Risk Factors for Treatment Failure in Patients Who Have Knee Periprosthetic Joint Infection Treated With Two-Stage Exchange Arthroplasty as Well as Their Fate

Isolation of Multiple Positive Cultures at Resection Arthroplasty is a Predictor of Failure Following Reimplantation

BACKGROUND

Although it is well established that the type of organism can be a risk factor for failure in patients with periprosthetic joint infection (PJI), no study to date has examined the impact of the number of positive cultures on treatment outcomes in patients undergoing 2-stage exchange. The purpose of this multicenter study was to determine the prognostic utility of multiple positive cultures at resection as a predictor of failure following reimplantation.

METHODS

This retrospective multicenter study identified 437 patients with chronic knee PJI who had undergone 2-stage exchange arthroplasty with a minimum of 1 year of follow-up following reimplantation. PJI was defined with use of the 2013 Musculoskeletal Infection Society (MSIS) criteria. Patients with culture-negative PJI were excluded (n = 138). Treatment failure was defined as either any reoperation for infection or PJI-related mortality. Multivariable regression controlling for risk factors for failure after a 2-stage arthroplasty was performed to determine whether ≥2 positive intraoperative cultures at resection can predict outcomes following reimplantation when compared with a single positive culture.

RESULTS

Two hundred and ninety-nine patients were included. At a mean follow-up of 6.2 ± 2.6 years, 48 patients (16.1%) experienced failure. Patients who had a failure were more likely to have had a longer interstage interval (p = 0.038) and were also more likely to have had ≥2 positive cultures at the time of resection arthroplasty (95.8% versus 75.3%; p = 0.001). On regression analysis, ≥2 positive cultures at resection was the only variable that was identified as a risk factor for failure following reimplantation in both the univariate (odds ratio [OR], 7.55 [95% CI, 2.24 to 47.0]; p = 0.006) and multivariable models (OR, 8.12 [95% CI, 2.31 to 51.9]; p = 0.005).

CONCLUSIONS

This is the first study to examine the impact of the number of positive cultures on outcomes in patients with PJI. We found that the presence of ≥2 positive cultures at resection was an indicator of a poor prognosis and resulted in a greater than eightfold increase in the risk of treatment failure in patients undergoing a 2-stage exchange.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Nocardia Prosthetic Knee Infection Treated with 2-Stage Exchange Following Total Knee Arthroplasty: A Case Report

CASE

A 63-year-old man presented with right knee pain and swelling 16 months after undergoing right total knee arthroplasty. Inflammatory markers were elevated, and after 6 weeks of incubation, cultures grew Nocardia nova. Treatment included 2-stage exchange of the prosthetic joint, multiple wound debridements, and an extended course of antibiotics. A Staphylococcus epidermidis infection complicated treatment, but all infections were considered resolved 14 months after the initial joint infection diagnosis.

CONCLUSION

This report underscores the need to consider Nocardia nova as a cause of prosthetic joint infections and the potential for prolonged treatment.

Can a 1.5-Stage Revision Be an Effective Alternative for Chronic Periprosthetic Hip and Knee Infections? A Systematic Review and Meta-Analysis

BACKGROUND

A 1.5-stage revision could be an alternative to a 2-stage revision for treating hip and knee chronic periprosthetic infections, guaranteeing the maintenance of joint function and infection control and preventing infection-free patients from undergoing further surgery. Our systematic review aimed to answer several questions about the indication, the infection eradication rate, and the long-term functional outcome of 1.5-stage revisions used to treat chronic periprosthetic infections of the hip and knee.

METHODS

A systematic review of the literature was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, including studies dealing with the use of 1.5-stage and two-stage surgery for chronic periprosthetic joint infection following total knee arthroplasty or total hip arthroplasty The Coleman Methodology Score and the Methodological Index for Nonrandomized Studies score were used to assess the quality of the studies. A meta-analysis was performed to evaluate the infection eradication rate using either the 1.5-stage revision or the 2-stage technique. A total of 494 patients (111 hips and 385 knees) who underwent 1.5-stage with a mean age of 69 years (range, 61 to 82) were identified in the ten included studies.

