Patellar Instability

The patella or the kneecap is located in the frontal part of the knee and communicates with the trochlear groove of the femur (thigh bone).  The patella slides up and down the trochlear groove to facilitate bending of the knee.

The patella connects to the quadriceps tendon from above and the patellar tendon from below and the patellar tendon connects to the tibia (shin bone).  The patella acts as a pulley for the quadriceps tendon facilitating effective knee flexion.   The patella can become loose and slip out of the trochlear groove causing partial or complete dislocation.  This condition is known as patellar instability.  Pain rising from the patella or patellofemoral joint is termed as anterior knee pain.


The knee commonly gets injured due to trauma during contact sports and become unstable.  Knee injuries are often complex in that it can affect several structures and it is vital to assess the knee to pinpoint the extent of the damage.  Radiographic investigation such as X-ray is done to visualise the bony framework and ultrasound or MRI to visualise the cartilage, ligaments, menisci, etc.  Rest and physiotherapy is the sufficient treatment for dislocation of the patella only.  If there are frequent dislocations or other structures have been damaged or there is chronic pain, surgery may be needed.  Radiographic imaging will reveal the true extent of the damage to the knee and can require surgical repair.

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Development Instability

One of the main reasons for patellar dislocation is change in shape and size of the patella and the trochlear groove.  If the trochlear groove becomes shallow or incompatible with the shape of the patella, the patella can tend to become partially or fully dislocated.

The patella can slip out of its normal position to one side either because of surrounding tissues being too tight or the quadriceps tendon being very near to the side of the patella.  This condition can also result in instability.

Treatment for Patellar Instability

Physiotherapy is sometimes sufficient to relocate the patella if it has slipped out of place. If physiotherapy is not sufficient and the knee is still painful and feels unstable, then surgery can be an option for treatment.  Surgery is done to relieve the tension by releasing the tissues which will allow the patella to relocate in its normal position.

In case of frequent dislocations due to abnormal anatomy of the bones, surgical intervention to the patella or femur may be needed.  Surgery is done to alter the shape and resurface the joint.

Your Consultant will explain to you the most appropriate plan of management suitable for you.

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Contact Us Today

If you want to obtain more information on patellar instability or if you want to book an appointment, please do not hesitate to contact us.  Our team of professional surgeons and nurses are dedicated to answer any queries you may have and will book for you an appointment with a Consultant Knee Surgeon.

You can contact us on 98450-54810 or email us at [email protected]