Treatment of periprosthetic infections: an economic analysis

Microbiological profiles in periprosthetic joint infections after total knee arthroplasty: a comparative analysis of diabetic and non-diabetic patients

AIM OF THE STUDY

The purpose of this study is to conduct a comparative analysis of the microbiological profiles in periprosthetic joint infections (PJIs) after total knee arthroplasty (TKA) between diabetic and non-diabetic patients. The study aims to address what are the variations in microbial colonization and infection patterns between diabetic and non-diabetic patients undergoing total knee arthroplasty.

METHODS

A retrospective analysis of 2,569 culture-positive cases of PJIs post-TKA was conducted, comparing outcomes between diabetic (n = 321) and non-diabetic (n = 2,248) patients. Demographic, clinical, and microbiological data were collected and analyzed using descriptive statistics, chi-squared tests, logistic regression, and other statistical tests.

RESULTS

Diabetic patients exhibited distinct microbial colonization patterns, with a higher prevalence of pathogens such as Staphylococcus aureus (p = 0.033), Pseudomonas aeruginosa (p < 0.001), Streptococcus spp. (Streptococcus agalactiae and Streptococcus dysgalactiae; p = 0.010, 0.016 respectively), Candida spp. (p = 0.010), and Corynebacterium spp. (p = 0.024). Additionally, diabetic patients were at increased risk of polymicrobial infections. Comorbidities associated with diabetes, including chronic pulmonary disease, renal insufficiency, and peripheral artery disease, were significantly more prevalent in diabetic patients and further complicated PJI outcomes.

CONCLUSION

This study underscores the importance of tailored perioperative antimicrobial strategies and vigilant infection control measures in diabetic patients undergoing TKA. Understanding the differential microbial profiles and associated comorbidities can inform targeted interventions to mitigate the risk of PJIs and improve outcomes in this high-risk population. Further research is warranted to elucidate the underlying mechanisms and optimize management strategies for diabetic patients undergoing TKA.

Advances in antimicrobial orthopaedic devices and FDA regulatory challenges

Implant-associated infections, caused by the formation of biofilms especially antibiotic resistant organisms, are among the leading causes of orthopaedic implant failure. Current strategies to combat infection and biofilm focus on either inhibiting bacterial growth or preventing bacterial adherence that could lead to biofilm creation. Despite research on developing numerous antimicrobial orthopaedic devices, to date, no robust solution has been translated to the clinic. One of the key bottlenecks is the disconnect between researchers and regulatory agencies. In this review, we outline recent strategies for minimizing orthopaedic implant-associated infections. In addition, we discuss the relevant Food and Drug Administration regulatory perspectives, challenges. We also highlight emerging technologies and the directions the field that is expected to expand. We discuss in depth challenges that include identifying strategies that render implants antibacterial permanently or for a long period of time without the use of antimicrobial compounds that could generate resistance in pathogens and negatively impact osseointegration.

The treatment of bacterial biofilms cultivated on knee arthroplasty implants using the bioelectric effect

Introduction: The formation of bacterial biofilms on knee arthroplasty implants can have catastrophic consequences. The aim of this study was to analyze the effectiveness of the bioelectric effect in the elimination of bacterial biofilms on cultivated knee arthroplasty implants. Methods: A novel device was designed to deliver a bioelectric effect on the surface of knee arthroplasty implants. 4-femoral prosthetic implants were cultivated with a staphylococcus aureus inoculum for 15 days. The components were divided into four different groups: A (not treated), B (normal saline 20-minutes), C (bioelectric effect 10-minutes), D (bioelectric effect 20-minutes). The implants were sonicated, and the detached colonies were quantified as the number of colony-forming unit (CFUs). The implants were sterilised and the process was repeated in a standardized manner four more times, to obtain a total of five samples per group. Results: The number of the CFUs after a 10-minute exposure to the bioelectric effect was of 208.2 ± 240.4, compared with 6,041.6 ± 2010.7 CFUs in group A, representing a decrease of 96.5% ± 4.3 (p = 0.004). And a diminution of 91.8% ± 7.9 compared with 2,051.0 ± 1,364.0 CFUs in group B (p = 0.109). The number of bacterial colonies after a 20-minute exposure to the bioelectric effect was 70 ± 126.7 CFUs, representing a decrease of 98.9% ± 1.9 (p = 0.000) compared with group A. And a decrease of 97.8% ± 3.0 (p = 0.019) compared with group B. Conclusions: The bioelectric effect was effective in the elimination of bacterial biofilm from knee arthroplasty implants. This method could be used in the future as part of conventional surgical procedures.

Systemic Inflammatory Response Syndrome and Prosthetic Joint Infection

BACKGROUND

The development of systemic inflammatory response syndrome (SIRS) criteria leads to increased mortality. Little is known about development of SIRS in patients who have prosthetic joint infection (PJI). We aimed to determine the incidence, risk factors, clinical outcomes, and causative organisms in patients who develop SIRS with PJI.

METHODS

We retrospectively identified 655 patients (321 men, 334 women; 382 total hip, 273 total knee) who have hip or knee PJI at 1 institution between July 1, 2015 and December 31, 2020. We formed 2 groups: patients who have SIRS alert (PJI + SIRS) and patients who do not have SIRS alert (PJI). We analyzed clinical outcomes, comorbidities, and operating room culture results.

RESULTS

Of 655 patients, 63 developed SIRS with PJI (9.6%). Intensive care unit (ICU) admission rates (27.0 versus. 6.9%, P < .001) and length of stay (7.7 versus. 5.6 days, P = .003) were greater in PJI + SIRS. At 2 years, reoperation (36.5 versus. 22.3%, P = .01) and mortality rates (17.5 versus. 8.8%, P = .03) were greater in PJI + SIRS. Risk factors included deficiency anemia (P = .001), blood loss anemia (P = .013), uncomplicated diabetes (P = .006), diabetes with complication (P = .001), electrolyte disorder (P < .00001), neurological disorder (P = .0001), paralysis (P = .026), renal failure (P = .005), and peptic ulcer disease (P = .004). Staphylococcus aureus more commonly speciated on tissue cultures in PJI + SIRS (P = .002).

CONCLUSION

The incidence of SIRS is 10% among patients who have PJI. Development of PJI + SIRS is associated with increased lengths of stay, ICU admissions, and 2-year reoperation and mortality rates. Identifying certain comorbidities can stratify patients' risk of developing PJI + SIRS.

Preventative and therapeutic potential of tocotrienols on musculoskeletal diseases in ageing

Musculoskeletal health is paramount in an ageing population susceptible to conditions such as osteoporosis, arthritis and fractures. Age-related changes in bone, muscle, and joint function result in declining musculoskeletal health, reduced mobility, increased risk of falls, and persistent discomfort. Preserving musculoskeletal wellbeing is essential for maintaining independence and enhancing the overall quality of life for the elderly. The global burden of musculoskeletal disorders is significant, impacting 1.71 billion individuals worldwide, with age-related muscle atrophy being a well-established phenomenon. Tocotrienols, a unique type of vitamin E found in various sources, demonstrate exceptional antioxidant capabilities compared to tocopherols. This characteristic positions them as promising candidates for addressing musculoskeletal challenges, particularly in mitigating inflammation and oxidative stress underlying musculoskeletal disorders. This review paper comprehensively examines existing research into the preventive and therapeutic potential of tocotrienols in addressing age-related musculoskeletal issues. It sheds light on the promising role of tocotrienols in enhancing musculoskeletal health and overall wellbeing, emphasizing their significance within the broader context of age-related health concerns.

Emergency Department Visits Following Patellofemoral Arthroplasty

BACKGROUND

Readmissions are a typical postoperative metric; however, postoperative emergency department (ED) utilization also negatively affects patient care. Few studies have explored this metric after patellofemoral arthroplasty (PFA); thus, we investigated the incidence, timing, predictive factors, and reasons for ED utilization within 90 days after PFA.

METHODS

Using the 2010 to 2021 PearlDiver M151Ortho data set, a national billing claims database containing information of over 151 million US orthopaedic patients across all payer types, the study examined weekly ED visits up to 90 days after PFA and conducted univariate and multivariate analyses to identify predictive factors.

RESULTS

Of 7765 PFA patients, 11.2% (922) had ED visits within 90 days, with 46.7% (431) occurring in the first 3 weeks. Independent predictors of ED utilization included younger age (OR 1.40 per decade decrease), higher Elixhauser Comorbidity Index (OR 1.44 per 2-point increase), surgery in the South or Midwest (OR 1.27 and 1.31), and Medicaid insurance (OR 1.74). Postoperative pain accounted for 50.6% of visits.

CONCLUSIONS

11.2% of PFA patients visited the ED within 90 days, primarily for postoperative pain. Younger, more comorbid, and Medicaid-insured patients were most likely to use the ED. This study suggests the need for targeted perioperative pain management to reduce ED utilization after PFA.