RESULTS

The most common cause of reoperation was the conversion to the definitive prosthesis, followed by aseptic loosening. Infection control was reached in 84.6% of the 1.5-stage and 76.1% of the two-stage cohorts. The infection recurrence rate was higher in the two-stage cohort than the 1.5-stage group (21.8 versus 14.3%).

CONCLUSIONS

The 1.5-stage technique represents a valid treatment option in selected patients who have chronic periprosthetic joint infection who cannot undergo further surgeries, adding together the benefits of the 1- and 2-stage procedures. Furthermore, the 1.5-stage showed a better success rate in the infection resolution than the 2-stage technique.

Predictive Factors for Risk of Reinfection in Septic Two-Stage Revision of Total Hip and Knee Arthroplasties

BACKGROUND

The two-stage septic exchange is the most common therapy concept in the treatment of periprosthetic hip and knee infections. However, before the second-stage reimplantation can be carried out, the physician has to assess whether or not the eradication of the periprosthetic joint infection (PJI) has been successful. Therefore, the aim of this study was to evaluate possible predictive parameters for the successful treatment of PJI before and at the time of reimplantation.

METHODS

This study investigated a total of 145 patients with periprosthetic hip infection and 93 patients with periprosthetic knee infection, who all underwent a two-stage septic exchange between 2017 and 2021. In order to identify possible risk factors for reinfections, the patients underwent preoperative examination of serological inflammatory parameters, microbiological and histological examination of the periprosthetic membrane at the time of reimplantation, as well as postoperative evaluations at regular intervals for a period of at least 24 months.

RESULTS

During the follow-up period, reinfection occurred in 11.3% of cases after the two-stage septic revision. None of the serological, microbiological, or histological parameters were able to significantly predict the risk of reinfection. Risk factors associated with reinfection were BMI and previous revision surgery.

CONCLUSIONS

Currently, there is no reliable predictive factor indicating the risk of reinfection at the time of reimplantation. New diagnostic methods need to be developed to evaluate the possibility and timing of endoprosthesis reimplantation.

Risk factors of recurrent periprosthetic joint infection of the knee after two-stage reimplantation

INTRODUCTION

Prosthetic joint infection (PJI) is one of the most common and detrimental complications of total knee replacement arthroplasty (TKA). Despite extensive efforts, including two-stage reimplantation, to eradicate PJI, it still recurs in a substantial number of patients. However, the risk factors of recurrence after two-stage reimplantation of the knee have not been established. In this study, it is hypothesized that there will be certain risk factors of recurrence after two-stage reimplantation for PJI of the knee.

MATERIALS AND METHODS

From March 2002 to December 2022, 65 knees that underwent two-stage reimplantation for PJIs in a single, tertiary hospital were retrospectively reviewed, and 44 patient-related, laboratory-related, and surgery-related factors, including body mass index, pathogen type, and the usage of transfusions, were selected as the potential risk factors for recurrence. Survival analysis using the Kaplan-Meier method and subsequent Cox proportional hazard regression were performed.

RESULTS

Out of the 65 knees that underwent two-stage reimplantation, infection recurred in 15 knees (23.1%) in a median 11 (range 4-108) months. The Cox proportional hazards regression showed that infection of revision TKA, mixed pathogen-type infection, and higher serum erythrocyte sedimentation rate (ESR, mm/h) level increases the risk of recurrence (p-values < 0.001, 0.04, and 0.009; hazard ratios 40.29, 1.53, and 1.03, respectively).

CONCLUSIONS

A significant portion of PJI of the knees recurred after two-stage reimplantation. Revision TKA at the time of initial PJI, mixed pathogen-type infection, and higher serum ESR level were three significant risk factors of PJI recurrence. Surgeons should be more cautious in suspecting PJI relapse for these specific occasions.

LEVEL OF EVIDENCE

III, retrospective cohort study.

High and Low Dosage of Vancomycin in Polymethylmethacrylate Cements: Efficacy and Mechanical Properties

INTRODUCTION

Prosthetic joint infections (PJIs) are difficult to treat and represent a significant burden to the healthcare system. Two-stage revision surgery with placement of an antibiotic-loaded cement spacer is currently the gold standard for treatment in the United States for late-onset infections. We evaluate the efficacy of varying doses of vancomycin added to antibiotic-containing acrylic cement spacers and discuss the biomechanical and antimicrobial properties of using high versus low doses of vancomycin in cement spacers in the hip and knee.

