Silver-coated (Agluna®) tumour prostheses can be a protective factor against infection in high risk failure patients

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.

What Are the Complication Rates and Factors Associated With Total Femur Replacement After Tumor Resection? Findings From the Japanese Musculoskeletal Oncology Group

BACKGROUND

Patients undergoing massive tumor resection and total femur replacement (TFR) face a substantial risk of hip dislocation and infection, often resulting in multiple implant revisions or hip disarticulation. These complications can impact their independence and prognosis. Additionally, their shorter life expectancy is influenced by challenges in achieving local radical resection and controlling metastases. Identifying suitable candidates for TFR is vital, necessitating investigations into dislocation, infection, implant failure rates, local recurrence, overall survival, and associated factors.

QUESTIONS/PURPOSES

(1) What is the postsurgical complication (hip dislocation and infection) rate and factors associated with postsurgical complications in patients who underwent TFR after tumor resection? (2) What is the local recurrence rate, implant failure rate, overall survival rate, and factors associated with local recurrence and implant failure?

METHODS

We retrospectively evaluated 42 patients (median [range] age 47 years [10 to 79 years]) who underwent TFR and tumor resection at the time of the same surgical procedure between 1990 and 2020 at 12 registered institutions that specialized in tumor treatment in Japan. A total of 55% (23) of the patients were men, and 79% (33) had bone sarcoma. The median (range) follow-up period was 36.5 months (2 to 327 months). Of the 42 patients, 12% (5) were lost to follow-up before 2 years without meeting a study endpoint (postsurgical complications, revision, or amputation), and another 19% (8) died before 2 years with implants intact, leaving 69% (29) of the original group who had either follow-up of at least 2 years or met a study endpoint before the minimum surveillance duration. Another 10% (4) had a minimum of 2 years of follow-up but had not been seen in the past 5 years. Infection was defined as deep-seated infection involving soft tissues, bones, joints, and the area around the implant. We did not consider superficial infections. Implant failure was defined when a patient underwent reimplantation or amputation. The complication and implant failure rates were assessed by the cumulative incidence function method, considering competing events. The Kaplan-Meier method was used to estimate the overall survival rate.

RESULTS

The 1-month, 6-month, 1-year, and 2-year dislocation rates were 5%, 12%, 14%, and 14%, respectively. The 1-month, 6-month, 1-year, and 2-year infection rates were 5%, 7%, 10%, and 15%, respectively. Multivariable analyses for hip dislocation and infection revealed that resection of the abductor muscles and large tumor size were positively associated with hip dislocation. The 6-month, 1-year, and 2-year local recurrence rates were 5%, 15%, and 15%, respectively. The 6-month, 1-year, 2-year, and 5-year implant failure rates were 5% (95% confidence interval 1% to 15%), 7% (95% CI 2% to 18%), 16% (95% CI 6% to 29%), and 16% (95% CI 6% to 29%), respectively. Multivariable analyses of local recurrence and implant failure that led to reimplantation or amputation revealed that a positive surgical margin was positively associated with local recurrence. The 1-year, 2-year, and 5-year overall patient survival rates were 95% (95% CI 87% to 102%), 77% (95% CI 64% to 91%), and 64% (95% CI 48% to 81%), respectively.

CONCLUSION

Hip dislocation, infection, and local recurrence were frequently observed in patients who received massive tumor resection and TFR in our study, eventually leading to reimplantation or amputation. Preserving the abductor muscles and resecting the tumor with a wide margin can prevent postoperative dislocation and local recurrence. Future research should focus on patient selection criteria, prevention of hip dislocation, and innovative treatments.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Immunomodulatory biomaterials for implant-associated infections: from conventional to advanced therapeutic strategies

