This operation is for patients who have recurring kneecap (patella) dislocations or instability symptoms where the kneecap tracks poorly in its groove. It is only undertaken after initial non-operative treatment (physiotherapy) has failed. It establishes a stronger connection between the inner border of the kneecap and the inner aspect of the thighbone (femur). It is sometimes undertaken in combination with a “tibial tubercle osteotomy” which repositions the kneecap in the groove by moving the attachment of the tendon below the knee where it reaches the shin bone.
MPFL reconstruction is normally carried out under a general anaesthetic with additional local anaesthetic used at the end of the procedure. The operation starts with a careful keyhole examination of the knee joint (arthroscopy) to directly visualize the tracking of the kneecap as the knee bends, and to check for (and treat) any cartilage damage that may have occurred. A section of tendon is then taken from one of the hamstrings in the back of the thigh, then this is passed through carefully-placed small drill holes in the inner border of the kneecap, then threaded underneath the muscle layer down to the bump on the inside of the knee (medial epicondyle) where it is buried into a blind-ending tunnel and fixed, (normally with a buried screw) after careful repeat checking of the kneecap tracking. An alternative method involves using an artificial graft for this purpose. The surgical cuts are then carefully sutured, covered with dressings and a compression bandage.
Factors to Consider
What are the risks of surgery?
Complications are rare following MPFL reconstruction but can occur.
• Infection – the risks of infection are low based on only small incisions being used and the surgery being relatively short, however a superficial infection can occur that can be treated successfully with oral antibiotics. Very rarely a deeper infection in the joint may require a further operation.
- Deep Vein Thrombosis (DVT) – is rare following this type of surgery but does sometimes occur (>1%). During surgery precautions are taken to minimise the risk by using pumps on your calves and you are encouraged to move shortly after surgery has been completed. If you have an increased risk of developing a DVT your surgeon may opt to treat you with medication to thin the blood for a short time after your surgery to reduce the risk.
- Nerve damage – as part of the surgery small nerves within the skin are cut which can result in permanent loss of sensation in a patch of skin around the knee.
- Stiffness – the surgery is designed to stabilize your kneecap, with the aim being to make it feel the same as your un-injured side. Rarely patients develop more scar tissue (arthrofibrosis) which can result in a greater level of stiffness than desired. This is a higher risk if surgery is undertaken too soon after the initial injury.
- Prominent screw – the fixation screw on the inner aspect of the knee can occasionally back out, becoming prominent and uncomfortable. If this happens then a small operation can be done to remove this (as the ligament will have healed in place within the first few months).
After Surgery
Rehabilitation
The aim of surgery is to stabilise the kneecap tracking and prevent further dislocation episodes, allowing you to return to normal function, including sports. The early post-operative recovery is focussed on pain control, regaining movement, and then restoring the strength of the quadriceps muscles on the front of the thigh. All of this will need to be guided by an experienced physiotherapist and will be tailored to your individual needs and will progress at the rate that matches your healing and progress. During the first few weeks it is beneficial to use a simple compression bandage and regular ice to help reduce the swelling.