The Gut Microbiome and Joint Microbiome Show Alterations in Patients with Knee Osteoarthritis Versus Controls: A Systematic Review.

PURPOSE: To assess the current scientific literature on the microbiome's relationship with knee osteoarthritis (OA), with specific focuses on the gut microbiome-joint axis and joint microbiome-joint axis. METHODS: A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, searching PubMed, Embase, and Cochrane databases for relevant English-language clinical studies on the gut and/or joint microbiomes' association with knee OA in humans. Bias was evaluated using the methodological index for non-randomized studies score. RESULTS: Thirty-five thousand bacterial species comprise the gut microbiome; approximately 90% are members of the phyla Bacteroides and Firmicutes. Symbiosis between the gut microbiome and host under normal physiological conditions positively affects host growth, development, immunity, and longevity. Gut microbiome imbalance can negatively influence various physiological processes, including immune response, inflammation, metabolism, and joint health including development of knee OA. In addition, next generation gene sequencing suggests the presence of microorganisms in the synovial fluid of osteoarthritic knees, and distinct microbiome profiles detected are presumed to play a role in the development of OA. With regard to the gut microbiome, consistent alterations in microbial composition between OA patients and controls are noted, in addition to several associations between certain gut bacteria with OA-related knee pain, patient-reported outcome measure performance, imaging findings, and changes in metabolic and inflammatory pathways. Regarding the joint microbiome, studies revealed increased levels of lipopolysaccharide (LPS) and LPS-binding protein in synovial fluid are associated with activated macrophages, and correlated with worsened osteophyte severity, joint space narrowing, and pain scores in knee OA patients. In addition, studies demonstrated various microbial composition differences in OA patients compared to control, with certain joint microbes directly associated with OA pathogenesis, inflammation, and metabolic dysregulation. CONCLUSIONS: The gut microbiome-joint axis and joint microbiome shows alterations in microbial composition between osteoarthritic patients and controls. These alterations are associated with perturbations of metabolic and inflammatory pathways, imaging findings, osteoarthritis-related pain, and patient reported outcome measure performance. LEVEL OF EVIDENCE: Systematic Review; Level III.

Arthroscopic Debridement of Mild and Moderate Knee Osteoarthritis Results in Clinical Improvement at Short-Term Follow-Up: A Systematic Review.

PURPOSE: To report the clinical outcomes of arthroscopic debridement for the treatment of Kellgren-Lawrence (KL) grade I and II (mild) and III (moderate) knee osteoarthritis (OA) at a minimum 1-year follow-up. METHODS: A systematic review of primary literature was performed in concordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines using the Medline, Embase, and Cochrane databases for studies regarding arthroscopic debridement/chondroplasty for management of knee OA at a minimum 1-year follow-up. Studies were included if they included KL grades I to III or dichotomized clinical outcomes by KL grade. The primary outcome was patient-reported outcome measures (PROMs) at the final follow-up. Bias was assessed using the Methodological Index for Non-Randomized Studies (MINORS) score. RESULTS: Eight studies including a total of 773 patients met inclusion criteria (range of patients in each study, 31-214). Mean age of patients ranged from 35.5 to 64 years, with most studies having a mean patient age of 55 to 65 years. Mean follow-up ranged from 1.5 to 10 years. Seven of the 8 (87.5%) studies reported good to excellent PROMs at a minimum 1- to 4-year follow-up after arthroscopic debridement. Improvements in PROMs were superior in patients with less severe knee OA (KL I-II) in comparison to KL III in most studies. Conversion to arthroplasty ranged from 7.6% to 50% in KL III patients compared with 0% to 4.5% in KL I-II patients after arthroscopic debridement. Two of the 3 studies with at least a 4-year clinical follow-up reported that clinical improvements diminished with time (improvements no longer significant in total Western Ontario and McMaster Universities Osteoarthritis Index score). The lone randomized controlled trial was the only investigation that did not find a benefit of arthroscopic debridement over quality nonoperative care. MINORS scores ranged from 6 to 10 (mean, 8.0) for the 5 nonrandomized studies without controls. CONCLUSIONS: Arthroscopic debridement for the management of mild to moderate knee OA is effective at short-term follow-up in patients who have exhausted conservative care. There is limited evidence demonstrating the durability of improvement following arthroscopic debridement after 2 years. LEVEL OF EVIDENCE: Level IV, systematic review of Level I to IV studies.

