Septic arthritis or adult-onset Still's disease (AOSD) - Analyzing the causes of recurrent fever after arthroscopic combined anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) reconstruction: a case report and literature review

Septic arthritis or adult-onset Still's disease (AOSD) - Analyzing the causes of recurrent fever after arthroscopic combined anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) reconstruction: a case report and literature review | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Case Report Septic arthritis or adult-onset Still's disease (AOSD) - Analyzing the causes of recurrent fever after arthroscopic combined anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) reconstruction: a case report and literature review Zenan Tian, Jianlong Ni, Wang Wei, Qichun Song, Shanshan Liu, and 7 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3753410/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 07 Oct, 2025 Read the published version in BMC Musculoskeletal Disorders → Version 1 posted 10 You are reading this latest preprint version Abstract Background AOSD and septic arthritis share similar clinical symptoms, including recurrent fever, affected joint pain and limited mobility. This similarity poses diagnostic challenges when encountering a case of arthroscopic combined ACL and PCL reconstruction, where clinical evidence is insufficient to establish a definitive diagnosis between the two diseases. In this case, through a series of examinations and diagnostic treatment, the final diagnosis was AOSD. Case presentation A 41-year-old male who underwent arthroscopic combined ACL and PCL reconstruction half a month prior was admitted to our hospital with a weeklong history of recurrent fever and polyarticular pain. The positive physical signs and test results were insufficient to establish a definitive diagnosis between AOSD and septic arthritis. Therefore, a multidisciplinary team consisting of the orthopedic, infectious disease, rheumatism and immunology, hematology, respiratory, and pharmaceutical departments was formed to determine the diagnosis and establish a treatment plan. During the treatment period, the patient developed a typical rash and pharyngalgia. Multiple highly effective antibiotics were ineffective during the patient’s treatment, but the symptoms improved significantly after the administration of methylprednisolone, aspirin, and tocilizumab. The diagnosis of AOSD was ultimately determined according to the Yamaguchi criteria. After treatment, the patient's condition remained stable, and he was discharged from the hospital. During the subsequent two-month follow-up, the patient's condition remained stable without recurrence of symptoms, and the knee joint function returned to normal. Discussion and conclusion We could not retrieve any relevant case reports of AOSD after arthroscopic combined ACL and PCL reconstruction in several databases. Therefore, we believe this may be the first reported case. In conjunction with the relevant literature, we summarize the differences in clinical symptoms between septic arthritis and AOSD. Reviewing the patient's hospitalization process, we discuss the "controversial" diagnostic and therapeutic measures taken by the multidisciplinary team, along with any doubts and considerations. In conclusion, in cases where it is difficult to establish a definitive diagnosis between AOSD and septic arthritis, a collaborative approach involving multiple departments can be used for diagnosis and treatment, thereby shortening the diagnostic time and avoiding unnecessary diagnosis and treatment. Recurrent fever septic arthritis AOSD ACL reconstruction PCL reconstruction combined ACL and PCL reconstruction case report Figures Figure 1 Figure 2 Figure 3 Background Fever is a common postoperative complication in surgical procedures. A study by Perlino CA found that noninfectious factors (including surgical trauma, transfusion reactions and medications) are the main cause of postoperative fever, accounting for 74%. Infectious factors (including wound infections, urinary tract infections and pulmonary infections) are secondary causes, accounting for 26% [ 1 ]. According to the time of fever onset, fever caused by drugs generally occurs within a few hours of drug administration and resolves after stopping the medication. Anesthesia-induced high fever typically occurs within 10 hours after surgery, and timely administration of dantraline can effectively treat it. Fever resulting from surgical trauma appears within 48 hours after surgery and can disappear spontaneously. Infections commonly cause fever within 3–5 days after surgery and may be accompanied by significant positive indicators, such as positive laboratory findings or cultures. Fevers caused by rheumatic immune diseases and tumors can persist for up to 3 weeks or even longer [ 1 ][ 2 ][ 3 ][ 4 ]. A fever with a temperature higher than 38.3℃ that occurs on several occasions and that lasts for at least 3 weeks and lacks a clear diagnosis after 1 week of hospital treatment is referred to as a fever of unknown origin (FUO) [ 5 ]. The common causes of FUO include infection, cancers, and noninfectious inflammatory diseases [ 5 ]. The patient experienced recurrent fever and polyarticular pain after 1 week of having arthroscopic combined ACL and PCL reconstruction, and the symptoms had been present for one week prior to admission. Based on the timeline of the symptoms and positive clinical signs, reasons such as trauma, anesthesia and drugs could be ruled out. There is a high possibility of preliminary suspicion of septic arthritis in joint infection and autoimmune diseases. However, it is necessary to rule out other infections, rheumatic immune diseases, tumors, hematological diseases, etc. [ 4 ][ 6 ][ 7 ]. AOSD is an agnogenic autoimmune inflammatory disease with typical symptoms, including recurrent fever, arthritis, rash and methemoglobinemia [ 8 ]. Laboratory tests typically show leukocytosis, increased neutrophil percentage, and elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels [ 9 ]. AOSD arthritis is characterized by joint pain and limited mobility, with the knee, wrist and ankle joints being more susceptible to being affected [ 10 ][ 11 ]. Despite the characteristic clinical manifestations of AOSD, the diagnosis still relies on exclusion due to the lack of specific serological and histopathological findings [ 12 ]. Several diagnostic criteria exist for AOSD, among which the Yamaguchi criterion is the most widely cited, with a sensitivity of 93.5% [ 13 ][ 14 ][ 15 ]. The typical clinical manifestations of septic arthritis include fever, joint pain, limited mobility, and erythema. Laboratory findings show leukocytosis and elevated ESR and CRP levels [ 16 ]. According to the guidelines for the management of septic arthritis in native joints published by the European Bone and Joint Infection Society (EBJIS) in 2022, the main criteria for diagnosing septic arthritis, particularly after ACL reconstruction, include purulent discharge/aspirate, sinus tract communication with the joint, and the presence of intraarticular pus, along with the identification of pathogenic bacteria in joint fluid culture [ 6 ]. However, a negative joint fluid culture cannot completely rule out the possibility of septic arthritis [ 6 ]. The guidelines also state that a high suspicion of septic arthritis should be kept in mind in any patient with a painful and/or inflamed joint (redness, hot, swelling, synovial effusion, and/or purulent drainage) with or without a fever. No clinical parameters can exclude or confirm septic arthritis [ 6 ]. Case presentation A 41-year-old Chinese male was admitted to the hospital with a weeklong recurrent high fever and polyarticular pain. He had undergone arthroscopic all-inside combined ACL and PCL reconstruction half a month prior due to a car accident that caused damage to his left knee cruciate ligaments. After the surgery, his condition remained stable, and he was discharged from the hospital. One week prior to admission, he developed an elevated body temperature with a maximum temperature of 38.5 °C, along with a rash on the chest and back. During the fever episodes, mild swelling and pain appeared in the left knee joint. The patient self-administered oral antibiotics and etoricoxib, which resulted in normalization of body temperature and relief from the knee joint pain. However, three days prior to admission, he experienced high fever again with a maximum temperature of 40 °C, along with chills and polyarticular pain. On admission, his initial body temperature was 39.5 °C. Physical examination revealed that a knee brace was worn on the left knee, and there was slight swelling in the joint, no redness or swelling on the anterior shin skin, a negative floating patellar test and limited flexion movement of the left knee joint with a maximum active flexion of approximately 90°. A chest CT scan showed chronic inflammatory changes in the lungs, benign nodules and a small amount of pleural effusion. The laboratory test results are shown in Table 1 (on admission). Table 1 Laboratory examination