Primary Septic Arthritis in the elderly – A Forgotten Killer? Five-Year Survival and Risk Factors in a Retrospective Cohort Study

Primary Septic Arthritis in the elderly – A Forgotten Killer? 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Five-Year Survival and Risk Factors in a Retrospective Cohort Study Lars Taubert, Jonas Neijhoft, Christoph G. Wölfl This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8269646/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 23 Feb, 2026 Read the published version in European Journal of Trauma and Emergency Surgery → Version 1 posted 9 You are reading this latest preprint version Abstract Introduction: Primary septic arthritis is an acute emergency associated with high morbidity and mortality in older adults. Rapid diagnosis and treatment are crucial. The study evaluates 5-year survival and identifies prognostic risk factors in elderly patients with primary septic arthritis, including age, ASA Physical Status (ASA PS) classification, joint involvement, implants, and pathogen spectrum. Methods: 50 patients aged ≥ 60 years treated for primary septic arthritis at two hospitals between 2008 and 2020 were included. Demographic, clinical, and microbiological data were collected retrospectively. Survival was assessed by Kaplan–Meier analysis, with log-rank tests to compare subgroups. Results: The mean age was 71.2 years. Overall survival was 76% at 1 year and 54% at 5 years. Survival declined significantly with increasing age (p = 0.004), higher ASA PS classification (p < 0.001), joint involvement (p = 0.027), and presence of implants (p < 0.001). Diabetes mellitus, osteoarthritis, and synovial culture status showed no significant effect. By joint, mean survival was 1331 days for the knee, 879 days for the shoulder, 935 days for the hip, 1825 days for the ankle and 36 days for the sacroiliac joint. Patients with implants had markedly shorter survival (402 vs. 1400 days). Pathogens were isolated in 72% of cases, most frequently Staphylococcus aureus (38%). Conclusion: Primary septic arthritis in older adults remains a life-threatening condition with high early- and mid-term mortality. Survival is strongly determined by age, ASA PS classification, joint involvement, and presence of implants, while comorbidities and pathogen detection show no prognostic relevance. septic arthritis joint elderly infection risk factors Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 1. Introduction Primary septic monoarthritis is a medical emergency associated with a significant higher morbidity and mortality[ 1 , 2 ]. Delayed diagnosis or insufficient treatment can lead to sepsis, multiple organ failure and death-. It is defined as an acute bacterial infection of a joint, leading to rapid destruction of cartilage and bone if not promptly treated. Despite its low overall incidence, the number of cases are rising in the recent years[ 3 ]. Diagnosis is often delayed, as clinical presentation can mimic other arthritides such as rheumatoid arthritis or gout, and common diagnostic tools such as synovial cultures or Gram stains are time-consuming and sometimes unreliable[ 2 , 4 ]. Risk factors include age, which is associated with characteristics such as immune senescence– an age-related decline in immune function – increased susceptibility and changes of the barrier function of the skin, thereby increasing the risk of infection[ 5 – 9 ]. Further risk factors are prior joint diseases or surgery, diabetes, skin infections or sores, as well as the presence of medical implants[ 2 , 5 , 10 ]. While any joint may be affected, the knee is most common (45–55%), followed by the shoulder (5–10%)[ 10 – 12 ]. Bacteria can enter the joint cavity via three main pathways: i) haematogenous spread during a systemic infection, ii) direct intra-articular inoculation through injections or surgery, or iii) contiguous spread of a local soft tissue infection by continuity into the joint[ 2 , 10 , 13 ]. Once in the joint and if left untreated, the infection will rapidly spread into the joint cavity and adjacent synovial membrane[ 14 , 15 ]. There the bone and cartilage gets attacked and, depending on the pathogen, they are causing irreversible damage leading to joint and bone destruction within 2–3 days[ 4 ]. Rapid diagnosis with promptly initiated, empiric antibiotic therapy and surgical relief is essential to lower morbidity and mortality[ 2 , 16 ]. Unfortunately, despite newer diagnostic and therapeutic options, the mortality rate ranges between 6.5–48.2%, depending on the study. In addition, 25–50% of patients continue to have functional limitations in the affected joint after completion of treatment[ 17 , 18 ]. This retrospective cohort study aimed therefore to analyze the 5-year survival of older adults with septic arthritis. In addition, further information and influencing factors on the bacterial pathogen spectrum as well as possible risk factors and their influence on survival are to be identified and evaluated. 2. Material and methods 2.1 Study design This retrospective cohort study includes 50 patients aged 60 or above who underwent surgery for primary septic arthritis at St Elisabeth and St. Josef hospital between January 2008 and March 2020. Clinical records were reviewed retrospectively and follow-up was performed until June 2024. 2.2 Analyzed data The following patient characteristics were included in the data set for the study: sex, age, side of the affected joint, day of death, medical implant, previous illness, follow-up in days, and ASA Physical Status (ASA PS) classification on the respective day of the first operation. Laboratory markers were analyzed, as well as the results of microbiological findings from joint aspirates and blood cultures. 2.3 Patient collective During the study period, 162 patients were admitted with suspected septic monoarthritis. Applying the diagnostic criteria of Newman et al. [ 11 ], 67 were classified as primary septic arthritis. After applying exclusion criteria, 50 patients were included in the final analysis. Diagnostic criteria comprised: (A) isolation of a pathogen from the affected joint; (B) pathogen detected from another source (e.g., blood) with a clinically septic joint; (C) no pathogen detected but histological, radiological, or typical clinical findings with prior antibiotic therapy; or (D) postmortem/pathological features consistent with septic arthritis. Differential diagnoses such as rheumatoid arthritis or gout were excluded [ 1 ]. There were the following exclusion criteria: 31 patients with an age ≤ 59 years were excluded, as well as two patients after a previous (< 6 months) penetrating trauma 46 patients were excluded with prior (< 6 months) surgery or orthopedic procedure in the area of the affected joint, as well as 6 patients with a periprosthetic or implant-associated joint infection. 19 patients with rheumatoid arthritis, acute gout or crystalloid arthropathy and 8 people with incomplete medical records or insufficient follow-up data were also not included in the study. Patients were identified retrospectively using hospital archives and ICD-10 codes for infectious arthropathies (M00–M99, M00–M25, M00–M03). A total of 162 cases of infectious arthropathies were collected for the period under review. They were then anonymously analyzed for inclusion or exclusion in our study based on their medical records with regard to our diagnostic criteria for septic arthritis. The medical records were analyzed for the following points: the reason for admission to the hospital with clinical examination and joint aspiration in the emergency room, if applicable; blood values, as well as blood cultures, the radiological findings of diagnostic imaging from X-ray, CT or MRI to determine osteoarthritis in the affected joint or to rule out possible osteomyelitis after the first operation; the microbiological results of the samples sent in from the aspirations and joint lavages, as well as the tissue samples obtained intraoperatively and the empirical antibiotic used and, if applicable, its switch to targeted antibiotic therapy after receipt of the microbiological tests. 2.4 Follow-up For the follow-up, subsequent clinical stays or documents of the respective patients in St Elisabeth and St Josef Hospital as well as publicly accessible obituaries in newspapers or internet portals and, if permitted by the patient in previous hospital stays, by telephone contact were recorded. 2.4 Statistical analysis The entire statistical analysis of the data set was performed using SPSS Statistics (Version 29, IBM Corporation, Armonk, USA). The descriptive analysis of the data was presented with relative and absolute frequencies, standard deviation, median and the arithmetic mean. The correctness of the calculated values was checked using 95% confidence intervals. The significance of the differences between two or more groups was tested using the t-test. The p-value, which indicates the statistical significance (α-level), was considered statistically significant at p < 0.05. The 1-year and 5-year survival probability of patients with septic arthritis was visualized graphically using Kaplan-Meier curves. In addition, the age groups, the respective classification of the person in the ASA PS classification before the first operation, the presence of medical implants and the affected joint were included in the Kaplan-Meier curves as factors for survival. For each factor, the log-rank test was also used to compare whether the presence of the respective factor had a significant negative impact on patient survival. In addition, the Kaplan-Meier survival curves were used to determine the 5-year mortality in our patient population. 