Polymethylmethacrylate Cement Research Articles

Bone Allograft Pedicle Screw Augmentation: A Biomechanical Study.

We performed a comprehensive cadaveric biomechanical study to compare the fixation strength of primary screws, screws augmented with bone allograft, and screws augmented with polymethylmethacrylate cement. To evaluate a novel technique for screw augmentation using morselized cortico-cancellous bone allograft to fill the widened screw track of failed pedicle screws. To date, there are no known biological methods available for failed pedicle screw augmentation or fixation. Biomechanical tests were performed using 2 different testing modalities to quantify fixation strength including axial screw pullout and progressive cyclic displacement tests. Fifty vertebrae were instrumented with pedicle screws. Our study showed that bone allograft augmentation using the same diameter screw was noninferior to the fixation strength of the initial screw. In the axial pullout test, screws undergoing bone allograft repair failed at 25% lower loads compared with native screws, and screws augmented with cement showed approximately twice as much strength compared with native screws. In the cyclic displacement test, screws fixed with cement resisted loosening the best of all the groups tested. However, screws augmented with bone graft were found to have an equal strength to native screw purchase. our study did not find a correlation with bone mineral density as a predictor for failure in axial pullout or cyclic displacement tests. Bone allograft augmentation for pedicle screw fixation was noninferior to the initial screw purchase in this biomechanical study. This bone allograft technique is a viable option for screw fixation in the revision setting when there is significant bone loss in the screw track.

Quasi-static and dynamic mechanical properties of a linoleic acid-modified, low-modulus bone cement for spinal applications

Background Polymethylmethacrylate (PMMA) bone cement is extensively used in spinal procedures such as vertebroplasty and kyphoplasty, while its use in percutaneous cement discoplasty (PCD) is not yet widely spread. A main issue for both application sites, vertebra and disc, is the mismatch in stiffness between cement and bone, potentially resulting in adjacent vertebral fractures and adjacent segment disease. Tailoring the cement modulus using additives is hence an interesting strategy. However, there is a lack of data on the tensile and tension-compression fatigue properties of these cements, relevant to the newly researched indication of PCD. Method A commercial PMMA cement (VS) was modified with 12%vol of linoleic acid (VSLA) and tested for quasi-static tensile properties. Additionally, tension-compression fatigue testing with amplitudes ranging from +/-5MPa to +/-7MPa and +/-9MPa was performed, and a Weibull three-parameter curve fit was used to calculate the fatigue parameters. Results Quasi-static testing revealed a significant reduction in VSLA’s Young’s Modulus (E=581.1±126.4MPa) compared to the original cement (E=1478.1±202.9MPa). Similarly, the ultimate tensile stress decreased from 36.6±1.5MPa to 11.6±0.8MPa. Thus, VSLA offers improved compatibility with trabecular bone properties. Fatigue testing of VSLA revealed that as the stress amplitude increased the Weibull mean number decreased from 3591 to 272 and 91 cycles, respectively. In contrast, the base VS cement reached run-out at the highest stress amplitude. However, the lowest stress amplitude used exceeds the pressures recorded in the disc in vivo, and VSLA displayed a similar fatigue life range to that of the annulus fibrosis tissue. Conclusions While the relevance of fully reversed tension-compression fatigue testing can be debated for predicting cement performance in certain spinal applications, the results of this study can serve as a benchmark for comparison of low-modulus cements for the spine. Further investigations are necessary to assess the clinical feasibility and effectiveness of these cements.

Enhanced osteogenesis and physicochemical properties of PMMA bone cement with SrBG/HA porous core-shell microspheres

