Narrow Results

This study is aimed to evaluate treatment research the effects of nicotine on fracture healing. Thirty rats were used. Nicotine was injected subcutanously at a dosage of 2 mg/kg/day to group A and 4 mg/kg/day to group B. Control group (group C) received 0.5 ml/kg/day saline solution.

Three weeks later, transverse fractures were performed on to the left ulnar and radial bones for each animal. Animals were designed to one of two follow-up groups which were euthanized either 2 or 3 weeks. On the 14th day of fracture, randomly chosen five rats from each group of A, B and C were sacrificed. At the 21st day of fracture, same procedure performed for all remaining rats. Both had surgical and histopathological evaluation were performed. Transverse fractures performed on the 21st day of study were confirmed by direct radiograms. One rat died spontaneously before completing the study was therefore excluded from the final analysis.

The results indicate that healing process proceeds in each group. There was no significant difference in fracture healing between groups A and B two weeks after the fracture. However, fracture healing was significantly delayed in nicotine treated group comparing to control group. We continue to support the notion that nicotine has a negative effect on fracture healing.

The aim of this prospective controlled study is to compare healing rate and amount of union callus formed in patients with long bone fractures and concomitant head or spinal cord injuries to patients with long bone fractures only. The healing markers of fractures were compared in three groups of patients: (A) patients with head injuries and long bone fractures, (B) patients with acute traumatic spinal cord injuries and long bone fractures, and (C) patients with long bone fractures only. The mean (range) time to union of long bone fractures in groups (A), (B), and (C) patients was 6.9 (3–20), 6.2 (3–7.7), and 22.4 (13–41) weeks. The mean (range) healing rate of long bone fractures in groups (A), (B), and (C) patients was 4.5(0.2–10.6), 4.7 (2.6–7.5), and 0.38(0.11–1) mm/week. The mean (range) thickness of callus formed at fracture sites in groups (A), (B), and (C) patients was 26(4–48), 29(10–48), and 1(2–20)mm. There were no cases of delayed or nonunion in groups (A) and (B) patients while 5 of 69 fractures (7.3%) had delayed union in group (C) and 9/69 (13%) fractures had nonunion. These results suggest acceleration of long bone fractures in patients with head or spinal cord injuries.

Bone fractures are one of the most common orthopedic cases, yet strategies to resolve excessive inflammation and non-unions still lack satisfactory treatment methods owing to the complex fracture microenvironment, as well as the interactions between the plethora of cell types involved. Fracture is a highly inflammatory process which involves the recruitment of various immune cells which in turn release various cytokines and growth factors to perpetuate inflammation and eventually healing resolution. Osteoimmunology is an interdisciplinary field investigating the extensive interactions between the immune system and skeletal system. Mesenchymal stem cells (MSCs) are resident in almost every adult tissue and are responsible for initiating reparative cascades in the event of injury. A key aspect of MSCs is their role as trophic mediators, secreting a milieu of signaling as well as immunomodulatory cytokines that play important roles in tissue regeneration. This paracrine signaling polarizes macrophages into their anti-inflammatory M2 phenotype, activates osteoblasts, inhibits osteoclasts, as well as suppresses conventional T cell proliferation and promotes regulatory T cell (Treg) proliferation. MSCs have been shown to resolve inflammation whilst also supporting osteogenesis; for these reasons, they are considered promising candidates for cellular therapies to treat musculoskeletal pathologies. Through pretreatment and genetic modifications, MSCs can be predisposed to release specific molecules that can modulate the microenvironment and regulate the activity of the immune system towards enhancing bone repair. By understanding the cross-talk between MSCs and the immune system in bone physiology, more targeted therapies directed towards specific cells and discrete signaling molecules become possible that may allow for expedited healing and improved standard of care in orthopedics. In this review, we discuss the interplay between immune cells and MSCs and the potential ways to harness this cross-talk to improve regenerative medicine strategies.