Induction Heating Triggers Antibiotic Release and Synergistic Bacterial Killing on Polymer-Coated Titanium Surfaces

Infection is a major complication associated with orthopedic implants. It often involves the development of biofilms on metal substrates, which act as barriers to the host's immune system and systemic antibiotic treatment. The current standard of treatment is revision surgery, often involving the delivery of antibiotics through incorporation into bone cements. However, these materials exhibit sub-optimal antibiotic release kinetics and revision surgeries have drawbacks of high cost and recovery time. Herein, a new approach is presented using induction heating of a metal substrate, combined with an antibiotic-loaded poly(ester amide) coating undergoing a glass transition just above physiological temperature to enable thermally triggered antibiotic release. At normal physiological temperature, the coating provides a rifampicin depot for >100 days, while heating of the coating accelerates drug release, with >20% release over a 1-h induction heating cycle. Induction heating or antibiotic-loaded coating alone each reduce Staphylococcus aureus (S. aureus) viability and biofilm formation on Ti, but the combination causes synergistic killing of S. aureus as measured by crystal violet staining, determination of bacterial viability (>99.9% reduction), and fluorescence microscopy of bacteria on surfaces. Overall, these materials provide a promising platform enabling externally triggered antibiotic release to prevent and/or treat bacterial colonization of implants.

The Impact of a Dedicated Multidisciplinary Team Approach for Prosthetic Joint Infections of the Lower Limb

Introduction

Prosthetic joint infections (PJI) of the hip and knee have significant morbidity and mortality, and present with varying local, host and microbiological factors. Given the broad presentation and complexity of PJI’s, we developed a dedicated multidisciplinary team (MDT) to manage this complex patient cohort, and report on our early outcomes.

Methods

This was a retrospective observational study of all patients diagnosed with a prosthetic joint infection of the hip or knee (n = 71) at our institution during a 4.5-year period. Patients treated after development of the MDT (post-MDT) (n = 44), were compared to a control group prior establishment of the MDT (pre-MDT) (n = 27).

Results

85.2% of individuals in the pre-MDT, and 85.7% of individuals in the post-MDT group were considered cured at a minimum 2 years post-operatively according to the Delphi-based definition. The total number of admissions to hospital (2.44 vs. 1.84) and total number of antibiotics used (3.37 vs. 2.75) decreased in the post-MDT group; however, differences were not considered statistically significant.

Discussion

Implementation of a dedicated MDT in the management of individuals with PJI’s of the lower limb at our hospital has allowed early and effective collaboration between healthcare personnel, with early promising results. Given the broad nature of PJI, future studies are ongoing to determine modifiable risk factors to reduce the incidence and improve outcomes of individuals with PJI’s where systems can then be implemented into already established MDTs to achieve the best clinical outcome for our patients.

Cost Drivers in Two-Stage Treatment of Hip Periprosthetic Joint Infection With an Antibiotic Coated Cement Hip Spacer

BACKGROUND

The current gold standard for treating chronic Periprosthetic Joint Infection (PJI) is a 2-stage revision arthroplasty. There has been little investigation into what specific patient and operative factors may be able to predict higher costs of this treatment.

METHODS

An institutional electronic health record database was retrospectively queried for patients who developed a PJI after a total hip arthroplasty, and underwent removal of the prosthesis and implantation of an antibiotic-impregnated articulating hip cement spacer. Patient demographics, surgical variables, hospital readmissions, emergency department visits, and post-operative complications were collected. Total costs were captured through an internal accounting database through 2 years post-operatively. Negative binomial regressions were utilized for multivariable analyses. A total of 55 hips with PJI were available for cost analyses.

RESULTS

A comorbidity index score was associated with a 70% increase (Odds Ratio (OR): 1.7 [1.18-2.5], P = .003) in total costs at 2-years. Illicit drug use was associated with a 70% increase in costs at 1-year post-operatively (OR 1.7 [1.18-2.5], P = .003). Metal-on-poly liners were associated with a 22% decrease in cost at 2-years post-operatively when compared to Cement-on-Bone articulating spacers, and Metal-on-poly -constrained liners accounted for 38% lower costs at 1-year (OR 0.62 [0.44-0.87], P = .004). Use of an intraoperative extended trochanteric osteotomy was associated with a 46 and 61% increase in cost at 1-year (OR 1.46 [1.14-1.89]) and 2-years (OR 1.61 [1.26-2.07], P < .001) post-operatively.

CONCLUSION

Age, comorbidity index score, drug use, and extended trochanteric osteotomy were associated with increased costs of PJI treatment. This may be used to improve reimbursement models and target areas of cost savings.

The efficacy of vancomycin-loaded biphasic calcium phosphate bone substitute in the promotion of new bone growth and the prevention of postoperative infection

Background: Due to the increasing need for suitable alternatives to bone grafts, artificial bones made of biphasic calcium phosphate (BCP) are currently being extensively researched. These porous bone substitutes have also demonstrated considerable incorporation with the host bone, and new bone is able to grow within the porous structure. They therefore offer a potential therapeutic approach for bone defects.

Methods: Vancomycin-loaded Bicera™, a BCP bone substitute, was investigated in order to prevent implant-associated osteomyelitis and postoperative infection after orthopedic surgery. The loading capacity of Bicera™ was measured to understand its potential antibiotic adsorption volume. An antibiotic susceptibility test was also carried out to analyze the effect of Bicera™ loaded with different concentrations of vancomycin on the growth inhibition of methicillin-resistant Staphylococcus aureus (MRSA). Vancomycin-loaded Bicera™ was implanted into rabbits with bone defects, and general gross, radiographic, and histological evaluation was undertaken at 4, 12, and 24 weeks after implantation.

Results: The maximum loading capacity of vancomycin-loaded Bicera™ was 0.9 ml of liquid regardless of the vancomycin concentration. Antibiotic susceptibility tests showed that vancomycin-loaded Bicera™ inhibited the growth of MRSA for 6 weeks. In addition, animal studies revealed that new bone grew into the vancomycin-loaded Bicera™. The percentage of new bone formation from 4 to 24 weeks after implantation increased from 17% to 36%.

Conclusion: Vancomycin-loaded Bicera™ could effectively inhibit the growth of MRSA in vitro. It was found to incorporate into the host bone well, and new bone was able to grow within the bone substitute. The results of this study indicate that vancomycin-loaded Bicera™ is a potential bone substitute that can prevent implant-associated osteomyelitis and postoperative infection.

One-stage revision arthroplasty in a patient with ochronotic arthropathy accompanied by joint infection: A case report

BACKGROUND

Ochronotic arthropathy (OcA) is a rare disease, which is caused by the accumulation of homogentisic acid in the joint. Patients with OcA have obvious joint pain and the disease progresses rapidly, eventually resulting in disability. Arthroplasty is an efficacious treatment in patients with OcA. However, when OcA patients have joint infection, is joint replacement an option? In the present report, we performed total knee arthroplasty in a patient with OcA and knee infection under the guidance of one-stage revision theory.

CASE SUMMARY

A 64-year-old male was referred to our hospital due to severe left knee pain with limited mobility for 2 years. On physical examination, the patient was found to have dark brown pigmentation of the sclera and auricle. Laboratory test results showed elevations in C-reactive protein level (65.79 mg/L) and erythrocyte sedimentation rate (90.00 mm/h). The patient underwent debridement of the left knee joint, during which the cartilage surface of the knee joint was found to be black-brown in color. Bacterial culture of synovial fluid revealed Achromobacter xylosoxidans. We then carried out arthroplasty under the guidance of the theory of one-stage revision. After surgery, the patient's left knee joint pain disappeared and function recovered without joint infection.

CONCLUSION

OcA accompanied by joint infection is rare. One-stage revision arthroplasty may be a treatment option for this disease.

A Decision Support Framework for Periprosthetic Joint Infection Treatment: A Cost-Effectiveness Analysis Using Two Modeling Approaches

Today, periprosthetic joint infection (PJI) is one of the leading indications for revision surgery and the most ominous complication in artificial joint patients. The current state of the art for treating PJI requires the development of methods for planning the costs at different scales to facilitate the selection of the best treatment methods. In this paper, we perform a cost-effectiveness assessment for strategies related to the treatment of PJI using a composite decision support modeling framework. Within the framework, two models are implemented: a detailed discrete-event probabilistic model based on the decision tree approach and a dynamic Markov model with generalized states. The application of the framework is demonstrated on the dataset which was provided by the Russian Scientific Research Institute of Traumatology and Orthopedics named after R.R. Vreden. The analyzed dataset contains 600 patient records divided into two groups (retrospective group, based on old records, and prospective group, based on real-time follow-up). The cost-effectiveness of treatment methods was compared based on associated costs and QALY units gained, with the mentioned two indicators calculated using two models independently from each other. As a result, two comparative rankings of cost-effectiveness of PJI treatment methods were presented based on the model output.

