Short or Long Antibiotic Regimes in Orthopaedics (SOLARIO): a randomised controlled open-label non-inferiority trial of duration of systemic antibiotics in adults with orthopaedic infection treated operatively with local antibiotic therapy

Fracture related infection in open tibial fractures

Open tibia fractures frequently occur following high-energy trauma. Contamination of the fracture site combined with limited soft tissue coverage and blood supply means that these open fractures are associated with a high rate of complications, including fracture related infection (FRI). FRI is associated with lowered patient outcomes and requires early recognition and appropriate surgical and medical management. The current evidence on FRI after open tibial fractures largely is limited to case series, small retrospective cohort studies and expert opinion. Recent expert consensus has produced guidelines with the aim of standardising care for these patients. This review summarises the current management strategies employed in treating FRI following open tibial fractures and where possible the evidence behind them.

Appropriate Duration of Antimicrobial Treatment for Prosthetic Joint Infections: A Narrative Review

Prosthetic joint infections are considered difficult to treat they needing aggressive surgery and long antimicrobial treatments. However, the exact duration of these therapies has been established empirically. In the last years, several studies have explored the possibility of reducing the length of treatment in this setting, with conflicting results. In this narrative review, we critically appraise the published evidence, considering the different surgical approaches (implant retention [DAIR] and one-step and two-step exchange procedures) separately. In patients managed with DAIR, usually treated for at least 12 weeks, a large, randomized trial failed to show that 6 weeks were non-inferior. However, another randomized clinical trial supports the use of 8 weeks, as long as the surgical conditions are favorable and antibiotics with good antibiofilm activity can be administered. In patients managed with a two-step exchange procedure, usually treated during 6 weeks, a randomized clinical trial showed the efficacy of a 4-week course of antimicrobials. Also, the use of local antibiotics may allow the use of even shorter treatments. Finally, in the case of one-step exchange procedures, there is a trend towards reducing the length of therapy, and the largest randomized clinical trial supports the use of 6 weeks of therapy.

[Bone cement as a local antibiotic carrier]

BACKGROUND

There is widespread consensus that adjuvant local use of antimicrobial agents in combination with their systemic administration can better prevent and treat implant-associated musculoskeletal infections. The advantage of local antibiotics lies in their particular pharmacokinetics with initially high antibiotic concentrations at the implant site with only low systemic uptake.

AIM OF TREATMENT

The aim of local application is to protect the foreign bodies directly at the implantation site from bacterial colonization and biofilm formation (prophylaxis) and to support the eradication of an already established infection after surgical debridement (treatment). Since the observations of Prof. Buchholz, bone cement has been the most frequently used local carrier system.

APPLICATION

In cases of infection, surgeons should ideally work together with microbiologists, infectiologists or clinical pharmacists to determine which anti-infective agents are indicated systemically for the patient and which ones are indicated locally with PMMA cement, based on the pathogen(s) and antibiograms. However, for the anti-infective agents administered with bone cement, there is still uncertainty about which agents can be added to this carrier material and at what concentrations. Accordingly, the authors of this review article not only summarize the rationale and evidence for local antibiotic use but also elaborate on the points that must be considered for admixing these agents to the cement.

Financial analysis of revision hip surgery at a tertiary referral centre as classified using the British Hip Society Revision Hip Complexity Classification

Aims

The burden of revision total hip arthroplasty (rTHA) continues to grow. The surgery is complex and associated with significant costs. Regional rTHA networks have been proposed to improve outcomes and to reduce re-revisions, and therefore costs. The aim of this study was to accurately quantify the cost and reimbursement for a rTHA service, and to assess the financial impact of case complexity at a tertiary referral centre within the NHS.

Methods

A retrospective analysis of all revision hip procedures was performed at this centre over two consecutive financial years (2018 to 2020). Cases were classified according to the Revision Hip Complexity Classification (RHCC) and whether they were infected or non-infected. Patients with an American Society of Anesthesiologists (ASA) grade ≥ III or BMI ≥ 40 kg/m² are considered "high risk" by the RHCC. Costs were calculated using the Patient Level Information and Costing System (PLICS), and remuneration based on Healthcare Resource Groups (HRG) data. The primary outcome was the financial difference between tariff and cost per patient episode.