results during hospitalization Component On admission 1st MDT 2nd MDT Reexamination Reference range WBC (×109/L) 24.64 22.93 22.08 41.88 3.50-9.50 Neutrophils (%) 86.5 90.7 86.7 83.90 40-75 Hemoglobin (g/L) 113 89 116 110 130-175 Platelet (×109/L) 456 539 522 523 125-350 CRP (mg/L) 165.04 125.26 ＜10 - ＜10 ESR (mm/h) 96 116 21 - 0-15 Total protein (g/L) 56.5 64.5 52.8 66.1 60-85 Albumin (g/L) 28.8 31.6 29.7 33.3 35-55 bilirubin, direct (umol/L) 1.20 4.65 2.46 1.62 ＜4 bilirubin, total (umol/L) 4.20 13.90 11.10 7.60 ＜23 ALT (U/L) 190.80 252 94 115 9-50 AST (U/L) 92.50 115 23 54 15-40 ALP (U/L) 162 288 166 108 45-125 INR 1.12 1.11 0.93 - 0.9-1.3 PT (s) 12.7 12.6 10.3 - 9.8-12.1 APTT (s) 25.0 19.5 17.8 - 22.7-31.8 D-Dimer (ng/mL) 1520.00 1050.00 700.00 - 0-1000 ANA weakly positive - - - negative RF (IU/L) ＜11.60 - - - 0-15.9 IL-6 (pg/mL) 74.98 198.35 - - 0-5.4 IL-1β (pg/mL) 15.38 - - - 0-12.4 ALP alkaline phosphatase, ALT alanine amino transaminase, APTT activated partial thromboplastin time, ANA antinuclear antibody, AST aspartate aminotransferase, CRP C-reactive protein, ESR erythrocyte sedimentation rate, INR international normalized ratio, PT prothrombin time, RF rheumatoid factor, WBC white blood cell Upon admission, the patient's COVID-19 nucleic acid test and urine culture were both negative. Bone marrow aspiration indicated peripheral leukocytosis. Thereafter, aerobic and anaerobic blood cultures were carried out every time the temperature increased significantly (a total of five times), and the results were all negative. To determine the diagnosis and establish a treatment plan, a multidisciplinary team consisting of the orthopedic, infectious disease, rheumatism and immunology, hematology, respiratory, and pharmaceutical departments was formed. The preliminary suspicion was sepsis and septic arthritis with a knee joint infection, so the patient was treated with an empirical antibiotic (ceftriaxone) and symptomatic supportive treatment. Additional examinations, including tests of TORCH, EBV, CMV and a recheck COVID-19 nucleic acid, had negative results. On the third day of admission, the patient’s temperature spiked again, reaching 40 °C, and a punctate congestive rash was distributed symmetrically over the neck and pharyngalgia. The results of the chest CT scan were the same as the previous scan, and the sacroiliac joint CT scan showed no abnormalities. Color Doppler ultrasound of the knee joint revealed soft tissue edema and joint effusion. Based on these findings, the multidisciplinary team considered a high possibility of septic arthritis but could not rule out AOSD. The previous antibiotic was replaced with meropenem for a duration of six days, during which the patient's temperature fluctuated between 36.1 °C and 40.0 °C, and there was no significant relief in symptoms. Subsequently, the patient was switched to moxifloxacin, cefotiam and linezolid, but his body temperature remained high. During this period, fungal D glucose and tuberculosis-infected T lymphocytes were both negative. On the 13th day of admission, the multidisciplinary team conducted a difficult case discussion. The orthopedics department believed that septic arthritis could be ruled out and considered a high possibility of AOSD. The Rheumatism and Immunology Department stated that AOSD should be considered an exclusion diagnosis and that septic arthritis could be ruled out, suggesting a diagnosis of SRIS and recommending symptomatic treatment while continuing to conduct further investigations to exclude infections, hematological disorders and tumors. Based on the discussion, additional examinations were conducted. The results of the Brucella agglutination test and PDD test were negative. Bone marrow aspiration indicated reactive bone marrow hyperplasia. NGS indicated parvovirus, but background contamination could not be ruled out. Fungal, viral, blood and urine cultures were all negative. The patient responded positively to diagnostic treatment with methylprednisolone, aspirin and tocilizumab. His symptoms improved significantly, with temperature control and rash regression. Based on the recent treatment effect and examination results, a second difficult case discussion was held on the 34th day of admission. According to the Yamaguchi criteria [13], the patient had four major features (spiking fever, arthralgia, rash, and leukocytosis) and two minor features (sore throat, negative ANA/RF). After excluding infectious diseases, hematological disorders and tumors, the patient was diagnosed with AOSD. After treatment for AOSD, the patient's temperature returned to normal, and both the rash and joint symptoms disappeared. The CRP level decreased to normal (<10 mg/L), while the ESR level was slightly higher (21 mg/L). After communication with the patient and his family, the patient was discharged with knee joint mobility ranging from 0 to 85°. A brief diagram of the patient’s disease changes is shown in Figure 1. After discharge, the patient continued to wear a left knee brace and continued to take prednisone 50 mg once a day. The symptoms were well controlled. The patient was readmitted and reexamined half a month later, and the results of the laboratory tests are shown in Table 1 (Reexamination). The patient was re-examined a month later, and X-ray of the knee showed postoperative changes in the combined ACL and PCL reconstruction with a good internal fixation position (Figure 2). MRI of the knee indicated postoperative changes in the combined ACL and PCL reconstruction with good internal fixation position and signal. A small amount of fluid had accumulated in the joint, and there was slight swelling of the surrounding soft tissues (Figure 3). During a 3-month follow-up, the patient's knee joint mobility returned to normal, with no recurrence of symptoms. Discussion Bywater first proposed AOSD in 1971 [17], but since that publication, the development of AOSD after arthroscopic combined ACL and PCL reconstruction has not been reported. We searched "Ligament reconstruction & AOSD", "anterior/posterior cruciate ligament reconstruction & AOSD" and "ACL-R/PCL-R & AOSD" in several databases, such as PubMed, but found no relevant cases. To our knowledge, this is possibly the first case report of AOSD after arthroscopic combined ACL and PCL reconstruction. Based on this case and relevant literature, we summarized the differences in clinical symptoms between septic arthritis and AOSD (Table 2) [16][18][19][20]. Table 2 Differences in the clinical features between septic arthritis and AOSD Clinical features Septic arthritis AOSD Fever Most cases are mild and only 30%–40% of individuals have a temperature >39℃ Peak fever and the highest temperatures (> 39 ℃) occurs at night Arthralgia and arthritis Most cases are monoarticular and only 10%-20% of individuals have a polyarticular disease Most cases are polyarthritis Dermatologic manifestations Erythema around the affected joint A macular or maculopapular evanescent salmon-pink skin rash appears together with the fever spikes Pharyngalgia Generally, not present, but can occur when accompanied by throat infections It occurs before or during the first month of each disease flare Others Occur rarely but shivering can occur It is common and includes myalgia, enlargement of the lymph nodes, splenomegaly, hepatomegaly, pleurisy, pericarditis, weight loss, etc. Looking back at the entire diagnosis and treatment process, the multidisciplinary team took some "controversial" measures: 1. Multiple studies, such as the clinical guidelines published by EBJIS in 2022, have emphasized that joint fluid aspiration and culture are essential for the diagnosis of septic arthritis [6][16][21]. Why was joint fluid aspiration and culture not performed in this case? The blood cultures were repeatedly negative, indicating a lack of positive evidence for infection. The patient did not exhibit significant symptoms in the operated joint, and the floating patella test was negative. Additionally, postoperative puncture may lead to secondary infection. Through the search of relevant literature, we found a case where AOSD was misdiagnosed as a prosthetic joint infection (PJI) and another case where AOSD was misdiagnosed as septic arthritis. Both of the patients of these cases underwent joint fluid aspiration and culture, and the results suggested joint infection [22][23]. Based on the two cases, the decision was correct to some extent in not performing joint fluid aspiration and culture. 2. EBJIS suggests that arthroscopic debridement should be performed as soon as the suspicion of septic arthritis is raised in cases with acute symptoms or in the early postoperative setting, even if the microbiological results are still pending [6]. Additionally, multiple studies have indicated that arthroscopic debridement is highly effective in SA treatment, especially after ACL reconstruction [6][16][21]. So why was arthroscopic debridement not performed in this case? We observed that the patient had polyarticular pain, but the operated joint did not exhibit significant swelling or pain. Arthroscopic debridement is an invasive treatment that increases the risk of nosocomial infection and would incur additional costs of treatment to the patient. Therefore, instead of arthroscopic debridement, we treated the patient with powerful and empirical antibiotics. 