TOTBİD Dergisi

TOTBİD Dergisi

2012, Cilt 11, Sayı, 4     (Sayfalar: 274-280)

Patellofemoral biomechanics

İlhami Kuru 1, Bahtiyar Haberal 1, Çağrı Avcı 1

1 Başkent Üniversitesi Tıp Fakültesi Ortopedi ve Travmatoloji Anabilim Dalı, Ankara

DOI: 10.5606/totbid.dergisi.2012.37
Görüntüleme: 369
İndirme : 784

Patellofemoral joint is one of the parts of knee stabilization, changing the muscle strength direction and expanding the force arm of quadriceps in the mechanism of knee extension. The reason for continuous change of the knee rotation center in the movement of knee from full flexion to full extension, is the rotation and slipping of femur on tibia while flexion. The angle between the proximal and distal tensile forces on patella is (measured between spina iliaca anterior superior (SIAS)-midpatella and midpatellatuberositas tibia) Q angle. Normally, this angle is 5-8 degrees. Knee flexion angle has an effect on patellofemoral joint reaction force (PFJRF). The patella and trochlea starts to contact after 20 degrees flexion and the joint reaction force on contact area is caused by the resultant force of quadriceps tendon and patellar tendon. The pressure of PFJRF caused by the increase of tensile forces of the body weight may be resolved by increased strength on the contact area. A decrease on the contact area, an increase in the stress forces, and knee flexion increase the pressure. The differences on the contact area and PFJRF may cause a pressure change and this will come up with pain and other advanced conditions in clinical practice. Increased body weight, vertical distance between the center of body weight and the center of knee rotation, and increased knee flexion may increase the pressure, while a decrease on the contact area and patellar tendon moment arm increases the pressure. The basic problem in a patient with anterior knee pain may be another problem causing an increase in patellofemoral pressure. Patellofemoral joint reaction force and patellofemoral contact pressure may vary according to the activity performed.

Anahtar Kelimeler : Biomechanics; patellofemoral joint reaction force; patellofemoral joint; Q angle