Results

In all, 199 revision episodes were identified in 168 patients: 25 (13%) least complex revisions (H1); 110 (55%) complex revisions (H2); and 64 (32%) most complex revisions (H3). Of the 199, 76 cases (38%) were due to infection, and 78 patients (39%) were "high risk". Median length of stay increased significantly with case complexity from four days to six to eight days (p = 0.006) and for revisions performed for infection (9 days vs 5 days; p < 0.001). Cost per episode increased significantly between complexity groups (p < 0.001) and for infected revisions (p < 0.001). All groups demonstrated a mean deficit but this significantly increased with revision complexity (£97, £1,050, and £2,887 per case; p = 0.006) and for infected failure (£2,629 vs £635; p = 0.032). The total deficit to the NHS Trust over two years was £512,202.

Conclusion

Current NHS reimbursement for rTHA is inadequate and should be more closely aligned to complexity. An increase in the most complex rTHAs at major revision centres will likely place a greater financial burden on these units.

Local Antibiotic Delivery Options in Prosthetic Joint Infection

Prosthetic Joint Infection (PJI) causes significant morbidity and mortality for patients globally. Delivery of antibiotics to the site of infection has potential to improve the treatment outcomes and enhance biofilm eradication. These antibiotics can be delivered using an intra-articular catheter or combined with a carrier substance to enhance pharmacokinetic properties. Carrier options include non-resorbable polymethylmethacrylate (PMMA) bone cement and resorbable calcium sulphate, hydroxyapatite, bioactive glass, and hydrogels. PMMA allows for creation of structural spacers used in multi-stage revision procedures, however it requires subsequent removal and antibiotic compatibility and the levels delivered are variable. Calcium sulphate is the most researched resorbable carrier in PJI, but is associated with wound leakage and hypercalcaemia, and clinical evidence for its effectiveness remains at the early stage. Hydrogels provide a versatile combability with antibiotics and adjustable elution profiles, but clinical usage is currently limited. Novel anti-biofilm therapies include bacteriophages which have been used successfully in small case series.

Microbial Persistence, Replacement and Local Antimicrobial Therapy in Recurrent Bone and Joint Infection

We report microbiological results from a cohort of recurrent bone and joint infection to define the contributions of microbial persistence or replacement. We also investigated for any association between local antibiotic treatment and emerging antimicrobial resistance. Microbiological cultures and antibiotic treatments were reviewed for 125 individuals with recurrent infection (prosthetic joint infection, fracture-related infection, and osteomyelitis) at two UK centres between 2007 and 2021. At re-operation, 48/125 (38.4%) individuals had an organism from the same bacterial species as at their initial operation for infection. In 49/125 (39.2%), only new species were isolated in culture. In 28/125 (22.4%), re-operative cultures were negative. The most commonly persistent species were Staphylococcus aureus (46.3%), coagulase-negative Staphylococci (50.0%), and Pseudomonas aeruginosa (50.0%). Gentamicin non-susceptible organisms were common, identified at index procedure in 51/125 (40.8%) and at re-operation in 40/125 (32%). Gentamicin non-susceptibility at re-operation was not associated with previous local aminoglycoside treatment (21/71 (29.8%) vs. 19/54 (35.2%); p = 0.6). Emergence of new aminoglycoside resistance at recurrence was uncommon and did not differ significantly between those with and without local aminoglycoside treatment (3/71 (4.2%) vs. 4/54 (7.4%); p = 0.7). Culture-based diagnostics identified microbial persistence and replacement at similar rates in patients who re-presented with infection. Treatment for orthopaedic infection with local antibiotics was not associated with the emergence of specific antimicrobial resistance.

Antimicrobial treatment of patients with a periprosthetic joint infection: basic principles

The antibiotic treatment of periprosthetic joint infections (PJI) is complicated by the presence of biofilm produced by bacteria on the abiotic surface of the implant. Bacteria within the deeper layers of the biofilm become metabolically less active, resulting in antibiotic tolerance due to several mechanisms. This review describes the basic principles of antibiotic treatment in PJI in relation to the behavior of bacteria within the biofilm. The concept of biofilm-active antibiotics will be explained from an in vitro as well as in vivo perspective. Evidence from clinical studies on biofilm-active antibiotics in PJI will be highlighted, mainly focusing on the role of rifampicin for Gram-positive microorganisms and fluoroquinolones for Gram-negative microorganisms. The optimal treatment duration will be discussed as the timing of switching to oral antibiotic therapy.

