Management of infection following reconstruction in bone tumors

Risk factors for peri-megaprosthetic joint infections in tumor surgery: A systematic review

BACKGROUND

Peri-megaprosthetic joint infections (PJI) in tumor surgery are complex and challenging complications that significantly impact the outcomes of the patients. The occurrence of PJI poses a substantial threat to the success of these operations. This review aims to identify and summarize the risk factors associated with PJI in tumor surgery with megaprosthetic reconstruction as well as to determine the overall risk of PJI in limb salvage surgery.

METHODS

A thorough examination of published literature, scrutinizing the incidence of PJI in tumor prostheses after limb salvage surgery was done. Research studies that documented the incidence of PJI in tumor patients who underwent limb salvage surgery, and explored the risk factors associated with the occurrence of PJI were deemed eligible.

RESULTS

A total of 15 studies were included in the analysis and underwent comprehensive examination. After the exploration of key parameters, several significant risk factors for PJI concerning the type of implant coating, surgical site characteristics, patient demographics, and procedural factors were recorded.

DISCUSSION

The findings underscore the need for a nuanced approach in managing tumor patients undergoing limb salvage surgery and megaprosthetic reconstruction, with emphasis on individualized risk assessments and individualized preventive strategies.

Strontium and Zinc Co-Doped Mesoporous Bioactive Glass Nanoparticles for Potential Use in Bone Tissue Engineering Applications

Mesoporous bioactive glass nanoparticles (MBGNs) have attracted significant attention as multifunctional nanocarriers for various applications in both hard and soft tissue engineering. In this study, multifunctional strontium (Sr)- and zinc (Zn)-containing MBGNs were successfully synthesized via the microemulsion-assisted sol-gel method combined with a cationic surfactant (cetyltrimethylammonium bromide, CTAB). Sr-MBGNs, Zn-MBGNs, and Sr-Zn-MBGNs exhibited spherical shapes in the nanoscale range of 100 ± 20 nm with a mesoporous structure. Sr and Zn were co-substituted in MBGNs (60SiO2-40CaO) to induce osteogenic potential and antibacterial properties without altering their size, morphology, negative surface charge, amorphous nature, mesoporous structure, and pore size. The synthesized MBGNs facilitated bioactivity by promoting the formation of an apatite-like layer on the surface of the particles after immersion in Simulated Body Fluid (SBF). The effect of the particles on the metabolic activity of human mesenchymal stem cells was concentration-dependent. The hMSCs exposed to Sr-MBGNs, Zn-MBGNs, and Sr-Zn-MBGNs at 200 μg/mL enhanced calcium deposition and osteogenic differentiation without osteogenic supplements. Moreover, the cellular uptake and internalization of Sr-MBGNs, Zn-MBGNs, and Sr-Zn-MBGNs in hMSCs were observed. These novel particles, which exhibited multiple functionalities, including promoting bone regeneration, delivering therapeutic ions intracellularly, and inhibiting the growth of Staphylococcus aureus and Escherichia coli, are potential nanocarriers for bone regeneration applications.

Evaluation of Absolute Neutrophil Count in the Perioperative Setting of Sarcoma Resection

Introduction

Limb salvage surgery (LSS) is the preferred surgical treatment for bone sarcomas. Preoperatively, many patients receive chemotherapy and may develop neutropenia. No study has evaluated the effect of a low preoperative absolute neutrophil count (ANC) on postoperative outcomes following LSS.

Methods

This was a retrospective review of 114 patients who underwent LSS for bone sarcoma from 2010 to 2020. Preoperative lab values were analyzed by logistic regression to identify the risk of developing surgical complications within 30 days, surgical site infection (SSI), and reoperation.

Results

Three (2.6%) patients experienced a surgical complication within 30 days. Twelve (10.53%) patients experienced postoperative SSI. Twenty-nine (25.4%) required reoperation. Preoperative ANC was not a significant predictor of surgical complications within 30 days, SSI, or reoperation. The only independent predictor of worse overall survival was the presence of a pathologic fracture at the time of surgery.

Conclusion

This is the first study to evaluate preoperative ANC on postoperative outcomes following LSS. We report no significant differences in surgical complications within 30 days, SSI, or reoperation with low preoperative ANC. Future studies with larger cohorts of neutropenic patients are needed to evaluate these outcomes, as our cohort had very few neutropenic patients due to selection bias.

The Intraoperative Use of Defensive Antibacterial Coating (DAC®) in the Form of a Gel to Prevent Peri-Implant Infections in Orthopaedic Surgery: A Clinical Narrative Review

Periprosthetic joint infections (PJIs) in arthroplasty and osteosynthesis-associated infections (OAIs) in reconstructive surgery still represent a challenging complication in orthopaedics and traumatology causing a burden worsening the patient's quality of life, for caregiver and treating physicians, and for healthcare systems. PJIs and OAIs are the result of bacterial adhesion over an implant surface with subsequent biofilm formation. Therefore, the clinical pathological outcome is a difficult-to-eradicate persistent infection. Strategies to treat PJIs and OAIs involve debridement, the replacement of internal fixators or articular prostheses, and intravenous antibiotics. However, long treatments and surgical revision cause discomfort for patients; hence, the prevention of PJIs and OAIs represents a higher priority than treatment. Local antibiotic treatments through coating-release systems are becoming a smart approach to prevent this complication. Hydrophilic coatings, loaded with antibiotics, simultaneously provide a barrier effect against bacterial adhesion and allow for the local delivery of an antibiotic. The intraoperative use of a hyaluronan (HY)-derivative coating in the form of a gel, loaded with antibiotics to prevent PJI, has recently raised interest in orthopaedics. Current evidence supports the use of this coating in the prophylaxis of PJI and IRIs in terms of clinical outcomes and infection reduction. Thus, the purpose of this narrative review is to assess the use of a commercially available HY derivative in the form of a gel, highlighting the characteristics of this biomaterial, which makes it attractive for the management of PJIs and IRIs in orthopaedics and traumatology.

