Role of the Gut Microbiota in Osteoarthritis, Rheumatoid Arthritis, and Spondylarthritis: An Update on the Gut-Joint Axis.

Dysregulation of the gut microbiota and their metabolites is involved in the pathogenic process of intestinal diseases, and several pieces of evidence within the current literature have also highlighted a possible connection between the gut microbiota and the unfolding of inflammatory pathologies of the joints. This dysregulation is defined as the "gut-joint axis" and is based on the joint-gut interaction. It is widely recognized that the microbiota of the gut produce a variety of compounds, including enzymes, short-chain fatty acids, and metabolites. As a consequence, these proinflammatory compounds that bacteria produce, such as that of lipopolysaccharide, move from the "leaky gut" to the bloodstream, thereby leading to systemic inflammation which then reaches the joints, with consequences such as osteoarthritis, rheumatoid arthritis, and spondylarthritis. In this state-of-the-art research, the authors describe the connections between gut dysbiosis and osteoarthritis, rheumatoid arthritis, and spondylarthritis. Moreover, the diagnostic tools, outcome measures, and treatment options are elucidated. There is accumulating proof suggesting that the microbiota of the gut play an important part not only in immune-mediated, metabolic, and neurological illnesses but also in inflammatory joints. According to the authors, future studies should concentrate on developing innovative microbiota-targeted treatments and their effects on joint pathology as well as on organizing screening protocols to predict the onset of inflammatory joint disease based on gut dysbiosis.

Orthobiologics in knee osteoarthritis, dream or reality?

Cartilage restoration or repair, also known as orthobiologic therapy, is indicated after the failure of conservative or supportive treatment. However, there is paucity in evidence supporting the efficacy of orthobiologic therapy. The blood-derived products, such as platelet-rich plasma (PRP), is one of the commonly used orthobiologic therapy for knee osteoarthritis. Several studies have shown that PRP is superior to other treatments, but the anatomic changes are scarce. Treatment with mesenchymal stem cells (MSCs) offers the greatest potential for curing degenerative disease due to their self-renewal ability, ability to migrate towards injured tissues (homing/trafficking), and ability to promote repair and regeneration of osteochondral defects. However, ethical concerns and high costs remain major challenges associated with MSC therapy. Gene therapy, another promising orthobiologic therapy, is currently in phase II clinical trial and has shown promising results. The key factors for successful orthobiologic therapy include patient selection, appropriate dosing, treatment of underlying mechanical problems, age, severity, and cost-effectiveness.

Debridement, antibiotics, and implant retention (DAIR) for the early prosthetic joint infection of total knee and hip arthroplasties: a systematic review.

PURPOSE: Early periprosthetic joint infection (PJI) represents one of the most fearsome complications of joint replacement. No international consensus has been reached regarding the best approach for early prosthetic knee and hip infections. The aim of this updated systematic review is to assess whether debridement, antibiotics, and implant retention (DAIR) is an effective choice of treatment in early postoperative and acute hematogenous PJI. METHODS: This systematic review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The diagnostic criteria defining a PJI, the most present pathogen, and the days between the index procedure and the onset of the PJI were extracted from the selected articles. Additionally, the mean follow-up, antibiotic regimen, and success rate of the treatment were also reported. RESULTS: The articles included provided a cohort of 970 patients. Ten studies specified the joint of their cohort in PJIs regarding either hip prostheses or knee prostheses, resulting in 454 total knees and 460 total hips. The age of the patients ranged from 18 to 92 years old. Success rates for the DAIR treatments in the following cohort ranged from 55.5% up to a maximum of 90% (mean value of 71%). CONCLUSION: Even though the DAIR procedure is quite limited, it is still considered an effective option for patients developing an early post-operative or acute hematogenous PJI. However, there is a lack of studies, in particular randomized control trials (RCTs), comparing DAIR with one-stage and two-stage revision protocols in the setting of early PJIs, reflecting the necessity to conduct further high-quality studies to face the burden of early PJI.

