Background: Periprosthetic joint infection (PJI) is a devastating complication of arthroplasty and is difficult to diagnose accurately. This study aims to explore the value of neutrophil extracellular traps in synovial fluid (SF-NETs, web-like structures released by neutrophils as a critical innate immune response) for diagnosing PJI. Methods: A retrospective cohort study was conducted, enrolling post-arthroplasty subjects from January 2018 to December 2023. Three components of SF-NETs (cell-free double-strand DNA, SF-dsDNA; citrullinated histone H3, SF-CitH3; SF-Nucleosome) and SF-NETs1+ (positive with one out of the three NET components), SF-NETs2+ (positive with two out of the three NET components), white blood cell count (SF-WBC), polymorphonuclear cell percentage (SF-PMN %), neutrophil count in SF (SF-PMN), microbiological examinations (Culture) and infection-related systemic indices were evaluated. Results: A total of 64 of 153 included subjects were diagnosed as PJI. SF-dsDNA and SF-CitH3 had significantly higher levels in the PJI group compared to the non-PJI group ( P < 0.001) and showed positive correlations with SF-WBC, SF-PMN % and SF-PMN (0.4 < ρ < 0.7), while SF-Nucleosome had no significant difference. Sensitivity and specificity of SF-NETs1+, SF-NETs2+ and Culture were 82.2 % and 78.7 %, 59.4 % and 95.5 %, and 54.1 % and 86.8 %, respectively. The NET related index (NETRI) was defined as 10.529 × SF-NETs 1 + + 28.114 × SF-PMN % + 8.210 × Culture-1.452, with the area under the receiver operating characteristic curve of 0.922, making it a novel indicator. Conclusions: SF-NETs1+ and SF-NETs2+ may serve respectively in the screening and exclusion of PJI. NETRI represented a new discriminator for PJI diagnosis.

Bone defects remain a substantial clinical burden. Exosomes have been extensively investigated as cell-free therapeutic candidates, exhibiting favorable biocompatibility and potential applicability in bone defect repair. Mechanisms relevant to bone regeneration are delineated, including activation of osteogenic and angiogenic programs, modulation of osteoblast–osteoclast coupling, immune regulation, and extracellular matrix remodeling. Engineering strategies that enhance targeting, stability, and potency are summarized. Delivery platforms that provide spatial and temporal control of release at defect sites are also appraised. Artificial intelligence (AI) has been examined as an accelerator of translation. Applications include high‑fidelity exosome characterization, data‑driven biomaterial and formulation design, and prediction of therapeutic response from multimodal data. Large language models further assist evidence synthesis and hypothesis generation. Persistent barriers include heterogeneity in isolation and analytics, low yield and limited scalability, lack of standardization, and insufficient validation in disease‑relevant and large‑animal models. A forward agenda emphasizes standardized manufacturing and quality control, mechanism‑informed cargo and surface engineering, responsive delivery systems and AI‑enabled design–control pipelines to realize precise and reproducible exosome therapies for complex bone defects.

This study reports the mid-term outcomes of primary total hip arthroplasty (THA) and investigates the effect of bony ankylosis on postoperative hip function in patients with ankylosing spondylitis (AS). We identified 544 primary THAs performed in 319 consecutive patients with AS (median age, 33 years) from 2012 to 2017. Survivorship of the implants, complications, and patient satisfaction were investigated. Functional outcomes were assessed by the measurement of hip flexion–extension range of motion (ROM), the Harris hip score (HHS), and the Western Ontario and McMaster Universities Arthritis Index (WOMAC). The hips undergoing THA were divided into a bony ankylosis group and a hip stiffness group based on the severity of hip involvement. The postoperative functional results of the two groups at the most recent follow-up were compared. Survivorship was 99.8