Staged Management of Infection with Adjustable Spacers After Megaprosthesis Implantation in Primary Sarcoma Patients

Background

While periprosthetic joint infection has always been a significant concern for orthopaedic surgeons, the rate of infection is five to ten times higher after tumor prosthesis implantation. With the growing use of mega-implants, the number of these infections has also increased. We aimed to investigate the results of our patients with a primary malignant musculoskeletal tumor, who underwent two-stage revision surgery for an infected mega-prosthesis. We also presented the emerging complicatons and required soft tissue reconstruction procedures.

Methods

The study included 32 primary bone and soft tissue sarcoma patients who underwent a two-stage revision procedure for infection. After a rigorous bone and soft tissue debridement procedure at the first stage, antibiotic-loaded bone cement was wrapped around a cloverleaf type intramedullary nail and inserted into the forming gap. After a minimum of 6 weeks of antibiotic therapy, depending on patients' clinical signs and serum infection markers, the reimplantation stage was undertaken.

Results

The mean oncologic follow-up period was 28 months (range 5-96 months). During this period, 11 patients died because of non-infection related causes, 12 patients were alive with their disease, whereas 9 patients were totally free of their oncologic condition. The infection was eradicated in all survivors except one patient, where a high-level transfemoral amputation became necessary.

Conclusion

Periprosthetic infection after tumor proshesis implantation in cancer patients can be managed with same principles as conventional arthroplaty procedures, taking care that they are immunocompromised and vulnerable patients and their bone stock loss is significant which makes surgical options more challenging.

Iodine-supported implants in prevention and treatment of surgical site infections for compromised hosts: a prospective study

BACKGROUND

Surgical site infection (SSI) is a common complication following orthopedic implantation. We developed an iodine coating for titanium implants to reduce implant-related infections and conducted a prospective clinical study to evaluate the efficacy and potential drawbacks of iodine-supported implants.

PATIENTS AND METHODS

Between July 2008 and July 2017, 653 patients (377 male and 27 female patients; mean age, 48.6) with postoperative infection or a compromised status were treated using iodine-loaded titanium implants. The mean follow-up period was 41.7 months. In 477 patients, iodine-supported implants were used to prevent infection and in 176 patients, to treat active infection (one-stage surgery, 89 patients; two-stage surgery, 87 patients). In the limbs and pelvis, the primary diagnoses included the following: 161 tumors, 92 deformities/shortening, 47 pseudarthrosis, 42 fractures, 32 infected TKA, 25 osteoarthritis, 21 pyogenic arthritis, 20 infected THA, and 6 osteomyelitis. In the spinal cases, there were 136 cases of tumors, 36 cases of pyogenic spondylitis, and 35 cases of degeneration. Five modes of implant failure were identified and classified as follows: soft tissue failure (type 1), aseptic loosening (type 2), structural failure (type 3), infection (type 4), and tumor progression (type 5).

RESULTS

The overall failure rate in our series was 26.3% (172/653). There were 101 mechanical failures, including 22 type 1, 20 type 2, and 59 type 3 failures. Non-mechanical causes accounted for 71 failures, including 45 type 4 and 26 type 5 failures. The overall incidence of infections was 6.8%. The mean time to the onset of infection after implantation was 9.1 months. The overall infection rate was 3.7% in the prevention cases and 15.3% in the treatment cases. There was no difference between one-stage replacement (14.6%) and two-stage replacement (16.0%). There were 11 cases of treatment for SSI of spine surgery, and the re-infection rate was 0% using iodine-coated instruments.

CONCLUSIONS

The five modes of failure of the iodine-supported implant were satisfactory compared with previous reports. In particular, because the infection rate of iodine-coated implants used for compromised hosts is low compared with other methods, postoperative infection is more easily controlled. It can be considered highly effective for spinal infections that require one-stage revision surgery.

LEVEL OF EVIDENCE IV

Trial registration Prospective, Observation study.

Multifunctional Zn and Ag co-doped bioactive glass nanoparticles for bone therapeutic and regeneration

Bone cancer has traditionally been treated using surgery, radiotherapy, and/or chemotherapy. The nonspecific distribution of chemotherapy and implantable infections are significant risk factors for the failure of the bone to heal. Multifunctional zinc and silver co-doped bioactive glass nanoparticles (yAg-xZn-BGNPs) with a diameter of 150 ± 30 nm were successfully synthesized using modified sol-gel and two-step post-functionalization processes, tailored to provide antibacterial and anticancer activity whilst maintaining osteogenesis ability. Co-doped BGNPs with Zn and Ag did not significantly alter physicochemical properties, including size, morphology, glass network, and amorphous nature. Apatite-like layer was observed on the surface of yAg-xZn-BGNPs and resorbed in the simulated body fluid solution, which could increase their bioactivity. Human fetal osteoblast cell line (hFOB 1.19) treated with particles showed calcified tissue formation and alkaline phosphatase activity in the absence of osteogenic supplements in vitro, especially with 0.5Ag-1Zn-BGNPs. Moreover, these particles preferentially disrupted the metabolic activity of bone cancer cells (MG-63) and had an antibacterial effect against B. subtilis, E. coli, and S. aureus via the disc diffusion method. This novel 0.5Ag-1Zn-BGNP and 1Ag-1Zn-BGNPs, with wide-ranging ability to stimulate bone regeneration, to inhibit bone cancer cell proliferation, and to prevent bacterial growth properties, may provide a feasible strategy for bone cancer treatment. The 0.5Ag-1Zn-BGNPs and 1Ag-1Zn-BGNPs can be applied for the preparation of scaffolds or filler composites using in bone tissue engineering.

