There is growing clinical experience that tells us a medial patella luxation may be influenced by the length and/or strength of the quadriceps mechanism. We test for quadriceps influence on an MPL using the following evaluation sequence:

I. Evaluate the patella grade in standing using standard orthopedic testing

II. In lateral, reduce the patella, then place the quadriceps on stretch.

• If passive tension through the quadriceps causes the patella to luxate, then lengthening the quadriceps with stretches may improve the luxation.
• If stretch does not cause the patella to luxate, the influence of the quadriceps on the patella may be minimal.

III. In lateral, luxate the patella, then place the quadriceps on stretch.

• If passive tension through the quadriceps causes the patella to reduce, then strengthening the quadriceps to increase active tension with exercises may improve the luxation (rebounds, perturbations, then eventually squats - but only if the patella remains reduced).