3. Results 3.1 Inclusion and pathogen detection A total of 50 patients were included, comprising 37 men (74%) and 13 women (26%). The knee was the most commonly affected joint (n = 33, 66%), followed by the shoulder (n = 12, 24%), hip (n = 2, 4%), upper ankle (n = 2, 4%), and sacroiliac joint (n = 1, 2%). The right side was involved more frequently than the left (66% vs. 34%). Patient age at diagnosis ranged from 60 to 95 years (mean 71.2 years). The mean follow-up was 1200 days (3.29 years; SD ± 108.5 days, range 3–1825 days). Follow-up was complete in all cases. Overall survival was 76% at 1 year and 54% at 5 years. The average follow-up was 1200 days or 3.29 years (SD ± 108.5 days; minimum: 3 days, maximum 1825 days). Overall, the successful follow-up rate was 100%. Overall survival was 76% at 1 year and 54% at 5 years. A higher ASA PS classification, increasing age, the affected joint, as well as the presence of medical implants showed a significant impact on 5-year survival (p < 0.05). No significant influences were found for diabetes mellitus, osteoarthritis and various pathogens. Pathogens were identified in 36 of 50 cases (72%). Staphylococcus aureus was most frequent (n = 19, 38%), followed by Escherichia coli (n = 8, 16%). Table 1 lists all microbiological findings. 3.2 5-year survival by age groups A significant difference in 5-year survival was found between the different age groups. The chi-square test for the correlation between 5-year survival and the respective age classification yielded a value of 13.327. The cumulative survival probability of the groups is shown in Fig. 1 . The average survival of the entire study population was 1200.3 days, 3.29 years (SD ± 108.5 days; 95% CI: 987.6–1412.9). There were 14 (28%) patients in the age group 58–64 years. They had an average follow-up of 1588.9 days, 4.35 years (SD ± 155 days; 95% CI: 1283.2–1894.6). In the 19 (38%) 65-74-year-old patients, the mean follow-up was 1291.4 days, 3.54 years (SD ± 169.5 days; 95% CI: 959.2–1623.3). In the 12 (24%) 75-84-year-olds, the mean survival was 923.8 days, 2.53 years (SD ± 212.5; 95% CI: 507.3–1340.2). The 3 (6%) patients aged ≥ 85 years showed a mean survival of 429.4 days, 1.18 years (SD ± 350.9 days; 95% CI: .00–1117.2). So overall survival decreased progressively with age (log-rank p = 0.004). Mean survival ranged from 1589 days in patients aged 60–64 years to 429 days in those ≥ 85 years. The youngest age group thus had nearly fourfold longer survival compared to the oldest. 3.3 5-year survival by ASA PS Classification A higher ASA PS classification was significantly associated with poorer 5-year survival (log-rank p < 0.001). Patients classified as ASA II survived up to 5 years, while mean survival declined to 1432 days in ASA III and 482 days in ASA IV patients as seen in Fig. 2 : The chi-square test for the correlation between 5-year survival and the respective ASA PS classification yielded a value of 23.499. The cumulative survival probability of the different ASA PS classifications is shown in Fig. 2 . A total of 2 (4%) patients were classified with ASA II. These had an average follow-up of 1825 days, 5 years (SD ± 1825 days; 95% CI: 1825–1825). 35 (70%) patients were classified as ASA PS III. In this group, the mean follow-up was 1431.5 days, 3.92 years (SD ± 102.9 days; 95% CI: 1229.8–1633.1). 13 (26%) patients were also assigned to the ASA PS IV group. There, the mean value of the follow up was 481.7 days, 1.32 years (SD ± 209.4 days; 95% CI: 70.2–893.2). 3.4 5-year survival by affected joint Survival varied by affected joint (p = 0.027). Mean survival was longest in ankle infections (1825 days) and shortest in the sacroiliac joint (36 days). Knee infections showed intermediate survival (1331 days), followed by hip (935 days) and shoulder (879 days) involvement as seen in Fig. 3 : The chi-square test for the correlation between 5-year survival and the respective affected joint yielded a value of 10.984. In a total of 33 (66%) patients, the knee was the affected joint in primary septic arthritis. The mean survival of these patients was 1330.8 days, 3.65 years (SD ± 121.6 days; 95% CI: 1092.4–1569.2). The group of patients with septic arthritis of the shoulder included 12 (24%) patients. They had an average follow-up of 878.7 days, 2.41 years (SD ± 239.1 days; 95% CI: 410–1347.3). In the 2 (4%) patients with an affected upper ankle joint, the mean follow-up was 1825 days, 5 years (SD ± 1825 days; 95% CI: 1825–1825). In the 2 (24%) patients with septic arthritis of the hip, the mean survival was 934.5 days, 2.56 years, (SD ± 890.5; 95% CI: .00–2679.9). The 1 (2%) patient in whom the sacroiliac joint was affected showed a mean survival of 36 days, 0.1 years (SD ± 0 days; 95% CI: 36). 3.5 5-year survival by medical implants A significant difference in 5-year survival was found between patients with a medical implant and patients without (log rank p < 0.001, see Fig. 4 ). Patients with a predominant periprosthetic infection of a joint were excluded from this study. The chi-square test for the correlation between 5-year survival and patients with and without medical implants yielded a value of 22.499. A total of 40 (80%) patients had no medical implants at presentation with primary septic arthritis. They had an average follow-up of 1399.9 days, 3.84 years (SD ± 106.3 days; 95% CI: 1191.6–1608.2). In the total of 10 (20%) patients with a medical implant of any kind, the average follow-up was 401.8 days, 1.1 years (SD ± 189.3 days; 95% CI 29.5–774.1). 3.6 Microbial spectrum and synovial cultures In 15 cases (30%), no successful detection of bacteria was possible. However, in 35 out of 50 patients, a positive detection of bacteria was achieved (70%). Of these, 25 cases (71.4%) showed Gram-positive bacteria. In 10 cases (28.6%), Gram-negative bacteria were detected. A total of six different pathogens were found. The most frequently detected pathogen was Staphylococcus aureus with 19 detections (38%), of which 4 cases (8%) were MRSA. The next most common pathogen was Escherichia coli with 8 detections (16%). The results can be seen in Table 1 . Table 1 Distribution of pathogens isolated from synovial samples. This table summarizes the microbiological findings, dividing detected pathogens into gram-positive and gram-negative groups, including frequency of MRSA strains. Staphylococcus aureus is highlighted as the predominant organism (38%), reflecting its well-established role as a dominant agent in septic arthritis. The relatively high rate of culture-negative cases (30%) emphasises the limitations of pathogen detection in diagnosis. Pathogen n Negative synovial fluid culture 15 (30%) Grampositive Staphylococcus aureus [MRSA] 19 (38%) [4 (8%)] Staphylococcus epidermidis 4 (8%) Streptococcus parasanguinis 1 (2%) Staphylococcus hominis 1 (2%) Total Grampositive 25 (50%) Gramnegative Escherichia coli 8 (16%) Pseudomonas aeruginosa 2 (4%) Total Gramnegative 10 (20%) Total 50 (100%) No significant difference in 5-year survival was found between patients with positive and negative synovial cultures (p = 0.089, see Fig. 5 ). The chi-square test for the correlation between 5-year survival and a positive or negative synovial culture result yielded a value of 2.887. A total of 14 (28%) patients had no pathogen detection in the synovial cultures. They had an average follow-up of 1454.8 days, 3.99 years (SD ± 173.3 days; 95% CI: 1115.2–1794.4). In 36 (72%) patients, one or more pathogens were detected in the synovial culture. In this group, the average follow-up was 1091.2 days, 2.99 years (SD ± 133.3 days; 95% CI: 830–1352.5). 4. Discussion This retrospective study evaluated medium-term survival in 50 patients with primary septic arthritis over a 12-year period. The mean survival was 1.200 days (3.29 years), with a 1-year and 5-year survival rate of 76% and 54%, respectively. Age, ASA PS classification, joint location, and presence of implants were identified as significant prognostic factors, whereas osteoarthritis, diabetes, and gram stain results showed no significant association with survival. Gram-positive bacteria were the predominant pathogens (50% vs 22% gram-negative), with Staphylococcus aureus being the most frequently isolated organism. In 28% of cases, no pathogen could be identified. Staphylococcus aureus was by far the most common pathogen (38%), followed by E. coli (16%). 4.1 Survival rate comparison When compared with national life expectancy and other orthopedic conditions such as hip or periprosthetic fractures, overall survival in patients with septic arthritis—particularly of the shoulder—was markedly reduced[ 19 , 20 ]. To contextualize the mortality associated with primary septic arthritis, five-year mortality rates were compared with those reported for major malignancies in recent population-based analyses. The overall five-year mortality rate for patients with breast cancer is 16.3% [ 21 ], 10% for those with prostate cancer [ 22 ], and 31.7% for patients with colorectal cancer [ 23 ]. In comparison with these findings, our results demonstrate substantially higher mortality rates, with five-year mortality for primary septic arthritis of 46% on average whereas mortality rises to 66.7% in the case of an affected shoulder joint. This observation may be attributable to the anatomical separation of the shoulder joint into the glenohumeral joint and the subacromial space, which are divided by the rotator cuff. Infection may potentially spread between these two compartments, complicating surgical eradication. Furthermore, the clinical manifestations of septic arthritis in the shoulder may present later than in other joints, potentially delaying both surgical intervention and antibiotic therapy, which may contribute to poorer outcomes. The study underscores that septic arthritis can reflect an underlying compromised immune system and highlights the critical importance of early diagnosis and management, particularly in patients with systemic risk factors or joint implants. A strong association between ASA PS Classification and 5-year survival was observed. Higher ASA PS classifications were associated with increased risk of postoperative complications, mortality, and wound infections, being consistent with previous literature [ 24 , 25 ]. This reflects the fact that patients with ASA IV often have severe systemic diseases and typically undergo surgery only in emergencies, such as septic arthritis, making outcomes worse. As a result, the ASA PS classification of physical condition has been described as a valuable prognostic variable for postoperative medical complications and mortality [ 24 , 25 ]. Our study aligns with these findings. A higher ASA-PS classification is associated with a higher mortality rate, as these patients suffer from diseases that pose a permanent threat to life even without septic arthritis. 