Infections of Tumor Prostheses: An Updated Review on Risk Factors, Microbiology, Diagnosis, and Treatment Strategies

Several causes contribute to the high infection rate in tumor prostheses, including extensive tissue dissection and patients' immunosuppression due to the neoplastic disease. Most of these infections develop within the first 2 years following surgery with 70% of them occurring during the first year, while they are often associated with a low pathogen burden. The pathogenesis of infections in tumor prostheses is linked to bacteria developing in biofilms. Approximately half of them are caused by Staphylococcus spp., followed by Streptococcus spp., Enterococcus spp., and Enterobacteriaceae spp., while multiple pathogens may be isolated in up to 25% of the cases, with coagulase-negative Staphylococci (CoNS) and Enterococccus spp. being the most frequent pair. Although early detection and timely management are essential for complete resolution of these challenging infections, prompt diagnosis is problematic due to the highly varying clinical symptoms and the lack of specific preoperative and intraoperative diagnostic tests. Surgical management with one- or two-stage revision surgery is the mainstay for successful eradication of these infections. The recent advances in laboratory diagnostics and the development of biofilm-resistant prostheses over the past years have been areas of great interest, as research is now focused on prevention strategies. The aim of this study is to review and consolidate the current knowledge regarding the epidemiology, risk factors, microbiology, and diagnosis of infections of tumor prostheses, and to review the current concepts for their treatment and outcomes.

Novel reconstruction method by mega-prosthesis wrapped with vancomycin-containing cement after resection of malignancies

To introduce wrapping vancomycin-containing cement around a mega-prosthesis (MP) as a novel method to prevent prosthetic joint infection after reconstruction surgery for malignant bone and soft tissue tumors. Five patients with malignant bone and soft tissue tumors treated at our hospital from April 2009 to December 2019 were included. The average age was 71.4 years. Four males and one female were included. Three patients had a bone tumor, and two had a soft tissue tumor. Three right thighs and two left femurs were affected. These tumors were identified histologically as undifferentiated pleomorphic sarcoma, spindle cell sarcoma, diffuse large cell B-cell lymphoma, metastasis of renal cancer, and metastasis of lung cancer. All patients underwent tumor resection and reconstruction with a MP. In all cases, vancomycin-containing cement (2 g/40 g) was wrapped around the implant at the extension. The average follow-up period was 30.4 months. We surveyed whether infection occurred after surgical treatment. We also investigated the Musculoskeletal Tumor Society score and clinical outcome. We observed no postoperative infection. One case of local recurrence was observed, and a hip dissection was performed. The Musculoskeletal Tumor Society score was 79.26 ± 1.26 (mean ± standard deviation) (range: 76-80.3). Three patients remained disease-free, one survived but with disease, and one died of disease. Wrapping vancomycin-containing cement around the MP may be a useful method of preventing postoperative joint infections.

Treatment of Periprosthetic Joint Infection and Fracture-Related Infection With a Temporary Arthrodesis Made by PMMA-Coated Intramedullary Nails – Evaluation of Technique and Quality of Life in Implant-Free Interval

Background

Antimicrobial coating of intramedullary nails with polymethyl methacrylate (PMMA) bone cement promises infection control and stabilization for subsequent bone healing. However, when removing the implant, bone cement can debond and remain in the medullary cavity of the long bones, representing a nidus for reinfection. This work presents a technique comprising reinforcement of PMMA-coated intramedullary nails with cerclage wire to prevent such problems in patients treated for fracture-related infection (FRI) or knee periprosthetic joint infection (PJI) with a static spacer as temporary arthrodesis allowing weight-bearing in the implant-free interval. Outcomes of this surgical treatment were evaluated in terms of (i) associated complications and (ii) patient-reported quality of life.

Methods

In this retrospective case series, 20 patients with PJI (n = 14, 70%) and FRI (n = 6, 30%) treated with PMMA-coated intramedullary nails reinforced with cerclage wire between January 2021 and July 2021 were included. Quality of life during the implant-free interval was evaluated with the EQ-5D, SF-36, and an ICD-10 based psychological symptom rating and compared with previously analyzed cohorts of successfully treated PJI and FRI patients in whom eradication of infection and stable bone consolidation was achieved.

Results

Complications during the implant-free interval comprised a broken nail in one case (5.0%) and a reinfection in one case (5.0%). Coating-specific side effects and cement debonding during removal did not occur. The mean physical health component score of SF-36 was 26.1 ± 7.6, and the mean mental health component score reached a value of 47.1 ± 18.6. The mean EQ-5D index value was 0.36 ± 0.32 and the mean EQ-5D visual analogue scale rating was 47.4 ± 19.4. The scores were significantly lower than those in the successfully treated FRI cohort but not in the PJI cohort. The mean ICD-10-based symptom rating scores revealed psychological symptom burden on the depression scale and enhanced levels of anxiety in comparison with healed FRI and PJI patients.