Antibiotic-loaded bone substitutes therapy in the management of the moderate to severe diabetic foot infection: A meta-analysis

In recent years, local antibiotic-loaded bone substitutes (ALBS) have been used increasingly in the treatment of diabetic foot infection (DFI). The meta-analysis aimed to analyse the efficacy of ALBS on patients with moderate to severe DFI (with or without osteomyelitis). With an appropriate search strategy, 7 studies were selected for analysis (2 RCTs and 5 cohort studies). The result showed that the application of ALBS effectively reduced the length of hospital stay (WMD -5.55; 95% CI: -9.85 to -1.26; P = 0.01), the recurrence rates (RR 0.33; 95% CI: 0.15 to 0.69; P = 0.003) and the mortality rates (RR 0.22; 95% CI: 0.06 to 0.82; P = 0.02). Compared to the control groups, however, there was no difference in healing rates (RR 1.06; 95% CI: 0.96 to 1.18; P = 0.26), healing time (WMD -1.44; 95% CI: -3.37 to -0.49; P = 0.14), the number of debridement (WMD -1.98; 95% CI: -4.08 to 0.12; P = 0.06) and major amputation rates (RR 0.76; 95% CI: 0.35 to 1.61; P = 0.47). The ALBS appears to have some beneficial effects as an adjunct to standard surgery in the treatment of DFI with or without osteomyelitis, as it reduces recurrence rates, mortality rates, and length of hospital stay, but there was no statistically significant difference in enhancing wound healing.

The effect of guideline-based antimicrobial therapy on the outcome of fracture-related infections (EAT FRI Study)

AIM

This study investigated the compliance with a guideline-based antibiotic regimen on the outcome of patients surgically treated for a fracture-related infection (FRI).

METHOD

In this international multicenter observational study, patients were included when diagnosed with an FRI between 2015 and 2019. FRI was defined according to the FRI consensus definition. All patients were followed for at least one year. The chosen antibiotic regimens were compared to the published guidelines from the FRI Consensus Group and correlated to outcome. Treatment success was defined as the eradication of infection with limb preservation.

RESULTS

A total of 433 patients (mean age 49.7 ± 16.1 years) with FRIs of mostly the tibia (50.6%) and femur (21.7%) were included. Full compliance of the antibiotic regime to the published guidelines was observed in 107 (24.7%) cases. Non-compliance was mostly due to deviations from the recommended dosing, followed by the administration of an alternative antibiotic than the one recommended or an incorrect use or non-use of rifampin. Non-compliance was not associated with a worse outcome: treatment failure was 12.1% in compliant versus 13.2% in non-compliant cases (p = 0.87).

CONCLUSIONS

We report good outcomes in the treatment of FRI and demonstrated that minor deviations from the FRI guideline are not associated with poorer outcomes.

Study protocol: short against long antibiotic therapy for infected orthopedic sites - the randomized-controlled SALATIO trials

BACKGROUND

Few studies address the appropriate duration of post-surgical antibiotic therapy for orthopedic infections; with or without infected residual implants. We perform two similar randomized-clinical trials (RCT) to reduce the antibiotic use and associated adverse events.

METHODS

Two unblinded RCTs in adult patients (non-inferiority with a margin of 10%, a power of 80%) with the primary outcomes "remission" and "microbiologically-identical recurrences" after a combined surgical and antibiotic therapy. The main secondary outcome is antibiotic-related adverse events. The RCTs allocate the participants between 3 vs. 6 weeks of post-surgical systemic antibiotic therapy for implant-free infections and between 6 vs. 12 weeks for residual implant-related infections. We need a total of 280 episodes (randomization schemes 1:1) with a minimal follow-up of 12 months. We perform two interim analyses starting approximately after 1 and 2 years. The study approximatively lasts 3 years.

DISCUSSION

Both parallel RCTs will enable to prescribe less antibiotics for future orthopedic infections in adult patients.

TRIAL REGISTRATION

ClinicalTrial.gov NCT05499481. Registered on 12 August 2022.

PROTOCOL VERSION

2 (19 May 2022).

Local Antibiotics in the Treatment of Diabetic Foot Infections: A Narrative Review

Along with the increasing global burden of diabetes, diabetic foot infections (DFI) and diabetic foot osteomyelitis (DFO) remain major challenges for patients and society. Despite progress in the development of prominent international guidelines, the optimal medical treatment for DFI and DFO remains unclear as to whether local antibiotics, that is, topical agents and local delivery systems, should be used alone or concomitant to conventional systemic antibiotics. To better inform clinicians in this evolving field, we performed a narrative review and summarized key relevant observational studies and clinical trials of non-prophylactic local antibiotics for the treatment of DFI and DFO, both alone and in combination with systemic antibiotics. We searched PubMed for studies published between January 2000 and October 2022, identified 388 potentially eligible records, and included 19 studies. Our findings highlight that evidence for adding local antibiotic delivery systems to standard DFO treatment remains limited. Furthermore, we found that so far, local antibiotic interventions have mainly targeted forefoot DFO, although there is marked variation in the design of the included studies. Suggestive evidence emerging from observational studies underscores that the addition of local agents to conventional systemic antibiotics might help to shorten the clinical healing time and overall recovery rates in infected diabetic foot ulcers, although the effectiveness of local antibiotics as a standalone approach remains overlooked. In conclusion, despite the heterogeneous body of evidence, the possibility that the addition of local antibiotics to conventional systemic treatment may improve outcomes in DFI and DFO cannot be ruled out. Antibiotic stewardship principles call for further research to elucidate the potential benefits of local antibiotics alone and in combination with conventional systemic antibiotics for the treatment of DFI and DFO.