4.2 Joint location The knee was the most frequently affected joint, aligning with previous studies [ 10 , 12 , 26 ]. This may reflect the higher prevalence of degenerative joint disease in the knee compared to other joints, as osteoarthritis is an important risk factor for the development of septic arthritis[ 2 , 5 ]. The association between osteoarthritis and septic arthritis supports the concept that joint degeneration in the elderly increases vulnerability to infection 4.3 Pathogen influence and medical implants Staphylococcus aureus is the most common and significant pathogen. It should be noted that not only Staphylococcus aureus, but also other bacteria such as Staphylococcus epidermidis or Pseudomonas aeruginosa form biofilms on implants. Patients with medical implants had markely reduced survival, with 1-year and 5-year mortality rates of 60% and 90%, respectively, compared to 15% and 35% in patients without implants. Medical implants are a known risk factor for infections, including septic arthritis, largely due to biofilm formation by above-mentioned bacteria[ 27 , 28 ]. Biofilms, which develop in stages on implant surfaces, protect bacteria and enable persistent infections with potential for systemic spread[ 29 ]. Moreover, implant carriers often present with multiple comorbidities, further increasing susceptibility and mortality risk. 4.4 Diabetes mellitus In this study, diabetes mellitus did not have a statistically significant impact on survival in patients with primary septic arthritis, with one- and five-year mortality rates of 35.7% and 64.3%, respectively, compared with 25% and 41.7% in non-diabetic patients. Although not significant, these data suggest higher mortality in patients with diabetes, consistent with previous reports linking diabetes to increased susceptibility to bacterial infections and infection-related mortality [ 30 , 31 ]. Mechanisms such as hyperglycemia, immune dysfunction, and increased risk of infection with resistant strains may enhance bacterial growth and virulence, including biofilm formation and tissue adhesion[ 32 , 33 ]. Accordingly, pre-existing diabetes mellitus may increase both the risk and severity of septic arthritis, contributing to poorer outcomes in affected patients. 4.5 Limitations and strengths Retrospective studies, such as this one, face several limitations including data loss, unrecorded variables, and inconsistent documentation, which can affect the reliability of statistical results[ 34 ]. Over the 12-year study period, changes in diagnostics and treatment approaches introduced potential performance bias. It should be noted that almost all patients only underwent surgery once. Current guidelines and literature recommend repeated operations until sufficient reduction in laboratory inflammation values and clinical findings is achieved. Additionally, a follow-up rate of 86.8% may have led to selection bias and skewed survival data, especially for younger patients. While retrospective studies cannot establish causality, they are useful for analyzing rare diseases over long periods and identifying potential risk factors with relatively stable follow-up rates. 4.6. Future aspects In the context of demographic change and an increasingly ageing population, the incidence of primary septic arthritis is expected to rise. Given the persistently high mortality associated with this condition, further research is urgently needed. Future studies should prioritize well-designed, prospective, multicenter trials with sufficient case numbers to generate robust and generalizable data. These studies should evaluate empiric versus targeted antibiotic regimens in light of evolving treatment guidelines, pathogen prevalence, and resistance patterns. Moreover, further improvement and implementation of standardized diagnostic and therapeutic guidelines are essential to optimize patient outcomes and reduce the considerable morbidity and mortality associated with this disease. Conclusion Primary septic arthritis in the elderly is far from a resolved problem—it remains a devastating and frequently fatal condition. Despite advances in diagnostics and therapy, almost half of the affected patients die within five years of diagnosis. Survival is strongly determined by preoperative ASA PS classification, age, the affected joint, and the presence of implants, whereas common comorbidities such as diabetes or osteoarthritis appear to have limited impact. The high proportion of culture-negative cases emphasizes that early surgical intervention and empiric antibiotic coverage remain the cornerstones of treatment. With Staphylococcus aureus as the dominant pathogen, empiric regimens should continue to target Gram-positive organisms. With Staphylococcus aureus as the dominant pathogen, empiric regimens should continue to target Gram-positive organisms. Future prospective multicenter studies are urgently needed to develop and establish standardized diagnostic and therapeutic pathways to improve survival in this vulnerable and growing population. Declarations Ethics approval: The responsible ethics committee of the Rhineland-Palatine State Medical Association stated that this study was conducted according to the guidelines of the Declaration of Helsinki. They approved this study (protocol 2023-17107-retrospektiv, on 17. July 2023). Informed Consent Statement Informed consent was not applicable due to the anonymized data generation and retrospective analysis. This is consistent with the guidelines of the Declaration of Helsinki. Funding: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Author Contribution L.T.: Conceptualization, Software, Validation, Formal analysis, Investigation, Data curation, Writing – original draft, Writing – review & editing, VisualizationJ.N.: Software, Validation, Formal analysis, Data curation, Writing – original draft, Writing – review & editingC.W.: Conceptualization, Methodology, Validation, Writing – review & editing, Supervision, Project administration, Ressources Data Availability The data originate from a surgical and traumatological care unit at St. Elisabeth Hospital, Neuwied, as well as St. Josef Hospital, Bendorf, The data can be provided anonymously in a separate file upon request. A public dataset was not used to obtain the data presented. Author Contribution Institutional Review Board Statement Informed Consent Statement Informed consent was not applicable due to the anonymized data generation and retrospective analysis. This is consistent with the guidelines of the Declaration of Helsinki. 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Nephron Clin Pract. 2009;113(3):c214-217. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 23 Feb, 2026 Read the published version in European Journal of Trauma and Emergency Surgery → Version 1 posted Editorial decision: Revision requested 28 Dec, 2025 Reviews received at journal 27 Dec, 2025 Reviews received at journal 08 Dec, 2025 Reviewers agreed at journal 07 Dec, 2025 Reviewers agreed at journal 07 Dec, 2025 Reviewers invited by journal 07 Dec, 2025 Editor assigned by journal 07 Dec, 2025 Submission checks completed at journal 05 Dec, 2025 First submitted to journal 03 Dec, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8269646","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":557135981,"identity":"ca53118b-93b5-4f31-9336-50cecd2a2d93","order_by":0,"name":"Lars Taubert","email":"data:image/png;base64,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","orcid":"","institution":"Goethe University Frankfurt","correspondingAuthor":true,"prefix":"","firstName":"Lars","middleName":"","lastName":"Taubert","suffix":""},{"id":557135983,"identity":"e95d8379-a9cc-4b9b-bad6-217d08ca4957","order_by":1,"name":"Jonas Neijhoft","email":"","orcid":"","institution":"Goethe University Frankfurt","correspondingAuthor":false,"prefix":"","firstName":"Jonas","middleName":"","lastName":"Neijhoft","suffix":""},{"id":557135984,"identity":"4c307201-56f5-4722-adaa-f86fa4cd62d8","order_by":2,"name":"Christoph G. Wölfl","email":"","orcid":"","institution":"St. Elisabeth and St. Matthias Hospital Neuwied","correspondingAuthor":false,"prefix":"","firstName":"Christoph","middleName":"G.","lastName":"Wölfl","suffix":""}],"badges":[],"createdAt":"2025-12-03 11:23:26","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8269646/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8269646/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00068-026-03124-5","type":"published","date":"2026-02-23T15:57:26+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":97900599,"identity":"5b4aa8d6-0d3e-4151-8a3f-b4f532ad6cc9","added_by":"auto","created_at":"2025-12-10 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15:39:59","extension":"png","order_by":8,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":23277,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8269646/v1/29af2630894bf0c65a05e158.png"},{"id":97900286,"identity":"734ba7d8-8814-4451-b7bf-18ca8ec2627c","added_by":"auto","created_at":"2025-12-10 