Patellar dislocation causes the kneecap (patella) to "jump out" of the knee joint. It then no longer sits in the middle, but is shifted laterally. Those affected have severe pain and can not move the lower leg. Often, the dislocated kneecap slides by itself back to the starting position. Nevertheless, a patellar dislocation should always be examined by a doctor and treated if necessary. But before that is the first aid. How it looks, read here!

ICD codes for this disease: ICD codes are internationally valid medical diagnosis codes. They are found e.g. in medical reports or on incapacity certificates. M22S83ArtikelübersichtPatellaluxation

  • Quick Overview
  • What to do?
  • risks
  • When to the doctor?
  • Examinations at the doctor
  • Treatment by the doctor
  • Prevent patellar luxation

Quick Overview

  • What to do with a patellar luxation? Soothe those affected, restrain leg, possibly cool, bring to the doctor or call ambulance
  • Patellaluxation risks: Violation of surrounding structures (such as ligaments, bones); painful bruising in the joint; Inability to move the lower leg
  • When to the doctor? In principle, any patellar luxation should be evaluated and treated by a physician.


  • Never try to repair a cracked kneecap yourself. It would probably worsen the injury.
  • Never place ice cubes or coolpacks directly on the skin to cool the knee, but always with at least one layer of fabric in between. Otherwise threaten local frostbite.
  • If the articular cartilage is damaged during the patellar dislocation, this can lead to premature joint wear (arthrosis).
  • Even with optimal treatment, renewed patellar luxations are not excluded. This is especially true if the operation was late.
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Patellar Luxation: What to do?

A patellar dislocation is very painful - and often a shock to the person affected: If your own patella suddenly protrudes sideways out of your leg as a knobby, it can be very frightening. It is all the more important that you, as a first responder, act courageously when someone has knocked out the kneecap. What you should do is this:

  • Reassure the person concerned and explain to him everything you do. That creates trust.
  • Remove tight-fitting clothing in the wrist area (trousers). In the case of a dislocation, the area around the joint usually swells considerably.
  • Relieve the knee, that is: put the affected person down, if he does not already sit. Often people with a dislocation instinctively take a restraint in which the pain subsides somewhat. Do not force the affected person to another position.
  • Very important: Do not move your knee! Otherwise you could damage the surrounding ligaments, muscles and nerves!
  • If possible, cool the swollen area (for example with Coolpack). This can relieve bruising, swelling and pain.
  • Bring the victim to the doctor as soon as possible or call an ambulance. This also applies if the kneecap has slipped back into the joint by itself.
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Patellar luxation: risks

If the kneecap has jumped out, usually forms a bruise in the joint quickly. This increases the pressure within the joint, which increases the pain.

Occasionally, in the course of a patellar dislocation, smaller pieces of bone may break off the patella or femur. The bone fragments then float loose in the joint. The straps around the kneecap can tear.

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Patellar Luxation: When to the doctor?

If the kneecap has jumped out, it should be retracted as soon as possible by a doctor. Even if she has regained herself by herself, a doctor is needed: he can check whether surrounding structures have been damaged in the dislocation.