Localized, on-demand, sustained drug delivery from biopolymer-based materials

INTRODUCTION

Local drug delivery facilitiates higher concentrations of drug molecules at or near the treatment site to enhance treatment efficiency and reduce drug toxicity and other systemic side effects. However, local drug delivery systems face challenges in terms of encapsulation, delivery, and controlled release of therapeutics.

AREAS COVERED

We provide an overview of naturally derived biopolymer-based drug delivery systems for localized, sustained, and on-demand treatment. We introduce the advantages and limitations of these systems for drug encapsulation, delivery, and local release, as well as recent applications.

EXPERT OPINION

Naturally derived biopolymers like cellulose, silk fibroin, chitosan, alginate, hyaluronic acid, and gelatin are good candidates for localized drug delivery because they are readily chemically modified, biocompatible, biodegradable (with the generation of metabolically compatible degradation products), and can be processed in aqueous and ambient environments to maintain the bioactivity of various therapeutics. The tradeoff between the effective treatment dosage and the response by local healthy tissue should be balanced during the design of these delivery systems. Future directions will be focused on strategies to design tunable and controlled biodegradation rates, as well as to explore commercial utility in substituting biopolymer-based systems for currently utilized synthetic polymers for implants for drug delivery.

Mid- to long-term results of single-stage surgery for patients with chronic osteomyelitis using a bioabsorbable gentamicin-loaded ceramic carrier

AIMS

Excision of chronic osteomyelitic bone creates a dead space which must be managed to avoid early recurrence of infection. Systemic antibiotics cannot penetrate this space in high concentrations, so local treatment has become an attractive adjunct to surgery. The aim of this study was to present the mid- to long-term results of local treatment with gentamicin in a bioabsorbable ceramic carrier.

METHODS

A prospective series of 100 patients with Cierny-Mader Types III and IV chronic ostemyelitis, affecting 105 bones, were treated with a single-stage procedure including debridement, deep tissue sampling, local and systemic antibiotics, stabilization, and immediate skin closure. Chronic osteomyelitis was confirmed using strict diagnostic criteria. The mean follow-up was 6.05 years (4.2 to 8.4).

RESULTS

At final follow-up, six patients (six bones) had recurrent infection; thus 94% were infection-free. Three infections recurred in the first year, two in the second year, and one 4.5 years postoperatively. Recurrence was not significantly related to the physiological class of the patient (1/20 Class A (5%) vs 5/80 Class B (6.25%); p = 0.833), nor was it significantly related to the aetiology of the infection, the organisms which were cultured or the presence of nonunion before surgery (1/10 with nonunion (10%) vs 5/90 without nonunion (5.6%); p = 0.570). Organisms with intermediate or high-grade resistance to gentamicin were significantly more likely in polymicrobial infections (9/21; 42.8%) compared with monobacterial osteomyelitis (7/79 (8.9%); p < 0.001). However, recurrence was not significantly more frequent when a resistant organism was present (1/16 for resistant cases (6.25%) vs 5/84 in those with a microbiologically sensitive infection (5.95%); p = 0.958).

CONCLUSION

We found that a single-stage protocol, including the use of a high-delivery local antibiotic ceramic carrier, was effective over a period of several years. The method can be used in a wide range of patients, including those with significant comorbidities and an infected nonunion.Cite this article: Bone Joint J 2022;104-B(9):1095-1100.

Treatment of Infected Nonunions With Bone Defects Using Autologous Bone Graft and Absorbable Antibiotic-Loaded Calcium Sulfate-Hydroxyapatite Paste

BACKGROUND

Revision surgery in the presence of infection carries high risks. We describe our results using a new technique to treat these challenging problems. We treated infected nonunions with cavitary voids with adjuvant antibiotic loaded calcium sulfate-hydroxyapatite paste composite and autologous bone graft (ABG) layer technique coupled with stable fixation.

