Polymethylmethacrylate bone cements and additives: A review of the literature

Enhanced bone cement for fixation of prosthetic joint utilizing nanoparticles

Bone cement is commonly utilized to secure prosthetic joints in the body because of its robust fixation, stability, biocompatibility, and immediate load-bearing capability. However, issues such as loosening, leakage, and insufficient bioactivity can lead to its failure. Therefore, improving its mechanical, physical, and biological properties is crucial for enhancing its efficiency. This study examines the impact of incorporating four different nanomaterials-Titanium Dioxide (TiO2), Magnesium Oxide (MgO), Calcium Phosphate (Ca3(PO4)2), and Alumina Oxide (Al2O3)-into bone cement on its mechanical, physical, and biological properties. TiO2 and Al2O3 nanoparticles are selected to enhance the compression strength of bone cement, thereby preventing loosening. Magnesium Oxide (MgO) and Ca3(PO4)2 nanoparticles are chosen to improve cell adhesion and reducing the risk of cement leakage. Five specimens were prepared: the first with 100% pure bone cement powder, the second with 98% pure bone cement powder and modified with 2% MgO and TiO2, and the remaining three with 95% pure bone cement powder and modified with 5% varying ratios of MgO, TiO2, Ca3(PO4)2, and Al2O3. Compression, tensile, hardness, and bending strengths were assessed to determine improvements in mechanical properties. Setting temperature, porosity, and degradation were measured to evaluate physical properties. Cell adhesion and toxicity tests were conducted to examine the surface structure and biological properties. The results demonstrated that the modified specimens increased compression strength by 8.14%, tensile strength by 3.4%, and bending strength by 4.96%. Porosity, degradation, and setting temperature in modified specimens increased by 3.24%, 0.64%, and 5.17% respectively pure bone cement values. Cell adhesion in modified bone cement specimens showed normal attachment when scanned with FE-SEM. All of the tested modified specimens showed no toxicity, except for specimens with 2% Al2O3 that showed 25% toxicity which could be averted by employing antibiotics.

Integrating Micro- and Nanostructured Platforms and Biological Drugs to Enhance Biomaterial-Based Bone Regeneration Strategies

Bone defects resulting from congenital anomalies and trauma pose significant clinical challenges for orthopedics surgeries, where bone tissue engineering (BTE) aims to address these challenges by repairing defects that fail to heal spontaneously. Despite numerous advances, BTE still faces several challenges, i.e., difficulties in detecting and tracking implanted cells, high costs, and regulatory approval hurdles. Biomaterials promise to revolutionize bone grafting procedures, heralding a new era of regenerative medicine and advancing patient outcomes worldwide. Specifically, novel bioactive biomaterials have been developed that promote cell adhesion, proliferation, and differentiation and have osteoconductive and osteoinductive characteristics, stimulating tissue regeneration and repair, particularly in complex skeletal defects caused by trauma, degeneration, and neoplasia. A wide array of biological therapeutics for bone regeneration have emerged, drawing from the diverse spectrum of gene therapy, immune cell interactions, and RNA molecules. This review will provide insights into the current state and potential of future strategies for bone regeneration.

Operative Fires: Variables Associated with Polymethylmethacrylate Flammability

BACKGROUND

Operative fires are rare but unforgettable events, with the potential for devastating outcomes. It is estimated that 650 operating room (OR) fires occur each year in the United States, with the use of electrocautery devices and polymethylmethacrylate (PMMA) as the primary ignition and fuel sources. There are several case reports of OR fires caused by PMMA and electrocautery in the literature, but, to our knowledge, no formal studies have been performed exposing the flammability of PMMA and how PMMA reacts to an electrocautery ignition source.

METHODS

We studied the flammability of PMMA with electrocautery as an ignition source in a controlled laboratory setting. We used 2 different brands of PMMA, both with and without antibiotics. The PMMA was prepared according to the manufacturer's guidelines. In our model, which used a cadaveric leg, the PMMA was placed next to a femoral component that is used in total knee arthroplasty (TKA). Electrocautery was applied at 30-second intervals for a total of 15 minutes. Flammability was defined as any visualized spark or flame while using an electrocautery device. The heat resulting from the chemical reaction was recorded every 30 seconds with a thermal imaging camera (TIC). Video recording was used during the experiment to document the flammability events. A total of 108 tests were performed.

RESULTS

PMMA with and without antibiotics proved to be flammable with the use of electrocautery. All flammability occurred within 7 minutes of combining the monomer and the powder. Increased flammability was seen with the use of antibiotic additives.

CONCLUSIONS

PMMA was found to be highly flammable in the initial curing period when exposed to electrocautery as an ignition source. When PMMA is ready for application, we recommend that an "electrocautery timeout" be performed, wherein the electrocautery device is removed from the operating field for a minimum of 7 minutes or until the PMMA has fully hardened.