15:45:22","extension":"png","order_by":9,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":7483,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8269646/v1/d750725088037f01719beeb4.png"},{"id":97874112,"identity":"460ddfab-a27b-4429-b26c-7577b7a7533f","added_by":"auto","created_at":"2025-12-10 10:50:51","extension":"png","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":8222,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-8269646/v1/bd55ec9c1bed748bb32f31b4.png"},{"id":97898864,"identity":"0133d677-8f0b-4826-a4e1-05fb8367ed11","added_by":"auto","created_at":"2025-12-10 15:39:53","extension":"png","order_by":11,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":7188,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-8269646/v1/1ffddcbafcb2822b11389715.png"},{"id":97900001,"identity":"b2e28ec9-9e4d-4c7d-83f2-0e7d32e4054c","added_by":"auto","created_at":"2025-12-10 15:45:09","extension":"png","order_by":12,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":7987,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-8269646/v1/ed7fdcb6c10de3a6386333a3.png"},{"id":97874117,"identity":"da1356e9-f088-4662-a4bc-70c4111739e5","added_by":"auto","created_at":"2025-12-10 10:50:51","extension":"xml","order_by":13,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":83352,"visible":true,"origin":"","legend":"","description":"","filename":"8224629a2515458b81d0226fc9a494c31structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-8269646/v1/6d848c6fb1b75e98e2a8b520.xml"},{"id":97874118,"identity":"af9d2886-5e4d-498b-9797-0ec838bca986","added_by":"auto","created_at":"2025-12-10 10:50:51","extension":"html","order_by":14,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":90462,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8269646/v1/545a69d9e0ad42df2e266198.html"},{"id":97874100,"identity":"52ed2adc-4012-4686-943a-67beaa8e47b3","added_by":"auto","created_at":"2025-12-10 10:50:51","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1148341,"visible":true,"origin":"","legend":"\u003cp\u003eKaplan-Meier five-year survival by age group. This figure depicts the cumulative five-year survival probabilities stratified by age categories, demonstrating a progressive decline in survival with increasing age (log-rank p = 0.004). Notably, patients with aged 60 – 64 years show nearly fourfold longer survival compared to those ≥ 85 years, highlighting age as a major independent prognostic factor in primary septic arthritis.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8269646/v1/157d7cf43bcdb8236a82629f.png"},{"id":97874099,"identity":"2765e0cf-a15f-4241-a33f-1dd4cd05f1ab","added_by":"auto","created_at":"2025-12-10 10:50:51","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":27147,"visible":true,"origin":"","legend":"\u003cp\u003eKaplan–Meier five-year survival by ASA Physical Status classification. This figure shows the cumulative 5-year survival curves separated by ASA PS class (log-rank p \u0026lt; 0.001), demonstrating a significant reduction in survival with increasing ASA severity. Patients in ASA II display full long-term survival, whereas ASA IV patients experience a dramatic reduction to ~1.3 years, illustrating the prognostic value of perioperative physiological status.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8269646/v1/7df3b9c9e308c940f108d3a7.png"},{"id":97899805,"identity":"f6534c50-886e-4cd3-bcaa-b525cb9b12c9","added_by":"auto","created_at":"2025-12-10 15:44:55","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":29315,"visible":true,"origin":"","legend":"\u003cp\u003eKaplan–Meier five-year survival according to the affected joint region. This figure depicts survival depending on the infected joint (p = 0.027), with the ankle joint showing the best prognosis and the sacroiliac joint the worst. These findings imply that anatomical location and joint-specific surgical accessibility may influence infection clearance and long-term outcomes.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-8269646/v1/687d7b4ed4c297ca85a1bb3f.png"},{"id":97874107,"identity":"9d6313cb-08e4-4dbe-9d28-343311d588bc","added_by":"auto","created_at":"2025-12-10 10:50:51","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":27186,"visible":true,"origin":"","legend":"\u003cp\u003eKaplan–Meier five-year survival by presence of medical implants. This figure demonstrates a reduction in long-term survival among patients with pre-existing implants compared to those without (p \u0026lt; 0.001). The steep early mortality drop among implant carriers suggests the persistent biofilm-mediated infection and systemic vulnerability associated with the presence of foreign material.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-8269646/v1/aa842d5d94215fd3472069df.png"},{"id":97900201,"identity":"9b25433c-6d04-4c2f-a084-9effa37e1f86","added_by":"auto","created_at":"2025-12-10 15:45:17","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":29852,"visible":true,"origin":"","legend":"\u003cp\u003eKaplan–Meier five-year survival by synovial culture status. This graph compares survival rates of culture-positive and culture-negative cases, showing no statistically significant difference (p = 0.089). Notably, culture-negative patients even show a numerically longer survival, supporting the hypothesis that clinical severity rather than identification of the pathogen may drive mortality risk.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-8269646/v1/4e0cb7cea60c537524f931d9.png"},{"id":103765582,"identity":"7ecbaf6a-905a-46ec-b45d-8a3c62f9b543","added_by":"auto","created_at":"2026-03-02 16:05:10","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1385613,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8269646/v1/1c4b0d5c-9634-47b0-b9bf-27d6597c5d4c.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Primary Septic Arthritis in the elderly – A Forgotten Killer? Five-Year Survival and Risk Factors in a Retrospective Cohort Study","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003ePrimary septic monoarthritis is a medical emergency associated with a significant higher morbidity and mortality[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Delayed diagnosis or insufficient treatment can lead to sepsis, multiple organ failure and death-. It is defined as an acute bacterial infection of a joint, leading to rapid destruction of cartilage and bone if not promptly treated.\u003c/p\u003e\u003cp\u003eDespite its low overall incidence, the number of cases are rising in the recent years[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Diagnosis is often delayed, as clinical presentation can mimic other arthritides such as rheumatoid arthritis or gout, and common diagnostic tools such as synovial cultures or Gram stains are time-consuming and sometimes unreliable[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Risk factors include age, which is associated with characteristics such as immune senescence\u0026ndash; an age-related decline in immune function \u0026ndash; increased susceptibility and changes of the barrier function of the skin, thereby increasing the risk of infection[\u003cspan additionalcitationids=\"CR6 CR7 CR8\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Further risk factors are prior joint diseases or surgery, diabetes, skin infections or sores, as well as the presence of medical implants[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. While any joint may be affected, the knee is most common (45\u0026ndash;55%), followed by the shoulder (5\u0026ndash;10%)[\u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Bacteria can enter the joint cavity via three main pathways: i) haematogenous spread during a systemic infection, ii) direct intra-articular inoculation through injections or surgery, or iii) contiguous spread of a local soft tissue infection by continuity into the joint[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Once in the joint and if left untreated, the infection will rapidly spread into the joint cavity and adjacent synovial membrane[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. There the bone and cartilage gets attacked and, depending on the pathogen, they are causing irreversible damage leading to joint and bone destruction within 2\u0026ndash;3 days[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eRapid diagnosis with promptly initiated, empiric antibiotic therapy and surgical relief is essential to lower morbidity and mortality[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Unfortunately, despite newer diagnostic and therapeutic options, the mortality rate ranges between 6.5\u0026ndash;48.2%, depending on the study. In addition, 25\u0026ndash;50% of patients continue to have functional limitations in the affected joint after completion of treatment[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThis retrospective cohort study aimed therefore to analyze the 5-year survival of older adults with septic arthritis. In addition, further information and influencing factors on the bacterial pathogen spectrum as well as possible risk factors and their influence on survival are to be identified and evaluated.\u003c/p\u003e"},{"header":"2. Material and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Study design\u003c/h2\u003e\u003cp\u003eThis retrospective cohort study includes 50 patients aged 60 or above who underwent surgery for primary septic arthritis at St Elisabeth and St. Josef hospital between January 2008 and March 2020. Clinical records were reviewed retrospectively and follow-up was performed until June 2024.