Artificial bone graft with osteoconductivity, angiogenesis, and immunomodulation is promising clinical therapeutics for the reluctant healing process of bone defects. Among various osteogenic substitutes, polymethyl methacrylate (PMMA) bone cement is a quit competitive platform due to its easy deployment to the bone defects with irregular shape and biomimetic mechanical properties. However, the biologically inert essence of PMMA is reliant on the passive osseointegration and cannot provide sufficient biologic cues to induce fast bone repair. Bioactive glass could serve as an efficient platform for the active osteogenesis of PMMA via ionic therapy and construction of alkaline microenvironment. However, the direct of deployment of bioactive glass into PMMA may trigger additional cytotoxicity and hinder cell growth on its surface. Hence we incorporated ionic therapy as osteogenic cue into the PMMA to enhance the biomedical properties. Specifically, we synthesized core-shell microspheres with a strontium-doped bioactive glass (SrBG) core and hydroxyapatite (HA) shell, and then composited them with PMMA to introduce multifunctional effects of HA incorporation, alkaline microenvironment construction, and functional ion release by adding microsphere. We prepared xSrBG@HA/PMMA cements (x = 30, 40, 50) with varied microsphere content and evaluated impacts on mechanical/handling properties, ion release, and investigated the impacts of different composite cements on proliferation, osteogenic differentiation, angiogenic potential, and macrophage polarization. These findings provide new perspectives and methodologies for developing advanced bone biomaterials to promote tissue regeneration.

SOLUBILITY AND BIOMINERALIZATION ABILITY OF PMMA BONE CEMENT NANOCOMPOSITE FILLED WITH 40% NANOHYDROXYAPATITE FOR USE AS ROOT-END FILLING MATERIAL

Aim: This study was conducted to compare and evaluate the solubility and biomineralization ability of polymethyl-methacylate bone cement filled with prepared calcium phosphate based nano-fillers versus mineral trioxide aggregate when used as root end filling material. Materials and Methods: A total of forty two samples were prepared and classified into three main groups(n=14)according to the material type: Group I: white mineral trioxide aggregate, Group II: Polymethyl-methacrylate bone cement and Group III: Polymethyl-methacrylate bone cement loaded with 40% of prepared calcium phosphate based nanofillers. Each material type was mixed and packed into molds. Solubility testing was done following the ISO specification #4049 (2009). For the biomineralization ability testing, each specimen was immersed in 150 ml of simulated body fluid for 21 days. After that, the surface of the cements was analyzed by scanning electron microscope and energy dispersive X-ray analysis with computer-controlled software for elemental analysis. Results: Energy dispersive X-ray analysis results revealed the absence of both calcium and phosphorus elements in polymethyl-methacrylate bone cement samples. On the other hand, both calcium and phosphorus elements were present in the other two tested materials samples. Statistical analysis revealed a statistically significant difference between the tested groups (p<0.05). Regarding solubility, MTA (GroupI) was significantly the lowest having mean value of (0.010g/mm3), while Bone cement with nanofiller (group III) was significantly the highest having mean value (1.009 g/mm3). Conclusion: Within the limitations of the present study, it can be concluded that addition of nanohydroxyapatite to polymethyle-methacrylate bone cement enhanced its biomineralization ability to be capable of apatite formation and on the other hand, it increased its solubility.

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.

The addition of silicon nitride to PMMA bone cements reduces bacterial attachment while supporting preosteoblast viability

Injectable poly (methyl methacrylate) (PMMA) bone cements are widely used in orthopaedics to stabilize fractures and for implant fixation. However, bacterial attachment to bone cements leads to significant complications that can create a need for implant revision. Common attempts at reducing bacterial attachment are through the addition of antibiotics or antibacterial nanometals to the bone cements. However, clinical data is inconclusive on the effectiveness of antibiotic-loaded bone cements and a negative osteoblastic response has been reported for certain additive concentrations. There is therefore a need for an additive that can positively affect osteoblastic behaviour while inhibiting bacterial attachment. Silicon nitride (Si3N4) could be such an additive, with initial studies showing promise in achieving antipathogenic properties. The aim of this study was hence to investigate the possibility of creating a bone cement that can support osteoblast growth while reducing bacterial attachment by introducing silicon nitride powders into an injectable PMMA cement. To this end, commercially available bone cements were doped with 5%, 10% and 20% weight/weight (w/w) of Si3N4. Their mechanical properties were examined through compression testing and their radiopacity was evaluated through fluoroscopy imaging. The samples that fulfilled compressive strength requirements had their biological properties tested using Staphylococcus epidermidis bacteria for antibacterial properties and MC3T3-E1 preosteoblasts for the examination of cytotoxicity. Bone cements that were doped with up to 20% w/w Si3N4 were radiopaque (only 13% reduction in optical density compared to radiopaque controls) and retained their compressive strength (85.35 ± 2.1 MPa compared to 83.4 ± 1.9 MPa for the commercial cements), while significantly reducing bacterial attachment by more than 90% compared to commercial cements and achieving a similar level of preosteoblast metabolic activity. This study supports further evaluation of Si3N4 as an additive to injectable bone cements as a way to create mechanically stable, radiopaque, bacteriostatic bone cements that could improve osteointegration.

