Analysis of patellar stabilizers muscles and patellar kinematics in anterior knee pain subjects

Patella stabilizer muscle response and patellar kinematics were evaluated in 19 women with anterior knee pain (AKP) and 20 healthy women during maximum voluntary isometric contraction (MVIC) with the knee positioned at 15°, 30° and 45° flexion during open (OKC) and closed (CKC) kinetic chain exercises. Patellar kinematics was evaluated through patellar tilt and displacement, and the electrical activity of patellar stabilizers through the root mean square normalized during MVIC and OKC with the knee at 90° flexion. Data revealed that the vastus medialis oblique muscle (VMO) was more active in the control group compared to the AKP group during OKC exercises with the knee at 45° flexion. However, no difference in the patellar kinematics was observed between these groups; nevertheless, the correlation between these parameters also showed, with the knee at 45° flexion, that lateral patellar tilt increase was associated with a reduction in the activity of lateral patellar stabilizers in the control group and with an increase in the VMO activity in the AKP group. In conclusion, electrical activity is an important factor in evaluating AKP and in AKP treatment evolution.