3. The patient's symptoms and examinations indicated inflammation on admission, and we considered the possibility of infection. Why was septic arthritis suspected instead of other related infections? On the one hand, EBJIS states that a high suspicion of septic arthritis should be kept in mind in any patient with a painful and/or inflamed joint with or without a fever. On the other hand, multiple studies have found that septic arthritis is more common in infections after ACL reconstruction. Furthermore, arthroscopic combined ACL and PCL reconstruction involves a longer surgical duration and greater surgical trauma than isolated ACL reconstruction or PCL reconstruction, which increases the risk of postoperative infection [6][24][25][26]. Therefore, septic arthritis is given priority consideration in this case. Furthermore, there is controversy over the diagnostic criteria for septic arthritis because of the lack of high-quality evidence-based research, which also increases the difficulty of diagnosis in this case [16]. First, we considered septic arthritis as a strong possibility but could not exclude AOSD. Subsequent examinations, including five blood cultures performed during the periods of elevated body temperature, did not reveal evidence of infection. Empiric antibiotic treatment was ineffective. Septic arthritis was excluded at 13 days after admission and lasted for 13 days. Further examinations ruled out infection, blood disorders and tumors. In combination with effective diagnostic treatment, the diagnosis of AOSD was confirmed on the 34th day of admission, after a total of 31 days. Looking back at the entire diagnosis and treatment process, the multidisciplinary team presents the concerns and reflections: 1. Within the 13 days from suspicion to exclusion of septic arthritis, we performed five blood cultures (aerobic and anaerobic) during the periods of elevated body temperature, and all results were negative. Regarding the number of blood cultures, the guidelines by EBJIS in 2022 suggest that at least two sets of aerobic and anaerobic blood cultures should be performed, but they do not provide a specific upper limit [6]. However, the patient had taken antibiotics before admission, which necessitates an increased number of blood cultures to eliminate the impact of antibiotics. It is worth considering whether five blood cultures were excessive for the diagnosis? Could the number be reduced to 3-4? We should summarize our experience from this case and our clinical practice. 2. Referring to the two cases of AOSD, joint fluid aspiration and culture were performed, and PJI and septic arthritis were suspected according to the results. Arthroscopic debridement was performed several times in these two cases [22][23]. Therefore, can we consider that joint fluid aspiration and culture as well as arthroscopic debridement performed to exclude/diagnose septic arthritis when AOSD or SA is highly suspected have limited clinical value and are unnecessary? This requires collaborative efforts from clinical practitioners and researchers to answer the question. 3. On the 14th day of admission, the patient had been experiencing fever with a temperature higher than 38.3℃ on several occasions that lasted for at least 3 weeks and lacked a clear diagnosis after 1 week of hospital treatment. According to the criteria for FUO, the patient could then be diagnosed with FUO [5]. The common causes of FUO are infection, tumors and noninfectious inflammatory diseases. AOSD is the most common noninfectious inflammatory disease [5]. If diagnosed as FUO, AOSD can be considered and confirmed after excluding infection (multiple negative blood cultures, negative bacterial, fungal and viral tests) and tumor (ruled out by bone marrow aspiration and NGS). Comparing the 31 days it took to diagnose AOSD in this case, diagnosing AOSD based on the FUO criteria could significantly reduce the time needed for confirmation. Conclusion In conclusion, AOSD and septic arthritis share similar clinical symptoms. It is challenging to make a definitive diagnosis because the positive evidence is insufficient, which may prolong the diagnosis and treatment time, as seen in this case. In such situations, we believe that setting up a multidisciplinary team is beneficial for diagnosis and treatment. To shorten the diagnosis time and avoid unnecessary diagnosis and treatment, we should pay attention to subtle differences between symptoms and examinations and adopt empirical and diagnostic treatment measures. Abbreviations AOSD: adult-onset Still's disease; ACL: anterior cruciate ligament; PCL: posterior cruciate ligament; FUO: fever of unknown origin; ESR: erythrocyte sedimentation rate; CRP: C-reactive protein; PJI: prosthetic joint infection Declarations Acknowledgments Not applicable. Authors’ contributions All listed authors substantially contributed to the following aspects of the manuscript: Z.S., Z.T., J.N., Q.S. and S.L. participated in diagnosing and treating the patient and in acquisition of data. Z.T. and J.N. collected the findings and drafted the manuscript. D.W., R.L. and D.W. prepared figures 1-3. Z.J. and J.J. prepared tables 1-2. Z.S. and J.N. revised the manuscript. All authors read and approved the final manuscript. Z.S. guarantees the integrity of this work. Funding Not applicable. Data Availability Written consent was obtained from the patient for publication of the patient’s details. The data supporting this case report are from previously reported studies and datasets, which have been cited. The processed data are available upon request from the corresponding author. Declarations Ethics approval and consent to participate Not applicable. Consent for publication The authors have obtained the patient’s written informed consent for print and electronic publication of this case report. Competing interests The authors declare that they have no financial or other conflicts of interest in relation to this research and its publication. References Perlino CA. Postoperative fever. Med Clin North Am. 2001;85(5):1141-1149. Patel RA, Gallagher JC. Drug fever. Pharmacotherapy. 2010;30(1):57-69. Pile JC. Evaluating postoperative fever: a focused approach. Cleve Clin J Med. 2006;73 Suppl 1:S62-S66. Wright WF, Auwaerter PG. Fever and Fever of Unknown Origin: Review, Recent Advances, and Lingering Dogma. Open Forum Infect Dis. 2020;7(5):ofaa132. Kaya A, Ergul N, Kaya SY, et al. 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Cite Share Download PDF Status: Published Journal Publication published 07 Oct, 2025 Read the published version in BMC Musculoskeletal Disorders → Version 1 posted Editorial decision: Revision requested 29 Aug, 2024 Reviews received at journal 13 Apr, 2024 Reviewers agreed at journal 11 Apr, 2024 Reviews received at journal 08 Mar, 2024 Reviewers agreed at journal 28 Feb, 2024 Reviewers invited by journal 28 Feb, 2024 Editor assigned by journal 30 Dec, 2023 Editor invited by journal 27 Dec, 2023 Submission checks completed at journal 27 Dec, 2023 First submitted to journal 14 Dec, 2023 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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University","correspondingAuthor":false,"prefix":"","firstName":"Jiajun","middleName":"","lastName":"Jiang","suffix":""},{"id":264522316,"identity":"076fed26-8d8b-4761-8d1b-4cc0ff9082fd","order_by":11,"name":"Zhibin Shi","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAxklEQVRIiWNgGAWjYDACCQY2hgQgZmBvbHz4gRQtEgw8h5uNJYjWAqYk0tsEeIjRIT+7/dmDh218dQY3H7YBNdrJ6TYQ0MI454y5QcIZNgmD24ltDwoYko3NDhDQwiyRwyaRUAHW0m4gwXAgcRshLWwS6c8kEgyAWm4ebJPgIUYLj0SCGcSWG4xEapGQOQPUcoZNcuaZRGAgGxDhF1CISf5sO8bPd/z4w4cfKuzkCGqBgmNQ2oA45SBQQ7zSUTAKRsEoGHkAADCfPiTKEXNzAAAAAElFTkSuQmCC","orcid":"","institution":"The Second Affiliated Hospital Of Xi'an Jiaotong University","correspondingAuthor":true,"prefix":"","firstName":"Zhibin","middleName":"","lastName":"Shi","suffix":""}],"badges":[],"createdAt":"2023-12-14 12:14:15","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3753410/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3753410/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12891-025-08938-9","type":"published","date":"2025-10-07T15:57:56+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":49090126,"identity":"057fb4aa-6733-4066-9969-79487d291b98","added_by":"auto","created_at":"2024-01-03 01:41:21","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":72889,"visible":true,"origin":"","legend":"\u003cp\u003eBody temperature, neutrophils, important symptoms, and drugs timeline during hospitalization\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-3753410/v1/e36b0c4dfc85fc84adbae502.png"},{"id":49088474,"identity":"c02a256d-ee83-45d9-869a-838503f20372","added_by":"auto","created_at":"2024-01-03 01:25:21","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":174755,"visible":true,"origin":"","legend":"\u003cp\u003eRadiographs of the knee in adult onset Still's disease.