Introduction: Fractures are common in the old and are associated with increased morbidity. The pain of fractures and surgery can be managed using NSAIDs, but this may result in impaired healing. The inflammatory stage of bone healing is responsible for laying the foundation for subsequent proliferative stages. This may be the stage when NSAIDs may have their greatest impact and it is unclear if avoiding NSAIDs in this stage would result in differences in healing or whether different molecules have varied responses. This study sought to determine the differences in the histomorphometry of fracture callus in older rats when diclofenac and celecoxib were avoided in the first week after a fracture.

Methods: Fractures of the tibia were induced in 43 15-month-old (equivalent to 50 human years) rats which were then allocated to receive either diclofenac or celecoxib. Each group was further subdivided into early or late subgroups of 10 animals each receiving the study medication from the day after the fracture or eight days later, respectively. Histological and stereological examination of the callus on days 21 and 42 enabled comparison of histological grades, tissue proportions and cellular densities.

Results: The histological grade and amount of bone increased and the amount of cartilage reduced in all groups. The group that received celecoxib early had the least proportion of bone. The osteocyte and chondrocyte cellular densities increased in all groups across both time points.

Conclusion: Administration of celecoxib in the early fracture period in the old is associated with poorer histological grades, lower proportions of bone and increased cellularity which may result in delayed union of the fracture. Use of selective COX-2 inhibitors is discouraged for the management of pain in older patients with fractures especially in the first seven days.

Cigarette smoking is regarded as a risk factor for developing complications in fracture healing. To determine whether nicotine would retard fracture healing in the rat, 25 rats were divided into two groups and given nicotine or saline subcutaneously at a dose of 2 mg/kg a day, for four weeks. Then their right forelimbs were broken. The rats were killed and histopathologic sections of the radius and ulna were examined and graded at the 7th and 21st days after fractures. Nicotine or saline treatment continued throughout the experiment. Median fracture healing score was found to be 0 (min. 0 - max. 1) in nicotine-treated rats, and 1 (min. 0 - max. 2) in controls, at the 7th day. At the 21st day, the median scores were 2 (min. 1 - max. 3), and 3 (min. 2 - max. 3) in experimental and control groups, respectively. Scores were significantly decreased in nicotine-treated rats both at the 7th and 21st days (p = 0.0465 and p = 0.0175, respectively). We suppose that nicotine impaired fracture healing in the rat forearm model possibly by diminishing nutritional blood flow via vasoconstriction and by its direct effect on osteogenesis.

According to the mechanical conditions of fracture fixation and the oxygen levels in the tissues, a simulation model of fracture healing process was built to describe the relationship among mechanical stability, oxygen levels in tissues and tissue differentiation during the second fracture healing. Different from the previous simulation model, in this paper, we took the three-dimensional model as the research object, solved the mechanical stimulation by finite element method, established the partial differential equation to solve the spatial and temporal variation of the oxygen in tissues. The process of tissue differentiation was described by fuzzy control method. The initial stage of fracture healing, intramembranous ossification, chondrogenesis, cartilage calcification and endochondral ossification during the fracture healing process were simulated, and the properties of tissue materials were continuously updated to complete the iterative process. The simulation program of fracture healing process was independently developed in Eclipse environment, and the simulation results were compared with experimental data and those of other fracture healing simulation models to verify the simulation program in this paper. Finally, the processes of transverse fracture healing in rats with different axial stability under normoxic, hypoxic and hyperoxic conditions was simulated, and the effects of different tissue oxygen levels and interosseous stabilities on fracture healing were analyzed. It is concluded by simulation that the delayed healing or non-union of bone will occur when in state of tissue hypoxia or interosseous instability, normal healing will occur when in state of tissue normoxia, and the healing will be accelerated when in state of tissue hyperoxia.

