Fracture healing in HIV-positive populations

CD4+ and CD8+ T cells reduce inflammation and promote bone healing in response to titanium implants

T cells are adaptive immune cells essential in pathogenic response, cancer, and autoimmune disorders. During the integration of biomaterials with host tissue, T cells modify the local inflammatory environment by releasing cytokines that promote inflammatory resolution following implantation. T cells are vital for the modulation of innate immune cells, recruitment and proliferation of mesenchymal stem cells (MSCs), and formation of functional tissue around the biomaterial implant. We have demonstrated that deficiency of αβ T cells promotes macrophage polarization towards a pro-inflammatory phenotype and attenuates MSC recruitment and proliferation in vitro and in vivo. The goal of this study was to understand how CD4+ and CD8+ T cells, subsets of the αβ T cell family, impact the inflammatory response to titanium (Ti) biomaterials. Deficiency of either CD4+ or CD8+ T cells increased the proportion of pro-inflammatory macrophages, lowered anti-inflammatory macrophages, and diminished MSC recruitment in vitro and in vivo. In addition, new bone formation at the implantation site was significantly reduced in T cell-deficient mice compared to T cell-competent mice. Deficiency of CD4+ T cells exacerbated these effects compared to CD8+ T cell deficiency. Our results show the importance of CD4+ and CD8+ T cells in modulating the inflammatory response and promoting new bone formation in response to modified Ti implants. STATEMENT OF SIGNIFICANCE: CD4+ and CD8+ T cells are essential in modulating the peri-implant microenvironment during the inflammatory response to biomaterial implantation. This study shows that deficiency of either CD4+ or CD8+ T cell subsets altered macrophage polarization and reduced MSC recruitment and proliferation at the implantation site.

Is human immunodeficiency virus a risk factor for the development of nonunion?-a case-control study

Objective

Human immunodeficiency virus (HIV) infection has been suggested to be associated with an increased risk of the development of nonunion after a fracture. This prospective matched case-control study in South Africa investigated common risk factors, including HIV status, that influence the development of a nonunion after a femur or tibia fracture.

Methods

Adult participants (cases) with established nonunions of the femur or tibia shaft were recruited over a 16-month period, between December 2017 and April 2019. They were matched for (1) age; (2) sex; (3) fracture site; and (4) fracture management type, with "control" participants who progressed to fracture union within 6 months of injury. All participants were tested for HIV. Multivariable logistic regression models were constructed to investigate associations between known risk factors for the development of nonunion and impaired fracture healing.

Results

A total of 57 cases were matched with 57 "control" participants (44/57 male, 77.2% vs. 13/57 female, 22.8%, median age 36 years). HIV status was not associated with the development of nonunion after the management of tibia and femur fractures, on both univariate (odds ratio, 0.40; confidence interval, 0.10-1.32; P = 0.151) or multivariable (odds ratio, 0.86; confidence interval, 0.18-3.73; P = 0.831) analysis. No other confounding factors were shown to have any statistically significant impact on the odds of developing nonunion in this study cohort.

Conclusion

This study demonstrates that HIV does not seem to increase the risk of the development of nonunion and HIV-positive individuals who sustain a fracture can be managed in the same manner as those who are HIV negative.

Callus γδ T cells and microbe-induced intestinal Th17 cells improve fracture healing in mice

IL-17A (IL-17), a driver of the inflammatory phase of fracture repair, is produced locally by several cell lineages including γδ T cells and Th17 cells. However, the origin of these T cells and their relevance for fracture repair are unknown. Here, we show that fractures rapidly expanded callus γδ T cells, which led to increased gut permeability by promoting systemic inflammation. When the microbiota contained the Th17 cell-inducing taxon segmented filamentous bacteria (SFB), activation of γδ T cells was followed by expansion of intestinal Th17 cells, their migration to the callus, and improved fracture repair. Mechanistically, fractures increased the S1P receptor 1-mediated (S1PR1-mediated) egress of Th17 cells from the intestine and enhanced their homing to the callus through a CCL20-mediated mechanism. Fracture repair was impaired by deletion of γδ T cells, depletion of the microbiome by antibiotics (Abx), blockade of Th17 cell egress from the gut, or Ab neutralization of Th17 cell influx into the callus. These findings demonstrate the relevance of the microbiome and T cell trafficking for fracture repair. Modifications of microbiome composition via Th17 cell-inducing bacteriotherapy and avoidance of broad-spectrum Abx may represent novel therapeutic strategies to optimize fracture healing.

Interactions of B-lymphocytes and bone cells in health and disease

Bone remodeling occurs through the interactions of three major cell lineages, osteoblasts, which mediate bone formation, osteocytes, which derive from osteoblasts, sense mechanical force and direct bone turnover, and osteoclasts, which mediate bone resorption. However, multiple additional cell types within the bone marrow, including macrophages, T lymphocytes and B lymphocytes influence the process. The bone marrow microenvironment, which is supported, in part, by bone cells, forms a nurturing network for B lymphopoiesis. In turn, developing B lymphocytes influence bone cells. Bone health during homeostasis depends on the normal interactions of bone cells with other lineages in the bone marrow. In disease state these interactions become pathologic and can cause abnormal function of bone cells and inadequate repair of bone after a fracture. This review summarizes what is known about the development of B lymphocytes and the interactions of B lymphocytes with bone cells in both health and disease.

