Patellar instability, when kneecaps dislocate.

Meniscus tears of the knee | Arana Hills Physiotherapy

5 take aways about Patellar instability

  • Patellar instability and recurrent instability is not uncommon in adolescents.
  • Usually occurs due to combination of poor stabilising factors at the knee and sport or trauma.
  • Usually responds well to exercise and physiotherapy to strengthen the lower leg.
  • If surgery is required outcomes are very good.
  • still need to get strong after surgery , the jobs not quite finished yet.


Imagine you’re playing soccer or basketball, and suddenly your knee feels weird. It’s like your leg doesn’t want to hold you up anymore. That’s what it’s like for kids with recurrent patellar instability. Their knees give out unexpectedly, making it hard to play sports or even walk comfortably.

What is patellar instability ?

Patellar dislocation. Normal position of kneecap and Patella displaced. Anatomy of the Knee

Patellar instability might sound like a mouthful, but it’s a condition where the kneecap (patella) keeps popping out of place, causing pain and trouble moving.  In the majority of cases it pops to the outside  the knee joint.

This often ruptures the medial patella femoral ligament ,(MPF Lig), potentially leading to longterm recurrent episodes.

In some cases this. may only happen once or twice and cause very little long term issues.

In other cases it can be become a recurrent problem where it gets easier and easier for the kneecap to pop out of place, for example just moving your leg when sitting in a maths class, ( true story).


But why does patellar instability happen ?

Well, the patella sits in a groove at the end of the thigh bone, and it’s supposed to slide up and down smoothly when you move your leg. Sometimes the individuals anatomy doesn’t offer enough stability or  things go wrong playing sports or other activities.  Its often a combination of both these factors.

Risk factors include

  • The groove or trochlea is too shallow.
  • The muscles around the knee are too weak to stabilise the kneecap.
  • lack of MPF ligament support due to past dislocations.
  • The attachment of the thigh muscles into the tibia may not be developed enough.
  • Direct blow to the knee cap playing sport.
  • Twisting the knee awkwardly from landing in netball etc.

. These factors  can make the patella slip out of place, causing pain and instability and it is usually a combination that is at play.

What can you do about Patellar instability ?

So, what can be done to help people with this problem?

Physiotherapy and Patellar instability

Physiotherapy can be really helpful in managing this condition. Usually this takes the form of exercise based rehabilitation to strengthen the muscles around the hip and knee  improving how the patella slides and glides , strapping techniques for pain and even the use of specific braces so participation in sport and exercise can continue.

Patellar instability surgery.

when kneecaps pop out

Surgery is rarely the first choice of treatment, especially for those  whose bodies are still growing. It’s important to weigh the risks and benefits carefully and make sure the treatment plan is tailored to your  needs.

If physiotherapy isn’t enough and there are still episodes of instability then surgery might be needed.

One surgical option is to tighten the ligaments around the knee to hold the patella in place better. Another is to reshape the groove where the patella sits, making it deeper so the patella is less likely to slip out.

If surgery for recurrent patellar instability is required the good news is that it tends to be very successful. Those who have it done feel their knees were more stable, and they had less pain. But it’s important to follow up with physiotherapy after surgery to make sure the knee gets strong and flexible again.

Patellar instability where to next ?

In conclusion, recurrent patellar instability can be a challenging condition for kids to deal with, but there are treatments available to help. Physiotherapy and surgery are two options that can improve knee stability and reduce pain. By working with a team of healthcare professionals, people with recurrent patellar instability can get back to what they love and  stay active and healthy.


If you need help with patellar instability you book in here to see one of our team Book a Physio online