Direct Intra-articular Antibiotic Administration for Acute Prosthetic Joint Infection in Knee Arthroplasty

Prosthetic joint infection (PJI) remains a challenge to treat. We utilized intra-articular administration of antibiotics for the treatment of two infected total knee arthroplasties. The first patient developed an early post-operative infection with persistent wound drainage within a week after primary total knee arthroplasty (TKA). The second patient had an acute hematogenous infection, presenting with knee pain with a preceding history of leg cellulitis, one year after a primary TKA. Both patients were treated with surgical debridement, exchange of tibial insert with implant retention, and intra-articular administration of vancomycin for six weeks. Treatment was successful for both patients, with preservation of knee function and no recurrence of infection after one year. We reported two cases of PJI treated with direct intra-articular antibiotic administration following surgical debridement and implant retention.

Postoperative Infection Rates After Total Ankle Arthroplasty: A Comparison With and Without the Use of a Surgical Helmet System

Following total joint arthroplasty, surgical site infections (SSI) and periprosthetic joint infections (PJI) are associated with increased patient morbidity and healthcare utilization. Current positive-pressure surgical sterile helmet system (SHS) were developed as a feasible, useful version of the body exhaust system.The use of SHS has not yet been proven to decrease infection rates in the orthopedic literature. The primary purpose of this study is to compare the infection rates between patients who underwent total ankle arthroplasty (TAA) with a surgical team wearing SHS versus without SHS.A retrospective chart review in patients undergoing primary TAA with the surgeon wearing SHS (Group 1) or standard surgical attire (Group 2) was conducted. The primary outcome was postoperative SSI and PJI. The rate of wound complications, revision rates, and associated procedures were also analyzed. We identified 109 patients in Group 1 and 151 patients in Group 2. The rate of SSI was 12.8% in Group 1 and 14.6% in Group 2 (p = .411). The rate of PJI was 0.92% in Group 1 and 2.6% in Group 2 (p = .411). There was no difference in revision rates between the two groups. This study suggests that SHS does not appear to protect against postoperative SSI or PJI after TAA. Conversely, we did not find a higher infection rate compared to standard surgical attire despite recent in-vitro studies suggesting SHS as a source of wound contamination. The utility of SHS does not appear to influence the prevalence of postoperative SSI or PJI.

An in vitro model of microbial contamination in the operating room

Infection associated with tissue-contacting biomedical devices is a compelling clinical problem initiated by the microbial colonization of the device surface. Among the possible sources of contaminating bacteria is the operating room (OR) itself, where viable bacteria in the atmosphere can sediment onto a device surface intraoperatively. We have developed an aerosolizing system that can reproducibly spray small quantities of aerosolized bacteria onto a surface to mimic OR contamination. This paper describes the design of the system and characterizes key aspects associated with its operation. The area density of sprayed bacteria is on the order of 10² /cm² . Using titanium (Ti) alloy coupons as test substrates contaminated by staphylococci, we quantify the fraction of bacteria that are well adhered to the substrate, those that can be removed by sonication, and those that are not recovered after spraying. Despite the relatively low levels of surface contamination, we furthermore show that such a model is able to demonstrate a statistically significant reduction in colonization of Ti coupons modified by antimicrobial quaternary ammonium compounds relative to unmodified controls.

Does Surgical Approach for Total Hip Arthroplasty Impact Infection Risk in the Obese Patient? A Systematic Review

This systematic review evaluated the combined effects of obesity and surgical approach on periprosthetic joint infection (PJI) rates after total hip arthroplasty (THA). Wound complication and PJI rates were elevated among patients with body mass index (BMI) of 30 kg/m2 or greater and 35 kg/m2 or greater, respectively, with the direct anterior approach (DAA). A BMI of 30 kg/m2 or greater also increased the risk of PJI with the posterior approach. Patients with BMI of 30 kg/m2 or greater undergoing anterolateral approach THA did not have increased risk of PJI. Patients with elevated BMI (≥30 kg/m2) are at risk for PJI, regardless of approach. Patients undergoing DAA THA who have BMI of 35 kg/m2 or greater may have an increased risk of PJI compared with those undergoing THA with other approaches. [Orthopedics. 2022;45(2):e67-e72.].

In-hospital Mortality after Septic Revision TKA: Analysis of the New York and Florida State Inpatient Databases

The aims of this study were to investigate (1) in-hospital mortality rates following septic revision total knee arthroplasty (rTKA); (2) compare septic rTKA mortality rates between differing knee revision volume (KRV) hospitals; and (3) identify independent risk factors associated with in-hospital mortality after septic rTKA (up to 2-year follow-up). The Healthcare Cost and Utilization Project State Inpatient Databases of New York and Florida were used to identify septic rTKA, and control groups of aseptic rTKA and primary TKA between 2007 and 2012 via International Classification of Diseases, Ninth Revision codes. Mortality was compared between septic rTKA and aseptic rTKA/primary TKA control groups. Hospital KRV was stratified, and independent risk factors of in-hospital mortality were identified and analyzed using unadjusted and adjusted logistic regression analyses. In this study, 3,531 septic rTKA patients were identified; 105 (3%) patients suffered in-hospital mortality, compared with the control aseptic rTKA (n = 178; 1.7%; p < 0.0001) and primary TKA groups (n = 930; 0.6%; p < 0.0001). Being an octogenarian (adjusted odds ratio [AOR]: 2.361; 95% confidence interval [CI]: 1.514-3.683; p < 0.0002) and having a medium- or high-Elixhauser comorbidity score was associated with in-hospital mortality (AOR: 2.073; 95% CI: 1.334-3.223; p = 0.0012, and AOR: 4.127; 95% CI: 2.268-7.512, p < 0.0001). There were no significant in-hospital mortality rate differences in high- versus medium- versus low-KRV hospitals (1.9 vs. 3.6 vs. 2.9%, respectively, p = 0.0558). Age >81 years and higher comorbidity burden were found to contribute to increased risk of 2-year postoperative mortality after septic rTKA. This association could not be established for hospital KRV.

99mTc-HMPAO-WBC SPECT/CT versus 18F-FDG-WBC PET/CT in chronic prosthetic joint infection: a pilot study

PURPOSE

The aim of this study was to compare 99mTc-HMPAO-WBC-SPECT/CT combined with 99mTc-nanocollloid SPECT/CT and 18F-FDG-WBC-PET/CT combined with 99mTc-Nanocollloid SPECT/CT for the diagnosis and treatment evaluation of chronic prosthetic joint infection (PJI).

METHODS

Patients with suspected chronic PJI were examined with 99mTc-HMPAO-WBC SPECT/CT, 18F-FDG-WBC PET/CT, and 99mTc-nanocolloid SPECT/CT (to visualize bone marrow). The location and patterns of uptake were noted and compared between the two leukocyte examinations. Both leukocyte examinations were evaluated visually for infection. The PET examinations were also evaluated semiquantitatively. Chronic PJI was verified clinically by microbial culture and successfully treated PJI was confirmed by 12 months symptom-free follow-up after cessation of antibiotics.

RESULTS

Nineteen patients were included with 10 hip prostheses and nine knee prostheses. Fourteen were diagnosed with chronic PJI and five with successfully treated PJI. The sensitivity of visual evaluation of 99mTc-WBC-HMPAO SPECT/CT for all joints was 0.31 and for 18F-FDG-WBC PET/CT 0.38. The specificity was 0.80 and 0.83, respectively. All patients with a true-positive SPECT examination had a false-negative PET examination and vice versa. Semiquantitative evaluation of the hips gave an area under the curve of 0.905 using the iliac crest as the background. Semiquantitative evaluation of the knees did not produce significant results.

CONCLUSION

This pilot study showed no difference in the sensitivity or specificity of 99mTc-HMPAO-WBC SPECT/CT and 18F-FDG-WBC PET/CT when combined with 99mTc-nanocollloid SPECT/CT in the diagnosis or treatment evaluation of suspected late chronic PJI.

Sepsis and Total Joint Arthroplasty

The number of annual total joint arthroplasties (TJA) is increasing. Periprosthetic joint infections (PJI) occur when there is infection involving the prosthesis and surrounding tissue, which has the potential to develop into sepsis if left untreated. Sepsis in patients who have undergone TJA is life threatening and requires urgent treatment. If sepsis is due to PJI, the focus should be on early intravenous antibiotics with aspiration as soon as possible to diagnose the infection. Patients who develop sepsis after surgery for PJI are particularly at high risk for mortality and need to be treated in the intensive care unit.

Differences in Infection Rates by Surgical Approach in Total Hip Arthroplasty and Patient Sex: A Systematic Review

Background

There exists conflicting data that patient sex may influence complication and revision rates when undergoing total hip arthroplasty (THA), specifically when comparing different surgical approaches. Differences in body fat or muscular distribution are proposed mechanisms, but these are poorly understood and not well described in current literature.

Methods

A systematic review of the literature was conducted from PubMed, Embase, and Web of Science from inception of the database through September 15, 2020. Studies were included if they included patients undergoing primary elective unilateral THA, delineated infections by surgical approach, and delineated infections by patient sex. Basic science, cadaveric, and animal studies were excluded as were case reports. Two authors screened abstracts and then extracted data from the full text article.

