Kneecap stabilisation

What is it?

Kneecap stabilisation, or patellofemoral reconstruction, is a combination of surgical procedures. Which procedures are used depends on the  patient’s particular symptoms and the underlying cause of the unstable kneecap. Surgery is usually offered if non-operative measures, such as physiotherapy, have not been successful. Recurrent kneecap dislocations that are painful and may be affecting your quality of life will require surgery, enabling you to return to the activities you enjoy. 

Options available:

1. Medial patellofemoral ligament (MPFL) reconstruction:
   This involves keyhole surgery to reconstruct the ligament that runs from the kneecap to the thigh bone. This ligament acts as a rein, and if deficient, because of former trauma or a soft tissue disorder, a new graft can be put in place.  This graft is normally a single hamstring tendon harvested from the same leg, but occasionally  donor tissue or an artificial ligament can be used.
2. Bony realignment surgery:
   If your kneecap is either in a higher than normal or too lateral a position, a bony realignment procedure may necessary. This involves moving the attachment of the tendon at the front of your knee, which changes the forces exerted on your kneecap to prevent dislocation. The precise change in position is calculated using MRI or CT scans of the joint, which will be done before surgery. This procedure is often offered in combination with medial patellofemoral ligament reconstruction (see option 1).
3. Trochleoplasty:
   A significant number of more severe cases of kneecap instability are caused by abnormalities in the groove into which  the kneecap runs, meaning it is too flat or  domed. This leads to a very significantly unstable kneecap, and often multiple and frequent dislocations. Trochleoplasty involves creating a new groove in the knee bone,  underneath the cartilage, which is then laid back down into position and fixed with special dissolvable tapes and anchors. As the cartilage bed heals to the new knee groove underneath, the kneecap is able to track more comfortably and securely.

Why would I need a kneecap stabilisation procedure?

Kneecap stabilisation surgery is normally offered when non-operative measures have failed, and recurring knee dislocations are significantly impacting a patient’s quality of life. Having an unstable kneecap may be due to previous trauma or an anatomical abnormality that has been present since birth.

What happens after surgery?

Recovery following surgery depends on the combination of operations you have had. In some cases, you are able to leave hospital the same or following day, depending on how you feel after the  anaesthetic. Following a trochleoplasty, which is a larger operation, you will normally require a day or two in hospital having painkillers  through an epidural or intravenously, and intensive physiotherapy. On occasion you may be required to wear a knee brace after surgery, to restrict the range of movement and support the knee as it heals. Sometimes crutches are required to allow you to walk more comfortably.

Recovery milestones

Weeks 1 to 2: Following discharge from hospital we recommend you take adequate analgesia and regularly use ice on your knee to reduce the pain and swelling, and allow you to exercise to regain range of movement and strength in your leg. Depending on the procedure you have had, we may recommend a brace, to restrict the bend in your knee and  allow the graft to heal. If you have had a trochleoplasty, we normally recommend, as this helps the cartilage bed to  heal more efficiently.

Weeks 2 to 6: Your physiotherapist will encourage you to work on activating and strengthening your muscles, and improving your range of movement. At approximately six weeks, you will have your second check-up, to ensure your knee is healing as we would like.

Weeks 6 to 12: At some point during this time, you can start to manage without the brace or crutches and get back to fairly normal activities. Walking should be more comfortable and feel as though it is getting back to normal.

Months 3 to 6: As the strength in your leg returns and the coordination of your muscles improves, you will be able to return to running and sports as appropriate.

N.B. These timescales are based on average recovery following surgery. Your surgeon will discuss with you  what the likely recovery milestones will be for your particular combination of surgeries.

Frequently asked questions:

1) Do I need kneecap stabilisation surgery?

If you are experiencing frequent and regular knee dislocation, and physiotherapy has not been effective, we would recommend kneecap stabilisation surgery.

2) Which procedure would I need?

Your surgeon will take a full history and physical exam, and appropriate imaging will be obtained, so that we can get a clear idea of what is the cause of your kneecap instability, and from there recommend the best course of treatment.

3) How long before I can drive?

This will depend on which leg has undergone the operation,  the type of car you drive, and the surgery you have had. Most patients will require six weeks off driving.

4) When can I get back to playing sports?

You can normally return to taking part in to sport between 3 and 6 months after surgery. 

5) Will my kneecap ever dislocate again?

The aim of the surgery is to reduce hugely the chance of your kneecap dislocating again. Successful surgery will normally reduce pain and significantly improve your trust in the stability of your knee. While it is much more unlikely you will dislocate your knee following surgery, it is not impossible, particularly if you sustain another injury to that area.