METHODS

Thirty consecutive patients who underwent revision foot and ankle surgery for an infected nonunion were prospectively studied. Following multidisciplinary team workup, surgical debridement and biopsies were undertaken. Bone voids were measured and classified according to containment and size. ABG was mixed and layered with an adjuvant antibiotic-loaded calcium sulfate-hydroxyapatite paste followed by surgical reconstruction including arthrodesis and fixation. Empirical and pathogen-specific antibiotics were instituted until intraoperative sample-specific antibiotics were identified and used. Patients were prospectively followed up for a minimum of 1 year.

RESULTS

The male-female ratio was 16:14, mean age was 51.3 years, and 23.3% smoked at definitive surgery. Void volume was <1 cm³ (n=9), 1-2 cm³ (n = 13), and >2 cm³ (n=8). No patients either were lost to follow-up or had a further infective episode at a mean of 38.3 months; 86.7% united with fusion on imaging. Four patients had radiographic evidence of nonunion; 3 were asymptomatic and 1 required revision surgery (void >2 cm³). Independent ambulation was achieved at an average of 12 weeks, at 1 year mean American Orthopaedic Foot & Ankle Society score was 77.7 (SD 9.59), and the Manchester-Oxford Foot Questionnaire reached an effect size >0.5 in all domains at 1 year following surgery. The union rate was independent of smoking status and vitamin D deficiency (P = .94).

CONCLUSION

Layered autologous bone grafting with adjuvant antibiotic-loaded calcium sulfate-hydroxyapatite paste has been shown to be effective and safe in revision arthrodesis, with low comorbidities in void gaps without infection recurrence.

The effectiveness of systemic antibiotics for osteomyelitis of the foot in adults with diabetes mellitus: a systematic review protocol

Background

Osteomyelitis of the foot is a major complication of diabetes that can be limb and life threatening. Systemic antibiotic pharmacotherapy is often used first line to eradicate infection and allow restoration of devitalised bone.

The aim is to conduct a systematic review of the effectiveness of systemic antibiotics on osteomyelitis of the foot in adults with diabetes mellitus.

Methods

A systematic review of all interventional studies treating osteomyelitis with systemic antibiotics in participants with diabetes mellitus and an ulcer of the foot below the malleoli will be conducted. Studies not available in English and in people below the age of 18 will be excluded. Study selection will follow the Patient Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA-P guidelines). The quality of the studies will be assessed using the Cochrane risk-of-bias tool (RoB 2) for all randomised controlled trials and the Newcastle–Ottawa Scale (NOS) will be used for non-randomised controlled trials. Electronic databases will be searched with no timeline restrictions.

Data Extraction

All identified references will be imported to the Rayyan Application. Studies for eligibility will be screened by two reviewers. One reviewer will perform the data extraction and quality appraisal will be conducted by two authors. If sufficient data is available, the quality will be analysed and a meta-analysis will be performed. Data synthesis will be conducted, and meta-analysis undertaken using RevMan 5.4.1 Meta-analysis software. Non-parametric data may be compared between selective intervention and outcomes.

Discussion

The results of this systematic review will identify the effectiveness of systemic antibiotic therapy on osteomyelitis of the foot in people with diabetes based on the set outcome measure criteria. The findings will establish if there are existing consistent standards or variation in practice when treating diabetic foot osteomyelitis (DFO). The study may establish if guidelines are required to standardise practice when treating DFO with systemic antibiotic therapy. This systematic review protocol will synthesise the existing evidence on the effectiveness of systemic antibiotic therapy for treating DFO.

Trial registration

International Prospective Register for Systematic Reviews (PROSPERO) number CRD42021245424.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13047-022-00554-3.

Outcome Analysis of the Use of Cerament® in Patients with Chronic Osteomyelitis and Corticomedullary Defects

Background: Chronic osteomyelitis (OM) is a progressive but mostly low-grade infection of the bones. The management of this disease is highly challenging for physicians. Despite systematic treatment approaches, recurrence rates are high. Further, functional and patient-reported outcome data are lacking, especially after osseous defects are filled with bioresorbable antibiotic carriers. Objective: To assess functional and patient-reported outcome measures (PROM) following the administration of Cerament^® G or V due to corticomedullary defects in chronic OM. Methods: We conducted a retrospective study from 2015 to 2020, including all patients who received Cerament^® for the aforementioned reason. Patients were diagnosed and treated in accordance with globally valid recommendations, and corticomedullary defects were filled with Cerament^® G or V, depending on the expected germ spectrum. Patients were systematically followed up, and outcome measures were collected during outpatient clinic visits. Results: Twenty patients with Cierny and Mader type III OM were included in this study and followed up for 20.2 ± 17.2 months (95%CI 12.1–28.3). Ten of these patients needed at least one revision (2.0 ± 1.3 revisions per patient (95%CI 1.1–2.9) during the study period due to OM persistence or local wound complications. There were no statistically significant differences in functional scores or PROMs between groups. Conclusion: The use of Cerament^® G and V in chronic OM patients with corticomedullary defects appears to have good functional outcomes and satisfactory PROMs. However, the observed rate of local wound complications and the OM persistence rate may be higher when compared to previously published data.

