In addition to the non-muscular causes mentioned above, muscle weakness of the thigh muscles can also be responsible for altered joint function between the kneecap and thigh. A reduced ability to stabilize the knee joint in the various phases of walking (lack of muscular guidance) reduces the shock absorption in the knee joint.
Local muscle system at the knee joint
Similar to the spine, the knee joint also has a local and a global muscle system. The only local stabilizer at the knee is the vastus medialis obliquus (VMO) muscle, the inner part of the quadriceps muscle (thigh extensor). Its function is to actively pull the kneecap inwards/upwards and to compensate for the outward traction present in patellofemoral pain syndrome.
Physiotherapeutic examination of the local muscle system
Selective weakness of the internal muscle parts (vastus medialis) cannot be accurately investigated and proven as the cause of anterior knee pain, nor can it be trained in complete isolation without the involvement of the other quadriceps. Nevertheless, at the beginning of the training of the thigh muscles, it is advisable to put special emphasis on the training of the perception and the tension of the inner thigh muscles, i.e. the training goes from local to global. It is advantageous to use a biofeedback device (an electronic device that makes the tension and relaxation of a muscle visible), so that the patient can better perceive the conscious nervous control and tension of the VMO.
Physiotherapeutic technique: perception training and education of the VMO
Number of repetitions:3 series of 10 repetitions and 10 sec. Holding period/daily over a period of 3 months, after which the exercise frequency can be reduced Use of force:only approx. 20-30% of muscle power, as the local muscle system has little movement function, but mainly stabilisation and endurance function. Starting position Seated on the floor with long legs, weight cuff or sandbag over the foot, knee roll under the affected leg, the affected leg is turned outwards, view to the knee joint Exercise execution The back of the knee is pressed onto the knee roll, the foot stretches diagonally upwards towards the inner corner of the ceiling.
