Histopathology in Periprosthetic Joint Infection: When Will the Morphomolecular Diagnosis Be a Reality?

Diagnostics in Late Periprosthetic Infections-Challenges and Solutions

The rising number of arthroplasties is combined with a rising number of periprosthetic joint infections, which leads to life-concerning consequences for the patients, including extended antibiotic treatment, further surgery and increased mortality. The heterogeneity of the symptoms and inflammatory response of the patients due to, e.g., age and comorbidities and the absence of a single diagnostic test with 100% accuracy make it very challenging to choose the right parameters to confirm or deny a periprosthetic joint infection and to establish a standardized definition. In recent years, additional diagnostic possibilities have emerged primarily through the increasing availability of new diagnostic methods, such as genetic techniques. The aim of the review is to provide an overview of the current state of knowledge about the various tests, including the latest developments. The combination of different tests increases the accuracy of the diagnosis. Each physician or clinical department must select the tests from the available methods that can be best implemented for them in organizational and technical terms. Serological parameters and the cultivation of the samples from aspiration or biopsy should be combined with additional synovial tests to create an accurate figure for the failure of the prosthesis, while imaging procedures are used to obtain additional information for the planned therapeutic procedure.

A rare case of periprosthetic joint infection of the hip due to Kocuria spp

BACKGROUND

Kocuria spp. are ubiquitous bacteria that have gained recent attention as potential infectious agents. The most common bacteria in PJI are S. aureus und S. epidermidis.

CASE PRESENTATION

We present the case of a 72-year-old woman who received total hip arthroplasty after a traumatic medial femoral neck fracture. Postoperatively, due to the clinical presentation of periprosthetic joint infection (PJI) revision surgery was performed twice. The microbiological tissue samples were positive for Kocuria spp. Initially, this was considered contamination and the patient was treated with various antibiotic regimens as well as prednisolone due to the differential diagnosis of pyoderma gangraenosum. However, a specialized histopathology lab performed further testing which substantiated the suspicion of a rare case of PJI due to Kocuria spp.

CONCLUSIONS

To our knowledge, this is the first reported case of a PJI caused by Kocuria spp. Further clinical research is necessary to assess whether Kocuria spp. are an underestimated cause of PJI.

One-Stage Hip Revision Arthroplasty Using Megaprosthesis in Severe Bone Loss of The Proximal Femur Due to Radiological Diffuse Osteomyelitis

Managing substantial proximal and/or distal femoral bone defects is one of the biggest challenges in chronic hip periprosthetic joint infection. Most authors use two-stage arthroplasty with a temporary antibiotic-loaded cement spacer for the management of these patients. In this study, we show our experience with one-stage exchange arthroplasty in managing severe bone defects due to radiological-extensive proximal femoral osteomyelitis. Two patients were included in the study. They showed radiological-extensive proximal femoral osteomyelitis, and they were treated with one-stage exchange arthroplasty using megaprosthesis. Diffuse osteomyelitis was confirmed in both cases; in one case, the histology was compatible with osteomyelitis, and the other case had a positive culture identified in a bone sample. At a minimum of a four-year follow-up, the patients did not reveal any clinical, radiological or laboratory signs of infection. In conclusion, one-stage exchange arthroplasty and megaprosthesis is an option for the treatment of chronic hip periprosthetic joint infection associated with radiological-diffuse proximal femoral osteomyelitis.

Preventing Staphylococcus aureus stainless steel-associated infections in orthopedics. A systematic review and meta-analysis of animal literature