Integrating Phosphate Enhances Biomineralization Effect of Methacrylate Cement in Vital Pulp Treatment with Improved Human Dental Pulp Stem Cells Stimulation

Vital pulp treatment (VPT) is crucial for preserving the health and function of the tooth in cases where the pulp tissue remains vital despite exposure. Various materials are introduced for this purpose. However, challenges such as low strength, high solubility, and tooth discoloration persist. Methylmethacrylate-based cement (MC) offers excellent sealing ability, feasibility, and mechanical properties, making it a promising alternative for VPT. Phosphate-based glass (PBG) has the potential to promote hard tissue regeneration by releasing key inducers, phosphorus (P) and calcium (Ca), for reparative odontogenesis. This study investigates PBG-integrated MC (PIMC) by characterizing its properties, assessing human dental pulp stem cell activity related to initial inflammatory adaptation and odontogenic differentiation, and evaluating hard tissue formation using an in vivo dog pulpotomy model. Results indicate that a 5% PBG-integrated MC (5PIMC) maintains the physicochemical properties of MC. Furthermore, 5PIMC demonstrates cytocompatibility, excellent expression of osteo/odontogenic markers, and resistance to inflammatory markers, significantly outperforming MC. Enhanced hard tissue formation is observed in the dental pulp of mongrel dog teeth treated with 5PIMC. These findings suggest that 5PIMC could be an optimal and suitable material for reparative odontogenesis through VPT.

Antibiotic-loaded cement in total joint arthroplasty: a comprehensive review

This review evaluates the decision-making framework for using antibiotic-loaded cement (ALC) in the management of prosthetic joint infection (PJI). Drawing on available literature, we offer orthopaedic surgeons a guided discussion on several critical considerations. First, we explore the impact of antibiotic-loading on the mechanical properties of polymethylmethacrylate (PMMA) cement, assessing both strength and durability. We then explore the optimal antibiotic dosage to load into cement, aiming to achieve effective local concentrations for infection control without compromising mechanical stability. Furthermore, we explore how cement and antibiotic properties affect the overall antibiotic elution characteristics of ALC. Finally, we discuss risks of systemic toxicity, particularly acute kidney injury, when using ALC. The principal goal in this review is to provide a balanced approach based on best available evidence that optimises antibiotic elution from ALC whilst minimising potential harms associated with its use.

Investigating the role of temperature and moisture on the degradation of 3D-printed polymethyl methacrylate dental materials through molecular dynamics simulations

This study aimed to comprehensively investigate the degradation behavior of 3D printed polymethyl methacrylate (PMMA) dental materials, with a specific focus on the influential factors of temperature and moisture, by employing molecular dynamics simulations. Owing to their aesthetic properties, 3D-printed PMMA dental materials play a pivotal role in dental applications. However, understanding their degradation mechanisms, particularly in the context of temperature and moisture variations, is crucial for their long-term durability. A Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) was utilized for the molecular dynamics simulations. The simulation setup included temperature variations from 300 to 600 K and relative humidity (RH) levels ranging from 20 to 100%. Various mechanical properties and structural changes were analyzed to determine the degradation behavior. Energetic profiling during equilibration and the subsequent temperature variations were studied. The spatial distribution of the mean squared displacement, non-bond energy, Young's modulus, bending stress, and volume expansion coefficient of the particles were quantitatively analyzed, revealing temperature- and moisture-dependent trends. The study concluded that temperature and moisture significantly affected the degradation behavior of 3D-printed PMMA dental materials. Higher temperatures and increased humidity levels contribute to reduced mechanical strength and altered structural properties, emphasizing the importance of controlling environmental conditions during fabrication.

Adsorption and Morphology Analysis of Bovine Serum Albumin on a Micropillar-Enhanced Quartz Crystal Microbalance

The adsorption of bovine serum albumin (BSA), a widely used blood plasma protein, onto poly(methyl methacrylate) (PMMA) surface is a fundamental phenomenon attracting increasing interests in molecular biology, cell culture, immunology, diagnostics, and vaccinology. The nanostructured PMMA surfaces have shown a considerable effect on the BSA adsorption process. However, the effect of microstructures (e.g., micropillars) on BSA adsorption has seldom been studied. This research reports on the development of an acoustic resonance based method to explore the adsorption of BSA proteins on PMMA micropillars in terms of surface coverage, apparent binding constants, and pH-induced morphology variation. A theoretical model is developed to understand the frequency changes of QCM induced by BSA adsorption by taking into consideration the effects of the hydrodynamic force and an equivalent BSA/liquid layer formed on the micropillar surface. In addition, it was found that the resonance of micropillars with a quartz crystal microbalance (QCM) substrate significantly influenced BSA adsorption on micropillar surfaces.

