Dr. Mohamed Khairy El-Mesery, Department of Orthopedic Surgery, Faculty of Medicine, Tanta University, Tanta, 31527, El-Gharbia Governorate, Egypt E-mail: mohamed.khairy@med.tanta.edu.eg
Abstract
Background: Gout is a common metabolic arthritis resulting from monosodium urate (MSU) crystal deposition. While the knee is frequently affected, involvement of deep periarticular structures such as the popliteus tendon is uncommon and may mimic aggressive soft tissue lesions.
Case Report: We present a case of a 64-year-old male who presented with acute lateral knee pain and stiffness. Magnetic resonance imaging (MRI) demonstrated a soft tissue mass infiltrating the popliteus tendon with adjacent cortical erosion of the lateral femoral condyle, initially raising concern for an aggressive pathology. The diagnosis of gout was confirmed by the presence of negatively birefringent MSU crystals in the synovial fluid.
Results: The patient was managed conservatively with non-steroidal anti-inflammatory drugs, colchicine, and long-term urate-lowering therapy, resulting in significant clinical improvement.
Conclusion: This case highlights the importance of considering gout in the differential diagnosis of unusual periarticular soft tissue lesions of the knee to avoid unnecessary surgical intervention and ensure appropriate medical management.
Keywords: Gout, Popliteus tendon, Knee, Tophi, MRI in gout.
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