Patella Instability

When the knee is out straight at rest, there is no tension on the knee cap (patella) and it can easily be moved side to side if you push on it. In some people the knee cap moves excessively and they get an intense feeling that the knee will come out of joint if the knee cap is pushed sideways.


The knee cap can slip out of place and dislocate. This can either happen with little force or as a result of a definite injury. Two outcomes are seen

  • the knee settles down and heals with no further problem
  • the patella¬†continues to come out of joint causing notable problems

Physiotherapy is a very important part of treating patella dislocation and instability. The patella relies on the shape of the bones of the knee and the soft tissues around the knee to keep it in place. The muscles can get weak which makes the problem worse and they need to made as strong as possible to help keep the patella in place.

If you have a patella that keeps coming out or feels like it is giving way then you will need to have investigations to look at the shape of the knee. X-rays and MRI scans are usually needed to do this. There are a number of underlying causes that contribute to the patella being unstable and these will be assessed and if physiotherapy has not resolved the problem surgery is likely to be needed to keep the patella in the right place. Exactly what is needed depends on your particular anatomy and age. Mr Uglow will discuss the reasons why your knee cap is unstable and what needs to be done to help it stay in place.

Treatment is very important because if the patella continues to dislocate, damage can occur to the cartilage on the back of the knee cap and this will ultimately lead to arthritis if not resolved.