Mechanical and Bioactive Properties of PMMA Bone Cement: A Review

Over the past few decades, poly(methyl methacrylate) (PMMA) based bone cement has been clinically used extensively in orthopedics for arthroplasty and kyphoplasty, due to its biocompatibility and excellent primary fixation to the host bone. In this focused review, we discuss the use of various fillers and secondary chemical moieties to improve the bioactivity and the physicochemical properties. The viscosity of the PMMA blend formulations and working time are crucial to achieving intimate contact with the osseous tissue, which is highly sensitive to organic or inorganic fillers. Hydroxyapatite as a reinforcement resulted in compromised mechanical properties of the modified cement. The possible mechanisms of the additive- or filler-dependent strengthening or weakening of the PMMA blend are critically reviewed. The addition of layered double hydroxides with surface functionalization appears to be a promising approach to enhance the bonding of filler with the PMMA matrix. Such an approach consequently improves the mechanical properties, owing to enhanced dispersion as well as contributions from crack bridging. Finally, the use of emerging alternatives, such as nanoparticles, and the use of natural biomolecules were highlighted to improve bioactivity and antibacterial properties.

Effectiveness of RF ablation and cementoplasty in enhancing functional capacity in pelvic malignant bone metastases

PURPOSE

Pelvic and sacral bone metastases cause significant morbidity. The primary aim of the study is to thoroughly evaluate the increase in functional capacity resulting from combined RF ablation and cementoplasty surgery applied to malignant bone metastases of the pelvic bones.

METHODS

Twenty patients who underwent RF ablation and cementoplasty for malign pelvic bone and sacrum metastases between January 2014 and December 2021 were retrospectively identified. The inclusion criteria were having a life expectancy of more than 1 month, being > 18 years old, and having at least 1 month of follow-up. The Visual Anlogue Scale (VAS) pain, Karnofsky Performance Status (KP), and Musculoskelatal Tumor Society (MSTS) scores were calculated.

RESULTS

VAS pain values decreased, and KP values increased postoperatively (p = 0.006 and p = 0,013). There was no statistically significant increase in MSTS (p > 0.05). The correlation relationships between lesion filling ratio and VAS pain, KP, and MSTS scores were not statistically significant (p > 0.05). Cement leakage was observed in 5 patients (25.0%), and no symptoms related to this leakage were observed.

CONCLUSION

The pelvic region, given its close proximity to blood vessels, nerves, and joint areas, along with the distinct challenges associated with its surgery, requires separate evaluation. In studies evaluating applications in the isolated pelvic ring region, as in our study, functional gains have been most comprehensively assessed in this study, demonstrating that the procedure results in significant functional improvements.

Characterization and selection of a skull surrogate for the development of a biofidelic head model

This research paper explores the advancement of physical models simulating the human skull-brain complex, focusing on applications in simulating mild Traumatic Brain Injury (mTBI). Existing models, especially head forms, lack biofidelity in accurately representing the native structures of the skull, limiting the understanding of intracranial injury parameters beyond kinematic head accelerations. This study addresses this gap by investigating the use of additive manufacturing (AM) techniques to develop biofidelic skull surrogates. Materials such as Polylactic Acid (PLA), a bone-simulant PLA variant, and Hydroxyapatite-coated Poly(methyl methacrylate) (PMMA) were used to create models tested for their flexural modulus and strength. The trabecular bone regions were simulated by adjusting infill densities (30%, 50%, 80%) and print raster directions, optimizing manufacturing parameters for biofidelic performance. Among the tested materials, PLA and its bone-simulating variant printed at 80% infill density with a side (tangential) print orientation demonstrated the closest approximation to the mechanical properties of cranial bone, yielding a mean flexural modulus of 1337.2 MPa and a mean ultimate strength of 56.9 MPa. Statistical analyses showed that infill density significantly influenced the moduli and strength of the printed simulants. Digital Image Correlation (DIC) corroborated the comparable performance of the simulants, showing similar strain and displacement behaviors to native skull bone. Notably, the performance of the manufactured cortical and trabecular regions underscored their crucial role in achieving biofidelity, with the trabecular structure providing critical dampening effects when the native bone is loaded. This study establishes PLA, particularly its bone-simulant variant, as an optimal candidate for cranial bone simulants, offering significant potential for developing more accurate biofidelic head models in mTBI research.