PURPOSE:Total knee arthroplasty (TKA) can cause significant hidden blood loss after surgery, and transfusion or erythropoietin (EPO) treatment may be required. This study aimed to identify the factors associated with blood loss in patients undergoing TKA for osteoarthritis (OA). METHODS:We retrospectively enrolled 1444 OA patients undergoing primary TKA from January 2022 to June 2024. The patients were divided into two groups according to the grade of hidden blood loss. To identify the key influencing factors, we conducted a logistic regression analysis. RESULTS:This study analyzed 1,444 primary arthroplasty cases, identifying 236 patients with high hidden blood loss (HHBL). Coronary artery disease (CAD) was significantly more prevalent in the HHBL group (15.3% vs. 9.4%, p = 0.006). Preoperative EPO use was higher in the low hidden blood loss (LHBL) group (21.9% vs. 9.3%, p < 0.001). Significant preoperative lab differences included hemoglobin, hematocrit, and platelet count. Surgical factors associated with HHBL included left knee TKA, conventional mechanical TKA (CMTKA), longer operation times, and intraoperative blood loss (IBL) > 20%. Postoperatively, the HHBL group had significantly more transfusions and longer hospital stays. Logistic regression identified CAD, platelet count, left knee surgery, CMTKA, operation time, and preoperative EPO use as significant factors influencing HHBL. These findings highlight the need for targeted strategies to manage blood loss in knee arthroplasty patients. CONCLUSIONS:This study identifies several factors associated with high hidden blood loss in patients undergoing TKA for osteoarthritis. CAD, CMTKA, prolonged operation time, left-sided surgery, lower preoperative platelet count, and lack of preoperative erythropoietin (EPO) use were significantly linked to HHBL. While these associations highlight potential targets for intervention, further prospective studies are needed to confirm causality.

Pathological subchondral bone remodeling, characterized by aberrant osteoclastogenesis, exacerbates cartilage degeneration by disrupting osteochondral homeostasis. Here, a correlation between pathological osteoclastogenesis and oxidative stress dynamics is reported in a rat cartilage defect model. On the basis of these findings, CeO2@ZIF-8 nanotherapeutics are engineered to scavenge ROS and suppress pathological osteoclastogenesis, mitigating inflammation and cartilage degeneration. The developed system integrates cerium oxide nanoparticles (CeO2) into a zeolitic imidazolate framework-8 (ZIF-8) framework, exploiting pH-responsive degradation for controlled release in acidic osteochondral niches. In vitro and in vivo assessments confirmed that CeO2@ZIF-8 attenuated osteoclastogenesis, reduced Il-1b expression, and elevated Spp1 levels, and these changes are correlated with improved cartilage regeneration. Multiomics analysis revealed that conditioned supernatants from CeO2@ZIF-8-treated osteoclasts exert protective effects on chondrocytes via the PI3K-PKCs-ERK1/2-Cyp1a1 axis, maintaining the chondrocyte phenotype and inhibiting apoptosis. In summary, the findings established the feasibility for targeting osteoclast-chondrocyte communication through nanozyme-mediated osteoclast reprogramming and provided a mechanistic understanding of orchestrate pathological communication to drive tissue regeneration.

ABSTRACT Objectives Total hip arthroplasty (THA) with Ceramic‐on‐Ceramic (CoC) components achieved excellent outcomes. However, the long‐term outcomes of anatomic and tapered stems are controversial in clinical practice, and the difference in the survival rates between the tapered stems and anatomical stems over the long term remains unknown. Methods A retrospective cohort study was performed to evaluate the 11‐year follow‐up outcomes of anatomic and tapered femoral stems. Between January 2009 and December 2011, a total of 1438 patients with COC were included in this study initially. Among these hips, 30 patients (30 hips) experienced death, and 254 hips (17.6%) were lost to follow‐up. Finally, a total of 591 hips with Corail stem and a total of 334 hips with Ribbed stems were included in this study. The outcomes were evaluated by the modified Harris hip score (mHHS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and a questionnaire assessing articular noises. Results For the Corail stem, the survival rate with aseptic loosening or revision of any component for any reason as the endpoint was 99.1% at 11 years. The survival rate with reoperation for any reason as the endpoint was 98.8% at 11 years. For the Ribbed stem, the survival rate with aseptic loosening or revision of any component for any reason as the endpoint was 98.8% at 11 years. In patients with the Corail stem, the preoperative modified Harris hip score (mHHS) score, with a mean of 43.8 points, significantly improved to a mean of 93.5 points at the final follow‐up assessment (p < 0.001). In patients with the ribbed stem, the preoperative mHHS score, with a mean of 40.9 points, significantly improved to a mean of 92.8 points at the final follow‐up assessment (p < 0.001) during the follow‐up period. The incidence of squeaking and squaking in the Corail group was significantly higher than that in the ribbed group (squeaking: 22.7% vs. 6.9%; squaking: 17.4% vs. 4.2%). The incidence of postoperative thigh pain was 4% in patients with the Corail stem, significantly lower than that in patients with the ribbed stem (17.4% vs. 4%; p < 0.001). Conclusion In conclusion, CoC THA with Corail and Ribbed stems exhibits excellent clinical outcomes at the long‐term follow‐up. However, the incidence of postoperative thigh pain in the Ribbed group is significantly higher than that in the Corail group, while the incidence of squeaking was lower.