\u003c/p\u003e\n\u003cp\u003ePostoperative changes of the combined ACL and PCL reconstruction with good internal fixation position.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-3753410/v1/6c613d0d187b3d9e3b9470ef.png"},{"id":49089270,"identity":"e38944e1-61fe-42b9-ae6a-8080d4a59768","added_by":"auto","created_at":"2024-01-03 01:33:21","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":393905,"visible":true,"origin":"","legend":"\u003cp\u003eMRI of the knee in adult onset Still's disease.\u003c/p\u003e\n\u003cp\u003ePostoperative changes of the combined ACL and PCL reconstruction with good internal fixation position and signal. Small amount of fluid accumulation in the joint and slight swelling of the surrounding soft tissues.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-3753410/v1/898ad12a22da182f51e3b521.png"},{"id":93597320,"identity":"7a81a149-d684-4ca8-bf76-d7d9d2ac3a7f","added_by":"auto","created_at":"2025-10-15 14:07:30","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1471133,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3753410/v1/7f1a29ee-f6ce-42cf-a621-ea4be7fcd469.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Septic arthritis or adult-onset Still's disease (AOSD) - Analyzing the causes of recurrent fever after arthroscopic combined anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) reconstruction: a case report and literature review","fulltext":[{"header":"Background","content":"\u003cp\u003eFever is a common postoperative complication in surgical procedures. A study by Perlino CA found that noninfectious factors (including surgical trauma, transfusion reactions and medications) are the main cause of postoperative fever, accounting for 74%. Infectious factors (including wound infections, urinary tract infections and pulmonary infections) are secondary causes, accounting for 26% [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. According to the time of fever onset, fever caused by drugs generally occurs within a few hours of drug administration and resolves after stopping the medication. Anesthesia-induced high fever typically occurs within 10 hours after surgery, and timely administration of dantraline can effectively treat it. Fever resulting from surgical trauma appears within 48 hours after surgery and can disappear spontaneously. Infections commonly cause fever within 3\u0026ndash;5 days after surgery and may be accompanied by significant positive indicators, such as positive laboratory findings or cultures. Fevers caused by rheumatic immune diseases and tumors can persist for up to 3 weeks or even longer [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e][\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e][\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e][\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. A fever with a temperature higher than 38.3℃ that occurs on several occasions and that lasts for at least 3 weeks and lacks a clear diagnosis after 1 week of hospital treatment is referred to as a fever of unknown origin (FUO) [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. The common causes of FUO include infection, cancers, and noninfectious inflammatory diseases [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. The patient experienced recurrent fever and polyarticular pain after 1 week of having arthroscopic combined ACL and PCL reconstruction, and the symptoms had been present for one week prior to admission. Based on the timeline of the symptoms and positive clinical signs, reasons such as trauma, anesthesia and drugs could be ruled out. There is a high possibility of preliminary suspicion of septic arthritis in joint infection and autoimmune diseases. However, it is necessary to rule out other infections, rheumatic immune diseases, tumors, hematological diseases, etc. [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e][\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e][\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAOSD is an agnogenic autoimmune inflammatory disease with typical symptoms, including recurrent fever, arthritis, rash and methemoglobinemia [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Laboratory tests typically show leukocytosis, increased neutrophil percentage, and elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. AOSD arthritis is characterized by joint pain and limited mobility, with the knee, wrist and ankle joints being more susceptible to being affected [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e][\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Despite the characteristic clinical manifestations of AOSD, the diagnosis still relies on exclusion due to the lack of specific serological and histopathological findings [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Several diagnostic criteria exist for AOSD, among which the Yamaguchi criterion is the most widely cited, with a sensitivity of 93.5% [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e][\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e][\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe typical clinical manifestations of septic arthritis include fever, joint pain, limited mobility, and erythema. Laboratory findings show leukocytosis and elevated ESR and CRP levels [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. According to the guidelines for the management of septic arthritis in native joints published by the European Bone and Joint Infection Society (EBJIS) in 2022, the main criteria for diagnosing septic arthritis, particularly after ACL reconstruction, include purulent discharge/aspirate, sinus tract communication with the joint, and the presence of intraarticular pus, along with the identification of pathogenic bacteria in joint fluid culture [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. However, a negative joint fluid culture cannot completely rule out the possibility of septic arthritis [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. The guidelines also state that a high suspicion of septic arthritis should be kept in mind in any patient with a painful and/or inflamed joint (redness, hot, swelling, synovial effusion, and/or purulent drainage) with or without a fever. No clinical parameters can exclude or confirm septic arthritis [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e"},{"header":"Case presentation","content":"\u003cp\u003eA 41-year-old Chinese male was admitted to the hospital with a weeklong recurrent high fever and polyarticular pain. He had undergone arthroscopic all-inside combined ACL and PCL reconstruction half a month prior due to a car accident that caused damage to his left knee cruciate ligaments. After the surgery, his condition remained stable, and he was discharged from the hospital. One week prior to admission, he developed an elevated body temperature with a maximum temperature of 38.5 \u0026deg;C, along with a rash on the chest and back. During the fever episodes, mild swelling and pain appeared in the left knee joint. The patient self-administered oral antibiotics and etoricoxib, which resulted in normalization of body temperature and relief from the knee joint pain. However, three days prior to admission, he experienced high fever again with a maximum temperature of 40 \u0026deg;C, along with chills and polyarticular pain. On admission, his initial body temperature was 39.5 \u0026deg;C. Physical examination revealed that a knee brace was worn on the left knee, and there was slight swelling in the joint, no redness or swelling on the anterior shin skin, a negative floating patellar test and limited flexion movement of the left knee joint with a maximum active flexion of approximately 90\u0026deg;. A chest CT scan showed chronic inflammatory changes in the lungs, benign nodules and a small amount of pleural effusion. The laboratory test results are shown in Table 1 (on admission).\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"100%\" colspan=\"6\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;Table 1\u0026nbsp;\u003c/strong\u003eLaboratory examination results during hospitalization\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\"\u003e\n \u003cp\u003eComponent\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003eOn admission\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.402061855670103%\"\u003e\n \u003cp\u003e1st MDT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.371134020618557%\"\u003e\n \u003cp\u003e2nd MDT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003eReexamination\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003eReference range\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\"\u003e\n \u003cp\u003eWBC (\u0026times;109/L)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e24.64\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.402061855670103%\"\u003e\n \u003cp\u003e22.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.371134020618557%\"\u003e\n \u003cp\u003e22.08\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e41.