Osteo-Immunomodulatory Role of Interleukin-4-Immobilized Plasma Immersion Ion Implantation Membranes for Bone Regeneration

Barrier membranes for guided tissue regeneration are essential for bone repair and regeneration. The implanted membranes may trigger early inflammatory responses as a foreign material, which can affect the recruitment and differentiation of bone cells during tissue regeneration. The purpose of this study was to determine whether immobilizing interleukin 4 (IL4) on plasma immersion ion implantation (PIII)-activated surfaces may alter the osteo-immunoregulatory characteristics of the membranes and produce pro-osteogenic effects. In order to immobilize IL4, polycaprolactone surfaces were modified using the PIII technology. No discernible alterations were found between the morphology before and after PIII treatment or IL4 immobilization. IL4-immobilized PIII surfaces polarized macrophages to an M2 phenotype and mitigated inflammatory cytokine production under lipopolysaccharide stimulation. Interestingly, the co-culture of macrophages (on IL4-immobilized PIII surfaces) and bone marrow-derived mesenchymal stromal cells enhanced the production of angiogenic and osteogenic factors and triggered autophagy activation. Exosomes produced by PIII + IL4-stimulated macrophages were also found to play a role in osteoblast differentiation. In conclusion, the osteo-immunoregulatory properties of bone materials can be modified by PIII-assisted IL4 immobilization, creating a favorable osteoimmune milieu for bone regeneration.

Bone Healing Gone Wrong: Pathological Fracture Healing and Non-Unions-Overview of Basic and Clinical Aspects and Systematic Review of Risk Factors

Bone healing is a multifarious process involving mesenchymal stem cells, osteoprogenitor cells, macrophages, osteoblasts and -clasts, and chondrocytes to restore the osseous tissue. Particularly in long bones including the tibia, clavicle, humerus and femur, this process fails in 2-10% of all fractures, with devastating effects for the patient and the healthcare system. Underlying reasons for this failure are manifold, from lack of biomechanical stability to impaired biological host conditions and wound-immanent intricacies. In this review, we describe the cellular components involved in impaired bone healing and how they interfere with the delicately orchestrated processes of bone repair and formation. We subsequently outline and weigh the risk factors for the development of non-unions that have been established in the literature. Therapeutic prospects are illustrated and put into clinical perspective, before the applicability of biomarkers is finally discussed.

Osteoimmunology: The effect of autoimmunity on fracture healing and skeletal analysis

Understanding factors that affect bone response to trauma is integral to forensic skeletal analysis. It is essential in forensic anthropology to identify if impaired fracture healing impacts assessment of post-traumatic time intervals and whether a correction factor is required. This paper presents a synthetic review of the intersection of the literature on the immune system, bone biology, and osteoimmunological research to present a novel model of interactions that may affect fracture healing under autoimmune conditions. Results suggest that autoimmunity likely impacts fracture healing, the pathogenesis however, is under researched, but likely multifactorial. With autoimmune diseases being relatively common, significant clinical history should be incorporated when assessing skeletal remains. Future research includes the true natural healing rate of bone; effect of autoimmunity on this rate; variation of healing with different autoimmune diseases; and if necessary, development of a correction factor on the natural healing rate to account for impairment in autoimmunity.

Engineering immunomodulatory hydrogels and cell-laden systems towards bone regeneration

The well-known synergetic interplay between the skeletal and immune systems has changed the design of advanced bone tissue engineering strategies. The immune system is essential during the bone lifetime, with macrophages playing multiple roles in bone healing and biomaterial integration. If in the past, the most valuable aspect of implants was to avoid immune responses of the host, nowadays, it is well-established how important are the crosstalks between immune cells and bone-engineered niches for an efficient regenerative process to occur. For that, it is essential to recapitulate the multiphenotypic cellular environment of bone tissue when designing new approaches. Indeed, the lack of osteoimmunomodulatory knowledge may be the explanation for the poor translation of biomaterials into clinical practice. Thus, smarter hydrogels incorporating immunomodulatory bioactive factors, stem cells, and immune cells are being proposed to develop a new generation of bone tissue engineering strategies. This review highlights the power of immune cells to upgrade the development of innovative engineered strategies, mainly focusing on orthopaedic and dental applications.

Femoral Neck Fractures in HIV-Positive Patients: Analysis of 10 Years Short-Term Post-operative Complications

Introduction:

Aging and effect of antiretroviral therapy on bone mass could increase the risk of femoral neck fractures (FNF) in HIV patient. The aim of this study was specifically to determine whether intracapsular FNF in HIV-positive patients are more prone to short-term post-operative complications than similar fractures occurring in HIV-negative patients.

Materials and methods:

A group of 25 HIV-positive patients with intracapsular FNF were enrolled and matched to HIV-negative patient with similar fractures according to gender, age, a modified Charlson Comorbidity Index (CCI), fracture classification, surgical treatment and time interval between fracture event and surgery. For each group, length of stay, surgical time, early clinical outcomes and short-term surgical and medical complications were compared to determine the impact on the early outcome.

Results:

At the time of the fracture occurrence, 56% of HIV-positive patients were on antiretroviral therapy and 12% started with therapy in the perioperative period. At three months follow-up, there were no statistically significant differences between the two study groups in length of stay, Harris hip score and total number of early complications. However, a statistically significant increase in urinary tract infections and longer surgical time using hip sliding screw fixation were seen in the HIV-positive group. The poorest post-operative result was seen in a patient who failed to adequately adhere to the HIV therapy protocol.

Conclusions:

This study failed to show any statistically significant increase in short-term complications or worse clinical outcomes for intracapsular FNF in HIV-positive patients compared to HIV-negative patients to recommend their treatment in dedicated centres.

Fracture Healing in Patients With HIV in South Africa: A Prospective Cohort Study

BACKGROUND

HIV reduces bone mineral density, mineralization, and turnover and may impair fracture healing.

SETTING

This prospective cohort study in South Africa investigated whether HIV infection was associated with impaired fracture healing after trauma.