To investigate the effects of a 3D-printed Mn-Lut nanoflower-loaded biphasic hydrogel scaffold on the immune response and regenerative potential in a rat osteochondral defect model. The Mn-Lut-loaded biphasic hydrogel scaffold was synthesized and evaluated for its mechanical properties and biocompatibility. In vitro experiments with rat bone marrow mesenchymal stem cells (BMSCs) and bone marrow-derived macrophages (BMDMs) were performed to evaluate cell differentiation, survival, and immune modulation. The scaffold's in vivo regenerative effects were tested in a rat osteochondral defect model. The Mn-Lut-loaded scaffold supported osteogenesis and chondrogenesis by promoting BMSC differentiation. It also facilitated macrophage polarization to the anti-inflammatory M2 phenotype, mitigating oxidative stress. Histological and Micro-computed tomography (CT) analysis of in vivo samples revealed significantly enhanced osteochondral regeneration, including improved trabecular bone formation, cartilage repair, and overall bone density. The manganese-luteolin (Mn-Lut) nanoflower-loaded biphasic hydrogel scaffold modulates the immune microenvironment and enhances osteochondral regeneration, offering a promising therapeutic approach for joint repair.

Poor healing outcomes following rotator cuff injury are linked to insufficient endogenous repair capacity within tendon tissue. And the ATP deficiency caused by energy metabolic imbalance in tendon stem/progenitor cells (TSPCs) is a key pathological feature. Here, we identified energy metabolic changes under the oxidative stress microenvironment of rotator cuff injury, characterized by downregulated oxidative phosphorylation (OXPHOS) and tricarboxylic acid (TCA) cycle in mitochondria, coupled with enhanced glycolysis. Our data showed that Turmeric-derived Extracellular Vesicles (Tur-EVs) rescued this energy crisis, as manifested by the restoration of mitochondrial function and enhanced energy supply, while preserving the proliferation and differentiation capacities of TSPCs. Furthermore, our study revealed that Tur-EVs enhanced mitophagy and endogenous antioxidant capacity through the AMPK-FOXO3 pathway, as a potentially functional mechanism. In rat and rabbit rotator cuff injury models, Tur-EVs-loaded microneedle significantly improved rotator cuff healing quality in terms of locomotor gait, biomechanics, and histopathological outcomes. In summary, our findings demonstrate the potential of plant-derived extracellular vesicles in regulating energy metabolism, and suggest the dysregulated energy metabolism as a crucial therapeutic target in tendon repair.

PurposeWhile local immune responses in periprosthetic joint infection (PJI) are increasingly studied, systemic immune alterations remain poorly characterized. Therefore, this study aimed to investigate the change in peripheral lymphocyte subsets and immune-related protein profiles in patients with PJI, and explore the potential value of these indicators for the diagnosis of PJI.MethodsBetween July 2023 and January 2024, this prospective study recruited 82 patients who had been diagnosed with PJI or aseptic failure (AF), or who were healthy controls. Peripheral blood lymphocyte subpopulations and immune-related proteins were measured using flow cytometry or nephelometry and compared between groups. The diagnostic capability of different indicators for PJI was assessed. Besides, candidate markers were validated in an independent prospective cohort.ResultsCompared with the AF group, the proportion and absolute counts of natural killer (NK) cells in the PJI group were significantly higher, while those of B cells were lower. Differences in most immune-related proteins were observed between PJI and AF cases. Of them, the haptoglobin was the most notably increased in the PJI group than in the AF group (245.08 ± 99.00 mg/dl vs. 108.22 ± 52.37 mg/dl, P < 0.001), which exhibited the best diagnostic performance with an area under the curve (AUC) of 0.890.(95% CI, 0.803-0.978). When haptoglobin was combined with C-reactive protein (CRP), the AUC for the diagnosis of PJI increased to 0.937 (95% CI, 0.876-0.998). No significant differences were observed between the AF and primary total joint arthroplasty (TJA) groups regarding these immune-related indicators. In addition, the diagnostic efficacy of haptoglobin was validated in an independent cohort.ConclusionsThe systemic immune dysregulation observed in PJI patients can lay the foundation for further in-depth understanding of the immune response in PJI. The immune-related markers demonstrated promising value in diagnosing PJI, especially when synovial fluid was unavailable. Multicenter validation was warranted to confirm clinical utility.