Impact of Anti-Mycotic Drugs on the Osteogenic Response of Bone Marrow Mesenchymal Stem Cells In Vitro.

The treatment of fungal bone infections and infected non-unions is a huge challenge in modern trauma and orthopedics, which normally contain the local and systemic administration of anti-fungal drugs. Although frequently used, little is known about the impact of systemic and locally administered fungicides on the osteogenic regenerative capabilities of infected bone tissue, especially upon the osteogenesis of human bone marrow mesenchymal stem cells (BM-hMSCs). This study evaluates the effects of the three most common fungicides for the systemic treatment of bone infections, Voriconazole (VOR), liposomal Amphotericin B (LAMB), and Fluconazole (FLU), as well as the effects of VOR and LAMB-loaded Polymethylmethacrylate (PMMA) cement chips in different concentrations upon the osteogenic response of BM-hMSCs in vitro. Within this study, we compared the ability of BM-hMSC to differentiate into osteoblast-like cells and synthesize hydroxyapatite as assessed by radioactive 99mTechnetium-Hydroxydiphosphonate (99mTc-HDP) labeling, cell proliferation, and analyses of supernatants upon various osteogenic parameters. Our results revealed that VOR added to the cell culture medium affects the osteogenic potential of BM-hMSC negatively, while there were no detectable effects of LAMB and FLU. Moreover, we showed dose-dependent negative effects of high- and extended-dose fungicide-loaded PMMA cement due to cytotoxicity, with a higher cytotoxic potential of VOR than LAMB, while low-dose fungicide-loaded PMMA had no significant effect on the osteogenic potential of BM-hMSC in vitro.

Computed Tomography Volumetry of Bone Cement: Retrospective Blinded Validation of Commercially Available Semi-automated Edge Detection Software

Objective Cement volumes are increasingly linked to orthopedic oncology and neurosurgical outcomes (construct durability, adjacent fracture), but manual cement volumetry remains time prohibitive. The authors aim to report performance of PACS-integrated volumetric software specifically for barium-enhanced polymethylmethacrylate cement. Methods Institutional review board–approved single-institution retrospective review of patients from 2019–2022 undergoing kyphoplasty for pathological compression fractures with a quantitative cement infuser providing true cement volume. An operator blinded to true cement volumes retrospectively performed software-assisted volumetry on follow-up computed tomography scans. Results Included were 91 kyphoplasty levels in 56 patients: mean age, 62 years (range, 34–85 years), 73% female. True cement volume (available for 44 of 66 procedures) was mean 4.5 mL per level (range, 1.2–15.6 mL). Measured cement volume (available for all procedures) yielded a mean of 6.1 mL per level (range, 1.5–27.9 mL). For the 57 levels (39 patients) where both true and measured cement volumes were available, linear regression intercept and slope were 1.46 (95% CI = 0.97–1.95, P < 0.001) and 0.52 (CI = 0.47–0.57, P < 0.001), respectively, suggesting measured volume averaged 1.46 mL greater than true volume, with each additional milliliter of measured volume corresponding to approximately 0.52 mL of true volume. There was no significant difference in the relationship between estimated and actual cement volume in thoracic levels (intercept = −0.24, CI = −1.13 to 0.66, P = 0.61; slope = 0.03, CI = −0.14 to 0.19, P = 0.73) compared with lumbar levels. The goodness-of-fit of the regression model was strong (R 2 = 0.81). Discrepancies ranged from 90% underestimation to 52% overestimation; average, 17% overestimation. Conclusions Semi-automated volumetry maintained a strong correlation with true volumes across the thoracic and lumbar curvatures, overestimating cement volume by a mean of 17% or 1.46 mL.