Septic Failure After One-Stage Exchange for Prosthetic Joint Infection of the Hip: Microbiological Implications

BACKGROUND

The microbiological implications of septic failure after 1-stage exchange for prosthetic joint infection (PJI) of the hip remain unclear.

METHODS

Information was gathered on comorbidities, previous procedures, preoperative and postoperative microbiology results, methods of detection, and antibiotic resistance patterns, for all patients, who developed septic failure after 1-stage exchange for PJI of the hip performed at our institution during 2001-2017.

RESULTS

Seventy-seven patients were identified. Septic failure was diagnosed a mean of 1.7 (standard deviation 2.3, range 0-11.8) years later. Although the spectrum of microorganisms was similar to preoperative, in the majority of patients (55%), the initial microorganism(s) was (were) replaced by (a) totally different microorganism(s). Overall, there was a decrease in the number of polymicrobial PJIs. The number of patients with high virulent microorganisms decreased significantly from 52 to 36 (P = .034). The number of PJIs due to gram-negative pathogens remained similar (11 vs 14, P = .491). The number of rifampicin-resistant staphylococci, fluoroquinolone-resistant streptococci, enterococci, and fungi changed from 8 to 15, 0 to 2, 7 to 3, and 1 to 2, respectively, but these changes did not reach statistical significance.

CONCLUSION

The majority of reinfections is caused by different infecting bacteria, hence it is essential to perform a new diagnostic workup and not base treatment decisions (solely) on historical cultures. We were furthermore unable to irrefutably prove that, from a microbiological point of view, septic failure after 1-stage exchange comes with increased challenges. Given the time interval to failure, we propose that a longer follow-up of these patients is needed, than previously suggested.

In vitro drug release and antibacterial activity evaluation of silk fibroin coated vancomycin hydrochloride loaded poly (lactic-co-glycolic acid) (PLGA) sustained release microspheres

Currently, the treatment of osteomyelitis poses a great challenge to clinical orthopedics. The use of biodegradable materials combined with antibiotics provides a completely new option for the treatment of osteomyelitis. In this study, vancomycin hydrochloride (VANCO) loaded poly (lactic-co-glycolic acid) (PLGA) microspheres were prepared by a double emulsion solvent evaporation method, and the in vitro drug release behaviors of the drug loaded microspheres were explored after coating with different concentrations of silk fibroin (SF). Drug loading, encapsulation efficiency, Scanning electron microscopy, particle size analysis, Fourier transform infrared spectroscopy, hydrophilicity, in vitro drug release, and in vitro antibacterial activity were evaluated. The results showed that the drug loading of vancomycin loaded PLGA microspheres was (24.11 ±1.72)%, and the encapsulation efficiency was (48.21 ±3.44)%. The in vitro drug release indicated that the drug loaded microspheres showed an obvious initial burst release, and the drug loaded microspheres coated with SF could alleviate the initial burst release in varying degrees. It also can reduce the amount of cumulative drug release, and the effect of microspheres coated with 0.1% concentration of SF is the best. The time of in vitro drug release in different groups of drug loaded microspheres can be up to 28 days. The microspheres coated with (0.1%SF) or without (0%SF) SF showed a cumulative release of (82.50±3.51)% and (67.70±3.81)%,respectively. Therefore, the surface coating with SF of vancomycin loaded microspheres can alleviate the initial burst release, reduce the cumulative drug release, potentially prolong the drug action time, and improve the anti-infection effect.

What is the rate of reinfection with different and difficult-to-treat bacteria after failed one-stage septic knee exchange?

PURPOSE

Re-operation after septic failure of a one-stage exchange for prosthetic joint infection (PJI) of the knee is a highly challenging procedure with concerns over residual bone stock, soft tissues, and stability. The associated changes in microbiology in cases of reinfection are still largely unknown.

METHODS

A comprehensive analysis was performed of all patients treated at our tertiary institution between 2001 and 2017 who developed reinfection after a one-stage exchange for PJI of the knee. Prerequisites for inclusion were a certain diagnosis of PJI according to the ICM criteria and a minimum follow-up of three years. Data on comorbidities, previous surgical interventions, microbiological findings at the time of the initial one-stage exchange and at the time of reinfection, detection methods, and antibiotic resistance patterns were retrospectively studied.