ABSTRACT Objective Hip septic arthritis is a relatively rare yet severe cause of acute hip pain, with the potential to rapidly destroy articular cartilage, lead to osteonecrosis, and cause osteomyelitis. This life‐threatening infection demands early diagnosis and appropriate treatment. Our study aims to assess the surgical safety and efficacy of arthroscopic management for this condition and to optimize the arthroscopic treatment protocol by customizing surgical interventions based on intraoperative findings and disease stages. Methods We conducted a retrospective study of 28 patients (18 females, 10 males; average age of 49 ± 10.5 years) from January 2018 to March 2022. Diagnosis of hip septic arthritis was confirmed via synovial fluid examination, culture, or synovial pathology. Patients underwent arthroscopic joint lavage, synovectomy, and drainage tailored to the intraoperative situation and the Gächter stage. Antibiotics were administered based on drug‐sensitivity results or empirically. We recorded and analyzed symptoms, comorbidities, stages, inflammatory marker levels, culture results, antibiotic duration, outcomes, and complications. Results The mean time from symptom onset to surgery was 10.2 ± 8.6 (range, 4–45) days. All patients had elevated inflammatory markers. Pre‐operative bacterial cultures were positive in 6 cases, and post‐operative cultures were positive in 21 cases. Staphylococcus aureus was the most frequently detected pathogen (10 cases), accounting for approximately 47.6% of the positive culture cases. Antibiotic therapy lasted 4–6 weeks. The C‐reactive protein normalized on average 43 days after surgery; the erythrocyte sedimentation rate normalized 54 days postoperatively. At final follow‐up (mean 42 months), the visual analog scale score decreased from 6.6 ± 1.3 to 1.3 ± 0.2 (p = 0.003), and the modified Harris Hip Score improved from 52 ± 8.1 to 85 ± 8.6 (p = 0.001). Infection was controlled in all patients within 6 months. Two patients (Gächter stage III/IV) had recurrent infections at 8 and 11 months, successfully treated with repeat arthroscopy. Gächter stage III or IV was a significant risk factor for recurrence. Two patients underwent total hip arthroplasty due to secondary osteoarthritis and osteonecrosis. No major complications occurred. Conclusion Stage‐based arthroscopic lavage, synovectomy, and drainage combined with antibiotics is effective for hip septic arthritis. The optimized procedure offers a safe and effective option, particularly for early‐stage (Gächter I–II) disease, while advanced stages (III–IV) require cautious management due to higher recurrence risk.

Background Periprosthetic joint infection (PJI) is a serious complication after total joint arthroplasty (TJA). Although some risk factors of PJI were well studied, the association between trauma and PJI remains unknown in revision patients. Materials and methods Between 2015 and 2018, a total of 71 patients with trauma history before revisions (trauma cohort) were propensity score matched (PSM) at a ratio of 1 to 5 with a control cohort of revision patients without a history of trauma. Then, the cumulative incidence rate of PJI within 3 years after operation between the two groups was compared. The secondary endpoints were aseptic revisions within 3 postoperative years, complications up to 30 postoperative days, and readmission up to 90 days. During a minimal 3-year follow-up, the survival was comparatively analyzed between the trauma cohort and the control cohort. Results The cumulative incidence of PJI was 40.85% in patients with trauma history against 27.04% in the controls ( P = 0.02). Correspondingly, the cumulative incidence of aseptic re-revisions was 12.68% in patients with trauma history compared with 5.07% in the control cohort ( P = 0.028). Cox regression revealed that trauma history was a risk factor of PJI (HR, 1.533 [95%CI, (1.019,2.306)]; P = 0.04) and aseptic re-revisions (HR, 3.285 [95%CI, (1.790,6.028)]; P < 0.0001). Conclusions Our study demonstrated that revision patients with trauma history carried a higher risk of PJI compared to those without trauma history. Moreover, after revisions, the trauma patients were still at higher risk for treatment failure due to PJI, periprosthetic joint fracture, and mechanical complications.

