Nem todo paciente com dor anterior no joelho tem síndrome dolorosa patelofemoral: relato de um caso de sinovite vilonodular pigmentada localizada na região anterior do joelho / Not every patient with anterior knee pain has patellofemoral pain syndrome: report of a case of pigmented villonodular synovitis located in the anterior region of the knee

Abstract

Introduction: Patellofemoral pain syndrome is a term used to describe several conditions associated with anterior knee pain. This syndrome is very common in medical practice and is the most common cause of knee pain in adolescents and young adults. However, anterior knee pain may be associated with other differential diagnoses.

Objective: Report a case of a patient with a 5-year history of anterior knee pain. It progressed with slow but progressive worsening of symptoms, until a diagnosis of pigmented villonodular synovitis located in the anterior region of the knee was made.

Case Report: Male patient, 22 years old, with a 5-year history of pain in the left knee. He mentioned that he had previously undergone medical evaluation three times, where he was diagnosed and treated for pain of patellofemoral origin, without ever having performed an MRI. He reports that the functional limitation was progressively increasing, along with the increase in volume around the knee. He was instructed to perform an MRI of the left knee, which showed an expansive, intra-articular nodular formation, located in the space between Hoffa's fat and the anterior margin of the tibial epiphysis. Arthrotomy was performed with a medial parapatellar approach for resection of the lesion via an open approach. The resected lesion was brownish in color, firm in consistency, measuring 8.0 x 5.0 x 4.0 cm and had histopathological features of pigmented villonodular synovitis. One year after the operation he is asymptomatic, with no clinical signs suggestive of recurrence of the lesion, and with good knee function.

Conclusion: This case emphasizes the importance of evaluation with imaging tests in patients with anterior knee pain. Although patellofemoral pain syndrome is the most common cause of knee pain in young patients, other differential diagnoses should be kept in mind, such as localized pigmented villonodular synovitis, whose early diagnosis and treatment allow good functional results, with a low recurrence rate.