Paravertebral Nerve Block for Procedural Pain in Percutaneous Vertebroplasty.

This study aimed to unidimensionally measure procedural pain at each percutaneous vertebroplasty (PVP) stage and evaluate the effectiveness of paravertebral nerve block (PVNB) in reducing procedural pain. A retrospective study of prospectively collected data was conducted on 66 patients who underwent PVP for osteoporotic vertebral compression fractures. The patients were divided into 2 groups: group A (fluoroscopic-guided PVNB; 5 cm 3 of 0.75% ropivacaine on each side) and group B (local anesthesia). To investigate procedural pain associated with PVP, the visual analog scale score was assessed at each surgical stage: before the incision (stage 1), transpedicular approach (stage 2), and polymethylmethacrylate cement injection (stage 3). After the procedure, patients were asked about their surgical experience and satisfaction using the Iowa Satisfaction with Anesthesia Scale. Periprocedural complications were also recorded. A total of 63 patients (78.65 y of age) were finally enrolled: 30 from group A and 33 from group B. In both groups, a significant ≥2-point increase in procedural pain was observed during PVP compared with that during stage 1 ( P < 0.001). In stages 2 and 3, the pain intensity was significantly lower in group A ( P < 0.001). Upon discharge, the visual analog scale score improved in all groups; however, the Iowa Satisfaction with Anesthesia Scale score was significantly higher in group A ( P < 0.001). There was no difference in periprocedural complications between the two groups ( P = 0.743). PVP causes significant procedural pain, and PVNB is a potentially effective modality for enhancing patient satisfaction and reducing procedural pain.

Trends in Vertebral Augmentation Practice for Osteoporotic Vertebral Fracture

Osteoporosis is characterized by low bone mass, primarily affecting older individuals and a common complication is vertebral fractures. The collapse-induced height loss in vertebrae can result in spinal instability and progressive kyphotic deformity. Surgical intervention for osteoporotic vertebrae poses challenges due to poor bone quality and frequent medical comorbidities. In recent years, it has become the predominant method for vertebral augmentation in acute fractures, aiming to relieve pain, strengthen the vertebral structure, and prevent deformities by restoring height. These procedures involve percutaneous placement of cannulas into each collapsed vertebral body through a unipedicular or bipedicular approach.&#x0D; Novel products are emerging to strengthen vertebrae in treating osteoporotic compression fractures. Balloon kyphoplasty and vertebroplasty are widely accepted and recognized as effective vertebral augmentation methods. Treatment guidelines are evolving with the introduction of innovative systems like Vertebral Body Stenting, Titanium Mesh, and Sky Bone Expander, claiming to achieve exceptional vertebral height restoration. Controversies persist regarding the optimal timing for vertebral augmentation post-fracture.&#x0D; Polymethylmethacrylate cement is extensively used to stabilize fractured vertebral bodies. Additionally, new calcium phosphate-based nanocomposite cements are gaining prominence. These advancements underscore the ongoing development in the treatment of osteoporotic vertebral compression fractures. Each innovative implant introduces unique features and indications. Precise confirmation of the source of the painful fracture is crucial for effective and safe treatment, ensuring proper timing and indication.

Standalone Percutaneous Vertebroplasty for Hyperextension Injuries of the Ankylosed Thoracolumbar Spinal Kyphosis.

Hyperextension injuries of the ankylosed thoracolumbar spine, particularly those with preexisting kyphotic deformity, present significant therapeutic challenges. The authors viewed that such injuries without displacement or fractures of the posterior elements are reasonable candidates for standalone percutaneous vertebroplasty (PVP). In such cases, the posterior tension band is spared; thus, fractures are unstable not in the lateral direction, which would lead to the translation of the fracture, but in the vertical direction. Such vertical instability of the fracture can be stabilized if the open mouth-type vertebral cleft is adequately filled with a sufficiently large amount of polymethylmethacrylate (PMMA) cement. Our three patients receiving standalone PVP received injections of 12 mL, 16.5 mL, and 18 mL of PMMA cement. This minimally invasive surgical procedure achieved both short-term (immediate pain relief and mobilization) and long-term (fracture healing) goals.

