Symptoms
The malposition of the kneecap or the excessive lateral sliding of the patella in the gliding groove is in most cases only noticed when cartilage damage is already present. Occasionally, however, an unstable feeling can occur in the area of the patella, especially during sporting activities such as running, cycling and swimming, as if it were to “jump out” at any moment. If the joint cartilage of the patella is damaged or completely destroyed by the incorrect loading, localized knee pain occurs, which is usually felt during movement in the knee joint in the anterior knee area, directly behind the patella or its immediate surroundings. These pains are provoked in particular by walking downhill and down stairs as well as when getting up from a sitting position (so-called “theater knee”). The painful cartilage damage can be accompanied by a general irritation of the knee joint, which manifests itself in the form of knee swelling and effusion.
Diagnosis
In many cases, patellal lateralization can be diagnosed by physical examination. When lying down, lateralization can be detected by observing the patella during passive and active movements in the knee joint (transition from the extended to the flexed knee). In the same way, clinical tests can also provide information about collateral ligament instability, muscle shortening or imbalance, deviations in the ability of the patella to move out of its sliding bearing, as well as existing knob damage (e.g. Zohlen signs).
In some cases, compression pain may even be noticeable when pressure is applied to the patella. Further imaging can facilitate or support the diagnosis, and various procedures can be used. The means of choice is a simple x-ray of the knee joint, in which the centering of the patella can be accurately assessed, as well as x-rays in 30°, 60° and 90° functional positions.In addition, sonography allows for a targeted examination for pathologies or changes in the tendon of the quadriceps muscle, while magnetic resonance imaging provides a detailed assessment of ligament and cartilage structures.
- Patella with lateralization
- Knee-cap sliding bearing (femoro-patellar joint)
- Thigh (femoral condyle)