Evaluating the physico-chemical properties of water-based and 2% lidocaine hydrochloride-based aluminum-free glass polyalkenoate cements for distal radius fixation

Lidocaine hydrochloride is used as an anesthetic for clinical applications. This study considers the effects of the substitution of 2% lidocaine hydrochloride for deionized (DI) water on the rheological, mechanical, ion release, pH and injectable properties of two formulations of aluminum-free glass polyalkenoate cements (GPCs) using two distinct poly(acrylic) acids (PAA), E9 and E11, which have different molecular weights (Mw). The substitution of 2% lidocaine hydrochloride demonstrated increased injectability, but did not affect mechanical properties. The mechanical properties increased with time, as expected, and, in general, E9-based GPCs displayed significantly higher strengths over E11-based GPCs. With respect to ion release, which includes calcium (Ca), strontium (Sr), zinc (Zn) and silicon (Si); all ions displayed a steady and consistent increased release over time. Ca and Sr showed similar ion release patterns, whereby the GPC made with E11 PAA and lidocaine hydrochloride released significantly more ions than all other compositions likely due to similar chemical kinetics. However, Zn is also divalent in nature, but displayed only one significant difference across the GPC series at all time points, which was attributed to its higher electronegativity allowing for increased participation in the setting reaction. Finally, an analysis of the pH confirmed an increase in pH with time, suggesting that H+ ions were attacking the glass structure to allow for ion release. After 1 and 7 days, water-based GPCs environments achieved a higher pH than lidocaine hydrochloride-based GPCs, indicating that the lidocaine hydrochloride may be releasing additional protons upon bond formation with PAA.

Injectable bioactive poly(propylene fumarate) and polycaprolactone based click chemistry bone cement for spinal fusion in rabbits

Degenerative spinal pathology is a widespread medical issue, and spine fusion surgeries are frequently performed. In this study, we fabricated an injectable bioactive click chemistry polymer cement for use in spinal fusion and bone regrowth. Taking advantages of the bioorthogonal click reaction, this cement can be crosslinked by itself eliminating the addition of a toxic initiator or catalyst, nor any external energy sources like UV light or heat. Furthermore, nano-hydroxyapatite (nHA) and microspheres carrying recombinant human bone morphogenetic protein-2 (rhBMP-2) and recombinant human vascular endothelial growth factor (rhVEGF) were used to make the cement bioactive for vascular induction and osteointegration. After implantation into a rabbit posterolateral spinal fusion (PLF) model, the cement showed excellent induction of new bone formation and bridging bone, achieving results comparable to autograft control. This is largely due to the osteogenic properties of nano-hydroxyapatite (nHA) and the released rhBMP-2 and rhVEGF growth factors. Since the availability of autograft sources is limited in clinical settings, this injectable bioactive click chemistry cement may be a promising alternative for spine fusion applications in addressing various spinal conditions.

GMXPolymer: a generated polymerization algorithm based on GROMACS

CONTEXT

This work introduces a method for generating generalized structures of amorphous polymers using simulated polymerization and molecular dynamics equilibration, with a particular focus on amorphous polymers. The techniques and algorithms used in this method are described in the main text, and example input scripts are provided for the GMXPolymer code, which is based on the GROMACS molecular dynamics package. To demonstrate the efficacy of our method, we apply it to different glassy polymers exhibiting varying degrees of functionality, polarity, and rigidity. The reliability of the method is validated by comparing simulation results with experimental data in various structural and thermal properties, both of which show excellent agreement.

METHODS

This work implements the GMXPolymer simulated polymerization algorithm on the GROMACS program. GMXPolymer code controls the main polymerization loop. The energy minimizations and molecular dynamics simulations use the GROMACS program called by the GMXPolymer code. A new ITP file is generated when a new bond is formed, and the necessary additions to the ITP file are made to include new bonds, angles, and dihedrals. In preparing the ITP file of the monomer, the charge of the reactive atom must be modified before the code runs so that it is a correct value after bonding.

The Role of Bone Grafting vs. Bone Cement in the Treatment of Giant Cell Tumor of Bone: A Systematic Review and Meta-Analysis on the Risk of Recurrence in 1,454 Patients

BACKGROUND

Giant cell tumor of bone (GCTB) presents a challenge in management due to its invasive nature and propensity for local recurrence. While either bone grafting (BG) or bone cement (BC) can be utilized to fill defects after intralesional curettage, the optimal treatment remains contested. The purpose of this study was to examine the impact of defect filling with BC compared with BG on recurrence rates in patients with GCTB following intralesional curettage.

METHODS

A random-effects model binary outcome meta-analysis was performed utilizing recurrence rate for the BC and BG groups to evaluate the risk ratio (p < 0.05 considered significant). There were 1,454 patients included.

RESULTS

Intralesional curettage with BG had a recurrence risk ratio of 1.68 (95% confidence interval [CI], 1.22-2.31, p = 0.001) when compared with BC. The overall rate of recurrence for GCTB after intralesional curettage with BC was 20.05% vs. 29.74% with BG (95% CI, 0.17-0.23 vs. 0.26-0.33, p < 0.001).

