A Case Report of Acute on Chronic Osteomyelitis of Distal Femur Managed with Sequestrectomy, Saucerization, and Stimulan Placement

Abstract

Introduction: Osteomyelitis is a bone infection that may present acutely or chronically. Acute on chronic osteomyelitis refers to the exacerbation of symptoms in a patient with an underlying chronic infection. This case report presents a 19-year-old male diagnosed with acute on chronic osteomyelitis of the right distal femur, with no history of a discharging sinus for the past 6 months. Osteomyelitis is a bone infection commonly caused by bacteria, with Staphylococcus aureus being the most frequent pathogen. Chronic osteomyelitis can occasionally experience acute flare-ups, referred to as "acute on chronic osteomyelitis". This report discusses the presentation, diagnosis, and management of a 19-year-old male with acute on chronic osteomyelitis of the right distal femur.

Case report: A 19-year-old male presented with increasing pain, swelling, and warmth over his right distal femur for 2 weeks. The pain was deep, throbbing, worsened by weight-bearing, and unrelieved by analgesics. He had similar complaints 6 months ago but had no symptoms such as fever or discharging sinus since then. There was no history of trauma or injury. On physical examination, the patient exhibited localized tenderness, mild swelling, broadening, irregularity, and warmth over the distal femur. Movements of the knee were restricted, and pain was elicited with direct palpation of the femur. No open wounds or discharging sinuses were present, and neurological and vascular examinations were unremarkable.Radiographs of the right femur showed sclerosis and focal cortical thickening, indicating chronic osteomyelitis. Magnetic resonance imaging confirmed the presence of marrow edema, cortical irregularity, and periosteal reaction, supporting the diagnosis of chronic osteomyelitis with an acute exacerbation. Blood tests revealed an elevated white blood cell count and C-reactive protein, indicating an acute inflammatory response. The patient received intravenous antibiotics preoperatively, followed by sequestrectomy, saucerization, and stimulan placement over the site where necrotic bone was removed to promote healing. Over 6 weeks, the patient experienced significant improvement in symptoms. Repeat imaging showed resolution of the acute infection, and long-term oral antibiotics were prescribed to manage chronic osteomyelitis.This case emphasizes the challenges of diagnosing and treating acute on chronic osteomyelitis, particularly when typical signs like a discharging sinus are absent. Early diagnosis and prompt, targeted antibiotic therapy is crucial for preventing complications such as deformities, limb loss, or sepsis.

Conclusion: Effective management of acute on chronic osteomyelitis requires comprehensive evaluation through clinical history, imaging, and laboratory testing. Early intervention with surgical debridement and appropriate antibiotic therapy is vital to achieving favorable outcomes and preventing long-term complications.

Keywords: Acute on chronic osteomyelitis; distal femur; stimulan.

Figure 1

Pre-operative X-ray.

Figure 2

Computed tomography (CT) cuts showing sequestrum, abscess and cortical break along with CT report.

Figure 3

Computed tomography cuts showing sequestrum, abscess and cortical break.

Figure 4

Magnetic resonance imaging sagittal and axial T1 and T2 images showing edema and sequestrum.

Figure 5

Magnetic resonance imaging report.

Figure 6

Intra operative pics showing pus and sequestrum.

Figure 7

Stimulan preparation pics and C Arm pics.

Figure 8

Post-operative X-ray.

Figure 9

Follow up post-operative X-ray.

Figure 10

Histopathological report.