Low-grade infections as a possible cause of arthrofibrosis after total knee arthroplasty

A Comprehensive Approach to Stiffness in Total Knee Arthroplasty

This article is a summary of a symposium on knee stiffness in primary and revision TKAs presented at the 2024 American Association of Hip and Knee Surgeons (AAHKS) annual meeting. The purpose of this paper was to provide an overview of the genetics of arthrofibrosis, preoperative and perioperative risk factors associated with arthrofibrosis, ways to optimize modifiable risk factors, and early and late treatment options for stiffness and when it fails to improve with initial interventions.

A rare case of invasive Enterococcus cecorum infection and related diagnostic difficulties

Key Clinical Message

This report presents a rare case of invasive infection caused by Enterococcus cecorum. There are no specific guidelines regarding antibiotic therapy for this infection. Based on this case, it can be concluded that linezolid demonstrates in vivo activity against Enterococcus cecorum and can be successfully used in therapy.

Abstract

Enterococcus cecorum is an extremely rare pathogen in humans. Since 1984, when the microorganism was first described, only a dozen cases of invasive infections in humans have been reported in the literature. The diagnostic pathway may involve difficulties in correctly identifying this microorganism. Based on the case described, it can be thought that Enterococcus cecorum is a more challenging bacterium than the much more common Enterococcus faecium or Enterococcus faecalis. The described case underscores the importance of medical vigilance in clinical practice. It seems that due to increasingly advanced techniques in molecular biology, we will more frequently detect pathogens that were previously encountered only sporadically. Since not every center has access to modern and advanced microbiological diagnostic methods, publications that practically combine classical microbiological diagnostic methods with those less accessible but more modern are exceptionally valuable. In the case described, it is also worth noting that classical methods still play a significant and crucial role in conducting microbiological diagnostics. In the era of rapid diagnostic tool development, it is important to emphasize the necessity of combining different methods rather than replacing one with another.

Unexpected positive cultures in patients with arthrofibrosis following total hip and total knee arthroplasty

PURPOSE

It has been suggested that low-grade infections could be the cause of arthrofibrosis. However, this hypothesis has not been conclusively proven. The aim of this study is to assess the incidence of unexpected positive cultures (UPC) in patients undergoing revision total joint arthroplasty for a diagnosis of arthrofibrosis.

METHODS

A retrospective single-centre review was performed. All patients who underwent an aseptic revision due to histologically confirmed arthrofibrosis (based on the synovial-like interface membrane (SLIM) criteria) were included. The incidence of UPC was then calculated.

RESULTS

A total of 147 patients were included. Of these, 100 underwent a total knee arthroplasty (TKA) procedure and 46 a total hip arthroplasty (THA) surgery. One patient had a periprosthetic joint infection and was therefore excluded. Of the 146 included patients, 6 had confirmed UPC (4.08%). The following bacteria were identified: Anaerococcus octavius, Staphylococcus epidermidis, Enterobacter cloacae, Staphylococcus hominis, Streptococcus pluranimalium, Staphylococcus pettenkoferi.

CONCLUSIONS

Our results suggest that the incidence of UPC in patients with arthrofibrosis is low. It is lower than that of UPC in patients that undergo a revision for other causes. There is no proven relationship between histologically confirmed arthrofibrosis following total joint arthroplasty and prosthetic joint infection.

Comparative Genome Analysis of Enterococcus cecorum Reveals Intercontinental Spread of a Lineage of Clinical Poultry Isolates

Enterococcus cecorum is an emerging pathogen responsible for osteomyelitis, spondylitis, and femoral head necrosis causing animal suffering and mortality and requiring antimicrobial use in poultry. Paradoxically, E. cecorum is a common inhabitant of the intestinal microbiota of adult chickens. Despite evidence suggesting the existence of clones with pathogenic potential, the genetic and phenotypic relatedness of disease-associated isolates remains little investigated. Here, we sequenced and analyzed the genomes and characterized the phenotypes of more than 100 isolates, the majority of which were collected over the last 10 years from 16 French broiler farms. Comparative genomics, genome-wide association studies, and the measured susceptibility to serum, biofilm-forming capacity, and adhesion to chicken type II collagen were used to identify features associated with clinical isolates. We found that none of the tested phenotypes could discriminate the origin of the isolates or the phylogenetic group. Instead, we found that most clinical isolates are grouped phylogenetically, and our analyses selected six genes that discriminate 94% of isolates associated with disease from those that are not. Analysis of the resistome and the mobilome revealed that multidrug-resistant clones of E. cecorum cluster into a few clades and that integrative conjugative elements and genomic islands are the main carriers of antimicrobial resistance. This comprehensive genomic analysis shows that disease-associated clones of E. cecorum belong mainly to one phylogenetic clade. IMPORTANCE Enterococcus cecorum is an important pathogen of poultry worldwide. It causes a number of locomotor disorders and septicemia, particularly in fast-growing broilers. Animal suffering, antimicrobial use, and associated economic losses require a better understanding of disease-associated E. cecorum isolates. To address this need, we performed whole-genome sequencing and analysis of a large collection of isolates responsible for outbreaks in France. By providing the first data set on the genetic diversity and resistome of E. cecorum strains circulating in France, we pinpoint an epidemic lineage that is probably also circulating elsewhere that should be targeted preferentially by preventive strategies in order to reduce the burden of E. cecorum-related diseases.