Results

Three studies, including 1,694 patients undergoing 1,811 THA were included. 80 infections were included. No study reported a statistically significant difference in infection risk by patient sex or surgical approach, though there was substantial heterogeneity in study design, approach, and analysis.

Conclusion

Limited data suggests no relationship between sexes across surgical approaches for infection rates. However, poor reporting and small sample sizes preclude definitive conclusions from being drawn. Future studies should emphasize reporting differences in outcomes by patient sex to better elucidate differences, if any, in adverse outcomes between sexes following THA across surgical approaches. Level of Evidence: IV.

Long-term antibacterial properties of a nanostructured titanium alloy surface: An in vitro study

The demand for joint replacement and other orthopedic surgeries involving titanium implants is continuously increasing; however, 1%-2% of surgeries result in costly and devastating implant associated infections (IAIs). Pseudomonas aeruginosa and Staphylococcus aureus are two common pathogens known to colonise implants, leading to serious complications. Bioinspired surfaces with spike-like nanotopography have previously been shown to kill bacteria upon contact; however, the longer-term potential of such surfaces to prevent or delay biofilm formation is unclear. Hence, we monitored biofilm formation on control and nanostructured titanium disc surfaces over 21 days following inoculation with Pseudomonas aeruginosa and Staphylococcus aureus. We found a consistent 2-log or higher reduction in live bacteria throughout the time course for both bacteria. The biovolume on nanostructured discs was also significantly lower than control discs at all time points for both bacteria. Analysis of the biovolume revealed that for the nanostructured surface, bacteria was killed not just on the surface, but at locations above the surface. Interestingly, pockets of bacterial regrowth on top of the biomass occurred in both bacterial species, however this was more pronounced for S. aureus cultures after 21 days. We found that the nanostructured surface showed antibacterial properties throughout this longitudinal study. To our knowledge this is the first in vitro study to show reduction in the viability of bacterial colonisation on a nanostructured surface over a clinically relevant time frame, providing potential to reduce the likelihood of implant associated infections.

[Comparison of DRG revenues between fast and slow-track procedures for a two-stage replacement of prostheses for periprosthetic hip infections in the aG-DRG system 2020]

BACKGROUND

The treatment of periprosthetic hip infections is usually cost intensive, so it is generally not cost effective for hospitals. In chronic infections, a two-stage procedure is often indicated, which can be done as a fast-track procedure with a short prosthetic-free interim interval (2-4 weeks) or as a slow-track procedure with a long prosthetic-free interim interval (over 4 weeks).

AIM

The aim of this study was to elucidate the revenue situation of both forms of treatment in the aG-DRG-System 2020, taking into account revenue-relevant influencing factors.

METHODS

For fast-track and slow-track procedures with two-stage revision and detection of a staphylococcus aureus (MSSA), treatment cases were simulated using a grouper software (3M KODIP Suite) based on the diagnoses (ICD-10-GM) and procedures (OPS) and then grouped into DRGs. Revenue-relevant parameters, such as length of stay and secondary diagnoses (SD), were taken into account. In addition, two real treatment cases with fast-track and slow-track procedures were compared to each other.

RESULTS

The total revenues for the slow-track procedure with a length of stay of 25 days (without SD) were 27,551 € and for a length of stay of 42 days (with SD) even 40,699 €, compared to 23,965 € with the fast-track procedure with a length of stay of 25 days (without SD) and 27,283 € for a length of stay of 42 days (with SD). The real treatment cases also showed a big difference in the total revenues of 12,244 € in favor of the slow-track procedure.

DISCUSSION

Even in the aG-DRG-System 2020, the two-stage revision procedure with a long interim interval seems to be more interesting from a financial point of view and the hospital perspective compared to the fast-track procedure, especially with multimorbid patients. This creates a financial barrier to the treatment of such patients with a short interim interval.

Improving outcomes in acute and chronic periprosthetic hip and knee joint infection with a multidisciplinary approach

AIMS

Periprosthetic hip and knee infection remains one of the most severe complications following arthroplasty, with an incidence between 0.5% to 1%. This study compares the outcomes of revision surgery for periprosthetic joint infection (PJI) following hip and knee arthroplasty prior to and after implementation of a specialist PJI multidisciplinary team (MDT).

METHODS

Data was retrospectively analyzed from a single centre. In all, 29 consecutive joints prior to the implementation of an infection MDT in November 2016 were compared with 29 consecutive joints subsequent to the MDT conception. All individuals who underwent a debridement antibiotics and implant retention (DAIR) procedure, a one-stage revision, or a two-stage revision for an acute or chronic PJI in this time period were included. The definition of successfully treated PJI was based on the Delphi international multidisciplinary consensus.

RESULTS

There were no statistically significant differences in patient demographics or comorbidities between the groups. There was also no significant difference in length of overall hospital stay (p = 0.530). The time taken for formal microbiology advice was significantly shorter in the post MDT group (p = 0.0001). There was a significant difference in failure rates between the two groups (p = 0.001), with 12 individuals (41.38%) pre-MDT requiring further revision surgery compared with one individual (6.67%) post-MDT inception.

CONCLUSION

Our standardized multidisciplinary approach for periprosthetic knee and hip joint infection shows a significant reduction in failure rates following revision surgery. Following implementation of our MDT, our success rate in treating PJI is 96.55%, higher than what current literature suggests. We advocate the role of a specialist infection MDT in the management of patients with a PJI to allow an individualized patient-centred approach and care plan, thereby reducing postoperative complications and failure rates. Cite this article: Bone Jt Open 2021;2(7):509-514.

Debridement, antibiotics, and implant retention combined with direct intra-articular antibiotic infusion in patients with acute hematogenous periprosthetic joint infection of the knee

Background

Debridement, antibiotics, and implant retention (DAIR) is the recommended treatment for acute hematogenous periprosthetic joint infection (PJI) after total knee arthroplasty (TKA). However, DAIR is associated with a high percentage of unsuccessful outcomes. Since 2007, direct intra-articular antibiotic infusion, which can provide a high concentration of intra-articular antibiotic, has been used in combination with DAIR to improve treatment outcomes among patients in our institution. This study aimed to assess the outcomes of DAIR combined with direct intra-articular antibiotic infusion in patients who presented with acute hematogenous PJI after TKA.

Methods

We reviewed the data of all patients diagnosed with acute hematogenous PJI after primary TKA (from 2008 to 2015) who received DAIR combined with direct intra-articular antibiotic infusion.

Results

In total, 15 knees in 12 patients were semi-urgently treated with this method. The mean follow-up time was 93.3 (minimum: 56) months, and the longest follow-up time was 11 years. Two patients (n = 3 knees) had a well-functioning, non-infected prosthesis 6 and 10 years after the procedure. Two patients (n = 2 knees) had re-infection 2 and 5 years after surgery, and they required two-stage revision. None of the patients were lost to follow-up. Finally, 13 (86.6%) of 15 infected knees were successfully treated with this method.

Conclusions

DAIR combined with direct intra-articular antibiotic infusion is an effective treatment for acute hematogenous PJI after TKA.

Iron Deficiency Anemia is Associated with Increased Early Postoperative Surgical and Medical Complications Following Total Hip Arthroplasty

BACKGROUND

Iron deficiency anemia (IDA) is a medical comorbidity commonly diagnosed in those undergoing primary total hip arthroplasty (THA). The authors sought to evaluate IDA as a risk factor for early postoperative complications following discharge and describe the hospital resource utilization of this patient population.

METHODS

Patients with a diagnosis of IDA who underwent THA from 2005 to 2014 were identified in a national insurance database. The rates of postoperative medical complications and surgery-related complications, as well as hospital readmission, emergency department visits, and death were calculated. Additionally, 90-day and day of surgery cost and length of stay were calculated. IDA patients were then compared to a 4:1 matched control population without IDA using a logistic regression analysis to control for confounding factors.

RESULTS

In total, 98,681 patients with a preoperative diagnosis of IDA who underwent THA were identified and compared to 386,724 controls. IDA was associated with increased risk of 30-day emergency department visits (odds ratio [OR] 1.35, P < .001) and 30-day readmission (OR 1.49, P < .001). IDA was also associated with an increased 90-day medical complication rate (cerebrovascular accident OR 1.11, P = .003; urinary tract infection OR 1.14, P < .001; acute renal failure OR 1.24, P < .001; transfusion OR 1.40, P < .001), as well as 1-year periprosthetic joint infection (OR 1.27, P < .001), revision (OR 1.22, P < .001), dislocation (OR 1.25, P < .001), and fracture (OR 1.43, P < .001). Patients with IDA accrued higher hospital charges ($27,658.27 vs $16,709.18, P < .001) and lower hospital reimbursement ($5509.90 vs $3605.59, P < .001).