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e3.50-9.50\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\"\u003e\n \u003cp\u003eNeutrophils (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e86.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.402061855670103%\"\u003e\n \u003cp\u003e90.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.371134020618557%\"\u003e\n \u003cp\u003e86.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e83.90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e40-75\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\"\u003e\n \u003cp\u003eHemoglobin (g/L)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e113\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.402061855670103%\"\u003e\n \u003cp\u003e89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.371134020618557%\"\u003e\n \u003cp\u003e116\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e110\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e130-175\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\"\u003e\n \u003cp\u003ePlatelet (\u0026times;109/L)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e456\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.402061855670103%\"\u003e\n \u003cp\u003e539\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.371134020618557%\"\u003e\n \u003cp\u003e522\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e523\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e125-350\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\"\u003e\n \u003cp\u003eCRP (mg/L)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e165.04\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.402061855670103%\"\u003e\n \u003cp\u003e125.26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.371134020618557%\"\u003e\n \u003cp\u003e＜10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e＜10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\"\u003e\n \u003cp\u003eESR (mm/h)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e96\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.402061855670103%\"\u003e\n \u003cp\u003e116\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.371134020618557%\"\u003e\n \u003cp\u003e21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e0-15\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\"\u003e\n \u003cp\u003eTotal protein (g/L)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e56.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.402061855670103%\"\u003e\n \u003cp\u003e64.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.371134020618557%\"\u003e\n \u003cp\u003e52.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e66.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e60-85\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\"\u003e\n \u003cp\u003eAlbumin (g/L)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e28.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.402061855670103%\"\u003e\n \u003cp\u003e31.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.371134020618557%\"\u003e\n \u003cp\u003e29.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e33.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e35-55\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\"\u003e\n \u003cp\u003ebilirubin, direct (umol/L)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e1.20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.402061855670103%\"\u003e\n \u003cp\u003e4.65\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.371134020618557%\"\u003e\n \u003cp\u003e2.46\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e1.62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e＜4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\"\u003e\n \u003cp\u003ebilirubin, total (umol/L)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e4.20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.402061855670103%\"\u003e\n \u003cp\u003e13.90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.371134020618557%\"\u003e\n \u003cp\u003e11.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e7.60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e＜23\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\"\u003e\n \u003cp\u003eALT (U/L)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e190.80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.402061855670103%\"\u003e\n \u003cp\u003e252\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.371134020618557%\"\u003e\n \u003cp\u003e94\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e115\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e9-50\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\"\u003e\n \u003cp\u003eAST (U/L)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e92.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.402061855670103%\"\u003e\n \u003cp\u003e115\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.371134020618557%\"\u003e\n \u003cp\u003e23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e15-40\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\"\u003e\n \u003cp\u003eALP (U/L)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e162\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.402061855670103%\"\u003e\n \u003cp\u003e288\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.371134020618557%\"\u003e\n \u003cp\u003e166\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e108\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e45-125\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\"\u003e\n \u003cp\u003eINR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e1.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.402061855670103%\"\u003e\n \u003cp\u003e1.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.371134020618557%\"\u003e\n \u003cp\u003e0.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e0.9-1.3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\"\u003e\n \u003cp\u003ePT (s)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e12.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.402061855670103%\"\u003e\n \u003cp\u003e12.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.371134020618557%\"\u003e\n \u003cp\u003e10.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e9.8-12.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\"\u003e\n \u003cp\u003eAPTT (s)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e25.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.402061855670103%\"\u003e\n \u003cp\u003e19.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.371134020618557%\"\u003e\n \u003cp\u003e17.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e22.7-31.8\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\"\u003e\n \u003cp\u003eD-Dimer (ng/mL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e1520.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.402061855670103%\"\u003e\n \u003cp\u003e1050.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.371134020618557%\"\u003e\n \u003cp\u003e700.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e0-1000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\"\u003e\n \u003cp\u003eANA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003eweakly positive\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.402061855670103%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.371134020618557%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003enegative\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\"\u003e\n \u003cp\u003eRF (IU/L)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e＜11.60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.402061855670103%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.371134020618557%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e0-15.9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\"\u003e\n \u003cp\u003eIL-6 (pg/mL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e74.98\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.402061855670103%\"\u003e\n \u003cp\u003e198.35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.371134020618557%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e0-5.4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\"\u003e\n \u003cp\u003eIL-1\u0026beta; (pg/mL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e15.38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.402061855670103%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.371134020618557%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e0-12.4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"100%\" colspan=\"6\"\u003e\n \u003cp\u003e\u003cem\u003eALP\u003c/em\u003e alkaline phosphatase, \u003cem\u003eALT\u003c/em\u003e alanine amino transaminase, \u003cem\u003eAPTT\u003c/em\u003e activated partial thromboplastin time,\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eANA\u003c/em\u003e antinuclear antibody, \u003cem\u003eAST\u003c/em\u003e aspartate aminotransferase,\u003cem\u003eCRP\u003c/em\u003e C-reactive protein, \u003cem\u003eESR\u003c/em\u003e erythrocyte sedimentation rate, \u003cem\u003eINR\u003c/em\u003e international normalized ratio, \u003cem\u003ePT\u003c/em\u003e prothrombin time, \u003cem\u003eRF\u003c/em\u003e rheumatoid factor, \u003cem\u003eWBC\u0026nbsp;\u003c/em\u003ewhite blood cell\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eUpon