MATERIALS AND METHODS

Commercially available Copal cement containing either gentamicin and clindamycin (G + C) or gentamicin and vancomycin (G + V) was prepared with the manual addition of low (2 g) and high (6 g) doses of vancomycin. In vitro mechanical testing was then carried out according to ISO 5833 and DIN 53435, as well as inhibition zone assays against common PJI pathogens. Additionally, inhibition zone assays were conducted on two commercially available prefabricated spacers containing gentamicin: Copal Exchange G and Cemex Spacer-K.

RESULTS

In biomechanical testing, Copal G + V with the addition of 6 g of vancomycin failed to meet the ISO standard. Copal G + C and Copal G + V with low and high dosages of vancomycin were all effective against the tested pathogens and displayed constant efficacy for a duration of 42 days. High doses of vancomycin showed significantly lower mechanical stability. Moreover, Copal Exchange G showed significantly larger inhibition zones across 42 days.

DISCUSSION

While higher concentrations of vancomycin appear to improve the antimicrobial efficacy of cement, they also reduce its mechanical stability. Despite its smoother surface, the Copal Exchange G spacer exhibits large inhibition zones after 1 day and maintains consistently large inhibition zones over 6 weeks. Thus, it may be preferred for use in two-stage revision surgery.

CONCLUSION

Copal Exchange G is more effective than Cemex Spacer K against S. aureus and E. coli. The manual addition of vancomycin to cement containing double antibiotics is very effective. The influence on ISO compression is low, the ISO bending modulus is increased, and ISO bending, DIN bending, and DIN impact, are reduced.

Intramedullary Positive Tissue Culture Increases the Risk of Reinfection Following One-Stage Septic Revision Total Knee Arthroplasty

BACKGROUND

Intraoperative acquisition of representative tissue samples is essential during revision arthroplasty of the infected total knee arthroplasty (TKA). While the number of intraoperative tissue samples needed to identify the organism is well described in the literature, there is still a paucity of evidence regarding the location of positive intraoperative samples and their correlation to postoperative outcomes.

METHODS

There were forty-two patients who had septic failure following one-stage revision TKA for periprosthetic joint infection who were identified between January 2009 and December 2017. They were matched to a control group of patients who had successful one-stage revision TKA without septic failure. The location of positive intraoperative tissue samples was categorized as: 1) soft tissue; 2) interface between bone and prosthesis; and 3) intramedullary (IM). Chi-square, Student's t-, and Wilcoxon Mann-Whitney U-tests were used as appropriate. Univariate and multivariate logistic regression analyses were performed to evaluate predictors of septic failure.

RESULTS

Weight > 100 kilograms (P = .033), higher Charlson Comorbidity Index (P < .001), and positive IM cultures (P < .001) were associated with a higher risk of reinfection after one-stage revision TKA. A positive IM sample carried a nearly five-fold increase in odds of reinfection (odds ratio 4.86, 95% confidence interval 1.85 to 12.78, P = .001).

CONCLUSIONS

A positive IM culture sample is significantly associated with septic failure after one-stage exchange for periprosthetic joint infection of the knee. Patients who had positive IM cultures may benefit from longer postoperative antibiotic therapy for the treatment of one-stage exchange arthroplasty to minimize the risk of reinfection.

Above-knee amputation shows higher complication and mortality rates in line with lower functional outcome compared to knee arthrodesis in severe periprosthetic joint infection

Aims

In cases of severe periprosthetic joint infection (PJI) of the knee, salvage procedures such as knee arthrodesis (KA) or above-knee amputation (AKA) must be considered. As both treatments result in limitations in quality of life (QoL), we aimed to compare outcomes and factors influencing complication rates, mortality, and mobility.

Methods

Patients with PJI of the knee and subsequent KA or AKA between June 2011 and May 2021 were included. Demographic data, comorbidities, and patient history were analyzed. Functional outcomes and QoL were prospectively assessed in both groups with additional treatment-specific scores after AKA. Outcomes, complications, and mortality were evaluated.