Conclusion

Reinforcement of PMMA bone cement-coated implants seems to be a reasonable treatment option to create a temporary arthrodesis, preventing detachment of the bone cement when the implant was removed.

Level of Evidence: IV.

Biodegradable Bone Implants as a New Hope to Reduce Device-Associated Infections-A Systematic Review

Bone fractures often require fixation devices that frequently need to be surgically removed. These temporary implants and procedures leave the patient more prone to developing medical device-associated infections, and osteomyelitis associated with trauma is a challenging complication for orthopedists. In recent years, biodegradable materials have gained great importance as temporary medical implant devices, avoiding removal surgery. The purpose of this systematic review was to revise the literature regarding the use of biodegradable bone implants in fracture healing and its impact on the reduction of implant-associated infections. The systematic review followed the PRISMA guidelines and was conducted by searching published studies regarding the in vivo use of biodegradable bone fixation implants and its antibacterial activity. From a total of 667 references, 23 studies were included based on inclusion and exclusion criteria. Biodegradable orthopedic implants of Mg-Cu, Mg-Zn, and Zn-Ag have shown antibacterial activity, especially in reducing infection burden by MRSA strains in vivo osteomyelitis models. Their ability to prevent and tackle implant-associated infections and to gradually degrade inside the body reduces the need for a second surgery for implant removal, with expectable gains regarding patients' comfort. Further in vivo studies are mandatory to evaluate the efficiency of these antibacterial biodegradable materials.

Endoprosthetic Reconstruction in Ewing's Sarcoma Patients: A Systematic Review of Postoperative Complications and Functional Outcomes

Ewing's sarcoma (ES) is a rare primary bone cancer managed by radiotherapy, chemotherapy and surgical resection. The existing literature on limb salvage surgery with endoprostheses combines data for ES patients with osteosarcoma. This review aimed to evaluate surgical and functional outcomes of endoprosthetic reconstruction in exclusively Ewing's patients. We believe that this is the first comprehensive review to evaluate the outcomes of limb salvage surgery with endoprostheses exclusively in Ewing's sarcoma patients. Clinical data and outcomes were collected from PubMed, Embase, Medline and Scopus. The inclusion criteria were studies on limb salvage surgery in ES patients, where individual patient data was available. Seventeen studies with a total of 57 Ewing's patients were included in this review. Fifty-three of the ES patients preserved the limb after limb salvage with endoprostheses. The average five-year implant survivorship was 85.9% based on four studies in this review. Postoperative complications were categorised by Henderson's failure modes. Soft tissue failure was the most common, occurring in 35.1% of patients, followed by deep infection in 15.7% of patients. There was a suggestion of 'good' functional outcomes with limb salvage surgery. The salient limitation of this review is the variability and rarity of the patient population. Homogenous data in a larger population is necessary to provide more insight into outcomes of limb reconstruction in ES.

The Use of Megaprostheses in Nononcologic Lower-Extremity Total Joint Arthroplasty: A Critical Analysis Review

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As the number of primary total joint arthroplasty (TJA) procedures continues to rise, megaprostheses have found an emerging role in more complex revision arthroplasty cases that require additional reconstruction, stability, and restoration of function.

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Megaprosthesis options have evolved: in addition to cemented prostheses, cementless and even hybrid fixation designs optimize longevity. Proximal femoral replacement (PFR), distal femoral replacement (DFR), proximal tibial replacement (PTR), and total femoral replacement (TFR) are all limb salvage options in the setting of substantial bone loss, poor bone quality, and soft-tissue compromise.

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Dislocation is one of the most common complications after PFR, likely due to the loss of soft-tissue integrity, most notably the hip abductor musculature from the greater trochanter. The utilization of dual-mobility constructs, larger femoral heads, elevated acetabular liners, and constrained acetabular liners may reduce the risk of instability and improve overall hip function.

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Patients with megaprostheses may be more prone to periprosthetic joint infection and surgical site infection given multiple variables, such as the lengthy nature of the surgical procedure, prolonged wound exposure, extensive soft-tissue dissection and resection, poor soft-tissue coverage, and poorer host status.

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Despite advances in technology, complication and revision rates remain high after megaprosthesis reconstruction. Therefore, thorough attention to patient-specific factors must be considered for appropriate use of these constructs.

What Is the Implant Survivorship and Functional Outcome After Total Humeral Replacement in Patients with Primary Bone Tumors?

BACKGROUND

Total humeral replacement is an option to reconstruct massive bone defects after resection of locally advanced bone tumors of the humerus. However, implant survivorship, potential risk factors for implant revision surgery, and functional results of total humeral replacement are poorly elucidated because of the rarity of the procedure.

QUESTIONS/PURPOSES

We asked: (1) What is the revision-free implant and overall limb survivorship after total humerus replacement? (2) What factors are associated with implant revision surgery? (3) What is the functional outcome of the procedure as determined by the Musculoskeletal Tumor Society (MSTS) score and the American Shoulder and Elbow Surgeons (ASES) score?