Implant-associated infection (IAI) is increasingly emerging as a serious threat with the massive application of biomaterials. Bacteria attached to the surface of implants are often difficult to remove and exhibit high resistance to bactericides. In the quest for novel antimicrobial strategies, conventional antimicrobial materials often fail to exert their function because they tend to focus on direct bactericidal activity while neglecting the modulation of immune systems. The inflammatory response induced by host immune cells was thought to be a detrimental force impeding wound healing. However, the immune system has recently received increasing attention as a vital player in the host's defense against infection. Anti-infective strategies based on the modulation of host immune defenses are emerging as a field of interest. This review explains the importance of the immune system in combating infections and describes current advanced immune-enhanced anti-infection strategies. First, the characteristics of traditional/conventional implant biomaterials and the reasons for the difficulty of bacterial clearance in IAI were reviewed. Second, the importance of immune cells in the battle against bacteria is elucidated. Then, we discuss how to design biomaterials that activate the defense function of immune cells to enhance the antimicrobial potential. Based on the key premise of restoring proper host-protective immunity, varying advanced immune-enhanced antimicrobial strategies were discussed. Finally, current issues and perspectives in this field were offered. This review will provide scientific guidance to enhance the development of advanced anti-infective biomaterials.

Implant surface modifications as a prevention method for periprosthetic joint infection caused by Staphylococcus aureus: a systematic review and meta-analysis

Abstract. Background: Periprosthetic joint infection is the most common infection due to joint replacement. It has been reported that, over a 5-year time span, 3.7 % of cases occurred annually. This statistic has increased to 6.86 % over 16 years. Thus, an effective method is required to reduce these complications. Several strategies such as coating methods with various materials, such as antibiotics, silver, and iodine, have been reported. However, the best preventive strategy is still undetermined. Therefore, this systematic review aims to evaluate the outcome of coating methods on joint arthroplasty as a treatment or preventive management for infection complications. Methods: Eligible articles were systematically searched from multiple electronic databases (PubMed, Cochrane library, and ScienceDirect) up to 2 June 2022. Based on the criterion inclusion, eight articles were selected for this study. The Newcastle–Ottawa scale (NOS) was used to assess the quality of the study, and the meta-analysis test was conducted with Review Manager 5.4. Results: The quality of the articles in this study is in the range of moderate to good. It was found that the application of modified antibiotic coatings significantly reduced the occurrence of periprosthetic joint infection (PJI) (p 0.03), and silver coating could not significantly (p 0.47) prevent the occurrence of PJI. However, according to the whole aspect of coating modification, the use of antibiotics, silver, and iodine can minimize the occurrence of PJI (p <0.0001). Conclusion: Coating methods using antibiotics are an effective method that could significantly prevent the occurrence of PJI. On the other hand, coating with non-antibiotic materials such as silver could not significantly prevent the incidence of PJI.

Surgical Site Infection after Bone Tumor Surgery: Risk Factors and New Preventive Techniques

The management of malignant bone tumors requires multidisciplinary interventions including chemotherapy, radiation therapy, and surgical tumor resection and reconstruction. Surgical site infection (SSI) is a serious complication in the treatment of malignant bone tumors. Compared to other orthopedic surgeries, the surgical treatment of malignant bone tumors is associated with higher rates of SSIs. In patients with SSIs, additional surgeries, long-term administrations of antibiotics, extended hospital stays, and the postponement of scheduled adjuvant treatments are required. Therefore, SSI may adversely affect functional and oncological outcomes. To improve surgical outcomes in patients with malignant bone tumors, preoperative risk assessments for SSIs, new preventive techniques against SSIs, and the optimal use of prophylactic antibiotics are often required. Previous reports have demonstrated that age, tumor site (pelvis and tibia), extended operative time, implant use, body mass index, leukocytopenia, and reconstruction procedures are associated with an increased risk for SSIs. Furthermore, prophylactic techniques, such as silver and iodine coatings on implants, have been developed and proven to be efficacious and safe in clinical studies. In this review, predictive factors of SSIs and new prophylactic techniques are discussed.