admission, the patient\u0026apos;s COVID-19 nucleic acid test and urine culture were both negative. Bone marrow aspiration indicated peripheral leukocytosis. Thereafter, aerobic and anaerobic blood cultures were carried out every time the temperature increased significantly (a total of five times), and the results were all negative. To determine the diagnosis and establish a treatment plan, a multidisciplinary team consisting of the orthopedic, infectious disease, rheumatism and immunology, hematology, respiratory, and pharmaceutical departments was formed. The preliminary suspicion was sepsis and septic arthritis with a knee joint infection, so the patient was treated with an empirical antibiotic (ceftriaxone) and symptomatic supportive treatment. Additional examinations, including tests of TORCH, EBV, CMV and a recheck COVID-19 nucleic acid, had negative results. On the third day of admission, the patient\u0026rsquo;s temperature spiked again, reaching 40 \u0026deg;C, and a punctate congestive rash was distributed symmetrically over the neck and pharyngalgia. The results of the chest CT scan were the same as the previous scan, and the sacroiliac joint CT scan showed no abnormalities. Color Doppler ultrasound of the knee joint revealed soft tissue edema and joint effusion. Based on these findings, the multidisciplinary team considered a high possibility of septic arthritis but could not rule out AOSD. The previous antibiotic was replaced with meropenem for a duration of six days, during which the patient\u0026apos;s temperature fluctuated between 36.1 \u0026deg;C and 40.0 \u0026deg;C, and there was no significant relief in symptoms. Subsequently, the patient was switched to moxifloxacin, cefotiam and linezolid, but his body temperature remained high. During this period, fungal D glucose and tuberculosis-infected T lymphocytes were both negative.\u003c/p\u003e\n\u003cp\u003eOn the 13th day of admission, the multidisciplinary team conducted a difficult case discussion. The orthopedics department believed that septic arthritis could be ruled out and considered a high possibility of AOSD. The Rheumatism and Immunology Department stated that AOSD should be considered an exclusion diagnosis and that septic arthritis could be ruled out, suggesting a diagnosis of SRIS and recommending symptomatic treatment while continuing to conduct further investigations to exclude infections, hematological disorders and tumors. Based on the discussion, additional examinations were conducted. The results of the Brucella agglutination test and PDD test were negative. Bone marrow aspiration indicated reactive bone marrow hyperplasia. NGS indicated parvovirus, but background contamination could not be ruled out. Fungal, viral, blood and urine cultures were all negative. The patient responded positively to diagnostic treatment with methylprednisolone, aspirin and tocilizumab. His symptoms improved significantly, with temperature control and rash regression. Based on the recent treatment effect and examination results, a second difficult case discussion was held on the 34th day of admission. According to the Yamaguchi criteria [13], the patient had four major features (spiking fever, arthralgia, rash, and leukocytosis) and two minor features (sore throat, negative ANA/RF). After excluding infectious diseases, hematological disorders and tumors, the patient was diagnosed with AOSD. After treatment for AOSD, the patient\u0026apos;s temperature returned to normal, and both the rash and joint symptoms disappeared. The CRP level decreased to normal (\u0026lt;10 mg/L), while the ESR level was slightly higher (21 mg/L). After communication with the patient and his family, the patient was discharged with knee joint mobility ranging from 0 to 85\u0026deg;. A brief diagram of the patient\u0026rsquo;s disease changes is shown in Figure 1.\u003c/p\u003e\n\u003cp\u003eAfter discharge, the patient continued to wear a left knee brace and continued to take prednisone 50\u0026thinsp;mg once a day. The symptoms were well controlled. The patient was readmitted and reexamined half a month later, and the results of the laboratory tests are shown in Table 1 (Reexamination). The patient was re-examined a month later, and X-ray of the knee showed postoperative changes in the combined ACL and PCL reconstruction with a good internal fixation position (Figure 2). MRI of the knee indicated postoperative changes in the combined ACL and PCL reconstruction with good internal fixation position and signal. A small amount of fluid had accumulated in the joint, and there was slight swelling of the surrounding soft tissues (Figure 3). During a 3-month follow-up, the patient\u0026apos;s knee joint mobility returned to normal, with no recurrence of symptoms.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eBywater first proposed AOSD in 1971 [17], but since that publication, the development of AOSD after arthroscopic combined ACL and PCL reconstruction has not been reported. We searched \u0026quot;Ligament reconstruction \u0026amp; AOSD\u0026quot;, \u0026quot;anterior/posterior cruciate ligament reconstruction \u0026amp; AOSD\u0026quot; and \u0026quot;ACL-R/PCL-R \u0026amp; AOSD\u0026quot; in several databases, such as PubMed, but found no relevant cases. To our knowledge, this is possibly the first case report of AOSD after arthroscopic combined ACL and PCL reconstruction. Based on this case and relevant literature, we summarized the differences in clinical symptoms between septic arthritis and AOSD (Table 2) [16][18][19][20].\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"100%\" colspan=\"3\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 2\u0026nbsp;\u003c/strong\u003eDifferences in the clinical features between septic arthritis and AOSD\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"23.46938775510204%\"\u003e\n \u003cp\u003e\u003cstrong\u003eClinical features\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"37.755102040816325%\"\u003e\n \u003cp\u003e\u003cstrong\u003eSeptic arthritis\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"38.775510204081634%\"\u003e\n \u003cp\u003e\u003cstrong\u003eAOSD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"23.46938775510204%\"\u003e\n \u003cp\u003eFever\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"37.755102040816325%\"\u003e\n \u003cp\u003eMost cases are mild and only 30%\u0026ndash;40% of individuals have a temperature \u0026gt;39℃\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"38.775510204081634%\"\u003e\n \u003cp\u003ePeak fever and the highest temperatures (\u0026gt; 39\u0026nbsp;℃) occurs at night\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"23.46938775510204%\"\u003e\n \u003cp\u003eArthralgia and arthritis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"37.755102040816325%\"\u003e\n \u003cp\u003eMost cases are monoarticular and only 10%-20% of individuals have a polyarticular disease\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"38.775510204081634%\"\u003e\n \u003cp\u003eMost cases are polyarthritis\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"23.46938775510204%\"\u003e\n \u003cp\u003eDermatologic manifestations\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"37.755102040816325%\"\u003e\n \u003cp\u003eErythema around the affected joint\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"38.775510204081634%\"\u003e\n \u003cp\u003eA macular or maculopapular evanescent salmon-pink skin rash appears together with the fever spikes\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"23.46938775510204%\"\u003e\n \u003cp\u003ePharyngalgia\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"37.755102040816325%\"\u003e\n \u003cp\u003eGenerally, not present, but can occur when accompanied by throat infections\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"38.775510204081634%\"\u003e\n \u003cp\u003eIt occurs before or during the first month of each disease flare\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"23.46938775510204%\"\u003e\n \u003cp\u003eOthers\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"37.755102040816325%\"\u003e\n \u003cp\u003eOccur rarely but shivering can occur\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"38.775510204081634%\"\u003e\n \u003cp\u003eIt is common and includes myalgia, enlargement of the lymph nodes, splenomegaly, hepatomegaly, pleurisy, pericarditis, weight loss, etc.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eLooking back at the entire diagnosis and treatment process, the multidisciplinary team took some \u0026quot;controversial\u0026quot; measures:\u003c/p\u003e\n\u003cp\u003e1. Multiple studies, such as the clinical guidelines published by EBJIS in 2022, have emphasized that joint fluid aspiration and culture are essential for the diagnosis of septic arthritis [6][16][21]. Why was joint fluid aspiration and culture not performed in this case?