METHODS

Between August 1999 and December 2018, 666 patients underwent megaprosthetic reconstruction after resection of a primary malignant or locally aggressive/rarely metastasizing tumor of the long bones at our department. In all, 23% (154) of these patients had a primary tumor located in the humerus. During the study, we performed total humeral replacement in all patients with a locally advanced sarcoma, in patients with pathological fractures, in patients with skip metastases, or in patients with previous intralesional contaminating surgery, who would have no sufficient bone stock for a stable implant fixation for a single joint megaprosthetic replacement of the proximal or distal humerus. We performed no biological reconstructions or reconstructions with allograft-prosthetic composites. As a result, 5% (33 of 666) of patients underwent total humerus replacement. Six percent (2 of 33) of patients were excluded because they received a custom-made, three-dimensionally (3-D) printed hemiprosthesis, leaving 5% (31) of the initial 666 patients for inclusion in our retrospective analysis. Of these, 6% (2 of 31) had surgery more than 5 years ago, but they had not been seen in the last 5 years. Median (interquartile range) age at the time of surgery was 15 years (14 to 25 years), and indications for total humeral replacement were primary malignant bone tumors (n = 30) and a recurring, rarely metastasizing bone tumor (n = 1). All megaprosthetic reconstructions were performed with a single modular system. The implanted prostheses were silver-coated beginning in 2006, and beginning in 2010, a reverse proximal humerus component was used when appropriate. We analyzed endoprosthetic complications descriptively and assessed the functional outcome of all surviving patients who did not undergo secondary amputation using the 1993 MSTS score and the ASES score. The median (IQR) follow-up in all survivors was 75 months (50 to 122 months), with a minimum follow-up period of 25 months. We evaluated the following factors for possible association with implant revision surgery: age, BMI, reconstruction length, duration of surgery, extraarticular resection, pathological fracture, previous intralesional surgery, (neo-)adjuvant radio- and chemotherapy, and metastatic disease.

RESULTS

The revision-free implant survivorship at 1 year was 77% (95% confidence interval 58% to 89%) and 74% (95% CI 55% to 86%) at 5 years. The overall limb survivorship was 93% (95% CI 75% to 98%) after 1 and after 5 years. We found revision-free survivorship to be lower in patients with extraarticular shoulder resection compared with intraarticular resections (50% [95% CI 21% to 74%] versus 89% [95% CI 64% to 97%]) after 5 years (subhazard ratios for extraarticular resections 4.4 [95% CI 1.2 to 16.5]; p = 0.03). With the number of patients available for our analysis, we could not detect a difference in revision-free survivorship at 5 years between patients who underwent postoperative radiotherapy (40% [95% CI 5% to 75%]) and patients who did not (81% [95% CI 60% to 92%]; p = 0.09). The median (IQR) MSTS score in 9 of 13 surviving patients after a median follow-up of 75 months (51 to 148 months) was 87% (67% to 92%), and the median ASES score was 83 (63 to 89) of 100 points, with higher scores representing better function.

CONCLUSION

Total humeral replacement after resection of locally advanced bone tumors appears to be associated with a good functional outcome in patients who do not die of their tumors, which in our study was approximately one- third of those who were treated with a resection and total humerus prosthesis. However, the probability of early prosthetic revision surgery is high, especially in patients undergoing extraarticular resections, who should be counseled accordingly. Still, our results suggest that if the prosthesis survives the first year, further risk for revision appears to be low. Future studies should reexamine the effect of postoperative radiotherapy on implant survival in a larger cohort and evaluate whether the use of soft tissue coverage with plastic reconstructive surgery might decrease the risk of early revisions, especially in patients undergoing extraarticular resections.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Antibacterial Titanium Implants Biofunctionalized by Plasma Electrolytic Oxidation with Silver, Zinc, and Copper: A Systematic Review

Patients receiving orthopedic implants are at risk of implant-associated infections (IAI). A growing number of antibiotic-resistant bacteria threaten to hamper the treatment of IAI. The focus has, therefore, shifted towards the development of implants with intrinsic antibacterial activity to prevent the occurrence of infection. The use of Ag, Cu, and Zn has gained momentum as these elements display strong antibacterial behavior and target a wide spectrum of bacteria. In order to incorporate these elements into the surface of titanium-based bone implants, plasma electrolytic oxidation (PEO) has been widely investigated as a single-step process that can biofunctionalize these (highly porous) implant surfaces. Here, we present a systematic review of the studies published between 2009 until 2020 on the biomaterial properties, antibacterial behavior, and biocompatibility of titanium implants biofunctionalized by PEO using Ag, Cu, and Zn. We observed that 100% of surfaces bearing Ag (Ag-surfaces), 93% of surfaces bearing Cu (Cu-surfaces), 73% of surfaces bearing Zn (Zn-surfaces), and 100% of surfaces combining Ag, Cu, and Zn resulted in a significant (i.e., >50%) reduction of bacterial load, while 13% of Ag-surfaces, 10% of Cu-surfaces, and none of Zn or combined Ag, Cu, and Zn surfaces reported cytotoxicity against osteoblasts, stem cells, and immune cells. A majority of the studies investigated the antibacterial activity against S. aureus. Important areas for future research include the biofunctionalization of additively manufactured porous implants and surfaces combining Ag, Cu, and Zn. Furthermore, the antibacterial activity of such implants should be determined in assays focused on prevention, rather than the treatment of IAIs. These implants should be tested using appropriate in vivo bone infection models capable of assessing whether titanium implants biofunctionalized by PEO with Ag, Cu, and Zn can contribute to protect patients against IAI.

Antibacterial hydrogel coating in joint mega-prosthesis: results of a comparative series

PURPOSE

Joint mega-prosthesis after bone tumors, severe trauma or infection is associated with high rates of post-surgical septic complications. A fast-resorbable antibacterial hydrogel coating (DAC®, Defensive Antibacterial Coating) has previously been shown to be able to significantly reduce surgical site infection in various clinical settings. Aim of the present study was to evaluate the safety and efficacy of the DAC hydrogel coating to prevent early periprosthetic joint infection after joint mega-prosthesis.

