Superficial prepatellar and infrapatellar bursitis: a pictorial essay

Josue Solis-Ugalde, Department of Medical Imaging, Hospital del Trauma; Department of Medical Imaging, MedCare Center. San Jose, Costa Rica;
Bruno Solis-Ugalde, Radiology Department, Memorial Sloan Kettering Cancer Center, New York, NY, USA;
Ronald Ocampo-Chacon, Department of Medical Imaging, Hospital del Trauma, San Jose, Costa Rica;

Because bursae play an essential role in mobility, their pathological entity –bursitis– requires specialized medical care. Superficial prepatellar bursitis and superficial infrapatellar bursitis are common causes of anterior knee inflammation and pain. This pictorial essay provides a detailed description of imaging findings and broadens the spectrum of conditions affecting the superficial prepatellar and superficial infrapatellar bursae. Ultrasound (US) is a first-line diagnostic tool because of its high sensitivity, wide availability, low cost, and ability to guide interventional diagnostic and therapeutic procedures. Magnetic resonance imaging (MRI) complements US in complex cases, allowing detailed evaluation of bursal contents and adjacent structures and excluding intra-articular abnormalities. Traumatic superficial prepatellar and infrapatellar bursitis are classified as aseptic, septic, or hemorrhagic; each has specific clinical and imaging characteristics. The differential diagnosis of superficial prepatellar and superficial infrapatellar bursitis of the knee includes soft tissue collections, hematomas, scar-related lesions, patellar tendon pathology, bone lesions, and, less frequently, tumors. Superficial prepatellar and superficial infrapatellar bursitis can develop as postoperative complications of anterior knee procedures, especially those involving the patella or the patellar tendon. The cause and severity determine treatment. Most cases respond well to conservative management, including PRICE therapy (protection, rest, ice, compression, and elevation) and non-steroidal anti-inflammatory drugs. Accurate imaging assessment of superficial prepatellar and superficial infrapatellar bursitis is essential to ensure appropriate management.

Keywords: Superficial prepatellar bursitis. Superficial infrapatellar bursitis. Knee bursae. Ultrasound. Magnetic resonance imaging. Computed tomography.