Orthopaedic Musculoskeletal Biologics Research Impacts Patient Care: The Second Annual Arthroscopy Orthobiologics Virtual Special Issue.

The field of orthobiologics is rapidly evolving, offering clinicians a shift in treatment from symptom relief to the potential for disease modification and tissue repair. These agents, derived from autologous tissues, components of blood, and growth factors, are used as surgical adjuncts or as standalone treatments. Their clinical applications are expanding to encompass a variety of conditions, supported by a growing base of research efforts. Arthroscopy and its companion publications are committed to evidence-based research with a robust history of publications that enhance clinical decision-making and impact patient care. This curated collection of articles highlights the year's most compelling advancements in orthopaedic musculoskeletal biologics research.

Bioabsorbable Screw Fixation Provides Good Results With Low Failure Rates at Mid-term Follow-up of Stable Osteochondritis Dissecans Lesions That Do Not Improve With Initial Conservative Treatment.

Purpose: To evaluate the clinical and radiographic outcomes of patients who have undergone bioabsorbable screw fixation for intact, stable grade I and II osteochondritis dissecans (OCD) lesions for which at least 6 months of conservative management has failed. Methods: A retrospective review of prospectively collected data from a single institution was performed to identify patients who underwent internal fixation of stable grade I and II OCD lesions (according to the Guhl classification) between January 2010 and January 2020. Patients were included regardless of the presence of concomitant procedures. The inclusion criteria consisted of (1) primary surgery, (2) failure of at least 6 months of conservative management, (3) the use of a bioabsorbable screw (or screws), and (4) minimum 2-year clinical follow-up. Radiographs were obtained at a minimum of 1 year postoperatively. Patient demographic characteristics, clinical patient-reported outcomes, complications, and failure rates were noted. Results: Twenty-four knees among 23 patients (96% follow-up) were analyzed and followed up for 6.36 ± 3.42 years (range, 2.0-12.7 years). Patients showed statistically significant postoperative improvements in all patient-reported outcomes including the Lysholm score, International Knee Documentation Committee score, and Knee Injury and Osteoarthritis Outcome Score subscales (P < .05). In 3 knees (12%), a reoperation was required due to failure at an average of 3.64 years after the index procedure. No specific complications were attributed to the use of bioabsorbable screws. Patients in whom primary surgical treatment failed did not differ in demographic characteristics, arthroscopic findings, or surgical treatment from those who had successful treatment. Conclusions: Internal fixation of stable grade I and II OCD lesions with bioabsorbable screws produces reliable results with a 12% rate of failure in appropriately indicated patients in whom at least 6 months of conservative management has failed. Clinical outcomes improved significantly during the mid-term follow-up period. Level of Evidence: Level IV, therapeutic case series.

Medical Students' Perceptions of Orthopedics as a Career for Women.

OBJECTIVES: To determine potential factors influencing female medical students' interest and subsequent application to orthopedics, and to evaluate female and male medical students' perceptions of women in the field of orthopedics. METHODS: An institutional review board-approved survey was distributed in March 2020 and subsequently in April 2022 to medical students in the classes of 2023 and 2024 at the University of Alabama at Birmingham Heersink School of Medicine. Study data were collected and managed using REDCap electronic data capture. An e-mail link to the REDCap survey was sent to students across the southeast region of the United States, followed by three reminder e-mails. All 25 allopathic medical schools in the southeastern United States with an Orthopedics Interest Group listed on their institution's Web site were invited to participate in the study. Nine Orthopedics Interest Group leaders interested in participating were asked to provide the researchers with a list of fourth-year medical students who attended an event hosted by that group (215). A total of 39 respondents who completed the survey were included in this study. RESULTS: Overall, the majority of students (n = 35, 90%) believed that women faced more barriers to a career in orthopedics than did men. The most significant barriers to women entering the field of orthopedics were the perceived expectations of an orthopedic surgeon (n = 34, 87%), difficulty balancing career and family (n = 28, 72%), and demanding schedule (n = 13, 33%). CONCLUSIONS: This study demonstrates that both male and female medical students believe there are significant additional barriers to success for women in the field. Study participants report that expectations set by physicians, other healthcare professionals, and patients contribute to creating greater barriers that deter medical students interested in orthopedics from ultimately applying to the specialty.