METHODS

In this three-centers, case-control study, 43 patients, treated with an antibacterial hydrogel coated mega-prosthesis for oncological (N = 39) or non-oncological conditions (N = 4), were retrospectively compared with 43 matched controls, treated with mega-implants without the coating. Clinical, laboratory and radiographic examinations were performed to evaluate the occurrence of post-surgical infection, complications and adverse events.

RESULTS

At a mean follow-up of 2 years, no evidence of infection or adverse events were observed in the DAC-treated group, compared to six cases of post-surgical infection in the control group.

CONCLUSION

This matched case-control study shows that a fast-resorbable, antibiotic-loaded coating can be safely used to protect joint mega-prosthesis, providing a reduction of early surgical site infections with no side effects. Larger prospective trials with longer follow-ups are warranted to confirm this report.

TRIAL REGISTRATION

RS1229/19 (Regina Elena National Cancer Institute Experimental Registry Number).

Application of Raman Spectroscopic Imaging to Assess the Structural Changes at Cell-Scaffold Interface

Raman spectroscopic imaging and mapping were applied to characterise three-compound ceramic composite biomaterial consisting of chitosan, β-1,3-d-glucan (curdlan) and hydroxyapatite (HA) developed as a bone tissue engineering product (TEP). In this rapidly advancing domain of medical science, the urge for quick, reliable and specific method for products evaluation and tissue–implant interaction, in this case bone formation process, is constantly present. Two types of stem cells, adipose-derived stem cells (ADSCs) and bone marrow-derived stem cells (BMDSCs), were cultured on composite surface. Raman spectroscopic imaging provided advantageous information on molecular differences and spatial distribution of compounds within and between the cell-seeded and untreated samples at a microscopic level. With the use of this, it was possible to confirm composite biocompatibility and bioactivity in vitro. Deposition of HA and changes in its crystallinity along with protein adsorption proved new bone tissue formation in both mesenchymal stem cell samples, where the cells proliferated, differentiated and produced biomineralised extracellular matrix (ECM). The usefulness of spectroscopic Raman imaging was confirmed in tissue engineering in terms of both the organic and inorganic components considering composite–cells interaction.

Intralesional curettage versus prosthetic replacement for bone tumors - a finite element analysis case of limb salvage simulation in biomechanics

BACKGROUND AND OBJECTIVES

To compare mechanical properties of femoral tumor treatments so that better operative strategy for limb tumors surgery is optimized.

METHODS

Fourteen femoral CT images were randomly selected to rebuild 3D models by MIMICS. They were then executed by reverse engineering softwares for simulative modes. Mode #1: Intralesional curettage with cement filled plus fixator; Mode #2: Distal femur resection with tumorous prosthesis replaced. Finally, the mechanical aspects such as stress and displacement were compared by finite element analysis.

RESULTS

Analyzed by AnSys, the observation indexes were measured as follows: for displacement of femurs, d=1.4762 (< a=3.9042 < c=3.9845 < b=4.1159) in mm is the most staple of all models; for displacement of implants (fixators or prostheses), it's similar to the behavior of femurs and with no significant difference; for stresses of femurs, no significant difference was found among all models; the stresses of implants (fixations and prostheses) were observed as d=39.6334 (< a=58.6206 < c=61.8150 < b=62.6626) in MPa correspondently, which is the least; for stresses of the general system, the average of peak values for integrated devices of all models are: d=40.8072 (< a=58.6206 < c=61.7831< b=62.6626) in MPa, which is also the least. As a final result, both maximum values for displacement and stress of mode 2 are lower than those of mode 1.

CONCLUSIONS

Our finite element analysis of limb salvage simulation in biomechanics proved that, to treat distal femoral bone tumors, prosthetic replacement is more efficient than intralesional curettage.

The Potential Innovative Use of Bacteriophages Within the DAC® Hydrogel to Treat Patients With Knee Megaprosthesis Infection Requiring "Debridement Antibiotics and Implant Retention" and Soft Tissue Coverage as Salvage Therapy

Infection is the most dramatic complication in patients with knee megaprosthesis. Its management is more complex in comparison with patients with primary arthroplasty, with a high risk of relapse. Lytic bacteriophages are considered to have a high potential in patients with prosthetic joint infection as it has been demonstrated that they have a synergistic anti-biofilm activity with antibiotics. The Defensive Antibacterial Coating (DAC®) hydrogel is a hydrogel available in the market that has been designed to prevent the adherence of bacteria on a prosthetic joint and to have the ability to transport and release anti-bacterial substances such as antibiotics. We report here the case of a patient with a catastrophic relapsing Staphylococcus aureus knee megaprosthesis infection without prosthesis loosening. We firstly perform phage susceptibility testing of the patient's strain to select an active cocktail, under the supervision of the French health authority. Then, we performed, as salvage therapy, a debridement and implant retention procedure with application of a selected cocktail of bacteriophages that was prepared extemporaneously within the DAC® hydrogel. A free flap for soft tissue coverage was required and empirical antibiotic treatment was started immediately after the surgery. Unfortunately, at 5 days after the surgery, while the local aspect of the surgical site was favorable, the patient developed myocardial infarction which required emergency stenting and dual antiplatelet therapy that were rapidly associated with bleeding at the surgical site, leading to a new prosthesis exposition. As a consequence, a transfemoral amputation was finally performed several months later. We also evaluated in vitro the impact of DAC® hydrogel on bacteriophage activity and showed that the selected phages were released very rapidly from the DAC® hydrogel, and then their titers were stable for at least 6 h. This case demonstrated the feasibility of the use of bacteriophages within a hydrogel to treat patients for knee megaprosthesis infection during a debridement procedure. The implementation requires identification of the pathogen before the debridement in order to perform phage susceptibility testing of the patient's strain and to identify a hospital pharmacist who will accept to do the preparation and to take the responsibility of the magistral preparation.