Octacalcium phosphate phase forming cements as an injectable bone substitute materials: Preparation and in vitro structural study

In the realm of regenerating damaged or degenerated bones through minimally invasive techniques, injectable materials have emerged as exceptionally promising. Among these, calcium phosphate bone cements (CPCs) have garnered significant interest due to their remarkable bioactivity, setting it apart from non-degradable alternatives such as polymethyl methacrylate cements. α-Tricalcium phosphate (α-TCP) is a widely used solid phase component in CPCs. It can transform into calcium-deficient hydroxyapatite (CDHAp) when it comes in contact with water. In this study, we aimed to create an injectable, self-setting bone cement using low-temperature synthesized α-TCP powder as a single precursor of the powder phase. We found that changes in the pH of the liquid phase (pH 6.0, pH 6.2, pH 7.0 and pH 7.4) significantly altered the cement's setting, handling, and mechanical properties. The formation of the octacalcium phosphate (OCP) phase was identified in our study, which positively affects the osteoblastic cell response. Hardened OCP-forming bone cements prepared using a liquid phase with pH 7.0 and 7.4 showed better osteogenic cell attachment and proliferation than those prepared with pH 6.0 and 6.2. Our study suggests that changes in the pH of the liquid phase can significantly affect the properties of α-TCP-based bone cement, and the presence of the OCP phase is crucial for optimal cement performance.

Development of modified PMMA cement in spine surgery

Development of modified PMMA cement in spine surgery

Quasi-static and dynamic mechanical properties of a low-modulus bone cement for spinal applications

Background Polymethylmethacrylate (PMMA) bone cement is extensively used in spinal procedures such as vertebroplasty and kyphoplasty, while its use in percutaneous cement discoplasty (PCD) is not yet widely spread. A main issue for both application sites, vertebra and disc, is the mismatch in stiffness between cement and bone, potentially resulting in adjacent vertebral fractures and adjacent segment disease. Tailoring the cement modulus using additives is hence an interesting strategy. However, there is a lack of data on the tensile and tension-compression fatigue properties of these cements, relevant to the newly researched indication of PCD. Method A commercial PMMA cement (VS) was modified with 12%vol of linoleic acid (VSLA) and tested for quasi-static tensile properties. Additionally, tension-compression fatigue testing with amplitudes ranging from +/-5MPa to +/-7MPa and +/-9MPa was performed, and a Weibull three-parameter curve fit was used to calculate the fatigue parameters. Results Quasi-static testing revealed a significant reduction in VSLA’s Young’s Modulus (E=581.1±126.4MPa) compared to the original cement (E=1478.1±202.9MPa). Similarly, the ultimate tensile stress decreased from 36.6±1.5MPa to 11.6±0.8MPa. Thus, VSLA offers improved compatibility with trabecular bone properties. Fatigue testing of VSLA revealed that as the stress amplitude increased the Weibull mean number decreased from 3591 to 272 and 91 cycles, respectively. In contrast, the base VS cement reached run-out at the highest stress amplitude. However, the lowest stress amplitude used exceeds the pressures recorded in the disc in vivo, and VSLA displayed a similar fatigue life range to that of the annulus fibrosis tissue. Conclusions While the relevance of fully reversed tension-compression fatigue testing can be debated for predicting cement performance in certain spinal applications, the results of this study can serve as a benchmark for comparison of low-modulus cements for the spine. Further investigations are necessary to assess the clinical feasibility and effectiveness of these cements.

Mechanically stable rifampin antibiotic cement inhibits Pseudomonas aeruginosa biofilm surface growth.