Allograft reconstruction for humeral head defects in the setting of shoulder instability: a systematic review.

Background: Glenohumeral joint instability and dislocation are common orthopedic pathologies that can produce osseous humeral head defects such as Hill-Sachs (HS) or Reverse Hill-Sachs (RHS) lesions. Numerous reconstruction techniques have been reported in the literature, including remplissage, disimpaction, and allograft reconstruction. No group has previously assessed the outcomes of allograft reconstruction for RHS lesions, nor compared the outcomes of allograft reconstruction for HS and RHS lesions. In this study, we aim to provide a comprehensive assessment of osteochondral allograft reconstruction for the distinct pathologies of RHS lesions and HS lesions by comparing postreconstruction patient-reported outcomes, complications, and radiographic assessments for each lesion. Methods: Using Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, a systematic review was performed to identify and include studies that reported patient outcomes after the use of osteochondral allografts in the reconstruction of HS or RHS lesions of the humeral head. A comprehensive search of the Google Scholar, PubMed, and Embase databases was conducted with the key terms "allograft," "Hill-Sachs," and "reverse Hill-Sachs." Results: Eight studies, with a total of 84 patients, were included for review. Of the 84 allograft-treated patients, there were 44 patients with HS lesions and 40 patients with RHS lesions. The average patient age was 27.3 years for HS lesions and 43.0 years for RHS lesions. Postoperative range of motion and average Constant-Murley score (87.9 for HS and 80.1 for RHS) appeared to be greater for those with HS lesions. In addition, 20.5% of HS patients experienced postoperative complications, whereas 42.5% of RHS patients had postoperative complications (P = .03). HS and RHS patients experienced similar proportions of graft resorption or collapse rate (22.7% for HS and 12.5% for RHS; P = .2). Conclusion: Patient-reported outcomes indicate that osteochondral allograft reconstruction for large RHS and HS lesions is an acceptable intervention. RHS patients had lower rates of graft resorption and collapse but worse postoperative range of motion and functional outcomes, although these differences were not statistically significant. HS patients experienced significantly fewer complications than those with RHS lesions.

Defining α-synuclein species responsible for Parkinson's disease phenotypes in mice.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by fibrillar neuronal inclusions composed of aggregated α-synuclein (α-syn). These inclusions are associated with behavioral and pathological PD phenotypes. One strategy for therapeutic interventions is to prevent the formation of these inclusions to halt disease progression. α-Synuclein exists in multiple structural forms, including disordered, nonamyloid oligomers, ordered amyloid oligomers, and fibrils. It is critical to understand which conformers contribute to specific PD phenotypes. Here, we utilized a mouse model to explore the pathological effects of stable ß-amyloid-sheet oligomers compared with those of fibrillar α-synuclein. We biophysically characterized these species with transmission EM, atomic-force microscopy, CD spectroscopy, FTIR spectroscopy, analytical ultracentrifugation, and thioflavin T assays. We then injected these different α-synuclein forms into the mouse striatum to determine their ability to induce PD-related phenotypes. We found that ß-sheet oligomers produce a small but significant loss of dopamine neurons in the substantia nigra pars compacta (SNc). Injection of small ß-sheet fibril fragments, however, produced the most robust phenotypes, including reduction of striatal dopamine terminals, SNc loss of dopamine neurons, and motor-behavior defects. We conclude that although the ß-sheet oligomers cause some toxicity, the potent effects of the short fibrillar fragments can be attributed to their ability to recruit monomeric α-synuclein and spread in vivo and hence contribute to the development of PD-like phenotypes. These results suggest that strategies to reduce the formation and propagation of ß-sheet fibrillar species could be an important route for therapeutic intervention in PD and related disorders.