METHODS

All adults with acute tibia and femur fractures who underwent intermedullary (IM) nailing for fracture fixation between September 2017 and December 2018, at 2 tertiary hospitals, were followed up for a minimum of 12 months postoperatively. The primary outcome was delayed bone union at 6 months (defined by the radiological union scoring system for the tibia score <9), and the secondary outcome was nonunion (defined as radiological union scoring system for the tibia score <9) at 9 months. Multivariable logistic regression models were constructed to investigate the associations between HIV status and impaired fracture healing.

RESULTS

In total, 358 participants, who underwent 395 IM nailings, were enrolled in the study and followed up for 12 months. Seventy-one of the 358 (19.8%) participants were HIV-positive [83/395 (21%) IM nailings]. HIV was not associated with delayed fracture healing after IM nailing of the tibia or femur (multivariable odds ratio: 1.06; 95% confidence interval: 0.50 to 2.22). HIV-positive participants had a statistically significant lower odds ratio of nonunion compared with HIV-negative participants (multivariable odds ratio: 0.17; 95% confidence interval: 0.01 to 0.92).

CONCLUSIONS

Fractures sustained in HIV-positive individuals can undergo surgical fixation as effectively as those in HIV-negative individuals, with no increased risk of delayed union or nonunion.

The Early Results of Vertebral Pathological Compression Fracture of Extra- nodal Lymphoma with HIV-positive Patients Treated by Percutaneous Kyphoplasty

BACKGROUND

Vertebral pathological compression fracture involving extra-nodal lymphoma impacts negatively on the quality of life of HIV-positive patients. The choice of a safe and effective approach to palliative care in this condition remains a challenge.

OBJECTIVE

The purpose of this study was to investigate the safety and efficacy of percutaneous kyphoplasty (PKP) in the treatment of vertebral pathological compression fracture of extra-nodal lymphoma in HIV-positive patients.

METHODS

A retrospective analysis, from January 2016 to August 2019, was performed on 7 HIVpositive patients, 3 males and 4 females, with extra-nodal lymphoma with a vertebral pathological compression fracture. The patients were treated using percutaneous kyphoplasty in our hospital. Preoperative assessment of the patients was conducted regarding their hematological profile, biochemical indicators, liver and kidney function, blood coagulation function, CD4+T lymphocyte count and viral load. Subsequently, the patients were placed on highly active antiretroviral therapy (HAART) and rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (RCHOP) regimen. Besides, antibiotics, nutritional support and immune-modulating drugs were also administered, rationally. Postoperatively, the height of the anterior edge of the injured vertebrae, Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI) values were evaluated. Patients were also monitored for any complications related to the operation.

RESULTS

The average CD4+T cell count for the patients was 164 (range 114 ~247 / ul), while the viral load was 26,269 (range 5,765 ~82,321 copies/ul). All patients received nutritional and immune support and registered significant improvements in the levels of ALB and Hb (P<0.05). In all cases, the operation was uneventful with neither cement leakage nor toxic reactions observed. Similarly, no opportunistic infections, other complications or deaths were reported. The height of the anterior vertebral body and the ODI score of the injured vertebrae were significantly improved immediately after surgery (P<0.05). Compared to the preoperative VAS (7.71±1.11), postoperative values were significantly reduced immediately after surgery (3.85±0.90) and at 2 weeks, 1 month and 6 months post-surgery: 2.71±0.76, 3.29±1.11, and 4.00±0.82, respectively (P<0.01).

CONCLUSION

Supported with appropriate perioperative treatment measures, PKP is safe and effective in the treatment of pathological vertebral compression fracture due to extra-nodal lymphoma in HIV-positive patients.

A tale of three pandemics: Shining a light on a hidden problem

An “epidemic” is an event in which a disease, infectious or non-infectious, is actively spreading within a population and designated area. The term “pandemic” is defined as “an epidemic occurring worldwide, or over a very wide area, crossing international boundaries and usually affecting a large number of people”.

The global response to the COVID-19 pandemic has not been seen since the outbreak of Human Immunodeficiency Virus in the early eighties. But there is another unseen pandemic running alongside the current COVID-19 pandemic, which affects a vast number of people, crossing international boundaries and occurring in every single country worldwide. The pandemic of traumatic injuries.

Traumatic injuries account for 11% of the current Global Burden of Disease, resulting in nearly 5 million deaths annually and is the third-leading cause of death worldwide. For every trauma-related death, it is estimated that up to 50 people sustain permanent or temporary disabilities. Furthermore, traumatic injuries occur at disproportionately higher rates in low- and middle-income countries, with approximately 90% of injuries and more than 90% of global deaths from injury occurring these countries.

Injuries are increasing worldwide, crossing international boundaries and affecting a large number of people, in the same manner Human Immunodeficiency Virus did in the 1980's and COVID-19 is today. The tremendous global effort to tackle the COVID-19 and Human Immunodeficiency Virus pandemics has occurred whilst ignoring the comparable pandemic of injury. Without change and future engagement with policy makers and international donors this disparity is likely to continue.

Intersectionality and trauma analysis in bioarchaeology

Intersectionality, the theory named by Kimberlé Crenshaw, outlines how multiple elements of an individual's social identity overlap to create and preserve societal inequalities and discrimination. Recently bioarchaeology's engagement with intersectionality has become increasingly explicit, as the field recognizes the lived experience of multiple axes of an individual's identity. Evidence of trauma can remain observable in an individual's skeleton for years, making it an ideal subject of study for intersectional analyses in bioarchaeology. Using contrasting case studies of two individuals who died in hospitals and were unclaimed after death, we explore the theoretical and methodological application of intersectionality to investigations of accidental and interpersonal trauma. Differences in identities and structural inequalities affect bone quality and health outcomes. As we demonstrate, a broken bone is the intersecting result of biological, histomorphological, sociocultural, and behavioral factors. This approach allows for a better acknowledgement of the inherent complexity of past lives, elevating and amplifying previously silenced voices. In this way, intersectionality in bioarchaeology demands social justice.

