Patellofemoral Instability & Osteotomy

Knee Conditions

Patellofemoral Instability & Osteotomy 

Patellofemoral instability affects the kneecap, and it can happen as a result of injury, or it can be chronic. We offer world-class treatment for patellofemoral instability and osteotomy at Sports Med London.  


Patellofemoral Instability Explained 

Tendons keep your kneecap (patella) attached to your thighbone (femur) and shinbone (tibia). The kneecap fits into a groove (the trochlear groove) at the end of the thighbone, which helps it slide up and down when you bend and straighten your knee. Patellofemoral instability happens if the kneecap moves out of the groove, which can happen partially or completely. 

When the kneecap slides partially out of the groove, it’s known as a subluxation. This usually happens with chronic patellofemoral instability. When the kneecap slides completely out of the groove, it’s known as a patellar dislocation, and it’s usually a result of a knee injury. 

Injuries that cause patellar dislocation and patellofemoral instability can be contact or non-contact. A knee-to-knee collision while playing football is an example of a contact injury. A non-contact injury may happen when the knee twists when extended and the foot rotates outwards. 

Patellofemoral instability symptoms usually include: 

  • Pain 
  • Swelling 
  • Difficulty walking 
  • Stiffness 
  • A locking or catching sensation in the knee 
  • The knee gives way 
  • A noticeable physical deformity appears in the knee 
Patellofemoral Instability Page

Diagnosing And Treating Patellofemoral Instability 

If your kneecap does not return to its normal position on its own, you should seek urgent medical attention. Our specialist performs a physical examination and may x-ray or perform an MRI scan on your knee when diagnosing patellofemoral instability. 

Non-surgical treatment – Our specialist may recommend that you rest and that you wear a brace and use crutches. You will be given physiotherapy exercises to perform after a period of rest. The exercises will help strengthen the muscles that keep the kneecap in the groove. 

Surgical treatment – In serious cases of patellofemoral instability, cartilage may come loose and lodge in the knee. Those bits of cartilage need to be removed. If ligaments such as the medial patellofemoral ligament are torn, they may need to be reconstructed. If the dislocations are recurring, your kneecap may need to be realigned. 


Tibial Tubercle Realignment Osteotomy 

If your recurring kneecap dislocations are due to a physical deformity, our specialist may perform a scan to measure the bump in the front of the shinbone (tibial tubercle) and trochlea groove to discover the extent of the deformity. If it needs to be raised, the specialist will recommend a tibial tubercle osteotomy. 

The procedure moves the bump on the tibial tubercle and the attached kneecap tendon toward the midline and attaches it with screws. You should be able to go home the following day, and you will need to wear a knee brace for a while. You can remove the brace about six weeks after the procedure. 


Technical Information:

What is a Tibial Tubercle Realignment Osteotomy?

If a patient suffers with patella (kneecap) instability such as recurrent dislocations or a feeling of the patella almost slipping out (subluxations) then an MRI or CT scan may be performed to measure the amount of deformity or TT-TG measurement (Tibial Tubercle – trochlea groove). If this is raised the tibial tubercle (bump in the front of the shin bone) may be transferred along with the attached patella tendon (kneecap tendon) towards the midline, it is then fixed with screws. This is called a tibial tubercle osteotomy and may be performed along with other procedures to treat patellar instability, patellofemoral pain, and osteoarthritis. It removes the load off the painful portions of the kneecap and reduces the pain. Surgical treatment is indicated when physical therapy and other nonsurgical methods have failed. Most patients are able to go home the next day, with the knee immobilised in a brace. Patients gradually  begin to bear their body weight after around two weeks and by six weeks most patients are able to bear their own weight without using a brace.