Improving bactericidal performance of implant composite coatings by synergism between Melittin and tetracycline

Methicillin resistance Staphylococcus aureus bacteria (MRSA) are serious hazards of bone implants. The present study was aimed to use the potential synergistic effects of Melittin and tetracycline to prevent MRSA associated bone implant infection. Chitosan/bioactive glass nanoparticles/tetracycline composite coatings were deposited on hydrothermally etched titanium substrate. Melittin was then coated on composite coatings by drop casting method. The surfaces were analyzed by FTIR, XRD, and SEM instruments. Tetracycline in coatings revealed multifunctional behaviors include bone regeneration and antibacterial activity. Releasing ALP enzyme from MC3T3 cells increased by tetracycline, so it is suitable candidate as osteoinductive and antibacterial agent in orthopedic implants coatings. Melittin increased the proliferation of MC3T3 cells. Composite coatings with combination of tetracycline and Melittin eradicate all MRSA bacteria, while coatings with one of them could no t eradicate all of the bacteria. In conclusion, chitosan/bioactive glass/tetracycline/Melittin coating can be suggested as a multifunctional bone implant coating because of its osteogenic and promising antibacterial activity. Graphical abstract.

Development of Silver-Containing Hydroxyapatite-Coated Antimicrobial Implants for Orthopaedic and Spinal Surgery

The prevention of surgical site infections is directly related to the minimization of surgical invasiveness, and is in line with the concept of minimally invasive spine therapy (MIST). In recent years, the incidence of postoperative infections has been increasing due to the increased use of spinal implant surgery in patients at high risk of infection, including the elderly and easily infected hosts, the limitations of poor bone marrow transfer of antibiotics, and the potential for contamination of surgical gloves and instruments. Thus, the development of antimicrobial implants in orthopedic and spinal surgery is becoming more and more popular, and implants with proven antimicrobial, safety, and osteoconductive properties (i.e., silver, iodine, antibiotics) in vitro, in vivo, and in clinical trials have become available for clinical use. We have developed silver-containing hydroxyapatite (Ag-HA)-coated implants to prevent post-operative infection, and increase bone fusion capacity, and have successfully commercialized antibacterial implants for hip prostheses and spinal interbody cages. This narrative review overviews the present status of available surface coating technologies and materials; describes how the antimicrobial, safety, and biocompatibility (osteoconductivity) of Ag-HA-coated implants have been demonstrated for commercialization; and reviews the clinical use of antimicrobial implants in orthopedic and spinal surgery, including Ag-HA-coated implants that we have developed.

Current approaches to management of bone sarcoma in adolescent and young adult patients

Bone tumors are a group of histologically diverse diseases that occur across all ages. Two of the commonest, osteosarcoma (OS) and Ewing sarcoma (ES), are regarded as characteristic adolescent and young adult (AYA) cancers with an incidence peak in AYAs. They are curable for some but associated with unacceptably high rates of treatment failure and morbidity. The introduction of effective new therapeutics for bone sarcomas is slow, and to date, complex biology has been insufficiently characterized to allow more rapid therapeutic exploitation. This review focuses on current standards of care, recent advances that have or may soon change that standard of care and challenges to the expert clinical research community that we suggest must be met.

Clinical outcomes of endoprosthetic reconstruction for proximal femoral resection

INTRODUCTION

The proximal femur is a common site for primary sarcomas and metastatic lesions. Although the early results of tumor prostheses are promising, the long-term results of reconstruction are unknown. The purpose of this study is to evaluate the prognostic factors affecting prosthesis survival and complications after proximal femoral resection and reconstruction.

METHODS

We reviewed the results of 68 patients who underwent proximal femoral resection and reconstruction with a modular bipolar-type tumor prosthesis between 2005 and 2017. The mean follow-up was 55.6 months (range 6-172 months). There were 50 male and 18 female patients with a mean age of 41.5 years (range 11-80 years). Cumulative survival analysis was performed to analyze the risk factors of prosthesis survival. We also evaluated the complications after operation.

RESULTS

Fourteen (21%) patients required further surgery at a mean 37 months post-operatively (range 5-125 months). There were three cases of infection (4%), six of local recurrence (9%), three of acetabular erosion (4%) and two of stem loosening (3%). The implant survival rates were 83.9% at 5 years and 59.8% at 10 years. Prosthesis survivals did not differ based on fixation method (P = 0.085), age (P = 0.329) or resection length (P = 0.61). Acetabular chondrolysis was identified in 18 (26%) patients and longer resection length (≥20 cm) showed a trend for risk of acetabular wear (P = 0.132).