Due to its unique structure, articular cartilage has limited abilities to undergo self-repair after injury. Additionally, the repair of articular cartilage after injury has always been a difficult problem in the field of sports medicine. Previous studies have shown that the therapeutic use of mesenchymal stem cells (MSCs) and their extracellular vesicles (EVs) has great potential for promoting cartilage repair. Recent studies have demonstrated that most transplanted stem cells undergo apoptosis in vivo, and the apoptotic EVs (ApoEVs) that are subsequently generated play crucial roles in tissue repair. Additionally, MSCs are known to exist under low-oxygen conditions in the physiological environment, and these hypoxic conditions can alter the functional and secretory properties of MSCs as well as their secretomes. This study aimed to investigate whether ApoEVs that are isolated from adipose-derived MSCs cultured under hypoxic conditions (hypoxic apoptotic EVs [H-ApoEVs]) exert greater effects on cartilage repair than those that are isolated from cells cultured under normoxic conditions. Through in vitro cell proliferation and migration experiments, we demonstrated that H-ApoEVs exerted enhanced effects on stem cell proliferation, stem cell migration, and bone marrow derived macrophages (BMDMs) M2 polarization compared to ApoEVs. Furthermore, we utilized a modified gelatine matrix/3D-printed extracellular matrix (ECM) scaffold complex as a carrier to deliver H-ApoEVs into the joint cavity, thus establishing a cartilage regeneration system. The 3D-printed ECM scaffold provided mechanical support and created a microenvironment that was conducive to cartilage regeneration, and the H-ApoEVs further enhanced the regenerative capacity of endogenous stem cells and the immunomodulatory microenvironment of the joint cavity; thus, this approach significantly promoted cartilage repair. In conclusion, this study confirmed that a ApoEVs delivery system based on a modified gelatine matrix/3D-printed ECM scaffold together with hypoxic preconditioning enhances the functionality of stem cell-derived ApoEVs and represents a promising approach for promoting cartilage regeneration.

ObjectiveThe role of hypoalbuminemia throughout the course of chronic periprosthetic joint infection (PJI) remains poorly understood. This study aimed to determine the prevalence and risk factors of hypoalbuminemia in periprosthetic joint infection (PJI) patients and to explore the association between hypoalbuminemia and treatment outcomes.MethodsThis retrospective cohort study included 387 PJI cases who underwent two‐stage exchange arthroplasty between January 2007 and August 2020, of which 342 were reimplanted. The mean follow‐up period was 7.9 years. Multivariate logistic regression analyses were performed to identify risk factors for hypoalbuminemia and to assess the effect of hypoalbuminemia at 1st‐ and 2nd‐stage exchange on the treatment outcome. Furthermore, the impact of dynamic changes in hypoalbuminemia was investigated.ResultsThe prevalence of hypoalbuminemia at 1st‐ and 2nd‐stage exchange was 22.2% and 4.7%, respectively. Patients with age ≥ 68 years and those with isolation of Staphylococcus aureus, Streptococcus, or Gram‐negative bacteria exhibited a higher risk of hypoalbuminemia. Hypoalbuminemia at 1st‐stage was significantly related to treatment failure (OR = 3.3), while hypoalbuminemia at 2nd‐stage raised the OR to 10.0. Patients with persistent hypoalbuminemia at both the 1st‐ and 2nd‐stage exchanges had a significantly higher rate of treatment failure than patients with hypoalbuminemia at the 1st‐stage but normal albumin levels at the 2nd‐stage exchange (55.6% vs 20.0%, p = 0.036).ConclusionOne in five patients with chronic PJI exhibits hypoalbuminemia. Hypoalbuminemia is more likely to develop in patients of advanced age and those infected by specific highly virulent organisms. Also, our results highlight the close association between hypoalbuminemia and treatment outcomes.