Rifampin has been proven to be effective in the treatment of prosthetic infections due to its ability to intercalate into biofilms. The use of rifampin in antibiotic spacers is not well described, which would be especially important in the local periprosthetic environment where parenteral doses have poor penetration. The null hypothesis tests if rifampin use in polymethyl methacrylate (PMMA) cement will show no clinically significant impact on mechanical strength at antibiotic concentrations that remain bactericidal. Test antibiotic cement samples supplemented with 0, 30, 50, 100, 150, or 200 mg of rifampin into a standard 40 g bag were tested for compression to failure using published ASTM standards. The samples were then inoculated with Pseudomonas aeruginosa and either evaluated for lipopolysaccharide (LPS) presence as a marker of biofilm or tested by elution as the Kirby Bauer assay. Rifampin concentrations of 30 and 50 mg, showed no statistically different mechanical characteristics from control PMMA (p > 0.05). The 100-mg sample fell within the acceptable range of compressive strength and had significantly less LPS and bacterial presence compared to the control at 12 and 24 h. The ability of PMMA with 100 mg of rifampin to maintain its structural integrity and have significant bacterial inhibition at 12 and 24 h makes it a great candidate as an antibiotic bone cement additive. PMMA loaded with up to 100 mg of rifampin shows promise in the treatment and prevention of periprosthetic joint infection for total knee and total hip arthroplasty.

Masquelet Technique for Reconstruction of a Fourth Metatarsal Defect Following a Low-velocity Gunshot Wound: A Case Report

The Masquelet technique has become increasingly popular in reconstruction scenarios such as osteomyelitis, cancer, and nonunions. The procedure is a two-staged approach: first, a polymethylmethacrylate (PMMA) cement spacer is inserted to fill a bone void. The spacer induces a membrane to form around it, and 6-9 weeks later, the second stage involves carefully extracting the spacer and filling the membrane with bone graft. Most of the current literature has published either femoral or tibial involvement for Masquelet studies, with limited published data on foot reconstruction. Here, the authors used the procedure for the fourth metatarsal. Despite complications, this case proves a more excellent utility and warrants further investigation into Masquelet techniques in the foot.

Proliferation and differentiation of MC3T3-E1 cells on polymethyl methacrylate cements containing Fe3O4 and TiO2 for hyperthermic treatment of metastatic bone tumors.

Polymethyl methacrylate (PMMA) bone cement is widely used to relieve pain caused by metastatic bone tumors. We previously found that PMMA bone cement containing 15 mass% or more of TiO2 showed good apatite-forming ability, and 25 mass% or more of Fe3O4 generated sufficient heat for hyperthermia under an alternating current (AC) magnetic field. In this study, the cytocompatibility of PMMA bone cement with Fe3O4:TiO2 weight ratios of 25:15 (F25T15-3/2-42) and 30:15 (F30T15-3/2-42) was evaluated using osteoblastic cells (MC3T3-E1). The proliferation and differentiation of MC3T3-E1 cells were suppressed for F25T15-3/2-42 and F30T15-3/2-42 compared to PMMA bone cement without Fe3O4 and TiO2 (F0T0-3/2-42). The release of methyl methacrylate (MMA) monomers from F25T15-3/2-42 and F30T15-3/2-42 at 7days was about 33 and 50times higher than that from F0T0-3/2-42, respectively. The remarkable release of MMA monomers from F25T15-3/2-42 and F30T15-3/2-42 may be responsible for the suppressed proliferation and differentiation of MC3T3-E1 cells. The release of MMA monomers was not reduced when the MMA/PMMA weight ratio was decreased from 3/2 to 1/1, however, it was significantly reduced by increasing the content of benzoyl peroxide (BPO) and N, N-dimethyl-p-toluidine (DMPT) to 8 and 4 mass% against MMA, respectively. Proliferation and differentiation of MC3T3-E1 cells on PMMA-type cements containing Fe3O4 and TiO2 with increased BPO and DMPT contents need to be investigated in the future; however, our findings will be useful for designing PMMA cements for the hyperthermic treatment of metastatic bone tumors.

Daptomycin-Impregnated PMMA Cement against Vancomycin-Resistant Germs: Dosage, Handling, Elution, Mechanical Stability, and Effectiveness.