\u003c/p\u003e\n\u003cp\u003eThe blood cultures were repeatedly negative, indicating a lack of positive evidence for infection. The patient did not exhibit significant symptoms in the operated joint, and the floating patella test was negative. Additionally, postoperative puncture may lead to secondary infection. Through the search of relevant literature, we found a case where AOSD was misdiagnosed as a prosthetic joint infection (PJI) and another case where AOSD was misdiagnosed as septic arthritis. Both of the patients of these cases underwent joint fluid aspiration and culture, and the results suggested joint infection [22][23]. Based on the two cases, the decision was correct to some extent in not performing joint fluid aspiration and culture.\u003c/p\u003e\n\u003cp\u003e2. EBJIS suggests that arthroscopic debridement should be performed as soon as the suspicion of septic arthritis is raised in cases with acute symptoms or in the early postoperative setting, even if the microbiological results are still pending [6]. Additionally, multiple studies have indicated that arthroscopic debridement is highly effective in SA treatment, especially after ACL reconstruction [6][16][21]. So why was arthroscopic debridement not performed in this case?\u003c/p\u003e\n\u003cp\u003eWe observed that the patient had polyarticular pain, but the operated joint did not exhibit significant swelling or pain. Arthroscopic debridement is an invasive treatment that increases the risk of nosocomial infection and would incur additional costs of treatment to the patient. Therefore, instead of arthroscopic debridement, we treated the patient with powerful and empirical antibiotics.\u003c/p\u003e\n\u003cp\u003e3. The patient\u0026apos;s symptoms and examinations indicated inflammation on admission, and we considered the possibility of infection. Why was septic arthritis suspected instead of other related infections?\u003c/p\u003e\n\u003cp\u003eOn the one hand, EBJIS states that a high suspicion of septic arthritis should be kept in mind in any patient with a painful and/or inflamed joint with or without a fever. On the other hand, multiple studies have found that septic arthritis is more common in infections after ACL reconstruction. Furthermore, arthroscopic combined ACL and PCL reconstruction involves a longer surgical duration and greater surgical trauma than isolated ACL reconstruction or PCL reconstruction, which increases the risk of postoperative infection [6][24][25][26]. Therefore, septic arthritis is given priority consideration in this case.\u003c/p\u003e\n\u003cp\u003eFurthermore, there is controversy over the diagnostic criteria for septic arthritis because of the lack of high-quality evidence-based research, which also increases the difficulty of diagnosis in this case [16]. First, we considered septic arthritis as a strong possibility but could not exclude AOSD. Subsequent examinations, including five blood cultures performed during the periods of elevated body temperature, did not reveal evidence of infection. Empiric antibiotic treatment was ineffective. Septic arthritis was excluded at 13 days after admission and lasted for 13 days. Further examinations ruled out infection, blood disorders and tumors. In combination with effective diagnostic treatment, the diagnosis of AOSD was confirmed on the 34th day of admission, after a total of 31 days. Looking back at the entire diagnosis and treatment process, the multidisciplinary team presents the concerns and reflections:\u003c/p\u003e\n\u003cp\u003e1. Within the 13 days from suspicion to exclusion of septic arthritis, we performed five blood cultures (aerobic and anaerobic) during the periods of elevated body temperature, and all results were negative. Regarding the number of blood cultures, the guidelines by EBJIS in 2022 suggest that at least two sets of aerobic and anaerobic blood cultures should be performed, but they do not provide a specific upper limit [6]. However, the patient had taken antibiotics before admission, which necessitates an increased number of blood cultures to eliminate the impact of antibiotics. It is worth considering whether five blood cultures were excessive for the diagnosis? Could the number be reduced to 3-4? We should summarize our experience from this case and our clinical practice.\u003c/p\u003e\n\u003cp\u003e2. Referring to the two cases of AOSD, joint fluid aspiration and culture were performed, and PJI and septic arthritis were suspected according to the results. Arthroscopic debridement was performed several times in these two cases [22][23]. Therefore, can we consider that joint fluid aspiration and culture as well as arthroscopic debridement performed to exclude/diagnose septic arthritis when AOSD or SA is highly suspected have limited clinical value and are unnecessary? This requires collaborative efforts from clinical practitioners and researchers to answer the question.\u003c/p\u003e\n\u003cp\u003e3. On the 14th day of admission, the patient had been experiencing fever with a temperature higher than 38.3℃ on several occasions that lasted for at least 3 weeks and lacked a clear diagnosis after 1 week of hospital treatment. According to the criteria for FUO, the patient could then be diagnosed with FUO [5]. The common causes of FUO are infection, tumors and noninfectious inflammatory diseases. AOSD is the most common noninfectious inflammatory disease [5]. If diagnosed as FUO, AOSD can be considered and confirmed after excluding infection (multiple negative blood cultures, negative bacterial, fungal and viral tests) and tumor (ruled out by bone marrow aspiration and NGS). Comparing the 31 days it took to diagnose AOSD in this case, diagnosing AOSD based on the FUO criteria could significantly reduce the time needed for confirmation.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn conclusion, AOSD and septic arthritis share similar clinical symptoms. It is challenging to make a definitive diagnosis because the positive evidence is insufficient, which may prolong the diagnosis and treatment time, as seen in this case. In such situations, we believe that setting up a multidisciplinary team is beneficial for diagnosis and treatment. To shorten the diagnosis time and avoid unnecessary diagnosis and treatment, we should pay attention to subtle differences between symptoms and examinations and adopt empirical and diagnostic treatment measures.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eAOSD: adult-onset Still\u0026apos;s disease; ACL: anterior cruciate ligament; PCL: posterior cruciate ligament; FUO: fever of unknown origin; ESR: erythrocyte sedimentation rate; CRP: C-reactive protein; PJI: prosthetic joint infection\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors’ contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll listed authors substantially contributed to the following aspects of the manuscript: Z.S., Z.T., J.N., Q.S. and S.L. participated in diagnosing and treating the patient and in acquisition of data. Z.T. and J.N. collected the findings and drafted the manuscript. D.W., R.L. and D.W. prepared figures 1-3. Z.J. and J.J. prepared tables 1-2. Z.S. and J.N. revised the manuscript. All authors read and approved the final manuscript. Z.S. guarantees the integrity of this work.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWritten consent was obtained from the patient for publication of the patient’s details. The data supporting this case report are from previously reported studies and datasets, which have been cited. The processed data are available upon request from the corresponding author.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclarations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors have obtained the patient’s written informed consent for print and electronic publication of this case report.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no financial or other conflicts of interest in relation to this research and its publication.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003ePerlino CA. Postoperative fever. Med Clin North Am. 2001;85(5):1141-1149.\u003c/li\u003e\n\u003cli\u003ePatel RA, Gallagher JC. Drug fever. Pharmacotherapy. 2010;30(1):57-69.\u003c/li\u003e\n\u003cli\u003ePile JC. Evaluating postoperative fever: a focused approach. Cleve Clin J Med. 2006;73 Suppl 1:S62-S66.\u003c/li\u003e\n\u003cli\u003eWright WF, Auwaerter PG. Fever and Fever of Unknown Origin: Review, Recent Advances, and Lingering Dogma. Open Forum Infect Dis. 2020;7(5):ofaa132.\u003c/li\u003e\n\u003cli\u003eKaya A, Ergul N, Kaya SY, et al. The management and the diagnosis of fever of unknown origin. Expert Rev Anti Infect Ther. 2013;11(8):805-815.\u003c/li\u003e\n\u003cli\u003eRavn C, Neyt J, Benito N, et al. Guideline for management of septic arthritis in native joints (SANJO). J Bone Jt Infect. 2023;8(1):29-37.\u003c/li\u003e\n\u003cli\u003eSteele GM, Franco-Paredes C, Chastain DB. Noninfectious causes of fever in adults. Nurse Pract. 2018;43(4):38-44.\u003c/li\u003e\n\u003cli\u003eMahroum N, Mahagna H, Amital H. Diagnosis and classification of adult Still\u0026apos;s disease. J Autoimmun. 2014;48-49:34-37.\u003c/li\u003e\n\u003cli\u003eColafrancesco S, Priori R, Valesini G. Presentation and diagnosis of adult-onset Still\u0026apos;s disease: the implications of current and emerging markers in overcoming the diagnostic challenge. Expert Rev Clin Immunol. 