Surgical site infection in the presence of orthopedic implants poses significant healthcare and socioeconomic burden. To assess the potential of various prevention strategies against Staphylococcus-induced stainless steel-associated infections, a review of animal evidence was designed. The databases of PubMed, Embase, and CENTRAL were searched until March 10, 2020, for articles including animal models with stainless steel instrumentation and techniques to prevent Staphylococcus infection. We conducted a random-effects meta-analysis of standardized mean differences (SMD) with subgroup analysis linked to various protection strategies and we recorded complications. Quality was assessed with the SYRCLE's risk of bias tool. Twenty-five studies were included. Combined active coating (featuring organic antibacterial compound release) and degradable passive finishing (lipid- or polymer-based structure modification reducing bacterial adhesion) was favored over untreated controls (SMDs for methicillin-sensitive Staphylococcus aureus [MSSA] and methicillin-resistant Staphylococcus aureus [MRSA] were -3.46, 95% CI [-4.53 to -2.4], p < .001 [n = 4 head-to-head comparisons]; and -6.67, 95% CI [-10.53 to -3], p < .001 [n = 5 head-to-head comparisons], respectively). Systemic vitamin D supplementation and systemic antibiotic administration with or without local antibiotics demonstrated favorable outcomes against MSSA infection. On the contrary, no benefit was seen following vaccination. Of note, no side effects were documented. On the basis of data gathered from eight studies, which comprised 294 animals, a bioresorbable polymer- or lipid-based surface modification supplemented with organic coating yielded improved infection-related outcomes against MSSA and MRSA stainless steel infections, and therefore, this strategy could be further investigated in human research.

Current Guideline for Diagnosis of Periprosthetic Joint Infection: A Review Article

The nature of implant-related infections is complex. Currently, there is no definitive test for periprosthetic joint infection (PJI) and diagnosis remains challenging despite recent developments. Failure to diagnose and investigate pathologies of the hip appropriately results in delayed management and prolonged patient morbidity. A systematic approach to establishing clear diagnostic criteria for PJI is needed to improve our ability to avoid devastating outcomes associated with these infections. In the current review, we describe an algorithmic approach to the diagnosis of PJI and current controversies surrounding novel diagnostic methods.

Elevated plasma D-dimer concentration has higher efficacy for the diagnosis of periprosthetic joint infection of the knee than of the hip-A single-center, retrospective study

The aim of this study is to evaluate the value of D-dimers in the diagnosis of periprosthetic joint infection (PJI). The analysis was performed for revision total hip (rTHA) and revision total knee arthroplasty (rTKA) together and separately with two thresholds, one calculated by statistical methods and the second adopted from the ICM 2018 definition. The study group comprised 133 patients who underwent rTHA or rTKA: 68 patients diagnosed according to the ICM 2018 definition (PJI group) and 65 with aseptic implant loosening, instability, malposition, or implant failure with the exclusion of infection (aseptic revision total joint arthroplasty or arTJA group). Mean D-dimer concentrations were 0.36 ± 0.25 μg/ml in the arTJA group and 0.87 ± 0.78 μg/ml in the PJI group (p < .001). For rTHA and rTKA together, the sensitivity and specificity of the evaluation were 75% and 73.8% according to the calculated cut-off value (0.45 μg/ml), and 33.8% and 95.4% based on the ICM 2018 threshold (0.85 μg/ml). Separately, for rTHA, sensitivity and specificity were 62.5% and 62.1% for the calculated value (0.43 μg/ml) and 6.3% and 96.6% for the ICM 2018 threshold; for rTKA, sensitivity was 86.1% and specificity was 88.9% for the calculated threshold (0.48 μg/ml) and 58.3% and 94.4% for the ICM 2018 value. Our findings indicate that plasma D-dimers have potential as markers of knee PJI, but moderate to low value for hip PJI.

Outcomes after antibiotic megaspacer implantation in patients with severe chronic periprosthetic infections

Periprosthetic joint infection (PJI) is a rare postoperative complication that is treated with antibiotic spacers. Some patients develop severe, treatment-resistant, chronic PJI despite multiple attempts at salvaging the joint. Permanent resection of the joint or amputation may be the only definitive treatment. The purpose of this study is to describe the outcomes, infection resolution rate, and complications of two-stage revision, utilizing extensive resection of the affected bone and application of antibiotic megaspacers as a modality for limb-salvage. A review of 12 patients, initially referred for amputation due to chronically failed PJI, was conducted. All patients underwent extensive resection of the bone and surgical implantation of a custom-made antibiotic megaspacer between December 2016 and June 2019. Thirteen megaspacers were placed in 13 infected joints in 12 patients with a history of chronic PJI. Six patients (50%) had a diagnosis of osteomyelitis. Eradication of the infection leading to limb-salvage was successful in nine patients. Visual Analog Scale pain scores improved by 3.5, or 50%, after two-stage revision with megaprosthesis reimplantation (p = .008), and six patients (54.5%) had improvement in ambulation. Complication rates, not including reinfection or recurrence, following megaspacer and megaprosthesis reimplantation were 58.3% and 27.3%, respectively. One patient underwent amputation due to a life-threatening infection while two other patients underwent amputation due to debilitating complications following limb-salvage surgery. Statement of Clinical Significance: In patients whose PJI becomes treatment-resistant after multiple failed attempts at traditional two-stage exchange, performing extensive boney resection with placement of an antibiotic-laden megaspacer can be an effective method of achieving limb-salvage.