Results

A total of 98 patients were included, 52 treated with arthrodesis and 47 with AKA. The mean number of revision surgeries between primary arthroplasty and arthrodesis or AKA was 7.85 (SD 5.39). Mean follow-up was 77.7 months (SD 30.9), with a minimum follow-up of two years. Complications requiring further revision surgery occurred in 11.5% of patients after arthrodesis and in 37.0% of AKA patients. Positive intraoperative tissue cultures obtained during AKA was significantly associated with the risk of further surgical revision. Two-year mortality rate of arthrodesis was significantly lower compared to AKA (3.8% vs 28.3%), with age as an independent risk factor in the AKA group. Functional outcomes and QoL were better after arthrodesis compared to AKA. Neuropathic pain was reported by 19 patients after AKA, and only 45.7% of patients were fitted or were intended to be fitted with a prosthesis. One-year infection-free survival after arthrodesis was 88.5%, compared to 78.5% after AKA.

Conclusion

Above-knee amputation in PJI results in high complication and mortality rates and poorer functional outcome compared to arthrodesis. Mortality rates after AKA depend on patient age and mobility, with most patients not able to be fitted with a prosthesis. Therefore, arthrodesis should be preferred whenever possible if salvage procedures are indicated.

Dual Surgical Setup Associated with Reduced Infection Recurrence for Hip and Knee Arthroplasty After Two-Stage Exchange

INTRODUCTION

Two-stage exchange (TSE) is the gold standard for the treatment of chronic periprosthetic joint infection (PJI) after total joint arthroplasty of the hip and knee in the United States. Failure of treatment can have devastating consequences for the patient, including poor functional outcomes, multiple further surgeries, and increased mortality. Several factors associated with infection recurrence have previously been identified in the literature. The purpose of this study was to evaluate whether the use of a dual surgical setup was associated with reduced risk of recurrence after TSE for PJI.

METHODS

A retrospective study was conducted between January 2000 and December 2021 to isolate patients who underwent TSE after total joint arthroplasty of the hip and knee. Failure was defined as infection recurrence requiring surgical intervention. Demographic factors (age, sex, body mass index, smoking status, American Society of Anesthesiologists status), preoperative comorbidities (hypertension, cardiac disease, diabetes status, depression diagnosis, pulmonary disease), operating surgeon, single versus dual setup, hospital setting, use of long-term antibiotics postoperatively after TSE, aspiration data, and infecting organism were compared between cohorts using multivariate regression analysis.

RESULTS

A total of 134 patients were identified who underwent TSE after diagnosis of PJI. The mean follow-up was 67.84 (range, 13 to 236) months. Dual setup (odds ratio, 0.13; confidence interval, 0.02 to 0.52; P = 0.0122) was found to be an independent predictive variable associated with a lower risk of infection recurrence.

CONCLUSION

Utilization of a dual surgical setup is a low-cost modifiable risk factor associated with a lower risk of recurrence of after TSE of the hip and knee for PJI.

Intermittent alternating magnetic fields diminish metal-associated biofilm in vivo

Prosthetic joint infection (PJI) is a complication of arthroplasty that results in significant morbidity. The presence of biofilm makes treatment difficult, and removal of the prosthesis is frequently required. We have developed a non-invasive approach for biofilm eradication from metal implants using intermittent alternating magnetic fields (iAMF) to generate targeted heating at the implant surface. The goal of this study was to determine whether iAMF demonstrated efficacy in an in vivo implant biofilm infection model. iAMF combined with antibiotics led to enhanced reduction of biofilm on metallic implants in vivo compared to antibiotics or untreated control. iAMF-antibiotic combinations resulted in a > 1 - log further reduction in biofilm burden compared to antibiotics or iAMF alone. This combination effect was seen in both S. aureus and P. aeruginosa and seen with multiple antibiotics used to treat infections with these pathogens. In addition, efficacy was temperature dependent with increasing temperatures resulting in a greater reduction of biofilm. Tissue damage was limited (< 1 mm from implant-tissue interface). This non-invasive approach to eradicating biofilm could serve as a new paradigm in treating PJI.