CONCLUSION

Patients with preoperative IDA undergoing THA are at greater risk of experiencing early postoperative complications and have greater utilization of hospital resources.

Surgical drainage after limb salvage surgery and endoprosthetic reconstruction: is 30 mL/day critical?

Background

Periprosthetic infection is a major cause of failure after segmental endoprosthetic reconstruction. The purpose of this study is to determine whether certain aspects of drain output affect infection risk, particularly the 30 mL/day criterion for removal.

Methods

Two hundred and ninety-five patients underwent segmental bone resection and lower limb endoprosthetic reconstruction at one institution. Data on surgical drain management and occurrence of infection were obtained from a retrospective review of patients’ charts and radiographs. Univariate and multivariate Cox regression analyses were performed to identify factors associated with infection.

Results

Thirty-one of 295 patients (10.5%) developed infection at a median time of 13 months (range 1–108 months). Staphylococcus aureus was the most common organism and was responsible for the majority of cases developing within 1 year of surgery. Mean output at the time of drain removal was 72 mL/day. Ten of 88 patients (11.3%) with ≤ 30 mL/day drainage and 21 of 207 patients (10.1%) with > 30 mL/day drainage developed infection (p = 0.84). In multivariate analysis, independent predictive factors for infection included sarcoma diagnosis (HR 4.13, 95% CI 1.4–12.2, p = 0.01) and preoperative chemotherapy (HR 3.29, 95% CI 1.1–9.6, p = 0.03).

Conclusion

Waiting until drain output is < 30 mL/day before drain removal is not associated with decreased risk of infection for segmental endoprostheses of the lower limb after tumor resection. Sarcoma diagnosis and preoperative chemotherapy were independent predictors of infection.

Is a single dose of preoperative antibiotic therapy effective for patients treated with megaendoprosthesis after metastatic bone tumour resection?

Purpose The timing and number of doses of antibiotics required for megaendoprosthetic replacement (MPR) in metastatic bone disease (MBD) is a matter of debate. The aim of our study is to present the results of a prospective cohort of MPR for MBD receiving a single dose of antibiotic at induction of anaesthesia.

METHODS

All patients who underwent primary MPR in MBD were included in this prospective study. All penicillin-sensitive patients received one dose of cefuroxime 1.5gm intravenous at induction. In penicillin-allergic patients, teicoplanin 1.2gm and ciprofloxacin 500 mg intravenous was administered. The patients were followed up in the wound clinic and the specialist MBD clinic at 2 weeks, 3 months, 6 months and then annually. Data collected included demographics, primary tumours, surgical procedures, complications and duration of follow-up. All calculations were performed using SPSS^® 25(IBM, USA). A p value ≤ 0.05 was considered to be significant.

RESULTS

There were 51 patients with a mean age of 65.4 years. Procedures included proximal femoral replacement (35), distal femoral replacement (7), proximal humeral replacement (4), distal humeral replacement (3) and total femoral replacement (2). Thirty-seven patients received cefuroxime, and fourteen patients received teicoplanin and ciprofloxacin at induction of anaesthesia. The deep infection rate was 1.9%. Thirty-seven patients died with a median survival of 10 months (1 to 51 months). Mean follow-up was 18.9 months (1 to 70 months).

CONCLUSION

Single dose of preoperative antibiotics at anaesthetic induction seems to be safe and effective for preoperative prophylaxis in orthopaedic oncology.

THE CROATIAN HEALTH INSURANCE FUND DOES NOT RECOGNIZE DIFFERENCES IN THE COST OF DIFFERENT TREATMENTS FOR REVISION TOTAL HIP ARTHROPLASTY

In recent years, there has been increased interest in the cost of treatment for revision interventions for hip and knee prostheses. In all publications so far, the authors note the high cost of treatment for revision interventions, especially if infection is present. The aim of this study was to compare the cost of treatment and health insurance reimbursements between revision total hip arthroplasty (THA) for infection and revision for aseptic indications (aseptic instability and periprosthetic fracture). Hospital data on 168 patients having undergone revision THA between 2010 and 2018 at the Department of Traumatology, Sestre milosrdnice University Hospital Centre from Zagreb were analyzed. Financial data were collected from the Hospital Information System. Financial analysis included total cost per patient, Croatian Health Insurance Fund reimbursements, cost of implants, and length of hospital stay. The difference between the mean total cost per patient and the mean Croatian Health Insurance Fund reimbursements was -262.83 € (-6.08%) for aseptic instability, -1694.94 € (-17.25%) for infection and -916.49 € (-17.33%) for periprosthetic fracture. The Croatian Health Insurance Fund does not recognize differences in the cost of revision THA for aseptic instability, infection and periprosthetic fracture. Health insurance reimbursement is inadequate for centers that offer revision hip surgery.

Characterization of an Acute Rodent Osteomyelitis Infectious Model Using a Tibial Intramedullary Implant Inoculation

Chronic osteomyelitis in presence of orthopedic implants is a condition observed in the field of biomaterials as it impairs early bone-implant contact, fixation and integration. In this study, a surgical intramedullary tibial insertion was performed using a titanium wire previously inoculated with Staphylococcus aureus in order to develop an osteomyelitis model in a clinically relevant long bone and in absence of any prophylactic treatment. As such, twenty-two male Sprague-Dawley rats received a sterile or inoculated intramedullary biomaterial with either 2 × 10⁶ or 1 × 10⁷S. aureus colony forming units. Bacterial burden, inflammation, morphological changes, as well as newly formed bone tissues were evaluated for histopathology following a period of either eight or fifteen days of implantation. The implant inoculated in presence of the highest bacterial load was effective to produce significant periprosthetic infection observations in addition to hard and soft tissue inflammation consistent with the development of osteomyelitis. In contrast, neither the sterile nor the low-dose implant inoculation showed inflammation and clinical infection signs, but rather produced an expected bone remodeling and appropriate healing associated with biomaterial implantation. Complete health assessment is presented with histopathological periprosthetic results.

Reactive Arthritis Provoked by Campylobacter jejuni Enterocolitis Mimicking Prosthetic Joint Infection: A Case Report

CASE

A 59-year-old man with previously well-functioning partial knee replacement was admitted with a warm, swollen, and painful knee. The clinical presentation was consistent with prosthetic joint infection (PJI), but the synovial fluid analysis was negative for microbial growth. Further discussion revealed earlier Campylobacter jejuni enterocolitis that subsequently provoked reactive arthritis (ReA) mimicking PJI. The patient was treated with oral naproxen and intra-articular injection of triamcinolone and recovered completely without antibiotics or surgery. After 29 months, the knee is functioning normally.

CONCLUSION

ReA is rare but should be included in the differential diagnosis of PJI.

Antimicrobial Silver Multilayer Coating for Prevention of Bacterial Colonization of Orthopedic Implants

Due to increasing rates of periprosthetic joint infections (PJI), new approaches are needed to minimize the infection risk. The first goal of this study was to modify a well-established infection model to test surface-active antimicrobial systems. The second goal was to evaluate the antimicrobial activity of a silver multilayer (SML) coating. In vitro tests with SML items showed a >4 Log reduction in a proliferation assay and a 2.2 Log reduction in an agar immersion test (7 d). In the in vivo model blank and SML coated K-wires were seeded with ~2 × 104 CFU of a methicillin-sensitive Staphylococcus epidermidis (MSSE) and inserted into the intramedullary tibial canal of rabbits. After 7 days, the animals were sacrificed and a clinical, microbiological and histological analysis was performed. Microbiology showed a 1.6 Log pathogen reduction on the surface of SML items (p = 0.022) and in loosely attached tissue (p = 0.012). In the SML group 7 of 12 SML items were completely free of pathogens (cure rate = 58%, p = 0.002), while only 1 of 12 blank items were free of pathogens (cure rate = 8%, p = 0.110). No silver was detected in the blood or urine of the SML treated animals and only scarcely in the liver or adjacent lymph nodes. In summary, an in vivo infection model to test implants with bacterial pre-incubation was established and the antimicrobial activity of the SML coating was successfully proven.

Is dental prophylaxis required following spinal fusion?-a systematic review and call for evidence

BACKGROUND

Controversy exists regarding the need for antimicrobial prophylaxis prior to dental procedures following spinal fusion. In this review, we attempt to synthesize a comprehensive summary of the published literature to provide recommendations on the use of antimicrobial prophylaxis before dental procedures in patients with a history of spinal fusion.

METHODS

We searched PubMed, Web of Science, Cochrane Library, and EMBASE databases from inception to February 2018. Eligible studies included patients with a history of spinal fusion treated with or without antimicrobial prophylaxis in preparation for dental procedures. Two reviewers independently assessed the eligibility of potential studies and extracted data. Outcomes of interest were the indications and efficacy of antimicrobial prophylaxis to protect against infection of spinal prostheses with dental origin.