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Analyzed data\u003c/h2\u003e\u003cp\u003eThe following patient characteristics were included in the data set for the study: sex, age, side of the affected joint, day of death, medical implant, previous illness, follow-up in days, and ASA Physical Status (ASA PS) classification on the respective day of the first operation. Laboratory markers were analyzed, as well as the results of microbiological findings from joint aspirates and blood cultures.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Patient collective\u003c/h2\u003e\u003cp\u003eDuring the study period, 162 patients were admitted with suspected septic monoarthritis. Applying the diagnostic criteria of Newman et al. [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e], 67 were classified as primary septic arthritis. After applying exclusion criteria, 50 patients were included in the final analysis. Diagnostic criteria comprised: (A) isolation of a pathogen from the affected joint; (B) pathogen detected from another source (e.g., blood) with a clinically septic joint; (C) no pathogen detected but histological, radiological, or typical clinical findings with prior antibiotic therapy; or (D) postmortem/pathological features consistent with septic arthritis. Differential diagnoses such as rheumatoid arthritis or gout were excluded [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThere were the following exclusion criteria: 31 patients with an age\u0026thinsp;\u0026le;\u0026thinsp;59 years were excluded, as well as two patients after a previous (\u0026lt;\u0026thinsp;6 months) penetrating trauma 46 patients were excluded with prior (\u0026lt;\u0026thinsp;6 months) surgery or orthopedic procedure in the area of the affected joint, as well as 6 patients with a periprosthetic or implant-associated joint infection. 19 patients with rheumatoid arthritis, acute gout or crystalloid arthropathy and 8 people with incomplete medical records or insufficient follow-up data were also not included in the study.\u003c/p\u003e\u003cp\u003ePatients were identified retrospectively using hospital archives and ICD-10 codes for infectious arthropathies (M00\u0026ndash;M99, M00\u0026ndash;M25, M00\u0026ndash;M03).\u003c/p\u003e\u003cp\u003eA total of 162 cases of infectious arthropathies were collected for the period under review. They were then anonymously analyzed for inclusion or exclusion in our study based on their medical records with regard to our diagnostic criteria for septic arthritis. The medical records were analyzed for the following points: the reason for admission to the hospital with clinical examination and joint aspiration in the emergency room, if applicable; blood values, as well as blood cultures, the radiological findings of diagnostic imaging from X-ray, CT or MRI to determine osteoarthritis in the affected joint or to rule out possible osteomyelitis after the first operation; the microbiological results of the samples sent in from the aspirations and joint lavages, as well as the tissue samples obtained intraoperatively and the empirical antibiotic used and, if applicable, its switch to targeted antibiotic therapy after receipt of the microbiological tests.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e2.4 Follow-up\u003c/h2\u003e\u003cp\u003eFor the follow-up, subsequent clinical stays or documents of the respective patients in St Elisabeth and St Josef Hospital as well as publicly accessible obituaries in newspapers or internet portals and, if permitted by the patient in previous hospital stays, by telephone contact were recorded.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003e2.4 Statistical analysis\u003c/h2\u003e\u003cp\u003eThe entire statistical analysis of the data set was performed using SPSS Statistics (Version 29, IBM Corporation, Armonk, USA).\u003c/p\u003e\u003cp\u003eThe descriptive analysis of the data was presented with relative and absolute frequencies, standard deviation, median and the arithmetic mean. The correctness of the calculated values was checked using 95% confidence intervals.\u003c/p\u003e\u003cp\u003eThe significance of the differences between two or more groups was tested using the t-test. The p-value, which indicates the statistical significance (α-level), was considered statistically significant at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e\u003cp\u003eThe 1-year and 5-year survival probability of patients with septic arthritis was visualized graphically using Kaplan-Meier curves. In addition, the age groups, the respective classification of the person in the ASA PS classification before the first operation, the presence of medical implants and the affected joint were included in the Kaplan-Meier curves as factors for survival. For each factor, the log-rank test was also used to compare whether the presence of the respective factor had a significant negative impact on patient survival. In addition, the Kaplan-Meier survival curves were used to determine the 5-year mortality in our patient population.\u003c/p\u003e\u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\u003ch2\u003e3.1 Inclusion and pathogen detection\u003c/h2\u003e\u003cp\u003eA total of 50 patients were included, comprising 37 men (74%) and 13 women (26%). The knee was the most commonly affected joint (n\u0026thinsp;=\u0026thinsp;33, 66%), followed by the shoulder (n\u0026thinsp;=\u0026thinsp;12, 24%), hip (n\u0026thinsp;=\u0026thinsp;2, 4%), upper ankle (n\u0026thinsp;=\u0026thinsp;2, 4%), and sacroiliac joint (n\u0026thinsp;=\u0026thinsp;1, 2%). The right side was involved more frequently than the left (66% vs. 34%).\u003c/p\u003e\u003cp\u003ePatient age at diagnosis ranged from 60 to 95 years (mean 71.2 years). The mean follow-up was 1200 days (3.29 years; SD\u0026thinsp;\u0026plusmn;\u0026thinsp;108.5 days, range 3\u0026ndash;1825 days). Follow-up was complete in all cases. Overall survival was 76% at 1 year and 54% at 5 years. The average follow-up was 1200 days or 3.29 years (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;108.5 days; minimum: 3 days, maximum 1825 days). Overall, the successful follow-up rate was 100%. Overall survival was 76% at 1 year and 54% at 5 years. A higher ASA PS classification, increasing age, the affected joint, as well as the presence of medical implants showed a significant impact on 5-year survival (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). No significant influences were found for diabetes mellitus, osteoarthritis and various pathogens.\u003c/p\u003e\u003cp\u003ePathogens were identified in 36 of 50 cases (72%). Staphylococcus aureus was most frequent (n\u0026thinsp;=\u0026thinsp;19, 38%), followed by Escherichia coli (n\u0026thinsp;=\u0026thinsp;8, 16%). Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e lists all microbiological findings.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\u003ch2\u003e3.2 5-year survival by age groups\u003c/h2\u003e\u003cp\u003eA significant difference in 5-year survival was found between the different age groups. The chi-square test for the correlation between 5-year survival and the respective age classification yielded a value of 13.327. The cumulative survival probability of the groups is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The average survival of the entire study population was 1200.3 days, 3.29 years (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;108.5 days; 95% CI: 987.6\u0026ndash;1412.9). There were 14 (28%) patients in the age group 58\u0026ndash;64 years. They had an average follow-up of 1588.9 days, 4.35 years (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;155 days; 95% CI: 1283.2\u0026ndash;1894.6). In the 19 (38%) 65-74-year-old patients, the mean follow-up was 1291.4 days, 3.54 years (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;169.5 days; 95% CI: 959.2\u0026ndash;1623.3). In the 12 (24%) 75-84-year-olds, the mean survival was 923.8 days, 2.53 years (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;212.5; 95% CI: 507.3\u0026ndash;1340.2). The 3 (6%) patients aged\u0026thinsp;\u0026ge;\u0026thinsp;85 years showed a mean survival of 429.4 days, 1.18 years (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;350.9 days; 95% CI: .00\u0026ndash;1117.2). So overall survival decreased progressively with age (log-rank p\u0026thinsp;=\u0026thinsp;0.004). Mean survival ranged from 1589 days in patients aged 60\u0026ndash;64 years to 429 days in those\u0026thinsp;\u0026ge;\u0026thinsp;85 years. The youngest age group thus had nearly fourfold longer survival compared to the oldest.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003e3.3 5-year survival by ASA PS Classification\u003c/h2\u003e\u003cp\u003eA higher ASA PS classification was significantly associated with poorer 5-year survival (log-rank p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Patients classified as ASA II survived up to 5 years, while mean survival declined to 1432 days in ASA III and 482 days in ASA IV patients as seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e: The chi-square test for the correlation between 5-year survival and the respective ASA PS classification yielded a value of 23.499. The cumulative survival probability of the different ASA PS classifications is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. A total of 2 (4%) patients were classified with ASA II. These had an average follow-up of 1825 days, 5 years (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;1825 days; 95% CI: 1825\u0026ndash;1825). 35 (70%) patients were classified as ASA PS III. In this group, the mean follow-up was 1431.5 days, 3.92 years (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;102.9 days; 95% CI: 1229.8\u0026ndash;1633.1). 13 (26%) patients were also assigned to the ASA PS IV group. There, the mean value of the follow up was 481.7 days, 1.32 years (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;209.4 days; 95% CI: 70.2\u0026ndash;893.2).