Diagnosis of popliteus tenosynovitis by ultrasound

Pain around the lateral aspect of the knee is a common occurrence, and precise diagnosis may be difficult on clinical examination alone. Routine imaging modalities include plain radiographs, Technitium 99m bone scanning, computed tomography, and magnetic resonance imaging. Ultrasound has been little used in the investigation of knee pathology. The authors present a case of recurrent tenosynovitis of the popliteus tendon in which the diagnosis was finally (after 22 years) made using ultrasound. The authors suspect that this condition may be more common than previously believed and that it may be misdiagnosed as meniscal pathology. The authors recommend the use of ultrasound imaging in swellings around the lateral aspect of the knee, avoiding unnecessary, expensive or invasive investigations.