Bone metabolism is a key factor for clinical outcome of tibial plateau fractures

Purpose

Given that tibial plateau fractures (TPF) are rare, they may pose a challenge to the treating surgeon due to their variety of complex fracture patterns. Numerous studies have identified potential fracture-specific, surgery-related, and patient-related risk factors for impaired patient outcomes. However, reports on the influence of bone metabolism on functional outcomes are missing.

Methods

In a retrospective multicenter cohort study, 122 TPF of 121 patients were analyzed with respect to radiological and clinical outcomes (Rasmussen) with a mean follow-up of 35.7 ± 24.9 months. The risk factor assessment included bone metabolism-affecting comorbidities and medication.

Results

The findings showed that 95.9% of the patients reported a good-to-excellent clinical outcome, and 97.4% reported a good-to-excellent radiological outcome. Logistic regression revealed that potentially impaired bone metabolism (IBM) was an independent risk factor for the clinical (p = 0.016) but not the radiological outcome (Table 4). Patients with 41-type B fractures and a potential IBM had a seven times higher risk to present a fair-to-poor clinical outcome [OR 7.45, 95 CI (4.30, 12.92)]. The most common objective impairment was a limited range of motion in 16.4% of the patients, especially in 41-type C fractures (p = 0.06). The individual failure analysis additionally identified surgery-related options for improvement.

Conclusion

This study demonstrated that potential IBM was an independent risk factor for a poor-to-fair clinical outcome.

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.

Osteoporosis and the Potential of Cell-Based Therapeutic Strategies

Osteoporosis, the most common chronic metabolic bone disease, is characterized by low bone mass and increased bone fragility. Nowadays more than 200 million individuals are suffering from osteoporosis and still the number of affected people is dramatically increasing due to an aging population and longer life, representing a major public health problem. Current osteoporosis treatments are mainly designed to decrease bone resorption, presenting serious adverse effects that limit their safety for long-term use. Numerous studies with mesenchymal stem cells (MSCs) have helped to increase the knowledge regarding the mechanisms that underlie the progression of osteoporosis. Emerging clinical and molecular evidence suggests that inflammation exerts a significant influence on bone turnover, thereby on osteoporosis. In this regard, MSCs have proven to possess broad immunoregulatory capabilities, modulating both adaptive and innate immunity. Here, we will discuss the role that MSCs play in the etiopathology of osteoporosis and their potential use for the treatment of this disease.

Comparison of risk factors for postoperative complications across age groups in patients undergoing ORIF of the ankle

INTRODUCTION

Risk factors associated with various adverse outcomes for patients undergoing open reduction and internal fixation (ORIF) of the ankle, and how these risks differ between younger and older patient populations, has not been clearly established. Objective quantitative data may aid physicians in surgical decision making, individualizing postoperative management, and targeting interventions for reducing postoperative comorbidity. The purpose of this study is to compare the incidence of and risk factors for adverse postoperative outcomes following ORIF of ankle fractures across patient age groups.

MATERIALS AND METHODS

Charts of patients age 18 years and older who underwent open reduction and internal fixation (ORIF) for any closed, non-polytraumatic, non-pilon ankle fracture at a single institution between the years 2008 and 2018 were reviewed. Demographic information, comorbidities, and postoperative outcomes were collected. Relative risks for adverse outcomes were calculated and compared between patients younger than 50 and patients 50 years and older.

RESULTS

A total of 886 patients were included, 375 (42.3%) of which were over age 50. In both age groups, risk of infection was significantly increased among patients with hypertension, although risk among older patients (RR = 3.52, p = 0.004) was greater than that among younger patients (RR = 2.46, p = 0.017). In patients younger than 50, significant risk of wound dehiscence was associated with tobacco use (RR = 3.39, p = 0.022), substance use (RR = 3.07, p = 0.020), and CHF (RR = 12.77, p < 0.001). Risk of implant failure was significantly increased among younger patients with HIV (RR = 4.33, p = 0.026), CHF (RR = 10.54, p < 0.001), and CKD (RR = 10.54, p < 0.001), and among older patients with HTN (RR = 4.51, p = 0.006), CHF (RR = 5.83, p < 0.001), and tobacco use (RR = 3.82, P = 0.001).

CONCLUSION

Patients undergoing ORIF of the ankle should be well-informed of the potential risks of surgery as they pertain to specific comorbidities. Multidisciplinary approaches are warranted for appropriate management of patients with multiple comorbidities.

Updates on Osteoimmunology: What's New on the Cross-Talk Between Bone and Immune System

The term osteoimmunology was coined many years ago to describe the research field that deals with the cross-regulation between bone cells and the immune system. As a matter of fact, many factors that are classically considered immune-related, such as InterLeukins (i.e., IL-6, -11, -17, and -23), Tumor Necrosis Factor (TNF)-α, Receptor-Activator of Nuclear factor Kappa B (RANK), and its Ligand (RANKL), Nuclear Factor of Activated T-cell, cytoplasmatic-1 (NFATc1), and others have all been found to be crucial in osteoclast and osteoblast biology. Conversely, bone cells, which we used to think would only regulate each other and take care of remodeling bone, actually regulate immune cells, by creating the so-called "endosteal niche." Both osteoblasts and osteoclasts participate to this niche, either by favoring engraftment, or mobilization of Hematopoietic Stem Cells (HSCs). In this review, we will describe the main milestones at the base of the osteoimmunology and present the key cellular players of the bone-immune system cross-talk, including HSCs, osteoblasts, osteoclasts, bone marrow macrophages, osteomacs, T- and B-lymphocytes, dendritic cells, and neutrophils. We will also briefly describe some pathological conditions in which the bone-immune system cross-talk plays a crucial role, with the final aim to portray the state of the art in the mechanisms regulating the bone-immune system interplay, and some of the latest molecular players in the field. This is important to encourage investigation in this field, to identify new targets in the treatment of bone and immune diseases.