RESULTS

Sixty-six patients were identified that met the inclusion criteria. Reinfection occurred after a mean time interval of 27.7 months (SD ± 33.9, range 1-165). Ten types of bacteria were found that were not present before the one-stage exchange. The causative pathogen remained identical in 22 patients (33%) and additional microorganisms were detected in ten patients (15%). Half of the reinfections were however due to (a) completely different microorganism(s). A significant increase in the number of PJIs on the basis of high-virulent (23 vs 30, p = 0.017) and difficult-to-treat bacteria (13 vs 24, p = 0.035) was found.

CONCLUSION

The present study provides a novel insight into the microbiological changes following septic failure after one-stage exchange for PJI of the knee. A higher prevalence of more difficult-to-treat bacteria might increase the complexity of subsequent procedures. Also, a longer follow-up of these patients than previously suggested seems in order.

Pathogenesis and Treatment of Cytokine Storm Induced by Infectious Diseases

Cytokine storm is a phenomenon characterized by strong elevated circulating cytokines that most often occur after an overreactive immune system is activated by an acute systemic infection. A variety of cells participate in cytokine storm induction and progression, with profiles of cytokines released during cytokine storm varying from disease to disease. This review focuses on pathophysiological mechanisms underlying cytokine storm induction and progression induced by pathogenic invasive infectious diseases. Strategies for targeted treatment of various types of infection-induced cytokine storms are described from both host and pathogen perspectives. In summary, current studies indicate that cytokine storm-targeted therapies can effectively alleviate tissue damage while promoting the clearance of invading pathogens. Based on this premise, "multi-omics" immune system profiling should facilitate the development of more effective therapeutic strategies to alleviate cytokine storms caused by various diseases.

Biodegradable Antimicrobial Agent/Analgesic/Bone Morphogenetic Protein-Loaded Nanofibrous Fixators for Bone Fracture Repair

Purpose

Postoperative infection and pain management are of great concern to orthopedic surgeons. Although there are several protocols available to deal with these aspects, they are fraught with complications, such as cartilage damage, cardiovascular and neurological intoxication, and systemic adverse responses. Therefore, it is necessary to develop safe and effective perioperative protocols. In the current study, antimicrobial agents/analgesics/growth factor-embedded biodegradable hybrid fixators (polycaprolactone fixator + poly[lactide-co-glycolide] sheath-core structured nanofibers) for bone fracture repair were designed.

Methods

The biodegradable hybrid fixators were fabricated using solution-extrusion three-dimensional printing and electrospinning. In vitro, the characteristics of the hybrid fixators were examined. Additionally, the release of the incorporated vancomycin, ceftazidime, lidocaine, and bone morphogenetic protein-2 (BMP-2) was evaluated. The in vivo efficacy including drug-eluting properties, fracture repair, and pain management of the biomolecule-loaded nanofibrous fixators was investigated in rabbit rib-fracture models.

Results

The nanofibrous fixators released vancomycin, ceftazidime, and lidocaine in a sustained manner under both in vitro and in vivo conditions and protected BMP-2 from burst release. The implantation of these hybrid fixators around the fractured rib significantly improved animal activities and bone union, indicating that the inclusion of analgesic in the fixator effectively reduced postsurgical pain and thereby helped in recovery.

Conclusion

The novel biomolecule-loaded nanofibrous hybrid fixators resulted in excellent therapeutic outcomes. These fixators may be effective in the repair of rib fractures in clinical settings and may help mitigate surgical complications, such as infection, nonunion, and intolerable postoperative pain.

Advances in pharmacotherapy for diabetic foot osteomyelitis

Introduction: The diagnosis of diabetic foot osteomyelitis (DFO) is usually clinical. Its severity is related to the location and depth of the lesion, and the presence of necrosis or gangrene. The aetiology of diabetic foot osteomyelitis (DFO) is usually polymicrobial, and DFO is often associated with chronic or recurring ulceration.Areas covered: We built on the  International Working Group on the Diabetic Foot (IWGDF) guidelines on the management of diabetic foot infection, providing an outline of the current and new concepts in pharmacotherapy in DFO. We assess future strategies in both medical, surgical and combination management of DFO.Expert opinion: Surgical removal of infected bone is considered as the standard treatment, but a medical approach of certain selected situations has now proven efficacy in selected patients. The combination of new modalities in local antibiotic delivery may provide better long-term solutions and more lasting remission and avoid the disadvantages of prolonged systemic antibiotics.

