Role of computed tomography in diagnosis and clarifying the classification of patello-femoral malalignment

ABSTRACT

The role of the conventiomal axial radiographs of the patellofemoral joint in assessing patients suffering from peripatellar pain is limited. Therefore Computed Tomography [CT] was used to evaluate 40 patients with persistent patello-femoral pain, and ten asymptomatic volunteers as a control group. Mid patellar transaxial cuts were taken for all of them at 0, 15, 30 and 45 dgress of knee flexion. The congruence angle, the patellar tilt angle and the femoral trochlear angle were obtained from each image. According to the values of these three angles, patients were classified using Merchant's classification of patello-femoral malalignment into Type I malalignment [patellar subluxation only - 12 cases]. Type II malalignment [patellar subluxation and tilt - 10 cases]. Type III malalignment [patellar tilt only - 13 cases]. The CT has a significant advantage in diagnosing and identifying the different patterns of patello-femoral malalignment particularly when surgical realignment is planned