People Living With HIV: Implications for Rehabilitation Nurses

PURPOSE

The aim of this study was to present a brief overview of challenges faced by people living with HIV (PLHIV) as they age, to discuss the relevance of HIV to rehabilitation nurses, and to provide evidence-based recommendations for rehabilitation professionals working with PLHIV.

DESIGN

Current issues article.

METHODS

Literature review related to age-related comorbidities in PLHIV with implications for rehabilitation nurses.

FINDINGS

Rehabilitation nurses must be prepared to address issues specific to people living with HIV including sensitivity and privacy regarding HIV status and increased risk of delayed or complicated healing. Rehabilitation nurses should also promote self-management behavior to optimize health in people living with HIV.

CONCLUSIONS

Understanding unique characteristics of PLHIV as well as applying focused assessment and tailored interventions in PLHIV will give rehabilitation nurses the tools to successfully guide PLHIV through the rehabilitation process and optimize clinical outcomes.

CLINICAL RELEVANCE

As people with HIV age and experience acute and chronic comorbidities, they will require the clinical expertise of rehabilitation nurses in the process to successfully transition through acute and subacute health care and regain function.

The Role of the Immune Cells in Fracture Healing

PURPOSE OF REVIEW

Bone fracture healing is a complex physiological process relying on numerous cell types and signals. Inflammatory factors secreted by immune cells help to control recruitment, proliferation, differentiation, and activation of hematopoietic and mesenchymal cells. Within this review we will discuss the functional role of immune cells as it pertains to bone fracture healing. In doing so, we will outline the cytokines secreted and their effects within the healing fracture callus.

RECENT FINDINGS

Macrophages have been found to play an important role in fracture healing. These immune cells signal to other cells of the fracture callus, modulating bone healing. Cytokines and cellular signals within fracture healing continue to be studied. The findings from this work have helped to reinforce the importance of osteoimmunity in bone fracture healing. Owing to these efforts, immunomodulation is emerging as a potential therapeutic target to improve bone fracture healing.

Analysis of the surgical treatment of fracture in HIV positive patients: A clinical study

Objective:

To evaluate the incidence of postoperative infection and fracture nonunion as well as the risk factors for postoperative infection in human immunodeficiency virus (HIV) positive patients.

Methods:

From May 2013 to March 2016, the HIV positive fracture patients treated surgically in orthopaedics department of our hospital were analyzed retrospectively, and fifty HIV negative fracture patients during the same period were selected as control. The clinical data of included patients were reviewed. The incidence of postoperative infection and fracture nonunion were compared between the two groups, and the risk factors for postoperative infection in HIV positive patients were evaluated.

Results:

The incidence of poor wound healing and incision infection in HIV positive group was higher than that in HIV negative group, but there were no significant differences between the two groups (p>0.05). Multivariable regression analysis demonstrated that HIV clinical category (p<0.05), CD4+T-lymphocyte category (p<0.01) and open fracture (p<0.05) were independent risk factors for postoperative wound infections, but age, gender, operation time, incision type, emergency operation, albumin and lymphocyte count were not (p>0.05). There was no significant difference in the rate of nonunion between the two groups (p>0.05).

Conclusion:

The incision can be healed, and fracture can be united normally in most of HIV positive patients with fracture, and postoperative wound infections were significantly associated with HIV clinical category, CD4+T-lymphocyte category and open fracture.

Osteoimmunology in Bone Fracture Healing

PURPOSE OF REVIEW

In the process of bone fracture healing, inflammation is thought to be an essential process that precedes bone formation and remodeling. We review recent studies on bone fracture healing from an osteoimmunological point of view.

RECENT FINDINGS

Based on previous observations that many types of immune cells infiltrate into the bone injury site and release a variety of molecules, recent studies have addressed the roles of specific immune cell subsets. Macrophages and interleukin (IL)-17-producing γδ T cells enhance bone healing, whereas CD8⁺ T cells impair bone repair. Additionally, IL-10-producing B cells may contribute to bone healing by suppressing excessive and/or prolonged inflammation. Although the involvement of other cells and molecules has been suggested, the precise underlying mechanisms remain elusive. Accumulating evidence has begun to reveal the deeper picture of bone fracture healing. Further studies are required for the development of novel therapeutic strategies for bone fracture.

HIV in Orthopaedic Surgery

The emergence of HIV in the United States has had important implications in the surgical setting. This blood-borne pathogen poses risks to both the surgeon and the patient undergoing an orthopaedic procedure. Although there has been research regarding the likelihood of orthopaedic surgeons contracting HIV during a surgical procedure, the correlation of HIV with postoperative prognosis has not been extensively examined. Because HIV-positive patients may be immunodeficient, they are at increased risk for certain postoperative complications, especially infection. Orthopaedic surgeons should have a thorough understanding of the effects of this disease on patients to optimize preoperative decision making, intraoperative care, and postoperative recovery.

