Single-stage revision for chronic periprosthetic joint infection after knee and hip arthroplasties: indications and treatments

Dynamics of Synovial Fluid Markers Following Single-Stage Exchange and Debridement, Antibiotics, and Implant Retention Procedure With Topical Antibiotic Infusion in Treating Periprosthetic Joint Infection

BACKGROUND

Periprosthetic joint infection (PJI) is a severe complication following total joint arthroplasty. This study aimed to investigate the dynamics of synovial fluid markers following single-stage exchange arthroplasty or debridement, combined with antibiotics and implant retention with topical antibiotic infusion for PJI.

METHODS

This retrospective study analyzed patient records at a tertiary hospital from March 1, 2018, to May 1, 2023. Patients who received single-stage exchange arthroplasty or debridement, combined with antibiotics and implant retention, followed by intra-articular antibiotic infusion for PJI, were included. Basic demographic details, comorbidities, Charlson Comorbidity Index scores, microorganism profile, presence of sinus tract, and antibiotic treatment type were collected. Synovial fluid samples were collected preoperatively and postoperatively every two days for 14 days to quantify synovial white blood cell (WBC) count and polymorphonuclear cell percentage (PMN%).

RESULTS

The study included 140 patients who had a mean age of 63 years and a mean body mass index of 25. The results showed a steady decrease in synovial WBC count from preoperative levels to day 14 postoperatively. Patients who had successful outcomes had significantly higher preoperative WBC counts compared to those who had a treatment failure. The synovial PMN% initially increased postoperatively, peaking at days one to two, and then gradually declined. Patients who had successful outcomes showed a faster decline in PMN% compared to those who had persistent infections. Different bacteria exhibited varying preoperative synovial WBC counts and PMN%, but these differences were not statistically significant.

CONCLUSIONS

Monitoring synovial WBC count and PMN% can help distinguish between normal postoperative inflammation and persistent infection. Higher preoperative synovial WBC counts are associated with successful outcomes, suggesting their potential role in predicting treatment success. Future research with larger sample sizes is necessary to further validate these findings and improve the management and diagnosis of PJI.

Exploring Acute Kidney Injury Incidence in Hip Periprosthetic Joint Infection Treatment With Combined Intravenous and Intra-articular Antibiotic Infusion

Background

Periprosthetic joint infections (PJIs) are a significant complication following total hip arthroplasty, impacting patient health and healthcare costs. This study examines the incidence of acute kidney injury (AKI) in patients undergoing hip PJI treatment with a combination of intravenous and intra-articular antibiotic infusion therapies.

Methods

A retrospective review of 151 patient records from May 1, 2010 to December 30, 2022 was conducted at a single academic hospital. Patients were treated for hip PJIs using debridement, antibiotics, and implant retention or single-stage revision surgeries. AKI was classified according to the Kidney Disease: Improving Global Outcomes criteria.

Results

Among 151 patients, 17 (11.26%) developed AKI, with 13 cases resolving transiently before discharge. The median onset of AKI was on postoperative day 2, with stage I AKI being the most prevalent, accounting for 64.71% of cases. Diabetes and low baseline serum creatinine levels were identified as independent risk factors for AKI, with odds ratios of 9.69 and 1.09, respectively.

Conclusions

The combined regimen of intra-articular and intravenous antibiotic infusion appears to have a manageable risk profile regarding AKI. This approach could serve as a viable alternative for PJI management, emphasizing the importance of careful patient monitoring and tailored antibiotic regimens. Further studies are recommended to optimize treatment protocols and mitigate risks.

What Are the Functional, Radiographic, and Survivorship Outcomes of a Modified Cup-cage Technique for Pelvic Discontinuity?

BACKGROUND

Pelvic discontinuity (PD) presents a complex challenge in revision hip arthroplasty. The traditional cup-cage construct, which involves a screw-secured porous metal cup and an overlying antiprotrusio cage, has shown promising mid- to long-term results. However, there is limited information on the outcomes of modifications to the original technique. Our study aims to evaluate a modified technique in which the cup position is determined by the placement of the overlying cage, allowing for adjustments to achieve optimal orientation.

QUESTIONS/PURPOSES

Among patients treated for PD with a cup-cage construct in which the cup position was dictated by the position of the cage: (1) What are Harris hip scores achieved at a minimum of 2 years of follow-up? (2) What is the Kaplan-Meier survivorship free from aseptic loosening or component migration? (3) What is the Kaplan-Meier survivorship free from revision for any reason? (4) What surgical complications are associated with the procedure?