The EBJIS definition of periprosthetic joint infection

Aims

The diagnosis of periprosthetic joint infection (PJI) can be difficult. All current diagnostic tests have problems with accuracy and interpretation of results. Many new tests have been proposed, but there is no consensus on the place of many of these in the diagnostic pathway. Previous attempts to develop a definition of PJI have not been universally accepted and there remains no reference standard definition.

Methods

This paper reports the outcome of a project developed by the European Bone and Joint Infection Society (EBJIS), and supported by the Musculoskeletal Infection Society (MSIS) and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group for Implant-Associated Infections (ESGIAI). It comprised a comprehensive review of the literature, open discussion with Society members and conference delegates, and an expert panel assessment of the results to produce the final guidance.

Results

This process evolved a three-level approach to the diagnostic continuum, resulting in a definition set and guidance, which has been fully endorsed by EBJIS, MSIS, and ESGIAI.

Conclusion

The definition presents a novel three-level approach to diagnosis, based on the most robust evidence, which will be useful to clinicians in daily practice.

Cite this article: Bone Joint J 2021;103-B(1):18–25.

Plasma Cell Infiltration on Histopathological Samples of Chronic Bone and Joint Infections due to Cutibacterium acnes: A series of 21 Cases

Introduction: Histopathological definition of bone and joint infection (BJI) is based on Mirra's criterion (≥ 5 polymorphonuclears (PMNs) per field in 5 high power fields (HPFs)). However, this definition does not seem appropriate for chronic BJIs caused by slow-growing germs such as Cutibacterium acnes (C. acnes). The aim of this study was to confirm that Mirra's criterion is not adequate for diagnosis of BJIs due to C. acnes. The second objective was to determine if plasma cell infiltration could be useful for the diagnosis of chronic BJIs due to C. acnes. Methods: We retrospectively selected 25 consecutive patients from 2009 to 2013 with chronic BJIs due to C. acnes. Histological analysis was performed on the 21 cases with at least two C. acnes positive cultures. In addition of Mirra's criterion, the number of plasma cells (≥5 plasma cells/5 HPFs, defined as "CRIOAc Lyon's criterion") was implemented in the histopathological analysis. Patients were defined as infected, if at least one of the two criteria were present. Results: According to Mirra's and CRIOAc Lyon's criteria, positive histopathology was observed in 12 (57.1%) and 15 (71.4%) cases respectively. Considering the 9 cases with negative Mirra's criterion, high plasma cell infiltration (≥5 plasma cells per field/5 HPFs) was observed in 5 cases (55.6%), and low plasma cells infiltration (2-5 plasma cells per field/5 HPFs) was observed in 4 other cases (44.4%). Conclusions: Adding CRIOAc Lyon's criterion to Mirra's criterion might restore some histopathological diagnosis of chronic BJIs due to C. acnes when a chronic BJI is clinically suspected.

Massive Osteolytic Lesion of the Femur after Total Knee Arthroplasty

Various failure mechanisms have been identified in total knee arthroplasty (TKA). We hereby present one case of failure, which stands out because of its rapid and destructive progression. We report the case of a 72-year-old Caucasian female patient who developed a large bone osteolytic lesion of the femur after TKA. The patient presented to our hospital 7 years after the initial surgery, complaining of persistent knee pain. The lesion affected the distal half of the femur and, after a diagnostic workup, required a resection of 20 cm and reconstruction with a tumor prosthesis. Subsequent pathological analysis revealed a reaction to cement and prosthesis components. Periprosthetic osteolysis continues to be a major problem, and a reaction to cement and prosthesis components can be an elusive cause of TKA failure.

