized complication of long-bone fractures which accounts for more than 25% of injuries in conflict zones. The aim of this study was to investigate the rate of malunion sustained by casualties with penetrating gunshot wounds in an International Committee of the Red Cross (ICRC) surgical substitution project in the Democratic Republic of Congo (DRC) and compare these results with current literature.

METHODS

A retrospective cohort study was performed. All patients admitted to the ICRC facility between the periods of 01.10.2014 and 31.12.2015 with long-bone fractures caused by gunshot wound were included, and data were collected retrospectively from the patient's hospital notes.

RESULTS

A total of 191 fractures caused by gunshot were treated in the DRC at the ICRC surgical substitution project during the study period. On average, the fractures were 3 days old on admission and were all open, with 62% also being comminuted. The ICRC management protocol, which emphasizes debridement, antibiotic prophylaxis and conservative fracture stabilization, was followed in all cases. Forty-eight percentage of the fractures were finally classified as 'union without complication'; however, 17% were classified as 'malunion'.

CONCLUSIONS

This study indicates that open long-bone fractures that are managed by the ICRC surgical substitution project in DRC may have an increased likelihood of malunion as compared to long-bone fractures treated in developed countries. Patient delay and mechanism of injury may have caused increased rates of infection which are likely behind these increased rates of malunion, alongside the lack of definitive fracture treatment options made available to the surgical team.