METHODS

Between October 2013 and January 2022, we performed 805 acetabular revisions. Among these, 33 patients with PD confirmed intraoperatively were considered potentially eligible for a cup-cage construct; no other method of surgical management was used. We performed 64% (21 of 33) of these procedures from October 2013 to January 2018, with 6% (2 of 33) of patients lost to follow-up before the minimum study follow-up of 2 years; these 19 patients were monitored over a period ranging from 70 to 115 months. A further 12 patients underwent this procedure from January 2018 to January 2022, with one lost to follow-up before the minimum study follow-up of 2 years; the other patients met the minimum 2-year follow-up requirement. The remaining 30 patients with data analyzed here (10 men, 20 women) had a mean ± SD age of 61 ± 12 years and a median BMI of 29 kg/m 2 (range 20 to 33 kg/m 2 ) at the time of revision surgery. Twenty-one patients underwent revision due to aseptic loosening, and nine due to periprosthetic joint infection (PJI). The causes of PD in our patients were as follows: cup aseptic loosening without significant osteolysis in 20% (6 of 30), where the loose cup caused erosion of the host bone, leading to PD; PJI in 30% (9 of 30); intraoperative iatrogenic PD in 3% (1 of 30); and osteolysis in 47% (14 of 30), which also resulted in aseptic loosening. The median follow-up time was 79 months (range 25 to 115 months). The Harris hip score was used to evaluate clinical outcomes, with preoperative values compared with the most recent follow-up. Radiographs were reviewed by two experienced surgeons at each follow-up visit to assess component loosening (defined as migration > 5 mm or the presence of circumferential radiolucent lines) or clear migration. PD was considered healed if bridging callus or trabecular bone was visible across the site of the discontinuity. Complications were assessed through a comprehensive review of electronic medical records. Kaplan-Meier analysis was used to estimate implant survivorship and radiographic loosening, with aseptic loosening or component migration as the endpoint, as well as survivorship free from any reoperation.

RESULTS

The Harris hip score improved from a median of 39 (range 30 to 66) preoperatively to a median of 76 (range 30 to 90) postoperatively (median difference 33 [range 2 to 48]; p < 0.01). Within the limitations of two-dimensional (2D) radiographic imaging, successful bone graft integration and the healing of PD were noted in 83% (25 of 30) of patients. Kaplan-Meier survivorship free from radiographic signs of aseptic loosening or component migration was 100% (95% CI 100% to 100%) at 115 months. When any revision related to the acetabular component was considered the endpoint, survivorship free from acetabular component revision at 115 months after revision surgery was 100% (95% CI 100% to 100%). When the need for any reoperation was considered the endpoint, survivorship free from needing reoperation at 115 months after revision surgery was 85% for all patients (95% CI 73% to 100%). When including only patients with a follow-up time of > 4 years (20 of 30), survivorship free from needing reoperation at 115 months after revision surgery was 90% (95% CI 78% to 100%). Postoperative complications during the follow-up period included one early dislocation on the fifth day after surgery, treated with closed reduction and 6 weeks of abduction bracing. One femoral stem loosening occurred at 56 months postoperatively, although the acetabular component remained securely fixed; this patient declined revision surgery. One patient experienced a dislocation 5 months after surgery but refused treatment and opted for prolonged bed rest. Additionally, one patient underwent a debridement, antibiotics, and implant retention procedure 1 week after the revision surgery and subsequently showed no signs of infection at the latest follow-up, 38 months postoperatively.

CONCLUSION

Our study highlights the effectiveness of a modified cup-cage technique in complex hip revisions, showing promising results in terms of construct survivorship and low complication rates. Surgeons could consider delaying screw fixation until after positioning the cage within the porous cup to allow for optimal adjustment and using metal augments for severe bone defects to achieve better alignment. Surgeon experience with the cup-cage technique is crucial for achieving optimal outcomes. Future studies should focus on long-term follow-up visits to assess the durability and effectiveness of these modifications and explore the comparative effectiveness versus other methods, such as custom triflange components and jumbo cups with distraction.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Low incidence of acute kidney injury with combined intravenous and topical antibiotic infusions in periprosthetic joint infection after total knee arthroplasty

Aims

This study aimed to assess the risk of acute kidney injury (AKI) associated with combined intravenous (IV) and topical antibiotic therapy in patients undergoing treatment for periprosthetic joint infections (PJIs) following total knee arthroplasty (TKA), utilizing the Kidney Disease: Improving Global Outcomes (KDIGO) criteria for classification.