Selected Nanomaterials' Application Enhanced with the Use of Stem Cells in Acceleration of Alveolar Bone Regeneration during Augmentation Process

Regenerative properties are different in every human tissue. Nowadays, with the increasing popularity of dental implants, bone regenerative procedures called augmentations are sometimes crucial in order to perform a successful dental procedure. Tissue engineering allows for controlled growth of alveolar and periodontal tissues, with use of scaffolds, cells, and signalling molecules. By modulating the patient's tissues, it can positively influence poor integration and healing, resulting in repeated implant surgeries. Application of nanomaterials and stem cells in tissue regeneration is a newly developing field, with great potential for maxillofacial bony defects. Nanostructured scaffolds provide a closer structural support with natural bone, while stem cells allow bony tissue regeneration in places when a certain volume of bone is crucial to perform a successful implantation. Several types of selected nanomaterials and stem cells were discussed in this study. Their use has a high impact on the efficacy of the current and future procedures, which are still challenging for medicine. There are many factors that can influence the regenerative process, while its general complexity makes the whole process even harder to control. The aim of this study was to evaluate the effectiveness and advantage of both stem cells and nanomaterials in order to better understand their function in regeneration of bone tissue in oral cavity.

USP1 inhibitor ML323 enhances osteogenic potential of human dental pulp stem cells

LIM homeobox 8 (LHX8) is expressed during embryonic development of craniofacial tissues, including bone and teeth. In a previous study, the overexpression of LHX8 inhibited osteodifferentiation of human dental pulp stem cells (DPSCs). In this study, a cDNA microarray analysis was performed to reveal the molecular changes which occur in response to LHX8 overexpression in DPSCs and discover possible targets for an osteoinductive agent. There were 345 differentially expressed genes (DEGs) in response to osteoinductive signaling and 53 DEGs in response to LHX8 overexpression and osteoinductive signaling, respectively. Thirty-eight genes were common in both conditions, and among these, genes upregulated in LHX8 DPSCs but downregulated in osteodifferentiated DPSCs were chosen. Five of them had commercial inhibitors available. Among the tested inhibitors, ML323, which target DNA-binding protein inhibitor ID-1, promoted osteodifferentiation of DPSCs. In conclusion, inhibition of ID-1 led to increased osteogenesis of human DPSCs.

Management of infected extremity endoprostheses: a systematic review

BACKGROUND

Endoprosthetic reconstructions have become increasingly common in the setting of significant bone loss. Indications include revision arthroplasty, trauma, and reconstruction in the setting of primary malignancies or bony metastases. Although the use of endoprostheses has several advantages, they carry a high risk of infection. The purpose of this review is to determine the success rates of surgical management of infected endoprostheses.

METHODS

The authors searched databases for relevant studies and screened in duplicate. Data extracted included overall infection rate, timing of infection, follow-up, isolated pathogen and operative treatment strategy, and subsequent failure rate. The overall quality of the evidence with the Methodological Index for non-randomized studies criteria.

RESULTS

A total of 16 studies and 647 patients met the inclusion criteria. 400 patients had operative management and reported outcomes. Failure rates of patients undergoing debridement, antibiotics, and implant retention (DAIR) were 55.1%. Failure rates of patients who underwent one-stage revision were 45.5%. Failure rates of patients undergoing two-stage revision were 27.3%. Failure occurred at 31.4 months (range, 0-228) postoperatively.

CONCLUSIONS

Rates of periprosthetic joint infection remain high in endoprosthetic reconstructions. Although DAIR procedures were found to have a low success rate, they remain a reasonable option in acute infections given the morbidity of staged revisions. There is a lack of comparative data in the current literature and the heterogeneity and low level of evidence does not allow for between group comparisons of results.

Antibiotic-laden cement wrap: A simple but effective way of treating patients with megaprosthesis infection

Infection is one of the commonest causes for megaprosthesis failure. The current treatment includes antibiotics but no surgery, debridement, prosthesis removal and joint fusion, prosthesis revision or amputation. Success in controlling infection may be less than 50% in implant revision. The overall risk of amputation is more than 20%. We believe that repeated debridement with antibiotic-laden cement wrap (ALCW) may be a reliable alternative for managing the megaprosthesis infection. The purposes of this article are to identify whether ALCW is an effective way of eradicating the megaprosthesis infection, the associated complications and the functional outcome after management by ALCW.

METHODS

This was a retrospective study of patients with megaprosthesis infection. From January 2014 to June 2016, there were five patients with tumour megaprosthesis infection who had undergone the ALCW procedure. Ages ranged from 17 to 59 years of age. Male to female ratio was 4:1. The patients studied had humeral (1), proximal femoral (1), distal femoral (1) and proximal tibial (2) prostheses. All patients had follow-ups more than 1 year (21-52 months) after treatment.

RESULTS

All patients recovered from their implant infection and the implants were retained in all patients. There was no sign of infection in the most recent follow-up. One patient died of osteosarcoma recurrence. One patient had a large block of cement causing plastic insert dislodgement in the shoulder joint 1 year after surgery. Another patient with a dislocated hip cup had revision carried out in the final debridement. The most recent Musculoskeletal Tumor society (MSTS) scores ranged from 21 to 30. All patients were satisfied with their treatment.