Momordica charantia (MC) is a plant belonging to the family Cucurbitaceae. MC has antidiabetic, antibacterial, antioxidant, antimutagenic, antiulcerative, antiinflammatory and antilipidemic effects. However, information on the effect of MC on fracture union is lacking. This study aimed to examine the effect of MC on fracture union histopathologically and biomechanically. A total of 42 male Wistar-Albino rats were randomly divided into 3 groups, 14 in each group. A diaphyseal fracture was created on the right tibia of all rats. All fractures were fixed with a Kirschner (K) wire. The rats in Group I did not undergo any further procedures (Control group). Group II rats were treated with 0.9% saline oral gavage at a dose of $500\mu$L/day for 28 days [Saline (S) group]. The rats in Group III were given 300mg/kg MC extract per day, dissolved in $500\mu$L 0.9% saline by oral gavage for 28 days [MC (Extract) group]. After 28 days, all rats were sacrificed. Each group was randomly divided into two subgroups. The histopathological examination was performed on the right tibia of rats in the first subgroup and the biomechanical examination in the second subgroup. The kidneys and livers of all rats were evaluated histopathologically. Fracture union was significantly better in the Extract group compared with the Control and S groups histopathologically. The fracture inflammation values were lower in the Extract group than in the other groups. No statistically significant difference was found between the groups in terms of possible side effects to kidneys and livers. In terms of biomechanics, fracture union was significantly better in the Extract group compared with the Control and S groups except yield displacement values. MC had a positive effect on fracture union histopathologically and biomechanically.

As the effect of many medical agents such as nonsteroidal anti-inflammatory drugs or antibiotics were investigated on bone fracture healing, there is no study about the anesthetic agents when compared histopathologically and biomechanically. We asked the question that if a superiority can be between them since we operate many fractures and see the delayed or nonunions. Although different anesthetic agents are used in general anesthesia, the effects of these substances on bone fracture healing are not clear. Here, we intended to research different anesthetic agents on fracture union in rats. The study was done between January 2020 and November 2021 in a university animal research laboratory. Totally 48 male Wistar-Albino rats weighing 250–300g were seperated into 3 groups as Tiyopental Na in Group 1, Ketamin in Group 2 and Propofol in Group 3. For anesthesia; 40, 100, 100mg/kg of single dosages were injected intraperitoneally, respectively. A shaft fracture was created bilaterally to the tibia of all rats. Kirschner (K) wire is used for the fixation of fractures. Biomechanical and histopathological examination in bones is performed at the end of the first and second months in terms of fracture healing. It has been found that the fracture union in group 1 was statistically signifigant higher than group 3 at the end of the first and second months histopathologically (P = 0.006, P = 0.002). It is also found there is a statistically significant difference between groups 1 and 3 after the second month biomechanically (P = 0.013). Although the union was higher in group 1 than group 2 histopathologically and biomechanically after the first and second months, there was no statistically significant difference (P = 0.376, 0.039; P = 0.028, 0.867). There was a general trend in the decrease of union measurements starting from group 1 to 3 at the end of the first and second month both histopathologically and biomechanically. In this study, it is found that there was a positive consistency between histopathological and biomechanical results with respect to bone union. They supported each other. Fracture healing is stronger in rats that were anesthetized by using thiopental than those using ketamine and propofol, we think that this may affect the choice of anesthetic agent and further studies are needed.

Fracture is one of the most important health problems in people’s life. Millions of people have fractures every year. However, there is no unified standard for fracture healing in the clinic. Most definitions of complete fracture healing are subjective evaluations based on X-ray films. However, it is not reliable to evaluate the biomechanical strength of bone according to the number of callus on X-ray, and the imaging time of callus lags behind the actual callus, which is not conducive to the evaluation of early fracture healing time. In addition, although more and more fracture patients have achieved imaging healing after injury, the bone quality and bone strength of the whole body and local fracture have not returned to the normal level, and the probability of re-fracture has increased significantly, which has brought great pain to their families. Fracture healing is affected by many factors, such as age, fracture site, whether to fix the fracture site, and osteoporosis. Therefore, when evaluating the fracture healing status of patients, we should not only evaluate whether the fracture is healed but also evaluate its healing. By analyzing the previous research methods of fracture healing, in this paper, we systematically summarize the evaluation methods of fracture healing from the perspectives of computer tomography, ultrasound, bone density, biosensors, and biomechanics by analyzing previous research methods of fracture healing, aiming to provide reference for researchers in related fields.