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\u003ch2\u003e3.4 5-year survival by affected joint\u003c/h2\u003e\u003cp\u003eSurvival varied by affected joint (p\u0026thinsp;=\u0026thinsp;0.027). Mean survival was longest in ankle infections (1825 days) and shortest in the sacroiliac joint (36 days). Knee infections showed intermediate survival (1331 days), followed by hip (935 days) and shoulder (879 days) involvement as seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e: The chi-square test for the correlation between 5-year survival and the respective affected joint yielded a value of 10.984. In a total of 33 (66%) patients, the knee was the affected joint in primary septic arthritis. The mean survival of these patients was 1330.8 days, 3.65 years (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;121.6 days; 95% CI: 1092.4\u0026ndash;1569.2). The group of patients with septic arthritis of the shoulder included 12 (24%) patients. They had an average follow-up of 878.7 days, 2.41 years (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;239.1 days; 95% CI: 410\u0026ndash;1347.3). In the 2 (4%) patients with an affected upper ankle joint, the mean follow-up was 1825 days, 5 years (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;1825 days; 95% CI: 1825\u0026ndash;1825). In the 2 (24%) patients with septic arthritis of the hip, the mean survival was 934.5 days, 2.56 years, (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;890.5; 95% CI: .00\u0026ndash;2679.9). The 1 (2%) patient in whom the sacroiliac joint was affected showed a mean survival of 36 days, 0.1 years (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;0 days; 95% CI: 36).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\u003ch2\u003e3.5 5-year survival by medical implants\u003c/h2\u003e\u003cp\u003eA significant difference in 5-year survival was found between patients with a medical implant and patients without (log rank p\u0026thinsp;\u0026lt;\u0026thinsp;0.001, see Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Patients with a predominant periprosthetic infection of a joint were excluded from this study. The chi-square test for the correlation between 5-year survival and patients with and without medical implants yielded a value of 22.499. A total of 40 (80%) patients had no medical implants at presentation with primary septic arthritis. They had an average follow-up of 1399.9 days, 3.84 years (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;106.3 days; 95% CI: 1191.6\u0026ndash;1608.2). In the total of 10 (20%) patients with a medical implant of any kind, the average follow-up was 401.8 days, 1.1 years (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;189.3 days; 95% CI 29.5\u0026ndash;774.1).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e\u003ch2\u003e3.6 Microbial spectrum and synovial cultures\u003c/h2\u003e\u003cp\u003eIn 15 cases (30%), no successful detection of bacteria was possible. However, in 35 out of 50 patients, a positive detection of bacteria was achieved (70%). Of these, 25 cases (71.4%) showed Gram-positive bacteria. In 10 cases (28.6%), Gram-negative bacteria were detected. A total of six different pathogens were found. The most frequently detected pathogen was Staphylococcus aureus with 19 detections (38%), of which 4 cases (8%) were MRSA. The next most common pathogen was Escherichia coli with 8 detections (16%). The results can be seen in Table \u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eDistribution of pathogens isolated from synovial samples. This table summarizes the microbiological findings, dividing detected pathogens into gram-positive and gram-negative groups, including frequency of MRSA strains. Staphylococcus aureus is highlighted as the predominant organism (38%), reflecting its well-established role as a dominant agent in septic arthritis. The relatively high rate of culture-negative cases (30%) emphasises the limitations of pathogen detection in diagnosis.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"2\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePathogen\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003en\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eNegative synovial fluid culture\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e15 (30%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003e\u003cb\u003eGrampositive\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eStaphylococcus aureus [MRSA]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e19 (38%) [4 (8%)]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eStaphylococcus epidermidis\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4 (8%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eStreptococcus parasanguinis\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1 (2%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eStaphylococcus hominis\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1 (2%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eTotal Grampositive\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e25 (50%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003e\u003cb\u003eGramnegative\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eEscherichia coli\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e8 (16%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePseudomonas aeruginosa\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2 (4%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eTotal Gramnegative\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e10 (20%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eTotal\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e50 (100%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eNo significant difference in 5-year survival was found between patients with positive and negative synovial cultures (p\u0026thinsp;=\u0026thinsp;0.089, see Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). The chi-square test for the correlation between 5-year survival and a positive or negative synovial culture result yielded a value of 2.887. A total of 14 (28%) patients had no pathogen detection in the synovial cultures. They had an average follow-up of 1454.8 days, 3.99 years (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;173.3 days; 95% CI: 1115.2\u0026ndash;1794.4). In 36 (72%) patients, one or more pathogens were detected in the synovial culture. In this group, the average follow-up was 1091.2 days, 2.99 years (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;133.3 days; 95% CI: 830\u0026ndash;1352.5).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThis retrospective study evaluated medium-term survival in 50 patients with primary septic arthritis over a 12-year period. The mean survival was 1.200 days (3.29 years), with a 1-year and 5-year survival rate of 76% and 54%, respectively. Age, ASA PS classification, joint location, and presence of implants were identified as significant prognostic factors, whereas osteoarthritis, diabetes, and gram stain results showed no significant association with survival. Gram-positive bacteria were the predominant pathogens (50% vs 22% gram-negative), with Staphylococcus aureus being the most frequently isolated organism. In 28% of cases, no pathogen could be identified. Staphylococcus aureus was by far the most common pathogen (38%), followed by E. coli (16%).\u003c/p\u003e\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e\u003ch2\u003e4.1 Survival rate comparison\u003c/h2\u003e\u003cp\u003eWhen compared with national life expectancy and other orthopedic conditions such as hip or periprosthetic fractures, overall survival in patients with septic arthritis\u0026mdash;particularly of the shoulder\u0026mdash;was markedly reduced[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. To contextualize the mortality associated with primary septic arthritis, five-year mortality rates were compared with those reported for major malignancies in recent population-based analyses. The overall five-year mortality rate for patients with breast cancer is 16.3% [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], 10% for those with prostate cancer [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e], and 31.7% for patients with colorectal cancer [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. In comparison with these findings, our results demonstrate substantially higher mortality rates, with five-year mortality for primary septic arthritis of 46% on average whereas mortality rises to 66.7% in the case of an affected shoulder joint.\u003c/p\u003e\u003cp\u003eThis observation may be attributable to the anatomical separation of the shoulder joint into the glenohumeral joint and the subacromial space, which are divided by the rotator cuff. Infection may potentially spread between these two compartments, complicating surgical eradication. Furthermore, the clinical manifestations of septic arthritis in the shoulder may present later than in other joints, potentially delaying both surgical intervention and antibiotic therapy, which may contribute to poorer outcomes. The study underscores that septic arthritis can reflect an underlying compromised immune system and highlights the critical importance of early diagnosis and management, particularly in patients with systemic risk factors or joint implants.\u003c/p\u003e\u003cp\u003eA strong association between ASA PS Classification and 5-year survival was observed. Higher ASA PS classifications were associated with increased risk of postoperative complications, mortality, and wound infections, being consistent with previous literature [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. This reflects the fact that patients with ASA IV often have severe systemic diseases and typically undergo surgery only in emergencies, such as septic arthritis, making outcomes worse. As a result, the ASA PS classification of physical condition has been described as a valuable prognostic variable for postoperative medical complications and mortality [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Our study aligns with these findings. A higher ASA-PS classification is associated with a higher mortality rate, as these patients suffer from diseases that pose a permanent threat to life even without septic arthritis.