Claire Dubois*
Department: Department of Musculoskeletal Medicine, Université Médicale de Lyon, France
Received: 01 September, 2025, Manuscript No. orthopedics-26-189241; Editor Assigned: 03 September, 2025, Pre QC No. orthopedics-26-189241; Reviewed: 17 September, 2025, QC No. Q-26-189241; Revised: 22 September, 2025, Manuscript No. orthopedics-26-189241; Published: 29 September, 2025, DOI: 10.4172/Orthopedics.8.3.004.
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Septic arthritis is a rapidly progressive joint infection that constitutes a medical emergency due to its potential to cause irreversible joint destruction and systemic complications. Prompt diagnosis and management are essential to preserve joint function and prevent mortality. We report a case of a 54-yearold immunocompetent male presenting with acute monoarticular knee pain, swelling, and fever following a minor skin abrasion. Initial symptoms were misinterpreted as gout, leading to delayed antibiotic therapy. Synovial fluid analysis confirmed Staphylococcus aureus infection. The patient was managed with urgent arthroscopic irrigation and intravenous antibiotics, resulting in significant clinical improvement. This case highlights the importance of early recognition, appropriate diagnostic evaluation, and aggressive management of septic arthritis even in immunocompetent individuals.
Septic arthritis is an infectious disease characterized by invasion of a joint space by microorganisms, most commonly bacteria. It leads to rapid destruction of articular cartilage due to inflammatory mediators and enzymatic degradation. The incidence is estimated at 4–10 cases per 100,000 person-years, with higher rates in older adults and individuals with comorbidities such as diabetes, rheumatoid arthritis, or immunosuppression.
The knee is the most commonly affected joint, followed by the hip, shoulder, and ankle. Staphylococcus aureus remains the predominant causative organism worldwide. Delayed diagnosis significantly increases morbidity, including irreversible joint dysfunction and systemic sepsis.
Case Presentation
A 54-year-old Caucasian male presented to the emergency department with a 3-day history of progressively worsening pain and swelling in the right knee. The patient reported fever (up to 38.9°C), chills, and inability to bear weight on the affected limb. He recalled a minor abrasion on the same knee one week prior while gardening.
Medical History
Physical Examination
Initial clinical suspicion included gout or traumatic effusion; however, the presence of fever and elevated inflammatory markers raised concern for septic arthritis.
Laboratory Investigations
Culture: Staphylococcus aureus (methicillin-sensitive)
Imaging Studies
Plain radiography of the knee showed soft tissue swelling without bony erosion. Ultrasound confirmed a large joint effusion. MRI was not required initially due to definitive synovial findings.
Diagnosis
Based on clinical presentation and laboratory findings, a diagnosis of acute septic arthritis of the right knee caused by methicillin-sensitive Staphylococcus aureus (MSSA) was established.
Treatment and Management
The patient was immediately started on empiric intravenous antibiotics:
Ceftriaxone 2 g daily
Vancomycin was initially added until culture results confirmed MSSA
Surgical Intervention
Urgent arthroscopic irrigation and debridement of the knee joint were performed within 12 hours of diagnosis. Approximately 1.2 liters of purulent fluid was evacuated, and extensive synovial lavage was completed.
Postoperative Care
Outcome and Follow-Up
The patient showed rapid clinical improvement:
At 6-week follow-up:
DISCUSSION
Septic arthritis is a time-sensitive orthopedic emergency requiring rapid intervention. Delay in treatment beyond 24–48 hours can result in irreversible cartilage damage. The knee joint is particularly vulnerable due to its large synovial surface and propensity for hematogenous spread.
Pathogenesis
The infection typically occurs via:
Once bacteria invade the synovial membrane, an intense inflammatory response leads to leukocyte infiltration, cytokine release, and proteolytic enzyme activation, causing cartilage degradation.
Diagnostic Challenges
Early septic arthritis can mimic conditions such as:
Synovial fluid analysis remains the gold standard for diagnosis.
Treatment Principles
Management includes:
Prognosis
Outcome depends on:
Early intervention, as in this case, significantly improves prognosis.
CONCLUSION
Septic arthritis should always be considered in patients presenting with acute monoarthritis accompanied by systemic symptoms. Even in immunocompetent individuals, minor skin injuries can serve as portals of entry for pathogens such as Staphylococcus aureus. Early diagnosis, urgent surgical drainage, and appropriate antibiotic therapy are essential to prevent permanent joint damage and ensure favorable outcomes.
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