In clinical practice, bone healing is monitored with X-rays and manipulation. Its assessment is thus subjective, depending on the skills of the operator. Alternative and quantitative approaches have been proposed, generally based on the estimation of bone stiffness, which is known to increase with the healing process.

The present study investigates the application of experimental modal analysis to fracture healing assessment focusing on fractures treated with an external fixator. The aim is to ascertain the capability of this approach to detect changes in the bone-callus stiffness as variations in the resonant frequencies despite the presence of the fixator, which might hide the bone response. In vitro tests were performed on a tibia phantom where the healing process was simulated creating three different types of callus surrogates, using glue and resin. The resonant frequencies of the phantom with screwed pins and of the phantom with the complete fixator were estimated. Results confirm an increase in the frequencies as the simulated bone-callus stiffness increases, encouraging the application of experimental modal analysis to fracture healing monitoring. This approach can offer remarkable advantages with respect to the actual standards: being non-invasive and quantitative, it would allow a more frequent healing monitoring.

Background: There is recent renewed interest in the effect of hand dominance on distal radius fractures. Current studies focus on functional or patient-reported outcomes, with lack of studies pertaining to radiological outcomes. The primary aim of this study is to examine the effect of hand dominance on time to fracture healing following surgical fixation of distal radius fracture. We also looked at the effect of age, gender, fracture comminution and American Society of Anaesthesiologists (ASA) status on time to fracture healing.

Methods: Patients who underwent distal radius fracture fixation surgery in our department from 1 January 2015 to 31 December 2015 were included. Time to fracture healing was taken from the day of surgery to when radiographic union was present as evidence by bridging callus or osseous bone. We looked at the effect of hand dominance, age, gender, fracture comminution and ASA status on time to fracture healing.

Results: One hundred and forty-five consecutive patients (80 females and 65 males) had a mean period of 56.2 ± 41.8 days to fracture healing post-operatively. Patients with dominant hand injury had a shorter duration to fracture healing than patients with non-dominant hand injury (mean 47.3 ± 31.1 days versus 62.1 ± 46.8 days, p = 0.023). Patients ≥ 65 years and with pre-existing medical conditions (ASA Class II and above) had a longer duration to fracture healing (mean 63.7 ± 53.0 days versus 51.9 ± 33.4 days, p = 0.036 and mean 47.9 ± 30.0 days versus 62.0 ± 47.7 days, p = 0.016, respectively). In addition, patients with comminuted fractures took longer to heal than patients with non-comminuted fractures (mean 57.6 ± 33.4 days versus 48.3 ± 20.8 days, p = 0.038).

Conclusion: Time to fracture healing post distal radius fracture fixation surgery was significantly related to hand dominance, as well as age, ASA classification and fracture configuration. Dominant wrist injuries had shorter time to fracture healing.

Level of Evidence: Level IV (Therapeutic)

It is assumed that bosentan, a non-selective ET-1 receptor antagonist, will enhance fracture healing. The aim of this prospective randomized controlled study was to investigate the effects of transcutaneous bosentan administration into diaphyseal bone fractures using radiology, histology, prostaglandin E₂ (PGE₂) and leukotrien C₄ (LTC₄) activity measurements.

A closed diaphyseal fracture was created in the hind limbs following intramedullary rod fixation of Guinea pigs. Bosentan was administred by repetitive weekly 0.1 μg transcutaneous injections into the fracture site. The effects of bosentan were evaluated by radiology and histology on weeks 1, 2 and 4, whereas prostaglandin E₂ (PGE₂)-like and leukotrien C₄ (LTC₄)-like activity was assessed on weeks 1 and 2.