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec17\" class=\"Section2\"\u003e\u003ch2\u003e4.2 Joint location\u003c/h2\u003e\u003cp\u003eThe knee was the most frequently affected joint, aligning with previous studies [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. This may reflect the higher prevalence of degenerative joint disease in the knee compared to other joints, as osteoarthritis is an important risk factor for the development of septic arthritis[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. The association between osteoarthritis and septic arthritis supports the concept that joint degeneration in the elderly increases vulnerability to infection\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec18\" class=\"Section2\"\u003e\u003ch2\u003e4.3 Pathogen influence and medical implants\u003c/h2\u003e\u003cp\u003eStaphylococcus aureus is the most common and significant pathogen. It should be noted that not only Staphylococcus aureus, but also other bacteria such as Staphylococcus epidermidis or Pseudomonas aeruginosa form biofilms on implants. Patients with medical implants had markely reduced survival, with 1-year and 5-year mortality rates of 60% and 90%, respectively, compared to 15% and 35% in patients without implants. Medical implants are a known risk factor for infections, including septic arthritis, largely due to biofilm formation by above-mentioned bacteria[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Biofilms, which develop in stages on implant surfaces, protect bacteria and enable persistent infections with potential for systemic spread[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Moreover, implant carriers often present with multiple comorbidities, further increasing susceptibility and mortality risk.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec19\" class=\"Section2\"\u003e\u003ch2\u003e4.4 Diabetes mellitus\u003c/h2\u003e\u003cp\u003eIn this study, diabetes mellitus did not have a statistically significant impact on survival in patients with primary septic arthritis, with one- and five-year mortality rates of 35.7% and 64.3%, respectively, compared with 25% and 41.7% in non-diabetic patients. Although not significant, these data suggest higher mortality in patients with diabetes, consistent with previous reports linking diabetes to increased susceptibility to bacterial infections and infection-related mortality [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. Mechanisms such as hyperglycemia, immune dysfunction, and increased risk of infection with resistant strains may enhance bacterial growth and virulence, including biofilm formation and tissue adhesion[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. Accordingly, pre-existing diabetes mellitus may increase both the risk and severity of septic arthritis, contributing to poorer outcomes in affected patients.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec20\" class=\"Section2\"\u003e\u003ch2\u003e4.5 Limitations and strengths\u003c/h2\u003e\u003cp\u003eRetrospective studies, such as this one, face several limitations including data loss, unrecorded variables, and inconsistent documentation, which can affect the reliability of statistical results[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. Over the 12-year study period, changes in diagnostics and treatment approaches introduced potential performance bias. It should be noted that almost all patients only underwent surgery once. Current guidelines and literature recommend repeated operations until sufficient reduction in laboratory inflammation values and clinical findings is achieved. Additionally, a follow-up rate of 86.8% may have led to selection bias and skewed survival data, especially for younger patients. While retrospective studies cannot establish causality, they are useful for analyzing rare diseases over long periods and identifying potential risk factors with relatively stable follow-up rates.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec21\" class=\"Section2\"\u003e\u003ch2\u003e4.6. Future aspects\u003c/h2\u003e\u003cp\u003eIn the context of demographic change and an increasingly ageing population, the incidence of primary septic arthritis is expected to rise. Given the persistently high mortality associated with this condition, further research is urgently needed. Future studies should prioritize well-designed, prospective, multicenter trials with sufficient case numbers to generate robust and generalizable data. These studies should evaluate empiric versus targeted antibiotic regimens in light of evolving treatment guidelines, pathogen prevalence, and resistance patterns. Moreover, further improvement and implementation of standardized diagnostic and therapeutic guidelines are essential to optimize patient outcomes and reduce the considerable morbidity and mortality associated with this disease.\u003c/p\u003e\u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003ePrimary septic arthritis in the elderly is far from a resolved problem\u0026mdash;it remains a devastating and frequently fatal condition. Despite advances in diagnostics and therapy, almost half of the affected patients die within five years of diagnosis. Survival is strongly determined by preoperative ASA PS classification, age, the affected joint, and the presence of implants, whereas common comorbidities such as diabetes or osteoarthritis appear to have limited impact. The high proportion of culture-negative cases emphasizes that early surgical intervention and empiric antibiotic coverage remain the cornerstones of treatment. With Staphylococcus aureus as the dominant pathogen, empiric regimens should continue to target Gram-positive organisms. With Staphylococcus aureus as the dominant pathogen, empiric regimens should continue to target Gram-positive organisms. Future prospective multicenter studies are urgently needed to develop and establish standardized diagnostic and therapeutic pathways to improve survival in this vulnerable and growing population.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eEthics approval:\u003c/p\u003e\n\u003cp\u003eThe responsible ethics committee of the Rhineland-Palatine State Medical Association stated that this study was conducted according to the guidelines of the Declaration of Helsinki. They approved this study (protocol 2023-17107-retrospektiv, on 17. July 2023).\u003c/p\u003e\n\u003cp\u003eInformed Consent Statement\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInformed consent\u0026nbsp;\u003c/strong\u003ewas not applicable due to the anonymized data generation and retrospective analysis. This is consistent with the guidelines of the Declaration of Helsinki.\u003c/p\u003e\n\u003cp\u003eFunding:\u003c/p\u003e\n\u003cp\u003eThis research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.\u003c/p\u003e\n\u003cp\u003eAuthor Contribution\u003c/p\u003e\n\u003cp\u003eL.T.: Conceptualization, Software, Validation, Formal analysis, Investigation, Data curation, Writing \u0026ndash; original draft, Writing \u0026ndash; review \u0026amp; editing, VisualizationJ.N.: Software, Validation, Formal analysis, Data curation, Writing \u0026ndash; original draft, Writing \u0026ndash; review \u0026amp; editingC.W.: Conceptualization, Methodology, Validation, Writing \u0026ndash; review \u0026amp; editing, Supervision, Project administration, Ressources\u003c/p\u003e\n\u003cp\u003eData Availability\u003c/p\u003e\n\u003cp\u003eThe data originate from a surgical and traumatological care unit at St. Elisabeth Hospital, Neuwied, as well as St. Josef Hospital, Bendorf, The data can be provided anonymously in a separate file upon request. A public dataset was not used to obtain the data presented.\u003c/p\u003e\n\u003cp\u003eAuthor Contribution\u003c/p\u003e\n\u003cp\u003eInstitutional Review Board Statement\u003c/p\u003e\n\u003cp\u003eInformed Consent Statement\u003c/p\u003e\n\u003cp\u003eInformed consent was not applicable due to the anonymized data generation and retrospective analysis. This is consistent with the guidelines of the Declaration of Helsinki.\u003c/p\u003e\n\u003cp\u003eConflicts of Interest\u003c/p\u003e\n\u003cp\u003eThe authors declare no conflict of interest.\u003c/p\u003e\n\u003cp\u003eFunding Statement\u003c/p\u003e\n\u003cp\u003eThis research received no external funding.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eMargaretten ME, Kohlwes J, Moore D, Bent S. Does this adult patient have septic arthritis? JAMA. 4. April 2007;297(13):1478\u0026ndash;88. \u003c/li\u003e\n\u003cli\u003eRoss JJ. Septic Arthritis of Native Joints. Infect Dis Clin North Am. 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A Review of Potential Options for Therapeutic Intervention. Front Immunol. 25. September 2019;10:2247. \u003c/li\u003e\n\u003cli\u003eSantoro A, Bientinesi E, Monti D. Immunosenescence and inflammaging in the aging process: age-related diseases or longevity? Ageing Res Rev. November 2021;71:101422. \u003c/li\u003e\n\u003cli\u003eCesari M, Prince M, Thiyagarajan JA, De Carvalho IA, Bernabei R, Chan P, u. a. Frailty: An Emerging Public Health Priority. J Am Med Dir Assoc. 