The roles of immune cells in bone healing; what we know, do not know and future perspectives

Key events occurring during the bone healing include well-orchestrated and complex interactions between immune cells, multipotential stromal cells (MSCs), osteoblasts and osteoclasts. Through three overlapping phases of this physiological process, innate and adaptive immune cells, cytokines and chemokines have a significant role to play. The aim of the escalating immune response is to achieve an osseous healing in the shortest time and with the least complications facilitating the restoration of function. The uninterrupted progression of these biological events in conjunction with a favourable mechanical environment (stable fracture fixation) remains the hallmark of successful fracture healing. When failure occurs, either the biological environment or the mechanical one could have been disrupted. Not infrequently both may be compromised. Consequently, regenerative treatments involving the use of bone autograft, allograft or synthetic matrices supplemented with MSCs are increasingly used. A better understanding of the bone biology and osteoimmunology can help to improve these evolving cell-therapy based strategies. Herein, an up to date status of the role of immune cells during the different phases of bone healing is presented. Additionally, the known and yet to know events about immune cell interactions with MSCs and osteoblasts and osteoclasts and the therapeutic implications are being discussed.

Fracture management in HIV positive individuals: a systematic review

PURPOSE

Human immunodeficiency virus (HIV) infection could potentially play an important role in the management of fractures as they have been shown to affect fracture healing and the post-operative risk of implant sepsis.

METHODS

A systematic review of the relevant literature was performed on PubMed and Scopus databases. Twenty-six studies were identified, critiqued and analysed accordingly. No randomised controlled trials were identified.

RESULTS

HIV positivity was not shown to influence an individual's risk of early wound infection in operatively managed closed fractures. The rate of pin track infection in open injuries managed with external fixators was low. However, in open injuries managed with internal fixation, early wound infection rates were increased in the HIV-positive population compared to HIV-negative individuals. Regarding late implant infection, in closed fractures there appeared to be no increased risk of infection but there is limited evidence for open injuries. Additionally, further evidence is needed to establish if the rate of union in both open and closed fractures are influenced by HIV status.

CONCLUSION

Overall, no evidence was found to suggest that surgical management of fractures in the HIV population should be avoided, and fixation of closed fractures in the HIV population appeared to be safe. The effect of anti-retroviral therapy is unclear and this should be further researched. However, based on the limited evidence, caution should be taken in the management of open fractures due to the potentially increased infection risk. The impact of anti-retroviral therapy on the outcomes of surgery needs further evaluation.

Evaluation of a novel tool for bone graft delivery in minimally invasive transforaminal lumbar interbody fusion

Study design

Disk material removed (DMR) during L4-5 and L5-S1 transforaminal lumbar interbody fusion (T-LIF) surgery was compared to the corresponding bone graft (BG) volumes inserted at the time of fusion. A novel BG delivery tool (BGDT) was used to apply the BG. In order to establish the percentage of DMR during T-LIF, it was compared to DMR during anterior diskectomy (AD). This study was performed prospectively.

Summary of background data

Minimal information is available as to the volume of DMR during a T-LIF procedure, and the relationship between DMR and BG delivered is unknown. BG insertion has been empiric and technically challenging. Since the volume of BG applied to the prepared disk space likely impacts the probability of arthrodesis, an investigation is justified.

Methods

A total of 65 patients with pathology at L4-5 and/or L5-S1 necessitating fusion were treated with a minimally invasive T-LIF procedure. DMR was volumetrically measured during disk space preparation. BG material consisting of local autograft, BG extender, and bone marrow aspirate were mixed to form a slurry. BG slurry was injected into the disk space using a novel BGDT and measured volumetrically. An additional 29 patients who were treated with L5-S1 AD were compared to L5-S1 T-LIF DMR to determine the percent of T-LIF DMR relative to AD.

Results

DMR volumes averaged 3.6±2.2 mL. This represented 34% of the disk space relative to AD. The amount of BG delivered to the disk spaces was 9.3±3.2 mL, which is 2.6±2.2 times the amount of DMR. The BGDT allowed uncomplicated filling of the disk space in <1 minute.

Conclusion

The volume of DMR during T-LIF allows for a predictable volume of BG delivery. The BGDT allowed complete filling of the entire prepared disk space. The T-LIF diskectomy debrides 34% of the disk relative to AD.

Common contra-indications and interactions of drugs in orthopaedic practice

Drug therapy forms an integral part of the management of many orthopaedic conditions. However, many medicines can produce serious adverse reactions if prescribed inappropriately, either alone or in combination with other drugs. Often these hazards are not appreciated. In response to this, the European Union recently issued legislation regarding safety measures which member states must adopt to minimise the risk of errors of medication. In March 2014 the Medicines and Healthcare products Regulatory Agency and NHS England released a Patient Safety Alert initiative focussed on errors of medication. There have been similar initiatives in the United States under the auspices of The National Coordinating Council for Medication Error and The Joint Commission on the Accreditation of Healthcare Organizations. These initiatives have highlighted the importance of informing and educating clinicians. Here, we discuss common drug interactions and contra-indications in orthopaedic practice. This is germane to safe and effective clinical care.

Delayed implants sepsis in HIV-positive patients following open fractures treated with orthopaedic implants

BACKGROUND

There has been concern that HIV-positive patients may be more susceptible to delayed infection (>1 month) after treatment of open fractures with orthopaedic implants. To date, the longest published follow-up for such patients is 6 months.

AIM

Long-term follow-up to identify rates of delayed implant sepsis in open fractures treated with internal fixation, in HIV positive patients and controls.

METHODS

Prospective observational study. Between March 2011 and April 2012, we attempted to contact all patients who were enrolled into a study looking at outcomes of open fractures treated with internal fixation between May 2008 and March 2009. Telephone questionnaires were used to screen for implant sepsis, and patients received clinical assessments at our research clinic.

RESULTS

Of 101 patients with in situ implants, we were able to follow 51 patients. Of the initial 33 HIV-positive patients, 13 were reassessed as part of this study. Only 1 of 13 HIV-positive patients developed delayed implant sepsis following a grade 3B open tibia fracture. Two of 23 HIV-negative patients developed delayed implant sepsis.