The widespread application of implantable materials has brought about a corresponding increase in implant-related complications, with implant-associated infections being the most critical. Biofilms, which often form on these implants, can significantly impede the effectiveness of traditional antibiotic therapies. Therefore, strategies such as surgical removal of infected implants and prolonged antibiotic treatment have been acknowledged as effective measures to eradicate these infections. However,the challenges of antibiotic resistance and biofilm persistence often result in recurrent or hard-to-control infections, posing severe health threats to patients. Recent studies suggest that phages, a type of virus, can directly eliminate pathogenic bacteria and degrade biofilms. Furthermore, clinical trials have demonstrated promising therapeutic results with the combined use of phages and antibiotics. Consequently, this innovative therapy holds significant potential as an effective solution for managing implant-associated infections. This paper rigorously investigates and evaluates the potential value of phage therapy in addressing orthopedic implant-associated infections, based on a comprehensive review of relevant scientific literature.

Despite previous attempts using multiphasic scaffolds to organize cells and bioactive elements, osteochondral repair still faces challenges, such as thin cartilage layers and uneven bone-cartilage interfaces. These issues are likely exacerbated by detrimental biochemical interactions and the formation of new blood vessels within the osteochondral unit, impacting tissue repair quality. In this study, we devised a novel freeze-welding technique to create a unified porous scaffold. Chitosan was chosen as the primary material due to its structural and compositional similarity to glycosaminoglycans in the ECM. In particular, by meticulously adjusting freezing and solute conditions, we engineered the scaffold to have an axially aligned porous structure in the cartilage layer and a radially aligned porous structure in the subchondral layer (scaffold A/R), each designed to meet the unique repair needs of the respective tissues. This scaffold showed enhanced mechanical compressibility, shape retention, and interfacial bonding capabilities. The results demonstrated that this unique spatial scaffold structure offers significant advantages over purely axial scaffolds in guiding osteochondral regeneration. These advantages were evident in its ability to independently promote cartilage and bone growth, reduce undesirable bone-cartilage crosstalk, particularly in the context of vessel invasion in the cartilage layer, and optimize the remodeling of the osteochondral interface. This study offers valuable insights into the structural design patterns for osteochondral regeneration, highlighting the potential importance of structural scaffold design in guiding endogenous tissue remodeling during heterogeneous tissue regeneration.

Background: The immune response associated with periprosthetic joint infection (PJI) is an emerging but relatively unexplored topic. The aim of this study was to investigate immune cell infiltration in periprosthetic tissues and identify potential immune-related biomarkers. Methods: The GSE7103 dataset from the GEO database was selected as the data source. Differentially expressed genes (DEGs) and significant modular genes in weighted correlation network analysis (WGCNA) were identified. Functional enrichment analysis and transcription factor prediction were performed on the overlapping genes. Next, immune-related genes from the ImmPort database were matched. The protein-protein interaction (PPI) analysis was performed to identify hub genes. CIBERSORTx was used to evaluate the immune cell infiltration pattern. Spearman correlation analysis was used to evaluate the relationship between hub genes and immune cells. Results: A total of 667 DEGs were identified between PJI and control samples, and 1847 PJI-related module genes were obtained in WGCNA. Enrichment analysis revealed that the common genes were mainly enriched in immune and host defense-related terms. TFEC, SPI1, and TWIST2 were the top three transcription factors. Three hub genes, SDC1, MMP9, and IGF1, were identified in the immune-related PPI network. Higher levels of plasma cells, CD4+ memory resting T cells, follicular helper T cells, resting mast cells, and neutrophils were found in the PJI group, while levels of M0 macrophages were lower. Notably, the expression of all three hub genes correlated with the infiltration levels of seven types of immune cells. Conclusion: The present study revealed immune infiltration signatures in the periprosthetic tissues of PJI patients. SDC1, MMP9, and IGF1 were potential immune-related biomarkers for PJI.