CONCLUSION

Intralesional curettage with BC for the treatment of GCTB demonstrated lower recurrence rates than intralesional curettage with BG. However, the rates of recurrence remain substantial for both groups, necessitating careful consideration of the benefits and potential pitfalls associated with BC vs. BG when considering salvage options after recurrences.

LEVEL OF EVIDENCE

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

Ultra-Long-Term Delivery of Hydrophilic Drugs Using Injectable In Situ Cross-Linked Depots

Achieving ultra-long-term release of hydrophilic drugs over several months remains a significant challenge for existing long-acting injectables (LAIs). Existing platforms, such as in situ forming implants (ISFI), exhibit high burst release due to solvent efflux and microsphere-based approaches lead to rapid drug diffusion due to significant water exchange and large pores. Addressing these challenges, we have developed an injectable platform that, for the first time, achieves ultra-long-term release of hydrophilic drugs for over six months. This system employs a methacrylated ultra-low molecular weight pre-polymer (polycaprolactone) to create in situ cross-linked depots (ISCD). The ISCD's solvent-free design and dense mesh network, both attributed to the ultra-low molecular weight of the pre-polymer, effectively minimizes burst release and water influx/efflux. In vivo studies in rats demonstrate that ISCD outperforms ISFI by achieving lower burst release and prolonged drug release. We demonstrated the versatility of ISCD by showcasing ultra-long-term delivery of several hydrophilic drugs, including antiretrovirals (tenofovir alafenamide, emtricitabine, abacavir, and lamivudine), antibiotics (vancomycin and amoxicillin) and an opioid antagonist naltrexone. Additionally, ISCD achieved ultra-long-term release of the hydrophobic drug tacrolimus and enabled co-delivery of hydrophilic drug combinations encapsulated in a single depot. We also identified design parameters to tailor the polymer network, tuning drug release kinetics and ISCD degradation. Pharmacokinetic modeling predicted over six months of drug release in humans, significantly surpassing the one-month standard achievable for hydrophilic drugs with existing LAIs. The platform's biodegradability, retrievability, and biocompatibility further underscore its potential for improving treatment adherence in chronic conditions.

Pioneering nanomedicine in orthopedic treatment care: a review of current research and practices

A developing use of nanotechnology in medicine involves using nanoparticles to administer drugs, genes, biologicals, or other materials to targeted cell types, such as cancer cells. In healthcare, nanotechnology has brought about revolutionary changes in the treatment of various medical and surgical conditions, including in orthopedic. Its clinical applications in surgery range from developing surgical instruments and suture materials to enhancing imaging techniques, targeted drug delivery, visualization methods, and wound healing procedures. Notably, nanotechnology plays a significant role in preventing, diagnosing, and treating orthopedic disorders, which is crucial for patients' functional rehabilitation. The integration of nanotechnology improves standards of patient care, fuels research endeavors, facilitates clinical trials, and eventually improves the patient's quality of life. Looking ahead, nanotechnology holds promise for achieving sustained success in numerous surgical disciplines, including orthopedic surgery, in the years to come. This review aims to focus on the application of nanotechnology in orthopedic surgery, highlighting the recent development and future perspective to bridge the bridge for clinical translation.

Cement-augmented locked plate fixation proximal humerus fractures in elderly patient: a systematic review and meta-analysis

BACKGROUND

This systemic review and meta-analysis aimed to evaluate the clinical outcomes of proximal humeral fracture in elderly patient fixation using locked plate with or without cement augmentation.

METHODS

The databases of PubMed, Embase, and Cochrane Library were searched in August 2023 for literature comparing the clinical outcomes of patients with PHFs treated with locked plate alone and locked plate augmented with cement. Data describing study design; level of evidence; inclusion criteria; demographic information; final follow-up; revision rate; implant failure rate; avascular necrosis rate; total complication rate; constant score; and disability of arm, shoulder, and hand (DASH) score were collected.

RESULTS

Eight studies (one randomized-controlled trial and seven observational studies), involving 664 patients, were identified. Compared with locked plates alone, using cement-augmented locked plates reduced the implant failure rate (odds ratio (OR) = 0.19; 95% confidence interval (CI) 0.10-0.39; P < 0.0001) and total complication rate (OR = 0.45; 95% CI 0.29-0.69; P = 0.0002) and improved DASH scores (mean difference (MD) = 2.99; 95% CI 1.00-4.98; P = 0.003). However, there was no significant difference in clinical outcomes, including revision rate, avascular necrosis rate, and constant score.

CONCLUSION

In this review and meta-analysis, fixation of the PHFs in elderly patients using locked plates with or without cement augmentation has no significant difference in revision rate, but the implant failure and total complication rates may be lesser on using the cement-augmented locked plate for fixation than on using a locked plate alone. Good results are expected for most patients treated with this technique.