CONCLUSION

The results of proximal femoral resection and reconstruction with a modular bipolar-type prosthesis were found to be acceptable with infection and local recurrence as short-term complications and loosening and acetabular erosion as long-term complications.

The role of silver coating for arthroplasty components

Periprosthetic joint infection (PJI) is one of the most dreaded complications after arthroplasty surgery; thus numerous approaches have been undertaken to equip metal surfaces with antibacterial properties. Due to its antimicrobial effects, silver is a promising coating for metallic surfaces, and several types of silver-coated arthroplasty implants are in clinical use today. However, silver can also exert toxic effects on eukaryotic cells both in the immediate vicinity of the coated implants and systemically. In most clinically-used implants, silver coatings are applied on bulk components that are not in direct contact with bone, such as in partial or total long bone arthroplasties used in tumour or complex revision surgery. These implants differ considerably in the coating method, total silver content, and silver release rates. Safety issues, such as the occurrence of argyria, have been a cause for concern, and the efficacy of silver coatings in terms of preventing PJI is also controversial. The application of silver coatings is uncommon on parts of implants intended for cementless fixation in host bone, but this option might be highly desirable since the modification of implant surfaces in order to improve osteoconductivity can also increase bacterial adhesion. Therefore, an optimal silver content that inhibits bacterial colonization while maintaining osteoconductivity is crucial if silver were to be applied as a coating on parts intended for bone contact. This review summarizes the different methods used to apply silver coatings to arthroplasty components, with a focus on the amount and duration of silver release from the different coatings; the available experience with silver-coated implants that are in clinical use today; and future strategies to balance the effects of silver on bacteria and eukaryotic cells, and to develop silver-coated titanium components suitable for bone ingrowth. Cite this article: Bone Joint J 2021;103-B(3):423-429.

Silver-coated megaprosthesis in prevention and treatment of peri-prosthetic infections: a systematic review and meta-analysis about efficacy and toxicity in primary and revision surgery

AIM

Prosthetic joint infection (PJI) is a common complication following orthopedic megaprosthetic implantations (EPR), estimated up to 50%. Silver coatings were introduced in order to reduce the incidence of PJI, by using the antibacterial activity of silver. Three different silver coatings are available: MUTARS^® (Implantcast), Agluna^® (Accentus Medical), PorAg^® (Waldemar Link). The aim of this review is to provide an overview on efficacy and safety of silver-coated EPR both in primary and revision surgery, comparing infection rate according to the type of implant.

METHODS

Through an electronic systematic search, we reviewed the articles concerning silver-coated EPRs. Infection rate, silver-related complications, local and blood concentrations of the silver were evaluated. Meta-analyses were performed to compare results from each study included.

RESULTS

Nineteen studies were included. The overall infection rate in patients with silver-coated implants was 17.6% (133/755). Overall infection rate in primary silver-coated EPR was been 9.2% (44/445), compared to 11.2% (57/507) of non-silver-coated implants. The overall infection rate after revisions was 13.7% (25/183) in patients with silver-coated EPR and 29.2% (47/161) when uncoated EPR were used, revealing a strength statistically significative utility of silver coatings in preventing infections in this group (p: 0.019). Generally, the use of MUTARS^® EPR had produced an almost constant decrease in the incidence of primary PJI but there are few data on the effectiveness in revisions. The results from the use of Agluna^® in both primary and revisions implants are inconstant. Conversely, PorAg^® had proven to be effective both in PJI prevention but, especially, when used in PJI revision settings. Local argyria was reported in 8 out of 357 patients (2.2%), while no systemic complications were described. Local and blood concentrations of silver were always reported very far to the threshold of toxicity, with the lowest concentration found using PorAg^®.

CONCLUSIONS

Silver-coated EPRs are safe and effective in reduction in PJI and re-infection rate, in particular when used in higher risk patients and after two-stage revisions to fight PJI.