This study aimed to report the mid-term functional outcomes of total hip arthroplasty (THA) for the treatment of advanced hip involvement in ankylosing spondylitis (AS) and identify the factors associated with poor hip flexion range of motion (ROM) after THA in patients with AS. We retrospectively investigated the mid-term functional outcomes in 313 AS patients (538 hips) who underwent primary THA from 2012 to 2017, with a mean follow-up of 7 years (range, 4–9 years). Postoperative functional outcomes were assessed by hip flexion ROM, Harris hip score (HHS), and the Western Ontario and McMaster Universities Arthritis Index (WOMAC). The hips were divided into poor (≤ 90°) and good hip flexion ROM (> 90°) groups based on the degree of hip flexion ROM recorded at the most recent follow-up. We grouped factors related to postoperative hip flexion ROM into three categories: preoperative (or patient-related), intraoperative (or surgery-related), and postoperative factors. Multivariate logistic regression was performed to identify the independent factors associated with postoperative poor hip flexion ROM. The overall flexion-extension ROM improved significantly with a median from 0° (0 120°) to 100° (30 130°) after THA (P < 0.001), and the mean HHS increased from 37 to 90 (P < 0.001). There were 102 hips (19

Microplastics (MPs) have been detected in various human tissues, including the liver, placenta, and blood. However, studies about MPs in the human locomotor system are limited. This study evaluated the presence of MPs in the synovium of 45 patients undergoing hip or knee arthroplasty using micro-Fourier transform infrared spectroscopy, scanning electron microscopy, and Raman microscopy and investigated their association with clinical indicators and local cellular responses. A total of 343 MPs of nine common types were identified, with a mean abundance of 5.24 ± 2.07 particles/g and ranging from 1.16 to 10.77 particles/g. Although there was no clear correlation between MP abundance and demographics, MP abundance was higher in hip samples than in knee samples. In addition, a potential association was observed between MP abundance and specific clinical diagnoses. Transcriptomic analysis revealed that a three-fold increase in MP abundance corresponded to enhanced local cellular stress responses, particularly heat shock protein reactions. Our findings demonstrate the presence of MPs in human joints and suggest that further studies are needed to explore the intricate associations between MPs and anatomical location, clinical diagnosis, and local cellular responses.

Objective Periprosthetic joint infection (PJI) caused by non‐tubercular mycobacteria (NTM) is uncommon but catastrophic. However, conclusive clinical data on PJI caused by NTM are lacking. In this case series and systematic review, the clinical manifestations, diagnosis, and management of NTM PJI are summarized and analyzed. Methods From 2012 to 2020, we retrospectively analyzed consecutive PJI cases caused by NTM in our institution. A literature review was also conducted from January 2000 to December 2021, utilizing the PubMed, MEDLINE, Cochrane Library, and EMBASE databases to identify all reported NTM‐induced PJI cases. The clinical characteristics, demographics, pathogen identification, treatment protocols, and prognosis of NTM PJI were summarized and analyzed. Results In this retrospective analysis, seven patients infected with NTM following total joint arthroplasty at our institution were included, including six cases of PJI caused by NTM and one case of septic arthritis (SA) caused by NTM. There were six men and one woman, and their average age was 62.3 years. The average interval between TJA and PJI onset was 4 months. The preoperative serological markers, including the mean ESR (51 mm/h), CRP (4.0 mg/dL), fibrinogen (5.7 g/L), and D‐dimer (1.1 g/L), were increased. Six patients underwent staged revision surgery, and one patient with SA received antibiotic‐loaded bone cement beads to treat the infection. After an average of 33 months of observation following surgical intervention, none of the patients showed any symptoms of infection recurrence. From 2000 to 2021, 68 patients with NTM PJI were found in 39 studies in the published literature. Reinfections occurred within 1 year after arthroplasty in more than half (53.2%) of the patients. M. fortuitum and M. abscesses were the most prevalent rapidly growing mycobacteria (RGM) in all PJI patients, whereas Mycobacterium avium intracellulare (MAC) was the most prevalent slowly growing mycobacterium (SGM). The corresponding antibiotics were amikacin and ethambutol. The rate of culture‐negative without specific clinical symptoms was as high as 36.4% (12/33), while 45% (18/40) utilized additional diagnostic techniques such as NGS. A final clinical follow‐up record was available for 59 patients (86.7%; mean follow‐up period, 29 months), and 10.1% of patients failed to respond to treatment. Conclusion Orthopaedic surgeons should consider NTM in patients with negative routine cultures who are at risk for Mycobacterium infection. Treatment options rely on the accurate result of microbiologic identification and drug sensitivity testing, and to achieve this, it may be necessary to send multiple culture specimens, extend the culture time, and change the culture medium. Every effort should be made to identify NTM and its various subtypes through modern diagnostic tools if necessary.