CONCLUSIONS

In this preliminary report of a small number of patients, ALCW has achieved 100% infection control. ALCW may be an easy and effective alternative for managing the megasprosthesis infection. The complications associated can be avoidable. The functional outcome is excellent.

Is malnutrition associated with postoperative complications in patients with primary bone sarcomas?

BACKGROUND

Modifiable risk factors that can be optimized to minimize postoperative complications in patients with bone sarcomas are yet to be identified.

METHODS

We retrospectively identified 275 patients aged 18 and older who underwent surgery for primary bone sarcomas who also had albumin values recorded within 4 weeks before surgery. Postoperative complications were defined as infection, hematoma, need for additional surgery, or wound complications.

RESULTS

In the multivariate analysis, age (P = 0.049) and neoadjuvant radiotherapy (P = 0.008) were independently associated with postoperative complications. We then performed a subanalysis of patients without a pelvic tumor who also did not receive radiotherapy (n = 178). In this population, albumin less than 2.8 g/dL was found to be independently associated with postoperative complications (odds ratio [OR], 4.69. 95% confidence intervals [CI], 1.03-21.97; P = 0.046).

CONCLUSIONS

This study demonstrates that hypoalbuminemia (albumin < 2.8 g/dL) is associated with postoperative complications in patients with nonpelvic bone sarcomas who do not receive radiation. Future studies are necessary to further elucidate the role of nutrition, and they may show that nutritional status is a modifiable risk factor that can be optimized to improve the outcome of surgery for primary bone sarcomas.

Cytotoxic Tolerance of Healthy and Cancerous Bone Cells to Anti-microbial Phenolic Compounds Depend on Culture Conditions

Carnosol and carnosic acid are polyphenolic compounds found in rosemary and sage with known anti-oxidant, anti-inflammatory, and anti-microbial properties. Here, we addressed the potential use of carnosol and carnosic acid for in vitro bone tissue engineering applications, specifically depending on their cytotoxic effects on bone marrow stromal and stem cells, and osteosarcoma cells in monolayer and 3D cultures. Carnosol and carnosic acid displayed a bacteriostatic effect on Gram-positive bacteria, especially on S. aureus. The viability results indicated that bone marrow stromal cells and bone marrow stem cells were more tolerant to the presence of carnosol compared to osteosarcoma cells. 3D culture conditions increased this tolerance further for healthy cells, while not affecting the cytotoxic potential of carnosol for osteosarcoma cells. Carnosic acid was found to be more cytotoxic for all cell types used in the study. Results suggest that phenolic compounds might have potential use as anti-microbial and anti-carcinogenic agents for bone tissue engineering with further optimization for controlled release.

High-activity chitosan/nano hydroxyapatite/zoledronic acid scaffolds for simultaneous tumor inhibition, bone repair and infection eradication

Implanted biomaterials combined tumor inhibition and bone repair property are urgently needed to address the huge bone destruction and the high local recurrence following primary surgery in bone tumor therapy. In this work, a high-activity chitosan/nano hydroxyapatite (CS/nHA) scaffold containing zoledronic acid (CS/nHA/Zol) was prepared with a facile method. The prepared CS/nHA/Zol scaffolds exhibited excellent tumor inhibition property towards giant cell tumor of bone (GCT) in vitro through inducing cells apoptosis by up-regulating pro-apoptosis genes expression and reducing the osteoclastic activity of tumor cells by down-regulating osteoclastic genes. Meanwhile, the prepared scaffolds possessed well biocompatibility and osteoinductivity as compared to pure CS/nHA scaffolds. Furthermore, the prepared scaffolds also presented outstanding antibacterial activity against clinical pathogenic S. aureus and E. coli. These overall findings successfully demonstrated the prepared CS/nHA/Zol scaffolds had a multifunction of tumor therapy, bone repair, and antibacterium, which provides a new approach possessed promising advantages in bone tumor therapy.

Dynamic relationship between postoperative infection and CRP, IL-6, and Livin in patients with bone tumors

BACKGROUND

The objective of the present study was to investigate the dynamic relationship between postoperative infection and levels of CRP, IL-6, and Livin in patients with bone tumors.

METHODS

A total of 126 patients with bone tumors admitted to our hospital from November 2013 to October 2015 were randomly selected and retrospectively analyzed. According to whether postoperative infection occurred, patients were divided into the infected group (N.=52) and the non-infected group (N.=74). Before surgery, and on the 1st, 3rd, 5th, 7th, and 10th day after surgery, the levels of serum CRP and IL-6 of patients in both groups were compared; the relative expression levels of Livin protein of patients in both groups were measured by Western blot.

RESULTS

After surgery, the levels of CRP and IL-6 of patients in both groups at all time points were significantly higher than those before surgery and the levels of CRP and IL-6 of the infected group were significantly higher than those of the non-infected group (P<0.05). The levels of CRP and IL-6 reached a peak on the 3rd day after surgery, and CRP declined rapidly. The levels of IL-6 declined slowly. On the 10th day after surgery, the levels of IL-6 of patients in both groups were higher than those before surgery and the levels of IL-6 of patients in the infected group were higher than those of the control group (P<0.05). The levels of Livin protein in patients of both groups were not significantly different (P>0.05).

CONCLUSIONS

The increase of the levels of CRP and IL-6 are closely related to infection. Livin has no close relationship with the occurrence of infection.