Prevention of Prosthetic Joint Infection: From Traditional Approaches towards Quality Improvement and Data Mining

A projected increased use of total joint arthroplasties will naturally result in a related increase in the number of prosthetic joint infections (PJIs). Suppression of the local peri-implant immune response counters efforts to eradicate bacteria, allowing the formation of biofilms and compromising preventive measures taken in the operating room. For these reasons, the prevention of PJI should focus concurrently on the following targets: (i) identifying at-risk patients; (ii) reducing “bacterial load” perioperatively; (iii) creating an antibacterial/antibiofilm environment at the site of surgery; and (iv) stimulating the local immune response. Despite considerable recent progress made in experimental and clinical research, a large discrepancy persists between proposed and clinically implemented preventative strategies. The ultimate anti-infective strategy lies in an optimal combination of all preventative approaches into a single “clinical pack”, applied rigorously in all settings involving prosthetic joint implantation. In addition, “anti-infective” implants might be a choice in patients who have an increased risk for PJI. However, further progress in the prevention of PJI is not imaginable without a close commitment to using quality improvement tools in combination with continual data mining, reflecting the efficacy of the preventative strategy in a particular clinical setting.

Antimicrobial silver-coating for locking plates shows uneventful osteotomy healing and good biocompatibility results of an experimental study in rabbits

Infections after internal fixation of fractures remain a challenge. Silver is known for its antimicrobial activity, including activity against multi-resistant strains. The aim of the current study was to analyze the biocompatibility and potential influence on the osteotomy healing process of a silver-coating technology for locking plates compared to silver-free locking plates in an established rabbit model. The implants used in this study were 7-hole titanium locking plates, and plasma electrolytic oxidation (PEO) silver-coated equivalents. A total of 24 rabbits were used in this study (12 coated, 12 non-coated). An osteotomy of the midshaft of the humerus was created and the humerus stabilized with the 7-hole locking plates with a total of 6 screws. Radiographs were taken on day 0, week 2, 4, 6, 8, and 10 for continuous radiographical evaluation. All animals were euthanized after 10 weeks and further assessment was performed using X-rays, micro-CT, non-destructive four-point bending biomechanical testing and semi-quantitative histopathological evaluation. Furthermore, silver concentration was measured in the blood, kidney, liver, spleen, brain, feces and soft tissue around the plate. Radiographs showed normal undisturbed and completed healing of the osteotomy in all animals without any differences between the two groups over the entire observation period. Micro-CT analysis revealed overall tissue volume as well as tissue density to be comparable between the two groups. Mechanical testing showed comparable stiffness with an average stiffness relative to contralateral bones of 75.7 ± 16.1% in the silver-free control group compared to 69.7 ± 18.5% (p-value: 0.46). Semi-quantitative histopathological evaluation showed no remarkable difference in the analysis of the osteotomy gap healing or in the surrounding soft tissue area. There were detectable silver concentrations in the soft tissue around the plate after 10 weeks. Silver in the blood was only found in 3 animals within the first two weeks and all animals were free of silver afterwards. There were no detectable silver concentrations in the brain, liver, spleen, axillary lymph nodes and kidney. This study shows undisturbed osteotomy healing of the presented antimicrobial silver surface coating and a good biocompatibility in this rabbit model.

[Risk factors and management strategies for early and late infections following reconstruction with special tumour endoprostheses]

BACKGROUND

Periprosthetic joint infection (PJI) of megaprostheses occur in about 10% of all cases. The criteria for PJI are defined by the "Musculoskleletal Infection Society" (MSIS) and apply to both primary arthroplasty and megaprostheses.

MANAGEMENT

The management strategies of PJI in megaprostheses are dependent on the duration of infection and the maturity of the bacterial biofilm. Implant retention with an exchange of the mobile components is only possible in the presence of an immature biofilm. In the presence of a mature biofilm, a one- or two-stage exchange must be performed. A complete exchange of all endoprosthetic components should be performed, if possible, since a partial retention of isolated components results in inferior treatment success rates.

RESULTS

The highest success rates are achievable with two-stage exchanges. Multiple risk factors such as skin necrosis, postoperative haematoma, prolonged wound secretion and operative times ≥ 2.5 h are risk factors for the development of PJI in megaprostheses. Knowledge regarding these risk factors allows for an identification of high-risk patients and early management of PJI.