1. M\u0026auml;rz 2016;17(3):188\u0026ndash;92. \u003c/li\u003e\n\u003cli\u003eFarage MA, Miller KW, Elsner P, Maibach HI. Characteristics of the Aging Skin. Adv Wound Care. Februar 2013;2(1):5\u0026ndash;10. \u003c/li\u003e\n\u003cli\u003eShirtliff ME, Mader JT. Acute septic arthritis. Clin Microbiol Rev. Oktober 2002;15(4):527\u0026ndash;44. \u003c/li\u003e\n\u003cli\u003eNewman JH. Review of septic arthritis throughout the antibiotic era. Ann Rheum Dis. Juni 1976;35(3):198\u0026ndash;205. \u003c/li\u003e\n\u003cli\u003eKaandorp CJ, Krijnen P, Moens HJ, Habbema JD, van Schaardenburg D. The outcome of bacterial arthritis: a prospective community-based study. Arthritis Rheum. Mai 1997;40(5):884\u0026ndash;92. \u003c/li\u003e\n\u003cli\u003eSmith JW, Chalupa P, Shabaz Hasan M. Infectious arthritis: clinical features, laboratory findings and treatment. Clin Microbiol Infect Off Publ Eur Soc Clin Microbiol Infect Dis. April 2006;12(4):309\u0026ndash;14. \u003c/li\u003e\n\u003cli\u003eGarc\u0026iacute;a-Arias M, Balsa A, Mola EM. Septic arthritis. Best Pract Res Clin Rheumatol. Juni 2011;25(3):407\u0026ndash;21. \u003c/li\u003e\n\u003cli\u003eSendi P, K\u0026uuml;hl R, Aeberli D, Zumstein M. Die septische Arthritis bei Erwachsenen. Swiss Med Forum ‒ Schweiz Med-Forum. 26. April 2017;17. \u003c/li\u003e\n\u003cli\u003eHorowitz DL, Katzap E, Horowitz S, Barilla-LaBarca ML. Approach to septic arthritis. Am Fam Physician. 15. September 2011;84(6):653\u0026ndash;60. \u003c/li\u003e\n\u003cli\u003eGupta MN, Sturrock RD, Field M. Prospective comparative study of patients with culture proven and high suspicion of adult onset septic arthritis. Ann Rheum Dis. 1. April 2003;62(4):327\u0026ndash;31. \u003c/li\u003e\n\u003cli\u003eWeston VC, Jones AC, Bradbury N, Fawthrop F, Doherty M. Clinical features and outcome of septic arthritis in a single UK Health District 1982-1991. Ann Rheum Dis. April 1999;58(4):214\u0026ndash;9. \u003c/li\u003e\n\u003cli\u003eMyers P, Laboe P, Johnson KJ, Fredericks PD, Crichlow RJ, Maar DC, u. a. Patient Mortality in Geriatric Distal Femur Fractures. J Orthop Trauma. M\u0026auml;rz 2018;32(3):111\u0026ndash;5. \u003c/li\u003e\n\u003cli\u003eMorri M, Ambrosi E, Chiari P, Orlandi Magli A, Gazineo D, D\u0026rsquo; Alessandro F, u. a. One-year mortality after hip fracture surgery and prognostic factors: a prospective cohort study. Sci Rep. 10. Dezember 2019;9:18718. \u003c/li\u003e\n\u003cli\u003eGiaquinto AN, Sung H, Miller KD, Kramer JL, Newman LA, Minihan A, u. a. Breast Cancer Statistics, 2022. CA Cancer J Clin. November 2022;72(6):524\u0026ndash;41. \u003c/li\u003e\n\u003cli\u003eWang L, Lu B, He M, Wang Y, Wang Z, Du L. Prostate Cancer Incidence and Mortality: Global Status and Temporal Trends in 89 Countries From 2000 to 2019. Front Public Health. 2022;10:811044. \u003c/li\u003e\n\u003cli\u003eHeidarnia MA, Monfared ED, Akbari ME, Yavari P, Amanpour F, Mohseni M. Social determinants of health and 5-year survival of colorectal cancer. Asian Pac J Cancer Prev APJCP. 2013;14(9):5111\u0026ndash;6. \u003c/li\u003e\n\u003cli\u003eFoley C, Kendall MC, Apruzzese P, De Oliveira GS. American Society of Anesthesiologists Physical Status Classification as a reliable predictor of postoperative medical complications and mortality following ambulatory surgery: an analysis of 2,089,830 ACS-NSQIP outpatient cases. BMC Surg. 21. Mai 2021;21(1):253. \u003c/li\u003e\n\u003cli\u003eWolters U, Wolf T, St\u0026uuml;tzer H, Schr\u0026ouml;der T. ASA classification and perioperative variables as predictors of postoperative outcome. Br J Anaesth. August 1996;77(2):217\u0026ndash;22. \u003c/li\u003e\n\u003cli\u003eGoldenberg DL. Septic arthritis. Lancet Lond Engl. 17. Januar 1998;351(9097):197\u0026ndash;202. \u003c/li\u003e\n\u003cli\u003eArcher NK, Mazaitis MJ, Costerton JW, Leid JG, Powers ME, Shirtliff ME. Staphylococcus aureus biofilms. Virulence. 2011;2(5):445\u0026ndash;59. \u003c/li\u003e\n\u003cli\u003eCunningham R, Cockayne A, Humphreys H. Clinical and molecular aspects of the pathogenesis of Staphylococcus aureus bone and joint infections. J Med Microbiol. M\u0026auml;rz 1996;44(3):157\u0026ndash;64. \u003c/li\u003e\n\u003cli\u003eHerrmann M, Vaudaux PE, Pittet D, Auckenthaler R, Lew PD, Schumacher-Perdreau F, u. a. Fibronectin, fibrinogen, and laminin act as mediators of adherence of clinical staphylococcal isolates to foreign material. J Infect Dis. Oktober 1988;158(4):693\u0026ndash;701. \u003c/li\u003e\n\u003cli\u003eHolt RIG, Cockram CS, Ma RCW, Luk AOY. Diabetes and infection: review of the epidemiology, mechanisms and principles of treatment. Diabetologia. Juli 2024;67(7):1168\u0026ndash;80. \u003c/li\u003e\n\u003cli\u003eDarwitz BP, Genito CJ, Thurlow LR. Triple threat: how diabetes results in worsened bacterial infections. Infect Immun. 10. September 2024;92(9):e0050923. \u003c/li\u003e\n\u003cli\u003eCarey IM, Critchley JA, DeWilde S, Harris T, Hosking FJ, Cook DG. Risk of Infection in Type 1 and Type 2 Diabetes Compared With the General Population: A Matched Cohort Study. Diabetes Care. M\u0026auml;rz 2018;41(3):513\u0026ndash;21. \u003c/li\u003e\n\u003cli\u003eKnapp S. Diabetes and infection: is there a link?--A mini-review. Gerontology. 2013;59(2):99\u0026ndash;104. \u003c/li\u003e\n\u003cli\u003eEuser AM, Zoccali C, Jager KJ, Dekker FW. Cohort studies: prospective versus retrospective. Nephron Clin Pract. 2009;113(3):c214-217. \u003c/li\u003e\n"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"european-journal-of-trauma-and-emergency-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ejot","sideBox":"Learn more about [European Journal of Trauma and Emergency Surgery](http://link.springer.com/journal/68)","snPcode":"68","submissionUrl":"https://submission.nature.com/new-submission/68/3","title":"European Journal of Trauma and Emergency Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"septic arthritis, joint, elderly, infection, risk factors","lastPublishedDoi":"10.21203/rs.3.rs-8269646/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8269646/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Introduction:\nPrimary septic arthritis is an acute emergency associated with high morbidity and mortality in older adults. Rapid diagnosis and treatment are crucial. The study evaluates 5-year survival and identifies prognostic risk factors in elderly patients with primary septic arthritis, including age, ASA Physical Status (ASA PS) classification, joint involvement, implants, and pathogen spectrum.\nMethods: 50 patients aged ≥ 60 years treated for primary septic arthritis at two hospitals between 2008 and 2020 were included. Demographic, clinical, and microbiological data were collected retrospectively. Survival was assessed by Kaplan–Meier analysis, with log-rank tests to compare subgroups.\nResults: The mean age was 71.2 years. Overall survival was 76% at 1 year and 54% at 5 years. Survival declined significantly with increasing age (p = 0.004), higher ASA PS classification (p \u003c 0.001), joint involvement (p = 0.027), and presence of implants (p \u003c 0.001). Diabetes mellitus, osteoarthritis, and synovial culture status showed no significant effect. By joint, mean survival was 1331 days for the knee, 879 days for the shoulder, 935 days for the hip, 1825 days for the ankle and 36 days for the sacroiliac joint. Patients with implants had markedly shorter survival (402 vs. 1400 days). Pathogens were isolated in 72% of cases, most frequently Staphylococcus aureus (38%).\nConclusion: Primary septic arthritis in older adults remains a life-threatening condition with high early- and mid-term mortality. Survival is strongly determined by age, ASA PS classification, joint involvement, and presence of implants, while comorbidities and pathogen detection show no prognostic relevance.","manuscriptTitle":"Primary Septic Arthritis in the elderly – A Forgotten Killer? Five-Year Survival and Risk Factors in a Retrospective Cohort Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-10 10:50:42","doi":"10.21203/rs.3.rs-8269646/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-12-28T19:49:08+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-27T14:46:09+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-08T16:48:00+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"305873121560866419315606719599858306950","date":"2025-12-07T18:16:05+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"305576842707248922892967340875606790830","date":"2025-12-07T18:04:26+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-12-07T17:11:01+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-12-07T08:48:35+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-12-05T15:44:11+00:00","index":"","fulltext":""},{"type":"submitted","content":"European Journal of Trauma and Emergency Surgery","date":"2025-12-03T11:13:49+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"european-journal-of-trauma-and-emergency-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ejot","sideBox":"Learn more about [European Journal of Trauma and Emergency Surgery](http://link.springer.com/journal/68)","snPcode":"68","submissionUrl":"https://submission.nature.com/new-submission/68/3","title":"European Journal of Trauma and Emergency Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"bac887c6-a9c6-4218-87e8-03ac602bafb8","owner":[],"postedDate":"December 10th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-03-02T16:01:38+00:00","versionOfRecord":{"articleIdentity":"rs-8269646","link":"https://doi.org/10.1007/s00068-026-03124-5","journal":{"identity":"european-journal-of-trauma-and-emergency-surgery","isVorOnly":false,"title":"European Journal of Trauma and Emergency Surgery"},"publishedOn":"2026-02-23 15:57:26","publishedOnDateReadable":"February 23rd, 2026"},"versionCreatedAt":"2025-12-10 10:50:42","video":"","vorDoi":"10.1007/s00068-026-03124-5","vorDoiUrl":"https://doi.org/10.1007/s00068-026-03124-5","workflowStages":[]},"version":"v1","identity":"rs-8269646","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8269646","identity":"rs-8269646","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}