2015;11(6):749-761.\u003c/li\u003e\n\u003cli\u003eRuscitti P, Giacomelli R. Pathogenesis of adult onset still\u0026apos;s disease: current understanding and new insights. Expert Rev Clin Immunol. 2018;14(11):965-976.\u003c/li\u003e\n\u003cli\u003eKadavath S, Efthimiou P. Adult-onset Still\u0026apos;s disease-pathogenesis, clinical manifestations, and new treatment options. Ann Med. 2015;47(1):6-14.\u003c/li\u003e\n\u003cli\u003eKong XD, Xu D, Zhang W, Zhao Y, Zeng X, Zhang F. Clinical features and prognosis in adult-onset Still\u0026apos;s disease: a study of 104 cases. Clin Rheumatol. 2010;29(9):1015-1019.\u003c/li\u003e\n\u003cli\u003eYamaguchi M, Ohta A, Tsunematsu T, et al. Preliminary criteria for classification of adult Still\u0026apos;s disease. J Rheumatol. 1992;19(3):424-430.\u003c/li\u003e\n\u003cli\u003eMasson C, Le Loet X, Liote F, et al. Comparative study of 6 types of criteria in adult Still\u0026apos;s disease. J Rheumatol. 1996;23(3):495-497.\u003c/li\u003e\n\u003cli\u003eQin A, Sun J, Gao C, Li C. Bibliometrics analysis on the research status and trends of adult-onset Still\u0026apos;s disease: 1921-2021. Front Immunol. 2022;13:950641.\u003c/li\u003e\n\u003cli\u003eGarc\u0026iacute;a-Arias M, Balsa A, Mola EM. Septic arthritis. Best Pract Res Clin Rheumatol. 2011;25(3):407-421.\u003c/li\u003e\n\u003cli\u003eBywaters EG. Still\u0026apos;s disease in the adult. Ann Rheum Dis. 1971;30(2):121-133.\u003c/li\u003e\n\u003cli\u003eShirtliff ME, Mader JT. Acute septic arthritis. Clin Microbiol Rev. 2002;15(4):527-544.\u003c/li\u003e\n\u003cli\u003eRoss JJ. Septic Arthritis of Native Joints. Infect Dis Clin North Am. 2017;31(2):203-218.\u003c/li\u003e\n\u003cli\u003eGerfaud-Valentin M, Jamilloux Y, Iwaz J, S\u0026egrave;ve P. Adult-onset Still\u0026apos;s disease. Autoimmun Rev. 2014;13(7):708-722.\u003c/li\u003e\n\u003cli\u003eColston J, Atkins B. Bone and joint infection. Clin Med (Lond). 2018;18(2):150-154.\u003c/li\u003e\n\u003cli\u003eJiao X, Li Z, An S, et al. An elderly female with adult-onset Still\u0026apos;s disease initially misdiagnosed as prosthetic joint infection after total knee arthroplasty: lessons in differential diagnosis and treatment. BMC Geriatr. 2020;20(1):512.\u003c/li\u003e\n\u003cli\u003eSong SJ, Bae DK, Noh JH, Seo GW, Nam DC. A Case of Adult Onset Still\u0026apos;s Disease Misdiagnosed as Septic Arthritis. Knee Surg Relat Res. 2011;23(3):171-176.\u003c/li\u003e\n\u003cli\u003eMoriarty P, Kayani B, Wallace C, Chang J, Plastow R, Haddad FS. Gentamicin pre-soaking of hamstring autografts decreases infection rates in anterior cruciate ligament reconstruction. Bone Jt Open. 2021;2(1):66-71.\u003c/li\u003e\n\u003cli\u003eErice A, Neira MI, Vargas-Prada S, Chiaraviglio A, Guti\u0026eacute;rrez-Guisado J, Rodr\u0026iacute;guez de Oya R. Septic arthritis following arthroscopic reconstruction of cruciate ligaments of the knee: retrospective case review. Artritis s\u0026eacute;ptica tras ligamentoplastia artrosc\u0026oacute;pica de la rodilla: an\u0026aacute;lisis retrospectivo de casos. Enferm Infecc Microbiol Clin (Engl Ed). 2018;36(6):336-341.\u003c/li\u003e\n\u003cli\u003eMayr HO, Zeiler C. Komplikationen nach Kreuzbandersatzplastiken [Complications after cruciate ligament reconstruction]. Orthopade. 2008;37(11):1080-1087.\u003c/li\u003e\n\u003c/ol\u003e"}],"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":"bmc-musculoskeletal-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmsd","sideBox":"Learn more about [BMC Musculoskeletal Disorders](http://bmcmusculoskeletdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://author-welcome.nature.com/12891","title":"BMC Musculoskeletal Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Recurrent fever, septic arthritis, AOSD, ACL reconstruction, PCL reconstruction, combined ACL and PCL reconstruction, case report","lastPublishedDoi":"10.21203/rs.3.rs-3753410/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3753410/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAOSD and septic arthritis share similar clinical symptoms, including recurrent fever, affected joint pain and limited mobility. This similarity poses diagnostic challenges when encountering a case of arthroscopic combined ACL and PCL reconstruction, where clinical evidence is insufficient to establish a definitive diagnosis between the two diseases. In this case, through a series of examinations and diagnostic treatment, the final diagnosis was AOSD.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCase presentation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA 41-year-old male who underwent arthroscopic combined ACL and PCL reconstruction half a month prior was admitted to our hospital with a weeklong history of recurrent fever and polyarticular pain. The positive physical signs and test results were insufficient to establish a definitive diagnosis between AOSD and septic arthritis. Therefore, a multidisciplinary team consisting of the orthopedic, infectious disease, rheumatism and immunology, hematology, respiratory, and pharmaceutical departments was formed to determine the diagnosis and establish a treatment plan. During the treatment period, the patient developed a typical rash and pharyngalgia. Multiple highly effective antibiotics were ineffective during the patient’s treatment, but the symptoms improved significantly after the administration of methylprednisolone, aspirin, and tocilizumab. The diagnosis of AOSD was ultimately determined according to the Yamaguchi criteria. After treatment, the patient's condition remained stable, and he was discharged from the hospital. During the subsequent two-month follow-up, the patient's condition remained stable without recurrence of symptoms, and the knee joint function returned to normal.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDiscussion and conclusion\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe could not retrieve any relevant case reports of AOSD after arthroscopic combined ACL and PCL reconstruction in several databases. Therefore, we believe this may be the first reported case. In conjunction with the relevant literature, we summarize the differences in clinical symptoms between septic arthritis and AOSD. Reviewing the patient's hospitalization process, we discuss the \"controversial\" diagnostic and therapeutic measures taken by the multidisciplinary team, along with any doubts and considerations. In conclusion, in cases where it is difficult to establish a definitive diagnosis between AOSD and septic arthritis, a collaborative approach involving multiple departments can be used for diagnosis and treatment, thereby shortening the diagnostic time and avoiding unnecessary diagnosis and treatment.\u003c/p\u003e","manuscriptTitle":"Septic arthritis or adult-onset Still's disease (AOSD) - Analyzing the causes of recurrent fever after arthroscopic combined anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) reconstruction: a case report and literature review","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-01-03 01:25:17","doi":"10.21203/rs.3.rs-3753410/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-08-29T08:13:38+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-04-13T13:38:02+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"52f244e2-c419-4f06-87fd-c3b64f80e19e","date":"2024-04-11T11:10:02+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-03-08T21:29:50+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"173d7811-6120-42a3-9d4b-4f20193df9dd","date":"2024-02-28T11:17:12+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-02-28T05:39:40+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2023-12-31T04:06:07+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2023-12-27T14:29:56+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2023-12-27T14:28:34+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Musculoskeletal Disorders","date":"2023-12-14T12:02:39+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-musculoskeletal-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmsd","sideBox":"Learn more about [BMC Musculoskeletal Disorders](http://bmcmusculoskeletdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://author-welcome.nature.com/12891","title":"BMC Musculoskeletal Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"2991ab91-39ac-4148-b74e-7424123ee26a","owner":[],"postedDate":"January 3rd, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-10-13T16:04:30+00:00","versionOfRecord":{"articleIdentity":"rs-3753410","link":"https://doi.org/10.1186/s12891-025-08938-9","journal":{"identity":"bmc-musculoskeletal-disorders","isVorOnly":false,"title":"BMC Musculoskeletal Disorders"},"publishedOn":"2025-10-07 15:57:56","publishedOnDateReadable":"October 7th, 2025"},"versionCreatedAt":"2024-01-03 01:25:17","video":"","vorDoi":"10.1186/s12891-025-08938-9","vorDoiUrl":"https://doi.org/10.1186/s12891-025-08938-9","workflowStages":[]},"version":"v1","identity":"rs-3753410","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3753410","identity":"rs-3753410","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}