Patella Dislocation

Patella Dislocation

Article by John Miller

Patella Dislocation

What is a Patella Dislocation?

In a healthy knee, your patella position is within a groove at the bottom of the femur (thigh bone).

patella dislocation

Patella dislocation refers to when the kneecap completely displaces out of its normal alignment. The most common direction for a patella to dislocate is outwardly (laterally). When this happens, the muscles and ligaments on the inside of the knee become overstretched and damaged.

Patella subluxation refers to when the kneecap partially displaces out of its normal position.

What Causes Patella Dislocation?

Dislocation of the patella is primarily caused by a traumatic incident (often twisting or a direct blow) to the knee.

However, there are a variety of factors which can predispose you to dislocate your patella. These include:

  • History of patella dislocation or subluxation
  • Patellofemoral joint hyperlaxity or mal-tracking
  • Shallow femoral groove
  • Weak inner quadriceps muscles
  • Tight lateral retinaculum, ITB, hip flexors, vastus lateralis and biceps femoris muscles.

Patella dislocation is most common in athletic teenagers. Pivoting your femur (thigh bone) internally on a planted foot while bending your knee if the most common dislocating movement. (Greiwe et al. 2010)

What are the Symptoms of Patella Dislocation?

patella dislocation

  • Patients with a dislocated patella will report that “my kneecap slipped out of place”. It may self-relocate. Otherwise, a health professional may need to relocate your patella.
  • Visible translation of the kneecap (often to the outside of the knee).
  • Pain, particularly with weight-bearing activities and active straightening of the knee.
  • Swelling and a wobbly kneecap.
  • Tenderness around your kneecap.
  • Feeling of instability or giving way during weight-bearing.
  • A weakness of the quadriceps muscles.

How is Patella Dislocation Diagnosed?

On examination, your physiotherapist or doctor will look for signs of patella dislocation and associated muscle and ligament damage. An X-ray, ultrasound or MRI may also be used to confirm the diagnosis and identify damaged structures surrounding the kneecap or to the patella joint surface, which is quite common.

For specific advice regarding your patella dislocation, please consult your trusted knee physiotherapist or doctor.

Patella Dislocation Treatment

Patella Relocation

The initial treatment would involve relocating the patella, which a health professional should only do if it did not occur spontaneously.


Most patients with patella dislocation start to feel better within a few hours of the relocation. However, your rehabilitation will take at least 8 to 12 weeks to rehabilitate and decrease your chance of recurrent dislocation successfully.

Your physiotherapy treatment will aim to:

  • Reduce pain and inflammation.
  • Protect the patella via taping or a patella alignment brace. e.g. patella brace
  • Normalise joint range of motion.
  • Strengthen your knee: esp quadriceps (esp VMO).
  • Strengthen your lower limb: calves, hip and pelvis muscles.
  • Improve patellofemoral (knee cap) alignment.
  • Normalise your muscle and retinaculum lengths.
  • Improve your proprioception, agility and balance.
  • Improve your knee motion technique and function, e.g. walking, running, squatting, hopping and landing.
  • Minimise your chance of re-dislocation.


The majority of patients with patellar dislocation will respond well to conservative treatment. Nikku et al. 2005 compared post-surgical repair and exercise treated patients at seven years follow up with no significant functional difference.

In some cases, however, surgery may be required to repair significant bone (e.g. patella joint surface) or ligament damage caused by the dislocation. An MRI will determine whether chondral (joint surface) damage has occurred.

Post-Surgical Rehabilitation

Post-operative knee rehabilitation is one of the most important, yet too often neglected, aspects of post-dislocation surgery. It is crucial to rebuilding your muscles and function to avoid future dislocations.

The most successful and quickest outcomes result from the guidance and supervision of an experienced Sports Physiotherapist.

Your rehabilitation following knee surgery focuses on restoring full knee motion, strength, power and endurance. You’ll also require balance, proprioception and agility retraining individualised towards your specific sporting or functional needs.

Your sports physiotherapist is an expert in this field. We suggest you contact them for the best advice in your circumstances.

How to Prevent Recurrent Patella Dislocations?

Following an initial patella dislocation, the risk of recurrence is almost 50% if no (or insufficient) rehabilitation is received. The risk of re-injury increases substantially with each repeat patella dislocation.

For this reason, it is vital to discuss your injury with your physiotherapist. They will advise you on the best treatment plan and ensure that you receive adequate rehabilitation to decrease your risk of ongoing knee problems significantly.

Return to Sport with Patella Dislocations?

Athletes often have particular difficulty once they have sustained a patella dislocation. There will be increased residual instability around the kneecap and residual weakness and balance as a result of the injury. Your physiotherapist will design an individualised exercise program to help you return to your previous level of function.

Patellofemoral Brace

An effective patellofemoral brace can be useful as an alternative to kneecap taping.

ITB Roller

Excellent for stretching your tight thigh structures: ITB, quadriceps and hamstrings.