An abnormal lateral position of the tibial tuberosity causes distal malalignment of the extensor mechanism of the knee and can lead to lateral tracking of the patella causing anterior knee pain or objective patellar instability, characterised by recurrent dislocation. Computer tomography is used for a precise pre-operative assessment of the tibial tubercle-trochlear groove distance. A distance ...

Tibial tubercle osteotomy is a common treatment option for a number of patellofemoral joint disorders including chondromalacia, "anterior knee pain" syndromes, patellofemoral arthritis, and patellar instability. Tibial tubercle osteotomy can modify tracking and/or patellofemoral contact forces to effect the unloading of chondral defects of the patella or trochlea, correct multiplanar suboptimal...

Patellar luxation is the result of progressive structural abnormalities in the soft and/or skeletal tissues of the dog’s pelvic limbs. There is an alteration of the patella-trochlear groove interaction with negative effects on the stifle stability and extensor mechanism integrity, on the trochlear articular cartilage nutrition and the adequate trochlear depth and length development and maintena...

Background: There are a number of different factors that are thought to play a role in patellar instability, including injuries to the medial patellofemoral ligament (MPFL), trochlear dysplasia, patella alta, and an increased tibial tuberosity-trochlear groove (TT-TG) distance. Objective: To use MRI to assess injury patterns to the MPFL, trochlear dysplasia, patellar height, and TT-TG distance ...

BACKGROUND Patellar stabilizing braces are used to alleviate pain and prevent subluxation/dislocation by having biomechanical effects in terms of improved patellar tracking. The purpose of this study is to analyze the effects of the dynamic patellar realignment brace, Patella Pro (Otto Bock GmbH, Duderstadt, Germany), on disease determinants in subjects with patellofemoral instability using upr...

Patellar instability is a common occurrence in the skeletally immature patient population, and multiple treatment options exist. Nonoperative treatment is appropriate for patients without osteochondral injuries and includes bracing and physical therapy focusing on strengthening of the gluteals as well as the vastus medialis obliquus muscles. Risk factors for recurrent instability include patell...

To the Editor: I read with interest the paper by Sillanpàà et al. [1] entitled ‘‘Ligament Reconstruction Versus Distal Realignment for Patellar Dislocation’’ published in the June 2008 issue. I congratulate the authors on their study, for the longterm followup and for the comparative study with distal realignment. However, I ask for clarification of two issues. First, what are the indications f...

Axial radiographs were obtained under valgus and external rotation stress at 45 degrees of knee flexion with and without contraction of the quadriceps muscle in order to assess the dynamics of patellar subluxation or dislocation. The radiography was performed on 82 knees in 61 patients with patellofemoral instability, and on 44 normal knees. The lateral patellofemoral angle and the congruence a...

Biomechanical studies have shown that external rotation of the femoral TKA component improves patellar tracking but does not restore it to physiologic values. We hypothesized that this could be due to differences in the trochlear groove geometry of TKA and normal knees. This was investigated via a virtual TKA procedure that mounted femoral components on to 3-dimensional models of healthy femurs...

Patellar instabilities are the most common knee pathologies during growth. Congenital dislocations are rare. Extensive, early soft tissue releases relocate the extensor mechanism and may enable normal development of the femoro-patellar anatomy.Conservative management is the preferred strategy after a 'first-time' traumatic dislocation. In cases with concomitant anatomical predisposing factors s...