Methods

We conducted a retrospective analysis of 162 knees (162 patients) that received treatment for PJI post-TKA with combined IV and topical antibiotic infusions at a single academic hospital from 1 January 2010 to 31 December 2022. The incidence of AKI was evaluated using the KDIGO criteria, focussing on the identification of significant predictors and the temporal pattern of AKI development.

Results

AKI was identified in 9.26% (15/162) of the cohort, predominantly presenting as stage 1 AKI, which was transient in nature and resolved prior to discharge. The analysis highlighted moderate anaemia and lower baseline serum creatinine levels as significant predictors for the development of AKI. Notably, the study found no instances of severe complications such as wound dehiscence, skin erosion, or the need for haemodialysis following treatment.

Conclusion

The findings suggest that the combined use of IV and topical antibiotic therapy in the management of PJIs post-TKA is associated with a low incidence of primarily transient stage 1 AKI. This indicates a potentially favourable renal safety profile, advocating for further research to confirm these outcomes and potentially influence treatment protocols in PJI management.

Impact of fixation method on femoral bone loss: a retrospective evaluation of stem loosening in first-time revision total hip arthroplasty among two hundred and fifty five patients

PURPOSE

Implant loosening represent the most common indication for stem revision in hip revision arthroplasty. This study compares femoral bone loss and the risk of initial revisions between cemented and uncemented loosened primary stems, investigating the impact of fixation method at primary implantation on femoral bone defects.

METHODS

This retrospective study reviewed 255 patients who underwent their first revision for stem loosening from 2010 to 2022, receiving either cemented or uncemented stem implants. Femoral bone loss was preoperatively measured using the Paprosky classification through radiographic evaluations. Kaplan-Meier analysis estimated the survival probability of the original stem, and the hazard ratio assessed the relative risk of revision for uncemented versus cemented stems in the first postoperative year and the following two to ten years.

RESULTS

Cemented stems showed a higher prevalence of significant bone loss (type 3b and 4 defects: 32.39% vs. 2.72%, p < .001) compared to uncemented stems, which more commonly had type 1 and 2 defects (82.07% vs. 47.89%, p < .001). In our analysis of revision cases, primary uncemented stems demonstrated a 20% lower incidence of stem loosening in the first year post-implantation compared to cemented stems (HR 0.8; 95%-CI 0.3-2.0). However, the incidence in uncemented stems increased by 20% during the subsequent years two to ten (HR 1.2; 95%-CI 0.7-1.8). Septic loosening was more common in cemented stems (28.17% vs. 10.87% in uncemented stems, p = .001). Kaplan-Meier analysis indicated a modestly longer revision-free period for cemented stems within the first ten years post-implantation (p < .022).

CONCLUSION

During first-time revision, cemented stems show significantly larger femoral bone defects than uncemented stems. Septic stem loosening occurred 17.30% more in cemented stems.

Editorial: Management of PJI/SSI after joint arthroplasty

The management of periprosthetic joint infection (PJI) and surgical site infection (SSI) after joint arthroplasty poses a major challenge in orthopedic surgery. This Editorial provides an overview of the studies published in the special issue "Management of PJI/SSI after Joint Arthroplasty", summarizing the key findings from these studies, which cover a wide range of topics, including stringent preventive strategies, comprehensive diagnostic methods, and personalized treatment modalities. The authors concluded the editorial with their perspectives regarding the status quo of research in this field and future directions for research, such as the development of novel antibiotics, biofilm research, patient-specific risk factors, and the integration of technological advancements (such as machine learning and artificial intelligence) into clinical practice. The authors emphasized the need for continued research, interdisciplinary collaboration, and the application of innovative technologies to enhance patient outcomes and mitigate the burden of these infections on healthcare systems.

Single-stage revision in the management of prosthetic joint infections after total knee arthroplasty - A review of current concepts

Introduction

Prosthetic joint infection (PJI) is a devastating complication following total knee arthroplasty (TKA); and the gold standard surgical approach involves a two-staged, revision TKA (TSR). Owing to the newer, emerging evidence on this subject, there has been gradual shift towards a single-stage revision approach (SSR), with the purported benefits of mitigated patient morbidity, decreased complications and reduced costs. However, there is still substantial lacuna in the evidence regarding the safety and outcome of the two approaches in chronic PJI. This study aimed to comprehensively review of the literature on SSR; and evaluate its role within Revision TKA post PJI.

Methods

The narrative review involved a comprehensive search of the databases (Embase, Medline and Pubmed), conducted on 20th of January 2024 using specific key words. All the manuscripts discussing the use of SSR for the management of PJI after TKA were considered for the review. Among the screened manuscripts, opinion articles, letters to the editor and non-English manuscripts were excluded.