Surgical strategies for prevention of amputation of the diabetic foot

Prevention of amputation has become a key objective of clinicians providing care to patients with high-risk diabetic foot problems. In this regard, the multidisciplinary diabetic foot team (MDFT) has been embraced as the most effective way to manage patients with foot ulcers, infections, and Charcot feet. Importantly, such specialized teams have also integrated various surgical specialties to enable more expedient management of these often complex conditions. Experienced diabetic foot surgeons over the last three or four decades have contributed much to this discipline, whereby foot-sparing reconstructive procedures or minor amputations have become fundamental strategies for limb preservation teams. Central to limb salvage, of course, is the recognition of underlying vascular insufficiency and the importance of prompt (endo)vascular intervention. Restoration of adequate perfusion is essential to allow the podiatric, orthopaedic, or plastic surgeon to perform indicated functional reconstructive or minor amputation procedures. This evidence-based overview discusses the various indications and surgical principles inherent in modern concepts aimed at preventing amputation in the high-risk diabetic foot.

A Hyaluronic Acid Hydrogel Loaded with Gentamicin and Vancomycin Successfully Eradicates Chronic Methicillin-Resistant Staphylococcus aureus Orthopedic Infection in a Sheep Model

Implantable orthopedic devices have had an enormously positive impact on human health; however, despite best practice, patients are prone to developing orthopedic device-related infections (ODRI) that have high treatment failure rates. One barrier to the development of improved treatment options is the lack of an animal model that may serve as a robust preclinical assessment of efficacy. We present a clinically relevant large animal model of chronic methicillin-resistant Staphylococcus aureus (MRSA) ODRI that persists despite current clinical practice in medical and surgical treatment at rates equivalent to clinical observations. Furthermore, we showed that an injectable, thermoresponsive, hyaluronic acid-based hydrogel loaded with gentamicin and vancomycin outperforms current clinical practice treatment in this model, eliminating bacteria from all animals. These results confirm that local antibiotic delivery with an injectable hydrogel can dramatically increase treatment success rates beyond current clinical practice, with efficacy proven in a robust animal model.

Medical Versus Surgical Treatment for the Management of Diabetic Foot Osteomyelitis: A Systematic Review

A systematic review and quality assessment was performed to assess the management of diabetic foot osteomyelitis by medical or surgical treatment. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist was used. All selected studies were evaluated using the Cochrane Risk of Bias Tool to assess the risk of bias for randomized controlled trials. The literature was revised using PubMed (Medline) and Embase (Elsevier) up to September 2020 to identify clinical trials assessing medical or surgical treatment to manage diabetic foot osteomyelitis. A total of six clinical trials that met our inclusion criteria, with a total of 308 participants. Healing rate, complete closure of the wound, and type of complications were the outcomes evaluated. Risk of bias assessment showed that only two of the six clinical trials included in the systematic review had a low risk of bias. Based on our findings, we believe that the management of diabetic foot osteomyelitis remains challenging. There are few high-quality clinical trials that both stratify clinical presentations and compare these treatments. We conclude that the available evidence is insufficient to identify the best option to cure diabetic foot osteomyelitis.

Financial analysis of revision knee surgery at a tertiary referral centre as classified according to the Revision Knee Complexity Classification (RKCC)

BACKGROUND

Revision total knee arthroplasty (rTKA) can be complex, with greater costs to the treating hospital than primary TKA. A rTKA regional network has been proposed in England. The aim of this work was to accurately quantify current costs and reimbursement for the rTKA service and to assess whether costs are proportional to case complexity at a tertiary referral centre within the National Health Service (NHS).

METHODS

A review of all rTKA performed at our institution over two consecutive financial years (2017-2019) was performed. Cases were classified according to the Revision Knee Complexity Classification (RKCC) and by mode of failure; "infected" and "non-infected". Financial data was acquired through Patient-Level Information and Costing System (PLICS). The primary outcome was the financial difference between tariff and cost per episode. Comparisons between groups were analysed using analysis of variance and two-tailed unpaired t-test as appropriate.

RESULTS

159 patients underwent 188 rTKA procedures. Length of stay and cost significantly increased between complexity groups (p < 0.0001) and for infected revisions (p < 0.0001). All groups sustained a mean deficit but this significantly increased with revision complexity (from £1,903 to £5,269 per case) and for infected revisions. The total deficit to the Trust for the two-year rTKA service was £667,091.

CONCLUSIONS

The current level of NHS reimbursement are inadequate for centres that offer rTKA and should be more closely aligned to case complexity. An increase in the most complex rTKA at major revision centres will undoubtedly place an even greater strain on the finances of these units.