CONCLUSION

With an average follow-up period of 39 months (range=34-43 months), this is the longest follow-up period to evaluate HIV-positive patients with open fractures who received orthopaedic implants. Despite its limitations of poor follow up, it provides the strongest available evidence that in our setting HIV positive patients are not at higher risk of delayed sepsis, and we would not suggest routine removal of metal work in these patients.

The UWEZO project-musculoskeletal health training in Kenya

A major cause of disability and pain, musculoskeletal conditions (MSC) affect all aspects of people's lives and have a significant socioeconomic impact. Access to early diagnosis, effective treatments and rehabilitation enables people with MSCs to maintain their mobility, to work and to have a good quality of life. Despite the significant impact of MSC on health, social and economic well-being in Africa, services for MSC health remain extremely under-resourced. The UWEZO project is a collaboration between Kenyan, UK and Swedish rheumatologists, patients and researchers. It aims to improve access to basic musculoskeletal health care at the local level in communities across Kenya through the development of a sustainable training programme to raise the knowledge and skills of health professionals working in the community in the early detection, diagnosis and management of MSC. A team of physicians and patients have been trained to deliver an MSC education programme to health providers working in 11 locations across Kenya. Over 500 health providers have been trained. The programme has the potential to be adapted for use in other low resource countries where access to care for musculoskeletal conditions is limited.

The treatment of intramedullary osteomyelitis of the femur and tibia using the Reamer–Irrigator–Aspirator system and antibiotic cement rods

Intramedullary infection in long bones represents a complex clinical challenge, with an increasing incidence due to the increasing use of intramedullary fixation. We report a prospective case series using an intramedullary reaming device, the Reamer–Irrigator–Aspirator (RIA) system, in association with antibiotic cement rods for the treatment of lower limb long bone infections. A total of 24 such patients, 16 men and eight women, with a mean age of 44.5 years (17 to 75), 14 with femoral and 10 with tibial infection, were treated in a staged manner over a period of 2.5 years in a single referral centre. Of these, 21 patients had had previous surgery, usually for fixation of a fracture (seven had sustained an open fracture originally and one had undergone fasciotomies). According to the Cierny–Mader classification system, 18 patients were classified as type 1A, four as 3A (discharging sinus tract), one as type 4A and one as type 1B. Staphylococcus species were isolated in 20 patients (83.3%). Local antibiotic delivery was used in the form of impregnated cement rods in 23 patients. These were removed at a mean of 2.6 months (1 to 5). Pathogen-specific antibiotics were administered systemically for a mean of six weeks (3 to 18). At a mean follow-up of 21 months (8 to 36), 23 patients (96%) had no evidence of recurrent infection. One underwent a planned trans-tibial amputation two weeks post-operatively due to peripheral vascular disease and chronic recalcitrant osteomyelitis of the tibia and foot. The combination of RIA reaming, the administration of systemic pathogen-specific antibiotics and local delivery using impregnated cement rods proved to be a safe and efficient form of treatment in these patients.

Cite this article: Bone Joint J 2014; 96-B:783–8.

Fracture union following internal fixation in the HIV population

INTRODUCTION

HIV is thought to be associated with increased rates of fracture non-union. We report on a prospective cohort of 96 HIV positive patients with 107 fractures that required internal fixation. The CD4 count was measured and patients were reviewed until eventual clinical or radiological union or non-union was established.

RESULTS

Four percent of fractures (4 out of 100) failed to unite. Three patients required one further procedure to induce union, and two developed avascular necrosis. The CD4 count was not related to fracture union.

CONCLUSION

Contrary to previous assumptions, this study suggests that HIV infection does not increase rates of non-union in surgically managed fractures.

T-lymphocytes enable osteoblast maturation via IL-17F during the early phase of fracture repair

While it is well known that the presence of lymphocytes and cytokines are important for fracture healing, the exact role of the various cytokines expressed by cells of the immune system on osteoblast biology remains unclear. To study the role of inflammatory cytokines in fracture repair, we studied tibial bone healing in wild-type and Rag1(-/-) mice. Histological analysis, µCT stereology, biomechanical testing, calcein staining and quantitative RNA gene expression studies were performed on healing tibial fractures. These data provide support for Rag1(-/-) mice as a model of impaired fracture healing compared to wild-type. Moreover, the pro-inflammatory cytokine, IL-17F, was found to be a key mediator in the cellular response of the immune system in osteogenesis. In vitro studies showed that IL-17F alone stimulated osteoblast maturation. We propose a model in which the Th17 subset of T-lymphocytes produces IL-17F to stimulate bone healing. This is a pivotal link in advancing our current understanding of the molecular and cellular basis of fracture healing, which in turn may aid in optimizing fracture management and in the treatment of impaired bone healing.

Human immunodeficiency virus envelope protein Gp120 induces proliferation but not apoptosis in osteoblasts at physiologic concentrations

Patients with HIV infection have decreased numbers of osteoblasts, decreased bone mineral density and increased risk of fracture compared to uninfected patients; however, the molecular mechanisms behind these associations remain unclear. We questioned whether Gp120, a component of the envelope protein of HIV capable of inducing apoptosis in many cell types, is able to induce cell death in bone-forming osteoblasts. We show that treatment of immortalized osteoblast-like cells and primary human osteoblasts with exogenous Gp120 in vitro at physiologic concentrations does not result in apoptosis. Instead, in the osteoblast-like U2OS cell line, cells expressing CXCR4, a receptor for Gp120, had increased proliferation when treated with Gp120 compared to control (P<0.05), which was inhibited by pretreatment with a CXCR4 inhibitor and a G-protein inhibitor. This suggests that Gp120 is not an inducer of apoptosis in human osteoblasts and likely does not directly contribute to osteoporosis in infected patients by this mechanism.