The influence of gut microbiome on periprosthetic joint infections: State-of-the art.

Early periprosthetic joint infection constitutes one of the most frightening complications of joint replacement. Recently, some evidence has highlighted the potential link between dysregulation of the gut microbiota and degenerative diseases of joints. It has been hypothesized that microbiome dysbiosis may increase the risk of periprosthetic joint infection by facilitating bacterial translocation from these sites to the bloodstream or by impairing local or systemic immune responses. Although the processes tying the gut microbiome to infection susceptibility are still unknown, new research suggests that the presurgical gut microbiota-a previously unconsidered component-may influence the patient's ability to resist infection. Exploring the potential impact of the microbiome on periprosthetic joint infections may therefore bring new insights into the pathogenesis and therapy of these disorders. For a successful therapy, a proper surgical procedure in conjunction with an antibacterial concept is essential. As per the surgical approach, different treatment strategies include surgical irrigation, debridement, antibiotic therapy, and implant retention with or without polyethylene exchange. Other alternatives could be one-stage or two-stage revisions surgery. Interventions that either directly target gut microbes as well as interventions that modify the composition and/or function of the commensal microbes represent an innovative and potentially successful field to be explored. In recent times, innovative therapeutic methods have arisen in the realm of microbiome restoration and the management of gut-related ailments. These progressive approaches offer fresh perspectives on tackling intricate microbial imbalances in the gastrointestinal tract. These emerging therapies signify a shift towards more precise and individualized approaches to microbiome restoration and the management of gut-related disorders. Once a more advanced knowledge of the pathways linking the gut microbiota to musculoskeletal tissues is gained, relevant microbiome-based therapies can be developed. If dysbiosis is proven to be a significant contributor, developing treatments for dysbiosis may represent a new frontier in the prevention of periprosthetic joint infections.

Prosthetic joint infection of the hip and knee due to Mycobacterium species: A systematic review.

BACKGROUND: Mycobacterium species (Mycobacterium sp) is an emerging cause of hip and knee prosthetic joint infection (PJI), and different species of this organism may be responsible for the same. AIM: To evaluate the profile of hip and knee Mycobacterium PJI cases as published in the past 30 years. METHODS: A literature search was performed in PubMed using the MeSH terms "Prosthesis joint infection" AND "Mycobacterium" for studies with publication dates from January 1, 1990, to May 30, 2021. To avoid missing any study, another search was performed with the terms "Arthroplasty infection" AND "Mycobacterium" in the same period as the previous search. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses chart was used to evaluate the included studies for further review. In total, 51 studies were included for further evaluation of the cases, type of pathogen, and treatment of PJI caused by Mycobacterium sp. RESULTS: Seventeen identified Mycobacterium sp were reportedly responsible for hip/knee PJI in 115 hip/knee PJI cases, whereas in two cases there was no mention of any specific Mycobacterium sp. Mycobacterium tuberculosis (M. tuberculosis) was detected in 50/115 (43.3%) of the cases. Nontuberculous mycobacteria (NTM) included M. fortuitum (26/115, 22.6%), M. abscessus (10/115, 8.6%), M. chelonae (8/115, 6.9%), and M. bovis (8/115, 6.9%). Majority of the cases (82/114, 71.9%) had an onset of infection > 3 mo after the index surgery, while in 24.6% (28/114) the disease had an onset in ≤ 3 mo. Incidental intraoperative PJI diagnosis was made in 4 cases (3.5%). Overall, prosthesis removal was needed in 77.8% (84/108) of the cases to treat the infection. Overall infection rate was controlled in 88/102 (86.3%) patients with Mycobacterium PJI. Persistent infection occurred in 10/108 (9.8%) patients, while 4/108 (3.9%) patients died due to the infection. CONCLUSION: At least 17 Mycobacterium sp can be responsible for hip/knee PJI. Although M. tuberculosis is the most common causal pathogen, NTM should be considered as an emerging cause of hip/knee PJI.