Fabrication of PLLA/C3S Composite Membrane for the Prevention of Bone Cement Leakage

Kyphoplasty is an important treatment for stabilizing spine fractures due to osteoporosis. However, leakage of polymethyl-methacrylate (PMMA) bone cement during this procedure into the spinal canal has been reported to cause many adverse effects. In this study, we prepared an implantable membrane to serve as a barrier that avoids PMMA cement leakage during kyphoplasty procedures through a hybrid composite made of poly-l-lactic acid (PLLA) and tricalcium silicate (C₃S), with the addition of C₃S into PLLA matrix, showing enhanced mechanical and anti-degradation properties while keeping good cytocompatibility when compared to PLLA alone and most importantly, when this material design was applied under standardized PMMA cement injection conditions, no posterior wall leakage was observed after the kyphoplasty procedure in pig lumbar vertebral bone models. Testing results assess its effectiveness for clinical practice.

Interaction Between Staphylococcal Biofilm and Bone: How Does the Presence of Biofilm Promote Prosthesis Loosening?

With the aging of population, the number of indications for total joint replacement is continuously increasing. However, prosthesis loosening can happen and is related to two major mechanisms: (1) aseptic loosening due to prosthesis micromotion and/or corrosion and release of wear particles from the different components of the implanted material and (2) septic loosening due to chronic prosthetic joint infection (PJI). The “aseptic” character of prosthesis loosening has been challenged over the years, especially considering that bacteria can persist in biofilms and be overlooked during diagnosis. Histological studies on periprosthetic tissue samples reported that macrophages are the principle cells associated with aseptic loosening due to wear debris. They produce cytokines and favor an inflammatory environment that induces formation and activation of osteoclasts, leading to bone resorption and periprosthetic osteolysis. In PJIs, the presence of infiltrates of polymorphonuclear neutrophils is a major criterion for histological diagnosis. Neutrophils are colocalized with osteoclasts and zones of osteolysis. A similar inflammatory environment also develops, leading to bone resorption through osteoclasts. Staphylococcus aureus, Staphylococcus epidermidis, and Staphylococcus lugdunensis are the main staphylococci observed in PJIs. They share the common feature to form biofilm. For S. aureus and S. epidermidis, the interaction between biofilm and immunes cells (macrophages and polymorphonuclear neutrophils) differs regarding the species. Indeed, the composition of extracellular matrix of biofilm seems to impact the interaction with immune cells. Recent papers also reported the major role of myeloid-derived suppressor cells in biofilm-associated PJIs with S. aureus. These cells prevent lymphocyte infiltration and facilitate biofilm persistence. Moreover, the role of T lymphocytes is still unclear and potentially underestimates. In this review, after introducing the cellular mechanism of aseptic and septic loosening, we will focus on the interrelationships between staphylococcal biofilm, immune cells, and bone cells.

Correlation of histological and microbiological findings in septic and aseptic knee implant failure

INTRODUCTION

The Musculoskeletal Infection Society (MSIS) has defined specific clinical and laboratory criteria for the diagnosis of periprosthetic joint infection (PJI). In this study we assessed the diagnostic utility of MSIS microbiological and histological criteria for PJI in 138 cases of septic and aseptic knee implant failure.

MATERIALS AND METHODS

Intra-operative samples from 60 cases of knee septic implant failure (SIF) and 78 cases of aseptic implant failure (AIF), defined on the basis of clinical, laboratory and operative findings/surgical management, were analysed microbiologically and histologically. Findings were correlated with the final clinical diagnosis and the specificity, sensitivity, accuracy, positive and negative predictive value of MSIS microbiological and histological criteria for knee PJI were assessed.

RESULTS

80% of SIF cases showed culture of the same organism from two or more samples (ie MSIS microbiological criteria for definite PJI); 8.3% grew an organism from one sample, and 11.7% showed no growth from any sample. 23.1% of AIF cases grew an organism from one sample and 76.9% showed no growth from any sample. MSIS histological criteria for PJI identified 96.7% of SIF cases. The sensitivity, specificity, accuracy and positive and negative predictive value of MSIS histological criteria for PJI were 96.7%, 100%, 98.6%, 100% and 97.5%, respectively. MSIS microbiological and histological criteria identified all AIF cases.

CONCLUSIONS

Knee PJI is more often identified by current MSIS histological than microbiological criteria. A significant proportion of SIF cases show either no growth or growth of an organism from only one sample. AIF is identified by both MSIS microbiological and histological criteria. Correlation of clinical, radiological and laboratory findings is required for the diagnosis of knee PJI.