Mesh migration following abdominal hernia repair: A case report, and literature review

BACKGROUND

Postoperative hematoma and seroma, foreign body reaction, infection, mesh rejection, and fistula formation are the complications associated with the use of surgical mesh. Mesh migration is a rare but serious and challenging complication after hernia repair. When this happens, infection, abscess, fistula, and bowel obstruction are the most common sequelae.

CASE PRESENTATION

Our patient was a 62-year-old woman with a history of appendectomy 30 years ago and then underwent 3 incisional hernia repair surgeries which the last one was 5 years ago using laparoscopic IPOM. The patient was nominated for surgery with a diagnosis of recurrent incisional hernia. The patient underwent laparotomy and after enterolysis, a small bowel loop was seen that adhered to McBurney's region, which was released. There was a mass inside the small bowel. Resection and anastomosis of the involved intestine were performed. After enterotomy, it was determined that this mass was the mesh used in the previous surgery.

CONCLUSION

Mesh migration is a rare consequence of incisional hernia repair with a prosthetic mesh. It can happen years after a hernia repair and it is additionally crucial to consider as a differential diagnosis in all patients who show unusual symptoms or abdominal pain.

Impact of Tibial Tubercle Osteotomy on Final Outcome in Revision Total Knee Arthroplasty: Our Experience and Technique in Pakistan

Backgroud

Due to extensive fibrosis during revision surgery, adequate exposure is essential and it can be achieved with several extensile approach options, such as tibial tubercle osteotomy. Information regarding surgical exposure during revision arthroplasty is limited in developing countries, such as Pakistan, due to the lack of adequate data collection and follow-up. Therefore, the purpose of this study was to evaluate the impact of tibial tubercle osteotomy on final outcome of revision total knee arthroplasty (TKA).

Methods

A total of 231 revision TKAs were performed between January 2008 and December 2017. Twenty-nine patients underwent tibial tubercle osteotomy for adequate exposure during revision surgery. Of these, 27 patients with complete follow-up were included in our study. Factors examined include age at the time of revision surgery, gender, comorbidities, arthroplasty site (right or left), body mass index (BMI), and primary indications for the tibial tubercle osteotomy during revision TKA. Functional outcome was measured by using Knee Society score (KSS) at 3 months and the final follow-up. All statistical analysis was done using SPSS version 20.0 with a p-value < 0.05 considered significant.

Results

Out of 27 patients, 6 patients (22.2%) were men and 21 patients (77.7%) were women. Right knee revision arthroplasty was performed in 15 patients (55.5%), left knee revision arthroplasty was performed in 12 patients (44.4%), and bilateral revision surgery was performed in only 1 patient (3.7%). The mean BMI was 29.2 kg/m². We used a constrained condylar knee in 20 patients (74%), a rotating hinge knee in 5 patients (18.5%), and mobile bearing tray plus metaphyseal sleeves in 2 patients (7.4%). The KSS was 52.21 ± 4.05 preoperatively, and 79.42 ± 2.2 and 80.12 ± 1.33 at 3 months and 12 months, respectively. Radiological union was achieved in all patients at 3 months. Of 27 patients, only 1 patient (3.7%) had proximal migration of the osteotomy site at 6 months: the patient was asymptomatic and union was also achieved and, therefore, no surgical intervention was performed.

Conclusions

Tibial tubercle osteotomy during revision TKA can be a safe and reliable technique with superior outcomes and minimal complication rates.

Discrimination of Staphylococcus aureus Strains from Coagulase-Negative Staphylococci and Other Pathogens by Fourier Transform Infrared Spectroscopy

Staphylococcus aureus is an extremely infectious and malignant pathogen among many bacteria species. The aim of this work is to provide a robust classification model that would be able to identify S. aureus independent of the culture growth stage and the variations in bacteria concentration in suspension and also one that would be able to identify the pathogen among both taxonomically close species of the same genus and taxonomically distant species of different genera, using Fourier transform infrared spectroscopy (FTIR). In total, the spectra of 141 isolates of 17 bacteria have been used. Based on a combination of principal component analysis (PCA) and linear discriminant analysis (LDA), an identification model providing 100% sensitivity and 98% specificity was built. Inherent reliability and flexibility of the model have been shown. The proposed method of analysis allows us to get closer to the diagnostic requirements in the field of clinical microbiology, and it can be utilized for typing of other pathogenic bacteria species.