The radiological degree of union (p = 0.001) at the fracture site and cortex-callus ratio (p = 0.02) was significantly better in the bosentan administered site at week 1 when compared to the control. Histology presented an initial stimulation of bone formation on weeks 1 and 2 in the experimental group. PGE₂-like activity was significantly higher (p = 0.002) on week 1 and 2 in the bosentan-administered side. LTC₄-like activity remained constant on week one and decreased on week two.

Transcutaneous repetitive bosentan administration into the fracture site initially stimulated periosteal bone healing that resulted with extracellular matrix mineralization. The inflammatory mediators PGE₂/LTC₄ played a significant role in this process.

Calcium phosphate ceramic has been known for its properties of bioactivity and osteoconductivity and has been widely used in orthopedic, plastic and craniofacial surgeries. The biocompatibility, unlimited availability, lower morbidity for the patient and cost-effectiveness of calcium phosphate ceramics represent important advantages over other biological bone graft, such as autografts and allografts. A new synthetic biphasic calcium phosphate (BCP), Bicera™ (60% HA and 40% β-TCP), is manufactured by Wiltrom Co., Ltd., as a new bone graft substitute. It shows good biocompatibility without cytotoxicity in in vitro test. To evaluate the possible application for clinical use, we used New Zealand white rabbit femur defect model to compare the osteoconductivity of this new bone substitute to another commercially available bone substitute (Triosite^®) which was used as the control material.

According to the macroscopic observation, both bone substitutes show good biocompatibility and no abnormal inflammation either infection was seen at the implantation sites. X-rays image of implant sites at one month, three months and six months showed all implanted materials were well incorporated with host bone. All of them were not fully absorbed and replaced after six months implantation. In the histological and hitomorphometric data, new bone grew into the surface of the peripheral pores in both bone substitutes and increased over time. Moreover, the degree of bone regeneration appeared to be relatively greater in the specimens with Bicera™ when compared with Triosite^®. We concluded that this new synthetic BCP (Bicera™) showed similar biocompatibility and osteoconductive characteristic comparing with commercial product Triosite^® in rabbit femur defects model.

The use of micro-computed tomography (micro-CT) in orthopedic research has flourished in recent years. It has been shown to be an objective measurement of the trabecular bone structure and a useful tool in the study of osteoporosis. With its application base in osteoporosis, the present chapter introduces a protocol for work on other orthopedic conditions such as fracture healing, spinal fusion, and anterior cruciate ligament tunnel healing. In addition to the quantification of structural parameters of mineralized tissue, protocols for the quantification of blood vessels and porous structure of biomaterials are also presented.

Since disuse can be induced by or associated with nerve injury in human beings, it is necessary to develop a neurogenic disuse model for studying the potential beneficial effects of both pharmaceutical and nonpharmaceutical interventions on the prevention and treatment of disuse-related problems, such as disuse-induced osteoporosis. Bone innervation plays an important role in the local modulation of bone metabolism in both intact bone and fracture healing. The establishment of an animal fracture model associated with denervation will facilitate further study of the effect of reinnervation on bone healing. The aim of this chapter is to describe the method for establishing and evaluating (1) the neurogenic disuse model by sciatic nerve resection and (2) the fracture model associated with sciatic nerve resection. The effects of sciatic nerve resection on the responses of both trabecular and cortical bones are usually studied in the tibia of the rat. Peripheral quantitative computed tomography (pQCT) and bone histomorphometry are frequently used methods for evaluating decrease in bone mass and deterioration of the bone microarchitecture in disused bone. The process of fracture healing can be evaluated by radiography, mechanical testing, pQCT, and histological methods. The related key findings are also included in this chapter, and will help in our understanding of the strengths and weaknesses or limitations of these methods for creating and evaluating the two relevant animal models. Practical tips for performing the experiments are provided, illuminating potential confounding factors and enhancing our awareness of potential limitations.