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Knee Patella Dislocation
Patella instability and dislocation is a condition where the patella (knee cap) is not guided centrally in the knee, and falls off to the side. This causes pain and apprehension in using the knee, stopping you from having an active life. Dr David Agolley is a knee surgeon on the Gold Coast who performs procedures to address patella instability and dislocation.
Recurrent patella instability and anterior knee pain are common symptoms that affect the young to middle aged. The patella is normally guided by pull from ligaments and muscle, in to a V-shaped groove in the femur (end of the thigh bone). Patella instability may occur in patients who have previously had a normal knee, and sustained a traumatic injury dislocating the patella and injuring the structures that guide the patella in to the V-shaped groove. Alternatively, patella instability may occur in patients that have a tendency for the condition because of how the ligaments and bones of the lower limb have developed around the knee. Patients may also have increased laxity of their ligaments.
What are the symptoms?
Pain is typically felt in the front of the knee that increases with activity. There may be cracking and crunching behind the patella. The knee gives way and confidence is lost in the performance of the knee. The patella may be felt to slip off to the side. Patients are typically in their teens to middle age.
What investigations will be required?
Plain x-rays that are taken while you are weight bearing on the knee, are essential to the work-up, and additional x-rays are taken from the hips to the ankles to assess the weight bearing alignment. A CT and/or MRI scan may be required to support the diagnosis, and to assess the cartilage in other parts of the knee joint.
When should I have surgery?
Non-surgical treatments such as low impact activity, keeping in a healthy weight range, changing your activity or occupation, bracing, taping and taking pain medication can be helpful. Specific training of the stabilising muscles of the patella, may also be helpful.
When the above non-surgical options are not working, Dr Agolley will discuss the surgical options with you. Surgical treatment options include realigning the line of pull on the patella to keep it on-track, releasing tight tissue that pulls the patella off-track, and reconstructing the major stabilising ligament of the patella, the medial patellofemoral ligament (MPFL). Not all of the procedures are required in all patients, and Dr Agolley will make an assessment as to what is appropriate for you.
The procedure and post-operative recovery
The specific type of procedures required during your knee patella stabilisation procedure will be discussed with you prior to the procedure. In general for most patients:
- Your anaesthetist will perform general anaesthetic
- 2 small keyhole incisions are made over your knee
- The knee joint is examined and the specific procedures required are undertaken
- A small incision is made to harvest hamstring graft for a MPFL reconstruction
- A longer incision over the tibial tubercle is made if a patellar tendon realignment procedure is required
- The necessary corrections are made
- The surgical site is thoroughly cleaned and closed
The post-operative recovery consists of:
- The majority of patients that have a patella realignment procedure are discharged on post-operative day 2-3
- Most patients are able to take full weight with crutches and a knee brace
- Return to sedentary work, school from 4 days
- Heavy labour and running sports from 3 months
There may be numbness around the surgical sites. This usually resolves quickly, but may persist for several weeks. Major nerve or blood vessel injury is extremely uncommon. Blood clots in the legs and lungs are also extremely uncommon and usually do not require prophylactic medical therapy. Infection is very uncommon. Recurrent instability is uncommon unless there is a repeat contact injury to the patella.
For more information, see the American Academy or Orthopaedic Surgeon website.