RESULTS

A total of 1,909 articles were initially screened. After inclusion and exclusion criteria were applied, one study was found specifically relating to dental prophylaxis and spine surgery. The survey, as well as objective studies and professional organization guidelines on dental prophylaxis in patients with total hip and knee replacements, were reviewed to add context to the controversy.

CONCLUSIONS

There is a significant paucity of literature regarding dental prophylaxis in spine surgery patients. Although there has been a recent movement away from recommending antimicrobial prophylaxis before dental work in patients with other forms of orthopaedic prostheses, the gap in the literature addressing spine patients represents an important question that requires more targeted and specific research.

Cost-effectiveness of oral versus intravenous antibiotics (OVIVA) in patients with bone and joint infection: evidence from a non-inferiority trial

Background: Bone and joint infections are becoming increasingly common and are usually treated with surgery and a course of intravenous antibiotics. However, there is no evidence to support the superiority of intravenous therapy and there is a growing body of literature showing that oral therapy is effective in treating these infections.Given this lack of evidence the clinical trial ‘Oral Versus Intravenous Antibiotics’ (OVIVA) was designed to assess the clinical and cost-effectiveness of intravenous versus oral antibiotics for the treatment of bone and joint infections, using a non-inferiority design. Clinical results from the trial indicate that oral antibiotics are non-inferior to intravenous antibiotics. The aim of this paper is to evaluate the cost-effectiveness of intravenous compared to oral antibiotics for treating bone and joint infections, using data from OVIVA. Methods: A cost-utility analysis was carried out, the main economic outcome measure was the quality adjusted life-year, measured using the EQ-5D-3L questionnaire, combined with costs to estimate cost-effectiveness over 12-months follow-up. Results: Results show that costs were significantly lower in the oral arm compared to the intravenous arm, a difference of £2,740 (95% confidence interval £1,488 to £3,992). Results of four sensitivity analyses were consistent with the base-case results. QALYs were marginally higher in the oral arm, however this difference was not statistically significant; -0.007 (95% confidence interval -0.045 to 0.031). Conclusions: Treating patients with bone and joint infections for the first six weeks of therapy with oral antibiotics is both less costly and does not result in detectable differences in quality of life compared to treatment with intravenous antibiotics. Adopting a practice of treating bone and joint infections with oral antibiotics early in the course of therapy could potentially save the UK National Health Service over £17 million annually.

A Systematic Review on the Value of Infrared Thermography in the Early Detection of Periprosthetic Joint Infections

BACKGROUND

Variations in the temperature of body and skin are symptoms of many pathological changes. Although joint replacement surgery of hip and knee has been very successful in recent decades, periprosthetic infection is a growing problem and the number one reason for revision. While many studies have investigated changes in blood levels, investigation of temperature has not been performed on a regular basis. The objective of this work is to determine whether reference literature exists for the infrared thermographic examination in knee and hip arthroplasty and if reference values can be derived for the methodology or if there is a peri- and postoperative benefit.

MATERIAL UND METHODS

By means of a systematic online database search and based on the Cochrane, PICOT and PRISMA guidelines, this systematic review retrieved 254 studies. All publications with thermographic examination in arthroplasty of the hip and knee were imbedded. 249 studies were excluded due to the defined inclusion and exclusion criteria and five studies with 251 patients have finally been included in the evaluation process. This was followed by an analysis and discussion of the methodology.

RESULTS AND CONCLUSION

Infrared thermography is a useful tool in the perioperative care of patients after arthroplasty of the knee and hip joint. The technology is portable, easy to use and non-invasive. Based only on these few publications, values can be derived, which provide a guidance for the thermographic aftercare in arthroplasty surgery.

Oral versus intravenous antibiotics for bone and joint infections: the OVIVA non-inferiority RCT

BACKGROUND

Management of bone and joint infection commonly includes 4-6 weeks of intravenous (IV) antibiotics, but there is little evidence to suggest that oral (PO) therapy results in worse outcomes.

OBJECTIVE

To determine whether or not PO antibiotics are non-inferior to IV antibiotics in treating bone and joint infection.

DESIGN

Parallel-group, randomised (1 : 1), open-label, non-inferiority trial. The non-inferiority margin was 7.5%.

SETTING

Twenty-six NHS hospitals.

PARTICIPANTS

Adults with a clinical diagnosis of bone, joint or orthopaedic metalware-associated infection who would ordinarily receive at least 6 weeks of antibiotics, and who had received ≤ 7 days of IV therapy from definitive surgery (or start of planned curative treatment in patients managed non-operatively).

INTERVENTIONS

Participants were centrally computer-randomised to PO or IV antibiotics to complete the first 6 weeks of therapy. Follow-on PO therapy was permitted in either arm.

MAIN OUTCOME MEASURE

The primary outcome was the proportion of participants experiencing treatment failure within 1 year. An associated cost-effectiveness evaluation assessed health resource use and quality-of-life data.

RESULTS

Out of 1054 participants (527 in each arm), end-point data were available for 1015 (96.30%) participants. Treatment failure was identified in 141 out of 1015 (13.89%) participants: 74 out of 506 (14.62%) and 67 out of 509 (13.16%) of those participants randomised to IV and PO therapy, respectively. In the intention-to-treat analysis, using multiple imputation to include all participants, the imputed risk difference between PO and IV therapy for definitive treatment failure was -1.38% (90% confidence interval -4.94% to 2.19%), thus meeting the non-inferiority criterion. A complete-case analysis, a per-protocol analysis and sensitivity analyses for missing data each confirmed this result. With the exception of IV catheter complications [49/523 (9.37%) in the IV arm vs. 5/523 (0.96%) in the PO arm)], there was no significant difference between the two arms in the incidence of serious adverse events. PO therapy was highly cost-effective, yielding a saving of £2740 per patient without any significant difference in quality-adjusted life-years between the two arms of the trial.

LIMITATIONS

The OVIVA (Oral Versus IntraVenous Antibiotics) trial was an open-label trial, but bias was limited by assessing all potential end points by a blinded adjudication committee. The population was heterogenous, which facilitated generalisability but limited the statistical power of subgroup analyses. Participants were only followed up for 1 year so differences in late recurrence cannot be excluded.

CONCLUSIONS

PO antibiotic therapy is non-inferior to IV therapy when used during the first 6 weeks in the treatment for bone and joint infection, as assessed by definitive treatment failure within 1 year of randomisation. These findings challenge the current standard of care and provide an opportunity to realise significant benefits for patients, antimicrobial stewardship and the health economy.

FUTURE WORK

Further work is required to define the optimal total duration of therapy for bone and joint infection in the context of specific surgical interventions. Currently, wide variation in clinical practice suggests significant redundancy that likely contributes to the excess and unnecessary use of antibiotics.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN91566927.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 38. See the NIHR Journals Library website for further project information.

The Efficacy and Safety of Inpatient Rehabilitation Compared With Home Discharge After Hip or Knee Arthroplasty: A Meta-Analysis and Systematic Review

BACKGROUND

Total hip and knee arthroplasties (THKAs) are successful procedures in managing end-stage arthritis when nonoperative treatments fail. The immediate postoperative period is an important time for the body to recuperate and rehabilitate. Studies have shown that early intensive rehabilitation can enhance recovery. Rehabilitation can be provided as inpatient rehabilitation (IR) or discharge with home rehabilitation. These options have been studied, but literature on the efficacy and safety of IR compared to home discharge is scarce, and evidence is not well established. This meta-analysis aims to compare the efficacy and safety of IR to home discharge with rehabilitation after THKA.

METHODS

A multidatabase search was performed according to PRISMA guidelines. Data from studies assessing the efficacy and safety of IR and home as discharge destinations after THKA were extracted and analyzed.

RESULTS

Fifteen studies were included, consisting of 37,411 IR patients and 172,219 home discharge patients. These studies had heterogeneous reporting methods, with some conflicting results. There was no clinically significant difference in clinical outcomes between the groups. Readmission was nearly 5 times (odds ratio = 4.87, 95% confidence interval = 3.24-7.33, P < .001) and periprosthetic complications nearly 3 times (odds ratio = 2.82, 95% confidence interval: 1.54-5.24, P < .001) higher in IR patients than those discharged home after THKA.

CONCLUSION

Although IR is associated with higher risks of complications and readmissions, this may be because of patient selection bias in the clinical setting. Following THKA, it is safe to discharge patients to home with rehabilitation whenever possible.

EVIDENCE LEVEL

Level II, Meta-analysis of heterogeneous studies.