Results

The literature search yielded a total 232 studies. Following a detailed scrutiny of these manuscripts, 26 articles were finally selected. The overall success rate following SSR is reported to range from 73 % to 100 % (and is comparable to TSR). SSR is performed in PJI patients with bacteriologically-proven infection, adequate soft tissue cover, immuno-competent host and excellent tolerance to antibiotics. The main difference between SSR and TSR is that the interval between the 2 stages is only a few minutes instead of 6 weeks. Appropriate topical, intraoperative antibiotic therapy, followed by adequate postoperative systemic antibiotic cover are necessary to ascertain good outcome. Some of the major benefits of SSR over TSR include reduced morbidity, decreased complications (such as arthrofibrosis or anesthesia-associated adverse events), meliorated extremity function, earlier return to activities, mitigated mechanical (prosthesis-associated) complications and enhanced patient satisfaction.

Conclusion

SSR is a reliable approach for the management of chronic PJI. Based on our comprehensive review of the literature, it may be concluded that the right selection of patients, extensive debridement, sophisticated reconstruction strategy, identification of the pathogenic organism, initiation of appropriate antibiotic therapy and ensuring adequate follow-up are the key determinants of successful outcome. To achieve this will undoubtedly require an MDT approach to be taken on a case-by-case basis.

Achieving High Accuracy in Predicting the Probability of Periprosthetic Joint Infection From Synovial Fluid in Patients Undergoing Hip or Knee Arthroplasty: The Development and Validation of a Multivariable Machine Learning Algorithm

Background and objective The current periprosthetic joint infection (PJI) diagnostic guidelines require clinicians to interpret and integrate multiple criteria into a complex scoring system. Also, PJI classifications are often inconclusive, failing to provide a clinical diagnosis. Machine learning (ML) models could be leveraged to reduce reliance on these complex systems and thereby reduce diagnostic uncertainty. This study aimed to develop an ML algorithm using synovial fluid (SF) test results to establish a PJI probability score. Methods We used a large clinical laboratory's dataset of SF samples, aspirated from patients with hip or knee arthroplasty as part of a PJI evaluation. Patient age and SF biomarkers [white blood cell count, neutrophil percentage (%PMN), red blood cell count, absorbance at 280 nm wavelength, C-reactive protein (CRP), alpha-defensin (AD), neutrophil elastase, and microbial antigen (MID) tests] were used for model development. Data preprocessing, principal component analysis, and unsupervised clustering (K-means) revealed four clusters of samples that naturally aggregated based on biomarker results. Analysis of the characteristics of each of these four clusters revealed three clusters (n=13,133) with samples having biomarker results typical of a PJI-negative classification and one cluster (n=4,032) with samples having biomarker results typical of a PJI-positive classification. A decision tree model, trained and tested independently of external diagnostic rules, was then developed to match the classification determined by the unsupervised clustering. The performance of the model was assessed versus a modified 2018 International Consensus Meeting (ICM) criteria, in both the test cohort and an independent unlabeled validation set of 5,601 samples. The SHAP (SHapley Additive exPlanations) method was used to explore feature importance. Results The ML model showed an area under the curve of 0.993, with a sensitivity of 98.8%, specificity of 97.3%, positive predictive value (PPV) of 92.9%, and negative predictive value (NPV) of 99.8% in predicting the modified 2018 ICM diagnosis among test set samples. The model maintained its diagnostic accuracy in the validation cohort, yielding 99.1% sensitivity, 97.1% specificity, 91.9% PPV, and 99.9% NPV. The model's inconclusive rate (diagnostic probability between 20-80%) in the validation cohort was only 1.3%, lower than that observed with the modified 2018 ICM PJI classification (7.4%; p<0.001). The SHAP analysis found that AD was the most important feature in the model, exhibiting dominance among >95% of "infected" and "not infected" diagnoses. Other important features were the sum of the MID test panel, %PMN, and SF-CRP. Conclusions Although defined methods and tools for diagnosis of PJI using multiple biomarker criteria are available, they are not consistently applied or widely implemented. There is a need for algorithmic interpretation of these biomarkers to enable consistent interpretation of the results to drive treatment decisions. The new model, using clinical parameters measured from a patient's SF sample, renders a preoperative probability score for PJI which performs well compared to a modified 2018 ICM definition. Taken together with other clinical signs, this model has the potential to increase the accuracy of clinical evaluations and reduce the rate of inconclusive classification, thereby enabling more appropriate and expedited downstream treatment decisions.