Luxação congênita da patela associada a hipoplasia: relato de caso

Abstract

Congenital patellar luxation (CPL) is a rare condition characterized by lateral subluxation or permanent luxation of the patella, resulting from abnormal development and deformity of the extensor mechanism, often associated with musculoskeletal anomalies such as genu valgum, bone torsions, and trochlear dysplasia. We report the case of a 13-year-old boy, with no history of trauma, who since childhood presented with knee pain and instability, difficulty walking, frequent falls, and limitation in daily activities. Physical examination revealed accentuated genu valgum, external tibial rotation, and bilateral flexion contracture. Imaging studies showed bilateral patellar dysplasia and hypoplasia, lateralization of the patellar tendon, femoral retroversion, external tibial torsion, and hypoplasia of the lateral femoral condyle, confirmed by magnetic resonance imaging and computed tomography. The diagnosis was bilateral congenital patellar luxation associated with multiple bone and muscular alterations. The patient underwent corrective surgery on the left knee, including lateral retinacular release, patellar tendon medialization, quadriceps V-Y lengthening, and medial patellofemoral ligament reconstruction. The postoperative period evolved satisfactorily, with gain in range of motion (0°–110°), preservation of the extensor mechanism, and improvement in patellar excursion, although with slight residual subluxation. This case illustrates the rarity of the association between CPL and multiple bone deformities, emphasizing the importance of early diagnosis and individualized surgical treatment for a better functional prognosis.