TRIAL REGISTRATION

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)21 guidelines were followed to conduct this systematic review and meta-analysis and was registered as a protocol in PROSPERO (CRD42022318798).

Combining antibiotic-loaded bone cement-based free vastus lateralis muscle-sparing flap with split-thickness skin grafts: A reliable strategy for reconstructing diabetic foot ulcers at non-weight-bearing areas

Diabetic foot ulcers (DFUs) present significant challenges due to their associated amputation rates, mortality, treatment complexity and excessive costs. Our earlier work introduced a wound surgical integrated treatment (WSIT) for DFUs, yielding promising outcomes. This study focuses on a specific WSIT protocol employing antibiotic-loaded bone cement (ALBC) in the first Stage, and free vastus lateralis muscle-sparing (VLMS) flaps and split-thickness skin grafts (STSGs) in the second stage to repair non-weight-bearing DFUs. From July 2021 to July 2023, seven DFU patients (aged 47-71 years) underwent this treatment. Demographic data, hospital stay and repair surgery times were collected. Histological and immunohistochemical analyses assessed angiogenesis, collagen deposition and inflammation. SF-36 questionnaire measured pre- and postoperative quality of life. Preoperative ultrasound Doppler showed that the peak blood flow velocity of the recipient area artery was significantly >30 cm/s (38.6 ± 6.8 cm/s) in all patients. Muscle flap sizes varied from 8 × 3.5 × 1 to 18 × 6 × 2 cm. The operation time of the repair surgery was 156.9 ± 15.08 minutes, and the hospital stay was 18.9 ± 3.3 days. Histological analysis proved that covering DFUs with ALBC induced membrane formation and increased collagen, neovascularization and M2 macrophages fraction while reducing M1 macrophages one. All grafts survived without amputation during a 7- to 24-month follow-up, during which SF-36 scores significantly improved. A combination of ALBC with free VLMS flaps and STSGs proved to be safe and effective for reconstructing non-weight-bearing DFUs. It rapidly controlled infection, enhanced life quality and foot function, and reduced hospitalization time. We advocate integrating this strategy into DFU treatment plans.

Retention of Antibiotic Cement Delivery Implants in Orthopedic Infection Associated With United Fractures Does Not Increase Recurrence Risk

OBJECTIVES

To evaluate whether retention of antibiotic cement delivery devices after resolution of orthopaedic infection is associated with recurrence.

METHODS

DESIGN

Retrospective cohort.

SETTING

Academic medical center.

PATIENT SELECTION CRITERIA

Patients with a fracture definitively treated with internal fixation that went on to unite and develop a confirmed fracture-related infection or osteomyelitis after a remote fracture surgery and had implantation of antibiotic-impregnated cement for infection management.

OUTCOME MEASURES AND COMPARISONS

Patients were divided into whom the antibiotic implants were retained (Retained Cohort) and whom the antibiotic implants were removed (Removed Cohort). Outcome measures included clinical infection resolution, infection recurrence, time to resolution of infection signs, symptoms and laboratory values, reoperation and readmission rates, and need for soft tissue coverage (local flap vs. free tissue transfer) because of recurrence.

RESULTS

Of 98 patients treated for fracture-related infection in united fractures or osteomyelitis after a remote fracture surgery, 39 (39.8%) underwent implantation of antibiotic-impregnated cement delivery devices: 21 (21.4%) beads, 7 (7.1%) rods, and 11 (11.2%) blocks. Twenty patients (51.3%) comprised the Retained Cohort and 19 patients (48.7%) comprised the Removed Cohort. There were few differences in demographics ([American Society of Anesthesiology Score, P = 0.026] and [diabetes, P = 0.047]), infection location, and pathogenic profiles. The cohorts demonstrated no difference in eventual resolution of infection (100% in the Retained Cohort, 95% in the Removed Cohort, P = 0.487) and experienced similar time to clinical infection resolution, based on signs, symptoms, and laboratory values ( P = 0.360). There was no difference in incidence of subsequent infection recurrence after clinical infection resolution (1 recurrence Retained vs. 2 recurrences Removed, P = 0.605) for those considered "cured." Compared with the Retained Cohort, the Removed Cohort underwent more reoperations (0.40 vs. 1.84 reoperations, P < 0.001) and admissions after implantation ( P < 0.001).

CONCLUSIONS

Retention of antibiotic-impregnated cement delivery devices in patients with orthopaedic infection after fractured bones that have healed was not associated with infection recurrence. Additional surgical intervention with the sole purpose of removing antibiotic delivery devices may not be warranted.