The number of periprosthetic joint infections caused by vancomycin-resistant pathogens is increasing. Currently, no PMMA cement is commercially available to cover VRE. Daptomycin shows promising results in treating infection, offering a good safety profile and a reduced risk of developing resistance. The purpose of this in vitro study was to investigate the mechanical stability, handling properties, elution behavior, and antimicrobial effectiveness of PMMA cement loaded with three different daptomycin concentrations in comparison to commercially available antibiotic-loaded bone cement (ALBC). Mechanical properties and handling characteristics (ISO 5833, DIN 53435), HPLC elution, antimicrobial effectiveness with proliferation assay (DIN 17025), and inhibition zone testing were investigated. All tested daptomycin concentrations met the ISO and DIN standards for mechanical strength. Loading of 40 g of PMMA cement with 0.5 g of daptomycin did not show any antimicrobial effectiveness, in contrast to 1.0 g and 1.5 g. PMMA cement with 1.5 g of daptomycin was the best in terms of elution and effectiveness, and it showed good ISO mechanical strength; ISO doughing was sticky for a little longer and setting was faster compared to the vancomycin-containing reference cement. PMMA cement containing 0.5 g of gentamicin and 1.5 g of daptomycin could be a good alternative to the already established COPAL® (Wehrheim, Germany) G+V for the treatment of PJIs caused by VRE.

Calcaneoplasty with radiofrequency cementing following balloon reduction

The standard surgical procedure for complex calcaneal fractures is open reduction, internal reduction and internal stable angle plate osteosynthesis via alateral approach. More recently, options for minimally invasive and percutaneous surgical strategies have been presented [4, 7]. As a possible procedural alternative for acovered, surgical treatment of calcaneal fractures, calcaneoplasty is discussed and applied in this context [5]. In this case series of five complex calcaneal fractures presented here, aballoon catheter was used for percutaneous reduction to restore the alignment of the calcaneus.This was followed by placement of PMMA cement in radiofrequency application and osteosynthesis using percutaneous cannulated screws. This Vicenti technique allows stable reduction and retention with early partial weight bearing with an overall low complication rate [17].

Management of segmental defects post open distal femur fracture using a titanium cage combined with the Masquelet technique A single-centre report of 23 cases

IntroductionThe segmental bone defects post open distal femur fracture presents a reconstructive challenge, which often requires extreme solutions. The present study reviewed a new treatment strategy which used a cylindrical titanium mesh cage as an adjunct to the Masquelet technique. MethodsWe retrospectively reviewed a consecutive series of 23 patients treated for segmental bone defects post open distal femur fracture using a titanium mesh cage combined with the Masquelet technique under a 2-staged protocol in our institution from 2017 to 2021. The study group consisted of 13 men and 10 women with an average age of 44.1 years. The surgical debridement was performed with antibiotic polymethylmethacrylate (PMMA) cement spacer implanted into the bone defect combined with cement-wrapped plate stabilization, or antibiotic beads with vacuum sealing drainage (VSD) to cover the wound. The second stage of the Masquelet technique for bone defect repair began at least 4–6 weeks after the first stage, once all signs of possible infection were eliminated. After the cement spacer was removed, the definitive reconstruction was completed with exchange to a cylindrical titanium mesh cage filled with cancellous autograft within the induced membrane. The bone defect with cage was stabilized with a distal femoral Less Invasive Stabilization System (LISS). The radiological and clinical records of the enrolled patients were retrospectively analyzed. ResultsThe mean follow-up was 38.6 months. The average number of operations before the second stage was 1.3. The mean interval between the two stages was 12.7 weeks. The average length of the defect measured 8.3 cm (ranging from 6.1 to 12.4 cm). All the defects filled with autograft within the cage achieved bony union, with a mean healing time of 8.4 months. At the latest follow-up, the mean knee extension measured 6.2° (ranging from 0° to 20°), and the mean flexion measured 101.8° (ranging from 60° to 120°). Complications included two instances of superficial stitch abscess, which eventually healed. ConclusionsThe use of a titanium cage implanted into an induced membrane in a 2-staged Masquelet protocol could achieve satisfactory clinical outcomes in cases of segmental defects following open distal femur fractures.