Cost-effectiveness of oral versus intravenous antibiotics (OVIVA) in patients with bone and joint infection: evidence from a non-inferiority trial

Background: Bone and joint infections are becoming increasingly common and are usually treated with surgery and a course of intravenous antibiotics. However, there is no evidence to support the superiority of intravenous therapy and there is a growing body of literature showing that oral therapy is effective in treating these infections.Given this lack of evidence the clinical trial 'Oral Versus Intravenous Antibiotics' (OVIVA) was designed to assess the clinical and cost-effectiveness of intravenous versus oral antibiotics for the treatment of bone and joint infections, using a non-inferiority design. Clinical results from the trial indicate that oral antibiotics are non-inferior to intravenous antibiotics. The aim of this paper is to evaluate the cost-effectiveness of intravenous compared to oral antibiotics for treating bone and joint infections, using data from OVIVA. Methods: A cost-utility analysis was carried out, the main economic outcome measure was the quality adjusted life-year, measured using the EQ-5D-3L questionnaire, combined with costs to estimate cost-effectiveness over 12-months follow-up. Results: Results show that costs were significantly lower in the oral arm compared to the intravenous arm, a difference of £2,740 (95% confidence interval £1,488 to £3,992). Results of four sensitivity analyses were consistent with the base-case results. QALYs were marginally higher in the oral arm, however this difference was not statistically significant; -0.007 (95% confidence interval -0.045 to 0.031). Conclusions: Treating patients with bone and joint infections for the first six weeks of therapy with oral antibiotics is both less costly and does not result in detectable differences in quality of life compared to treatment with intravenous antibiotics. Adopting a practice of treating bone and joint infections with oral antibiotics early in the course of therapy could potentially save the UK National Health Service over £17 million annually.

Cost-effectiveness of oral versus intravenous antibiotics (OVIVA) in patients with bone and joint infection: evidence from a non-inferiority trial

Background: Bone and joint infections are becoming increasingly common and are usually treated with surgery and a course of intravenous antibiotics. However, there is no evidence to support the superiority of intravenous therapy and there is a growing body of literature showing that oral therapy is effective in treating these infections. Given this lack of evidence the clinical trial ‘Oral Versus Intravenous Antibiotics’ (OVIVA) was designed to assess the clinical and cost-effectiveness of intravenous versus oral antibiotics for the treatment of bone and joint infections, using a non-inferiority design. Clinical results from the trial indicate that oral antibiotics are non-inferior to intravenous antibiotics. The aim of this paper is to evaluate the cost-effectiveness of intravenous compared to oral antibiotics for treating bone and joint infections, using data from OVIVA.

Methods: A cost-utility analysis was carried out, the main economic outcome measure was the quality adjusted life-year, measured using the EQ-5D-3L questionnaire, combined with costs to estimate cost-effectiveness over 12-months follow-up.

Results: Results show that costs were significantly lower in the oral arm compared to the intravenous arm, a difference of £2,740 (95% confidence interval £1,488 to £3,992). Results of four sensitivity analyses were consistent with the base-case results. QALYs were marginally higher in the oral arm, however this difference was not statistically significant; -0.007 (95% confidence interval -0.045 to 0.031).

Conclusions: Treating patients with bone and joint infections for the first six weeks of therapy with oral antibiotics is both less costly and does not result in detectable differences in quality of life compared to treatment with intravenous antibiotics. Adopting a practice of treating bone and joint infections with oral antibiotics early in the course of therapy could potentially save the UK National Health Service over £17 million annually.

Cost-effectiveness of oral versus intravenous antibiotics (OVIVA) in patients with bone and joint infection: evidence from a non-inferiority trial

Background: Bone and joint infections are becoming increasingly common and are usually treated with surgery and a course of intravenous antibiotics. However, there is no evidence to support the superiority of intravenous therapy and there is a growing body of literature showing that oral therapy is effective in treating these infections.Given this lack of evidence the clinical trial 'Oral Versus Intravenous Antibiotics' (OVIVA) was designed to assess the clinical and cost-effectiveness of intravenous versus oral antibiotics for the treatment of bone and joint infections, using a non-inferiority design. Clinical results from the trial indicate that oral antibiotics are non-inferior to intravenous antibiotics. The aim of this paper is to evaluate the cost-effectiveness of intravenous compared to oral antibiotics for treating bone and joint infections, using data from OVIVA. Methods: A cost-utility analysis was carried out, the main economic outcome measure was the quality adjusted life-year, measured using the EQ-5D-3L questionnaire, combined with costs to estimate cost-effectiveness over 12-months follow-up. Results: Results show that costs were significantly lower in the oral arm compared to the intravenous arm, a difference of £2,740 (95% confidence interval £1,488 to £3,992). Results of four sensitivity analyses were consistent with the base-case results. QALYs were marginally higher in the oral arm, however this difference was not statistically significant; -0.007 (95% confidence interval -0.045 to 0.031). Conclusions: Treating patients with bone and joint infections for the first six weeks of therapy with oral antibiotics is both less costly and does not result in detectable differences in quality of life compared to treatment with intravenous antibiotics. Adopting a practice of treating bone and joint infections with oral antibiotics early in the course of therapy could potentially save the UK National Health Service over £17 million annually.

Antibacterial coating of implants: are we missing something?

Implant-related infection is one of the leading reasons for failure in orthopaedics and trauma, and results in high social and economic costs. Various antibacterial coating technologies have proven to be safe and effective both in preclinical and clinical studies, with post-surgical implant-related infections reduced by 90% in some cases, depending on the type of coating and experimental setup used. Economic assessment may enable the cost-to-benefit profile of any given antibacterial coating to be defined, based on the expected infection rate with and without the coating, the cost of the infection management, and the cost of the coating. After reviewing the latest evidence on the available antibacterial coatings, we quantified the impact caused by delaying their large-scale application. Considering only joint arthroplasties, our calculations indicated that for an antibacterial coating, with a final user's cost price of €600 and able to reduce post-surgical infection by 80%, each year of delay to its large-scale application would cause an estimated 35 200 new cases of post-surgical infection in Europe, equating to additional hospital costs of approximately €440 million per year. An adequate reimbursement policy for antibacterial coatings may benefit patients, healthcare systems, and related research, as could faster and more affordable regulatory pathways for the technologies still in the pipeline. This could significantly reduce the social and economic burden of implant-related infections in orthopaedics and trauma. Cite this article: C. L. Romanò, H. Tsuchiya, I. Morelli, A. G. Battaglia, L. Drago. Antibacterial coating of implants: are we missing something? Bone Joint Res 2019;8:199-206. DOI: 10.1302/2046-3758.85.BJR-2018-0316.

Implementation of a multidisciplinary infections conference affects the treatment plan in prosthetic joint infections of the hip: a retrospective study

INTRODUCTION

Establishing a systematic multidisciplinary approach in the treatment of prosthetic joint infections (PJI) of the hip and analyzing its effect on clinical decision-making.

PATIENTS AND METHODS

Forty-six patients diagnosed with PJI of the hip were included in the retrospective study. The treatment plan was either established by a single-discipline approach (n = 20) or by a weekly multidisciplinary infections conference (n = 26) consisting of at least an orthopedic surgeon, microbiologist and pathologist. Recorded data included the length of hospital stay, number and type of surgeries, medical complications, recovered organisms as well as the number of applied antibiotics.

RESULTS

Patients discussed in the multidisciplinary infections conference showed a significantly shorter in-hospital stay (29 vs 62 days; p < 0.05), a significant reduction in surgeries (1.8 vs 5.1; p < 0.05) and a smaller number of antibiotics required (2.8 vs 4.2; p < 0.05). No significant difference could be found comparing inpatient complications between the two groups. Staphylococcus aureus and coagulase-negative staphylococci were the most frequently recovered organisms in both patient groups.

CONCLUSION

This study demonstrates the successful implementation of a weekly infections conference as an instrument to introduce a multidisciplinary approach to PJI of the hip. Implementation of these conferences significantly improves the treatment plan compared to a single-discipline approach, which we therefore highly recommend for other institutions. Multidiscipline may even affect clinical outcome which needs to be further investigated.

Economic Analysis in a Diagnosis Related Groups System for Two-stage Exchange of Prosthetic-joint Infections

Background: There is a constant increase of joint arthroplasties performed, with an infectious risk of 1-2%. Different therapeutic options for prosthetic-joint infections exist, but surgery remains essential. With a two-stage exchange procedure, a success rate above 90% can be expected. Currently, there is no consensus regarding the optimal interval duration between explantation and reimplantation. This retrospective study aimed to assess the economic impact of a two-stage exchange from a single-hospital perspective. Methods: 21 patients who have undergone a two-stage exchange of a hip or knee prosthetic-joint infection at the University Hospital of Lausanne (Switzerland) from 2012 to 2013 were included. The revenues earned according to the Swiss Diagnosis Related Groups (SwissDRG) system introduced in 2012 and the costs were compared for each hospital stay. Results: The remuneration ranged from 26'806 to 42'978 Swiss francs (CHF) (~ 22'905-36'723 EUR, median 36'338 CHF, ~ 31'049 EUR). The median total cost per patient was 76'000 CHF (~ 65'000 EUR) (51'151 to 118'263; hip median 79'744, knee median 66'708). The main determinant of the costs was the length of the hospital stay. Revenues never covered all the costs, even with a short-interval procedure. The hospital lost a median of 35'000 CHF per patient (~ 30'000 EUR) (22'280 to 64'666). Conclusion: The current DRG system may not be specific enough for rewarding prosthetic-joint infections. Several options could be considered to act on the length of the hospital stay. In order to cover costs in complicated cases, such as prosthetic-joint infections, more specific DRGs are needed.