LEVEL OF EVIDENCE

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

Cemented vs. Cementless Fixation in Primary Knee Replacement: A Narrative Review

Knee osteoarthritis (OA) is one of the leading causes of disability around the globe. Osteoarthritis is mainly considered a disease affecting the elderly. However, more and more studies show that sports overuse, obesity, or congenital disorders can initiate a pathologic cascade that leads to OA changes in the younger population. Nevertheless, OA mostly affects the elderly, and with increasing life expectancy, the disease will develop in more and more individuals. To date, the golden standard in the treatment of the end-stage of the disease is total joint replacement (TJR), which restores painless knee motion and function. One of the weakest elements in TJR is its bonding with the bone, which can be achieved by bonding material, such as poly methyl-methacrylate (PMMA), or by cementless fixation supported by bone ingrowth onto the endoprosthesis surface. Each technique has its advantages; however, the most important factor is the revision rate and survivor time. In the past, numerous articles were published regarding TJR revision rate, but no consensus has been established yet. In this review, we focused on a comparison of cemented and cementless total knee replacement surgeries. We introduced PICO rules, including population, intervention, comparison and outcomes of TJR in a PubMed search. We identified 783 articles published between 2010 and 2023, out of which we included 14 in our review. Our review reveals that there is no universally prescribed approach to fixate knee prostheses. The determination of the most suitable method necessitates an individualized decision-making process involving the active participation and informed consent of each patient.

Effect of using nano-particles of magnesium oxide and titanium dioxide to enhance physical and mechanical properties of hip joint bone cement

In this work, the effect of adding Magnesium Oxide (MgO) and Titanium Dioxide (TiO2) nanoparticles to enhance the properties of the bone cement used for hip prosthesis fixation. Related to previous work on enhanced bone cement properties utilizing MgO and TiO2, samples of composite bone cement were made using three different ratios (0.5%:1%, 1.5%:1.5%, and 1%:0.5%) w/w of MgO and TiO2 to determine the optimal enhancement ratio. Hardness, compression, and bending tests were calculated to check the mechanical properties of pure and composite bone cement. The surface structure was studied using Fourier transform infrared spectroscopy (FTIR) and Field emission scanning electron microscopy (FE-SEM). Setting temperature, porosity, and degradation were calculated for each specimen ratio to check values matched with the standard range of bone cement. The results demonstrate a slight decrease in porosity up to 2.2% and degradation up to 0.17% with NP-containing composites, as well as acceptable variations in FTIR and setting temperature. The compression strength increased by 2.8% and hardness strength increased by 1.89% on adding 0.5%w/w of MgO and 1.5%w/w TiO2 NPs. Bending strength increases by 0.35% on adding 1.5% w/w of MgO and 0.5% w/w TiO2 NPs, however, SEM scan shows remarkable improvement for surface structure.

Poly(methyl methacrylate) in Orthopedics: Strategies, Challenges, and Prospects in Bone Tissue Engineering

Poly(methyl methacrylate) (PMMA) is widely used in orthopedic applications, including bone cement in total joint replacement surgery, bone fillers, and bone substitutes due to its affordability, biocompatibility, and processability. However, the bone regeneration efficiency of PMMA is limited because of its lack of bioactivity, poor osseointegration, and non-degradability. The use of bone cement also has disadvantages such as methyl methacrylate (MMA) release and high exothermic temperature during the polymerization of PMMA, which can cause thermal necrosis. To address these problems, various strategies have been adopted, such as surface modification techniques and the incorporation of various bioactive agents and biopolymers into PMMA. In this review, the physicochemical properties and synthesis methods of PMMA are discussed, with a special focus on the utilization of various PMMA composites in bone tissue engineering. Additionally, the challenges involved in incorporating PMMA into regenerative medicine are discussed with suitable research findings with the intention of providing insightful advice to support its successful clinical applications.

Load, unload and repeat: Understanding the mechanical characteristics of zirconia in dentistry

OBJECTIVES

Zirconia-based dental restorations and implants are gaining attention due to their bioactivity, corrosion resistance and mechanical stability. Further, surface modification of zirconia implants has been performed at the macro-, micro- and nanoscale to augment bioactivity. While zirconia's physical and chemical characteristics have been documented, its relation to mechanical performance still needs to be explored. This extensive review aims to address this knowledge gap.

METHODS

This review critically compares and contrasts the findings from articles published in the domain of 'mechanical stability of zirconia\ in dentistry' based on a literature survey (Web of Science, Medline/PubMed and Scopus databases) and a review of the relevant publications in international peer-reviewed journals. Reviewing the published data, the mechanical properties of zirconia, such as fracture resistance, stress/tension, flexural strength, fatigue, and wear are detailed and discussed to understand the biomechanical compatibility of zirconia with the mechanical performance of modified zirconia in dentistry also explored.