Blistering Digital Dactylitis Complicated by Osteomyelitis and Amputation in an HIV-Positive Infant

HIV infection is rapidly emerging as a predominant cause of morbidity and mortality in children from developing countries. This probably accounts for the many reports that have emanated from resource-limited settings in the last decade. Reports highlighting bone infections and untoward complications in HIV-infected children are rare. This informed our decision to report the case of a 9-month-old HIV-positive Nigerian girl who presented with blistering dactylitis of the right middle finger. Plain radiograph of the right hand showed amputation of the terminal phalanx and changes consistent with osteomyelitis in the middle phalanx of the third finger. The case is discussed with a view of highlighting this rare complication and the challenges associated with management in a resource-limited setting.

HIV type 1 alters mesenchymal stem cell differentiation potential and cell phenotype ex vivo

An increased incidence of bone and lipid toxicities is associated with HIV-1 infection and its treatment. Mesenchymal stem cells (MSCs) are multipotent cells that can differentiate into both osteoblasts (OB) and adipocytes (AC). We hypothesize that the interaction of MSC and HIV-1 underlie these toxicities. Serum was collected from uninfected control and HIV-infected, antiviral-naive patients. Sera were divided into three groups: HIV-negative sera (n = 5), HIV-positive low viral load (LVL) (VL range 120; 4000, n = 5) or high viral load (HVL) (VL range 100,000; 500,000, n = 5). MSCs were exposed to these sera (5%) in an adipogenic/osteogenic condition and in nondifferentiating conditions in acute and chronic exposure models. Markers of adipogenesis/osteogenesis were examined in both MSCs induced to differentiated and nondifferentiating cells. Sera from HVL HIV-1-infected individuals induced a clear proadipogenic phenotype, as evidenced by an increase in adipocyte formation and the induction of increased expression of adipogenic markers including LPL and PPARγ. Both CD4 receptor blockade and treatment with the antiretroviral AZT attenuated these proadipogenic effects, suggesting that an infection event may underlie the observed phenomena. Finally, inhibition of COUP TF-1 by HIV-1 TAT was identified as a potential molecular mechanism for these effects. These results suggest that HIV-1 directly interacts with and may infect MSCs resulting in alterations of their differentiation potential, findings that significantly enhance our understanding of HIV-1-associated bone and fat toxicities.

Open tibia fractures in HIV positive patients

Open tibia fractures are common injuries, particularly in developing countries.Pedestrian or bicycle to motor car contact is the most common mechanism. These injuries result in high morbidity and often long-term disability. HIV infection complicates open fractures by raising the incidence of infectionin the open wound (5 of 7 patients in our series). This risk may be compounded if internal fixation techniques are used (5 of 12 HIV patients with internal fixation of any open fracture). There is also a suggestion that HIV may delay bone union (4 of 7 patients united at 6 months). External fixation offers an alternative method of fracture stabilisation. It avoids the risks associated with putting metal-ware in the wound, but creates a new issue of pin track sepsis. We found that pin track infection was more common in patients with HIV, but the rate at which pins required removal was 7%. We consider external fixation to be a lower-risk strategy than internal fixation in such patients but open fracture wound sepsis remains a problem. We have not yet demonstrated a difference in severity or frequency of complications in patients of low CD4 count, but logically one expects septic complications to increase as CD4 count falls. Antiretroviral medication decreases viral load and elevates the CD4 count. Research is underway regarding potential effectiveness of such drugs in reducing wound and fracture healing complications. Above all, meticulous and timely all-round care is required to achieve satisfactory results in immune-compromised patients. This includes, debridement, bony stability, and soft-tissue reconstruction.

Domestic water carrying and its implications for health: a review and mixed methods pilot study in Limpopo Province, South Africa

BACKGROUND

Lack of access to safe water remains a significant risk factor for poor health in developing countries. There has been little research into the health effects of frequently carrying containers of water. The aims of this study were to better understand how domestic water carrying is performed, identify potential health risk factors and gain insight into the possible health effects of the task.

METHODS

Mixed methods of data collection from six were used to explore water carrying performed by people in six rural villages of Limpopo Province, South Africa. Data was collected through semi-structured interviews and through observation and measurement. Linear regression modelling were used to identify significant correlations between potential risk factors and rating of perceived exertion (RPE) or self reported pain. Independent t-tests were used to compare the mean values of potential risk factors and RPE between sub-groups reporting pain and those not reporting pain.

RESULTS

Water carrying was mainly performed by women or children carrying containers on their head (mean container weight 19.5 kg) over a mean distance of 337 m. The prevalence of spinal (neck or back) pain was 69% and back pain was 38%. Of participants who carried water by head loading, the distance walked by those who reported spinal pain was significantly less than those who did not (173 m 95%CI 2-343; p = 0.048). For head loaders reporting head or neck pain compared to those who did not, the differences in weight of water carried (4.6 kg 95%CI -9.7-0.5; p = 0.069) and RPE (2.5 95%CI -5.1-0.1; p = 0.051) were borderline statistically significant. For head loaders, RPE was significantly correlated with container weight (r = 0.52; p = 0.011) and incline (r = 0.459; p = 0.018)

CONCLUSIONS

Typical water carrying methods impose physical loading with potential to produce musculoskeletal disorders and related disability. This exploratory study is limited by a small sample size and future research should aim to better understand the type and strength of association between water carrying and health, particularly musculoskeletal disorders. However, these preliminary findings suggest that efforts should be directed toward eliminating the need for water carrying, or where it must continue, identifying and reducing risk factors for musculoskeletal disorders and physical injury.