Economic Evaluation of Antibacterial Coatings on Healthcare Costs in First Year Following Total Joint Arthroplasty

BACKGROUND

Antibacterial coatings (ABCs) of implants have proven safe and effective to reduce postsurgical infection, but little is known about their possible economic impact on large-scale use. This study evaluated the point of economic balance, during the first year after surgery, and the potential overall annual healthcare cost savings of 3 different antibacterial technologies applied to joint arthroplasty: a dual-antibiotic-loaded bone cement (COPAL G + C), an antibacterial hydrogel coating (DAC), and a silver coating (Agluna).

METHODS

The variables included in the algorithm were average cost and number of primary joint arthroplasties; average cost per patient of the ABC; incidence of periprosthetic joint infections and expected reduction using the ABCs; average cost of infection treatment and expected number of cases.

RESULTS

The point of economic balance for COPAL G + C, DAC, and Agluna in the first year after surgery was reached in patient populations with an expected postsurgical infection rate of 1.5%, 2.6%, and 19.2%, respectively. If applied on a national scale, in a moderately high-risk population of patients with a 5% expected postsurgical infection rate, COPAL G + C and DAC hydrogel would provide annual direct cost savings of approximately €48,800,000 and €43,200,000 (€1220 and €1080 per patient), respectively, while the silver coating would be associated with an economic loss of approximately €136,000,000.

CONCLUSION

This economic evaluation shows that ABC technologies have the potential to decrease healthcare costs primarily by decreasing the incidence of surgical site infections, provided that the technology is used in the appropriate risk class of patients.

Cost-benefit analysis of antibiofilm microbiological techniques for peri-prosthetic joint infection diagnosis

BACKGROUND

Implant-related infections, including those of peri-prosthetic joint (PJIs), osteosynthesis and other biomaterials, are biofilm-related. Pathogen identification is considered the diagnostic benchmark; however, the presence of bacterial biofilms makes pathogen detection with traditional microbiological techniques only partially effective. To improve microbiological diagnostic accuracy, some biofilm debonding techniques have been recently proposed. Aim of this health economics assessment study was to evaluate their economic impact on hospital costs.

METHODS

Direct and indirect hospital costs connected with the routine introduction of sonication and dithiothreitol treatment applied to hip and knee PJIs and of tissue cultures were examined. In particular the consequences of diagnostic inaccuracy, the opportunities, costs, and risks of each technique were calculated.

RESULTS

Considering an average of five samples per patient, processed separately with traditional tissue culture with or without sonication of prosthetic components, or pooled together using the MicroDTTect device (a close system for sample collection, transport and treatment with Dithiothreitol for microbial release from biofilm), the overall mean direct cost per patient was € 397 and € 393 for sonication or MicroDTTect, respectively, compared to € 308 for traditional tissue cultures. In terms of opportunity costs, MicroDTTect was the most effective technique, allowing for a 35% or 55% reduction in time required for sample treatment, compared to tissue cultures combined or not with sonication, respectively. Pooling together direct and indirect costs associated with false positive and negative results of the different diagnostic techniques, unnecessary medical treatments and possible medical claims, MicroDTTect or sonication become increasingly cost-effective when the extra-costs, generated by diagnostic inaccuracy of traditional tissue culture, took place, respectively, in 2% or 20% or more of the patients.

CONCLUSIONS

This is the first study specifically focused on the economic impact of the routine clinical use of microbiological antibiofilm sampling and processing techniques in orthopaedics. Although our results may suffer from a potential country and hospital bias, as the data collection process for direct and indirect costs is specific to each institution and country, this analysis highlights the potential economic advantage to hospitals associated with the routine introduction of antibiofilm techniques for microbiological diagnosis of PJI.

Revision Total Knee Arthroplasty for Periprosthetic Joint Infection Is Associated With Increased Postoperative Morbidity and Mortality Relative to Noninfectious Revisions

BACKGROUND

Periprosthetic joint infection (PJI) after primary total knee arthroplasty (TKA) is a devastating complication. The short-term morbidity profile of revision TKA performed for PJI relative to non-PJI revisions is poorly characterized. The purpose of this study is to determine 30-day postoperative outcomes after revision TKA for PJI, relative to primary TKA and aseptic revision TKA.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program from 2005 to 2015 was queried for primary and revision TKA cases. Revision TKA cases were categorized into PJI and non-PJI cohorts. Differences in 30-day outcomes including postoperative complications, readmissions, operative time, and length of stay were compared using bivariate and multivariate analyses.

RESULTS

In total, 175,761 TKAs were included in this study, with 162,981 (92.7%) primary TKAs and 12,780 (7.3%) revision TKAs, of which 2196 (17.2%) revisions were performed for PJI. When compared to aseptic revision TKA, multivariate analysis demonstrated that PJI revisions had a significantly higher risk of major early postoperative complications including death (adjusted odds ratio [OR] 3.25) and sepsis (OR 8.73). In addition, nonhome discharge (OR 1.75), readmissions (OR 1.67), and length of stay (+2.1 days) were all greater relative to non-PJI revisions.

CONCLUSION

Utilizing a large, prospectively collected, national database, we found that revision TKA for PJI has a greater risk of short-term morbidity and mortality and requires a higher utilization of healthcare resources. These results have implications for patient counseling and alternative payment models that may eventually include revision TKA.

Surface topography of silicon nitride affects antimicrobial and osseointegrative properties of tibial implants in a murine model

While silicon nitride (Si₃ N₄ ) is an antimicrobial and osseointegrative orthopaedic biomaterial, the contribution of surface topography to these properties is unknown. Using a methicillin-resistant strain of Staphylococcus aureus (MRSA), this study evaluated Si₃ N₄ implants in vitro utilizing scanning electron microscopy (SEM) with colony forming unit (CFU) assays, and later in an established in vivo murine tibia model of implant-associated osteomyelitis. In vitro, the "as-fired" Si₃ N₄ implants displayed significant reductions in adherent bacteria versus machined Si₃ N₄ (2.6 × 10⁴ vs. 8.7 × 10⁴ CFU, respectively; p < 0.0002). Moreover, SEM imaging demonstrated that MRSA cannot directly adhere to native as-fired Si₃ N₄ . Subsequently, a cross-sectional study was completed in which sterile or MRSA contaminated as-fired and machined Si₃ N₄ implants were inserted into the tibiae of 8-week old female Balb/c mice, and harvested on day 1, 3, 5, 7, 10, or 14 post-operatively for SEM. The findings demonstrated that the antimicrobial activity of the as-fired implants resulted from macrophage clearance of the bacteria during biofilm formation on day 1, followed by osseointegration through the apparent recruitment of mesenchymal stem cells on days 3-5, which differentiated into osteoblasts on days 7-14. In contrast, the antimicrobial behavior of the machined Si₃ N₄ was due to repulsion of the bacteria, a phenomenon that also limited osteogenesis, as host cells were also unable to adhere to the machined surface. Taken together, these results suggest that the in vivo biological behavior of Si₃ N₄ orthopaedic implants is driven by critical features of their surface nanotopography. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3413-3421, 2017.

Chronic periprosthetic hip infection: micro-organisms responsible for infection and re-infection

PURPOSE

This study aimed to delineate the infecting micro-organisms identified at the first-time revision for infected THA, analyze pre-operative versus intra-operative findings, as well as intra-operative ones against re-infection micro-organisms.

MATERIAL AND METHODS

Microbiological laboratory findings were studied in 73 patients (mean age, 51.93 ± 10.9 years) with chronic periprosthetic hip infection pre-operatively and intra-operatively. Forty-three patients had a two-stage revision THA while 30 patients were treated with a modified resection arthroplasty using the Ilizarov apparatus. Re-infection developed in 29 cases. Its microbial species were identified.

RESULTS

Pre-operative findings on micro-organisms coincided 50.7 % with the intra-operative ones. Bacterial growth in the intra-operative tests was detected in 72 (98.5 %) cases. Gram-positive single genus infection was identified in 35 patients (48 %); microbe associations were present in 33 patients (45 %). Staphylococcus species prevailed. Gram-negative infection was detected in 5.5 % of cases. One case (1.5 %) did not have any microbe growth. Re-infection happened in 10 cases (23.2 %) in a two-stage revision THA. In the resection arthroplasty group, early re-infection was observed in 63.3 % of cases. Among a total of 29 re-infection cases, staphylococcus species were identified in 19 cases, present either in associations or as single germs.

CONCLUSION

Intra-operative microbiological tests at the first-time revision for infected THR detect a reliable spectrum of micro-organisms to assess microbial resistance to antibiotics, develop treatment protocols, and for prognostic purposes. Preventive measures at primary THR and strategies to fight periprosthetic infection and reinfection should be targeted on staphylococci.