RESULTS

A comprehensive insight into dental zirconia's critical fundamental mechanical characteristics and performance is presented. Further, research challenges and future directions in this domain are recommended.

SIGNIFICANCE

This review extends existing knowledge of zirconia's biomechanical performance and it they can be modulated to design the next generation of zirconia dental restorations and implants to withstand long-term constant loading.

A Toolbox of Bone Consolidation for the Interventional Radiologist

Bone consolidation is increasingly used in the treatment of both benign and malignant bone conditions. Percutaneous vertebroplasty, for example, has been shown to be useful in vertebral compression fractures in the VAPOUR trial which showed its superiority to placebo for pain reduction in the treatment of acute vertebral compressive fractures. Further tools have since been developed, such as kyphoplasty, spinal implants, and even developments in bone cements itself in attempt to improve outcome, such as chemotherapy-loaded cement or cement replacements such as radio-opaque silicon polymer. More importantly, bone fixation and its combination with cement have been increasingly performed to improve outcome. Interventional radiologists must first know the tools available, before they can best plan for their patients. This review article will focus on the tool box available for the modern interventional radiologist.

Cyclic Stability of Locking Plate Augmented with Intramedullary Polymethyl Methacrylate (PMMA) Strut Fixation for Osteoporotic Humeral Fractures: A Biomechanical Study

The locking plate may provide improved fixation in osteoporotic bone; however, it has been reported to fail due to varus collapse or screw perforation of the articular surface, especially in osteoporotic bone with medial cortex comminution. Using bone graft as an intramedullary strut together with plate fixation may result in a stronger construct. However, the drawbacks of bone grafts include limited supply, high cost, and infection risk. PMMA (so-called bone cement) has been widely used for implant fixation due to its good mechanical properties, fabricability, and biocompatibility. The risk of donor-site infection and the drawbacks of allografting may be overcome by considering PMMA struts as alternatives to fibular grafts for humeral intramedullary grafting surgeries. However, the potential effects of intramedullary PMMA strut on the dynamic behaviour of osteoporotic humerus fractures remain unclear. This study aimed to investigate the influence of an intramedullary PMMA strut on the stability of unstable proximal humeral fractures in an osteoporotic synthetic model. Two fixation techniques, a locking plate alone (non-strut group) and the same fixation augmented with an intramedullary PMMA strut (with-strut group), were cyclically tested in 20 artificial humeral models. Axially cyclic testing was performed to 450 N for 10,000 cycles, intercyclic motion, cumulated fragment migration, and residual deformation of the constructs were determined at periodic cyclic intervals, and the groups were compared. Results showed that adding an intramedullary PMMA strut could decrease 1.6 times intercyclic motion, 2 times cumulated fracture gap migration, and 1.8 times residual deformation from non-strut fixation. During cycling, neither screw pull-out, cut-through, nor implant failure was observed in the strut-augmented group. We concluded that the plate-strut mechanism could enhance the cyclic stability of the fixation and minimize the residual displacement of the fragment in treating osteoporotic proximal humeral unstable fractures. The PMMA strut has the potential to substitute donor bone and serve as an intramedullary support when used in combination with locking plate fixation. The intramedullary support with bone cement can be considered a solution in the treatment of osteoporotic proximal humeral fractures, especially when there is medial comminution.

Operative Fixation of a Humeral Shaft Periprosthetic Fracture After IlluminOss: A Case Report

CASE

An 82-year-old man sustained a periprosthetic fracture after IlluminOss photodynamic bone stabilization system (PBSS) stabilization for an impending pathologic fracture. Nonoperative management was unsuccessful, and he subsequently underwent operative fixation, which featured lag screw fixation of the spiral distal humeral shaft fracture and osteotomy followed by plate fixation of the pathologic humeral shaft fracture.

CONCLUSION

This is the first article to report this complication with IlluminOss PBSS stabilization and details regarding revision surgery.

Advancements in poly(methyl Methacrylate) bone cement for enhanced osteoconductivity and mechanical properties in vertebroplasty: A comprehensive review

The evolution of polymethyl methacrylate (PMMA) based bone cement (BC) from plexiglass to a biomaterial has revolutionized the joint and vertebral arthroplasties field. This widely used grouting material possesses exceptional properties for medical applications, including excellent biocompatibility, impressive mechanical strength, and favorable handling characteristics. PMMA-based BC is preferred in challenging conditions such as osteoporotic vertebral compression fractures, scoliosis, vertebral hemangiomas, spinal metastases, and myelomas, where it is crucial in withstanding stress. This review aims to comprehensively analyze the available reports and guide further research toward enhanced formulations of vertebral BC, focusing on its osteoconductive and mechanical properties. Furthermore, the review emphasizes the significant impact of BC's mechanical properties and osteoconductivity on the success and longevity of vertebroplasty procedures.