Patella Stabilisation
What is patella stabilisation surgery?
A patella stabilisation is an operation to prevent your kneecap dislocating from the groove it runs in at the front of the knee.
Who needs Patella stabilisation surgery?
The most common reason for patella stabilisation surgery is for the treatment of recurrent patella instability. This is when the kneecap has dislocated or subluxed (partially dislocated) more than 2-3 times, and you are no longer able to trust your knee for sporting or even day-to-day activities.
Some people require surgery after only one episode of dislocation. This is indicated when during the dislocation, a fragment of cartilage or bone is broken of the surface of the kneecap or the trochlea (groove) at the front of your knee. An MRI may be recommended to look for this. If this fragment is small it can move around the inside of your knee and cause locking or jamming of the knee joint. This can usually be removed with keyhole surgery. If the fragment is very large then repair of the fragment may be recommended. This requires open surgery to repair the damaged cartilage. The torn ligaments are repaired or reconstructed at the same time to prevent further damage from occurring.
Follow this link to learn more about patella instability.
What type of surgery do I need?
The exact type of operation you need will be decided after full assessment of your knee with examination, x-rays and potentially an MRI scan. You may require reconstruction of damaged ligaments (MPFL reconstruction) or realignment of the kneecap to improve tracing in the trochlea groove (tibial tubercle osteotomy), or a combination of both procedures.
What is MPFL reconstruction?
The medial patello-femoral ligament (MPFL) is a ligament on the inside of your knee that helps hold the kneecap in its groove as your knee moves. This ligament is torn when your kneecap dislocates. It is usually not possible to find the two ends of the ligament and stitch them together. Instead, the ligament is reconstructed by using one of the small hamstring tendons from the inside of your knee.
You will need a general anaesthetic. Three small (approximately 3cm) incisions are made on the inside of your knee. One is used to take the hamstring graft. The second is used to attach the new MPFL to your kneecap with two small bone anchors. The final incision is used to attach the new ligament to your femur (thighbone) with a screw. An arthroscopy (keyhole surgery) will also be performed to make sure the kneecap moves smoothly down the centre of its groove, and that the new ligament is not too loose or too tight. The incisions are closed with dissolving stitches and waterproof dressings are applied.
What is a tibial tuberosity osteotomy?
The tibial tuberosity is the knob of bone at the front of your knee, where your patella tendon attaches to your tibia (leg bone). If this sits too far off to the side compared to the groove in the front of your knee, the kneecap will have a tendancy to dislocate. In this case, the best way to stop your kneecap from dislocating is to move this tendon attachment into a better position in the centre of your leg.
You will require a general anaesthetic for this surgery. A small 5-8cm long incision is made just beside the tibial tuberosity. The bone is cut with a saw and moved into a better position. An arthroscopy (keyhole surgery) will then be performed to make sure the kneecap moves smoothly down the centre of its groove. Once the best position is achieved the bone is fixed with 2-3 screws. The incisions are closed with dissolving stitches and waterproof dressings are applied.
What is the recovery after Patella stabilisation surgery?
Patella stabilisation surgery is performed under a general anaesthetic. When you are asleep your anaesthetist may perform a nerve block. This is an injection which numbs some of the nerves around your knee and helps minimise pain after your operation. Most people will stay in hospital overnight and go home the next day after surgery. You will be able to walk with the aid of crutches and put weight on your leg. A knee splint may be provided to use for the first 1-2 weeks after surgery. You will be allowed to bend and straighten your knee. Before you leave hospital a physiotherapist will see you and make sure you know how to use crutches; they will also teach you some simple knee exercises to perform at home.
In the first six weeks after surgery the main goals are to reduce swelling and regain knee range of motion. From six weeks onwards rehabilitation is focused on strengthening your quadriceps muscles and improving balance and co-ordination. If a tibial tubercle osteotomy was performed then x-rays are taken at six weeks to check for healing. After 3-4 months, rehabilitation can focus on returning to full sporting activities.
HOW successful is surgery?
Surgery is generally very successful at preventing further dislocations. After surgery there is a 90 - 95% chance that your kneecap will not dislocate again.
What are the risks of surgery?
There are risks with any surgery. Problems after patella stabilisation are uncommon but can happen. The main risks include:
Bleeding - This is usually minimal.
Infection - The risk of infection after patella surgery is low. A superficial skin infection can be treated with antibiotics. A deep infection is very rare, but could necessitate further surgery.
Nerve injury - Due to the way the small skin nerves cross the knee joint, it is common to have a numb patch of skin around the surgical scar. This becomes less noticeable with time. Damage to the major nerves at the back of the knee is extremely unlikely.
Blood clots - Blood clots in the leg (DVT) can occur after any lower limb surgery. Clots which travel to the lungs (PE) can be potentially dangerous, but are very uncommon. You may be given blood thinning injections and stockings to wear after surgery to minimise your risk of blood clots. Please inform us if you have a known history of clots.
Fracture - Small bone anchors are used in the kneecap to secure the new ligament. If you fall heavily onto your knee early after surgery there is a small risk of fracture.
Re-injury - The repaired ligament takes time to heal. If you return to heavy physical activity or sport too early after surgery there is a risk that you can damage the repair.
Pain - The primary goal of surgery is to prevent your kneecap from dislocating. If there is already damage to the cartilage behind the kneecap from your previous dislocations, this may cause pain even after successful surgery. Often kneeling is not comfortable.
Stiffness - Patella stabilisation surgery requires tightening of the tissues on the inside of your knee. If you do not follow the rehabilitation advice after surgery you can develop scar tissue in the knee and experience stiffness in the knee joint.
When can I Drive after patella stabilisation surgery?
Driving should only be considered once you are safe to respond rapidly in an emergency situation. This will depend on your specific circumstances and progress. In general, after surgery to the left knee you should be able to drive an automatic car after 1-2 weeks. After surgery to your right knee or for a manual transmission car, driving is usually possible after 4-6 weeks. You should not drive if you are taking morphine-based pain relief or if you are still wearing a knee splint.
When can I return to work?
Your ability to return to work will depend on a number of different factors. Mr Gormack will be able to provide you with individualised advice after discussion about your specific work requirements. As a rough guide, office-based work is generally possible after 1-2 weeks. Returning to moderate work that involves a lot of standing and walking may take 6-8 weeks. It may take three months or more to return to a very physically demanding job.
When can I return to sport?
No sporting activities should be planned during the first six weeks after surgery. Once the initial swelling has settled at around two weeks post-surgery, you will be able to use a stationary exercise bike set at low resistance. Swimming and gym-based exercises can start after six weeks, and resistance can be slowly increased on your exercise bike. Jogging can be started after three months, and returning to full sport will normally take 4-6 months.