Knee Osteotomy (Realignment)
Knee Osteotomy (Realignment)
What is the aim of this surgery? When arthritis affects only one side of the knee (the inside or the outside part of the joint) then an Osteotomy can be used to make a subtle change in the alignment of the leg. This takes the pressure off the painful arthritic area and transfers loading to the healthy side of the knee. The aim is to alleviate pain and prolong the life of your knee before the need to consider knee resurfacing (replacement) surgery – typically 10 to 15 years.
Who might benefit from this procedure? This surgery is typically recommended when non-operative measures such as analgesia (if tolerated), weight reduction and physiotherapy, have failed to provide satisfactory relief from the painful symptoms from arthritis. I recommend this type of surgery in younger, more active patients in whom resurfacing of the knee joint would have an increased risk of wear and, as a result, poorer survival of the implants.
Will I need to stay in hospital overnight? Yes. You will normally stay in hospital for one night. The surgery is typically performed under general anaesthetic with a supplementary nerve block (see other information regarding what to expect before surgery).
What does the procedure involve? Before any surgery takes place I will carefully plan the realignment Osteotomy using powerful computer software for utmost precision. A full keyhole (arthroscopic) assessment of your knee joint will first be carried out to confirm that the “normal” side of your knee is in good enough condition to take the added load. Once confirmed a 10cm skin incision is made on the front/inner side of your knee just below the knee joint. A precise xray-guided cut is then made in the tibia bone as shown in Image 1. This cut isn’t all the way through the bone – it leaves a very small hinge point that will then allow a gap to be carefully opened (Image 2). Hence this is called an opening wedge osteotomy.
What are the chances of an improvement in my symptoms: Knee osteotomy has shown excellent clinical results and improvement in pain scores. Survival analysis data has shown that over 90% of patients are still significantly better at up to 10 years following surgery and up to 60% at 15 years.
What can I expect after surgery? – Once the local anaesthetic has worn off you will need tablet painkillers as the operative site will be sore, though this does settle within a few weeks. The plate is strong enough to withstand your full bodyweight immediately so you will be encouraged to mobilise early with the onsite specialist physiotherapy team. Once you are safe and confident with your mobility the team will discharge you home – typically the day after surgery. You will need to take blood thinning tablets (Aspirin commonly) or a daily injection for 2 weeks after surgery whilst less mobile and on crutches. Ongoing physiotherapy after surgery is essential in order to restore a good range of motion and ultimately to help you build muscle bulk for strength and control. You can only drive once you are no longer reliant on crutches (usually 4-6 weeks). Returning to sporting activities or heavy manual work can take up to 6 months to allow the bone to fully heal. Xrays are taken at regular intervals to confirm this.
What are the potential complications or risks associated with this surgery?
Bleeding/bruising: Bleeding is typically minimal and occurs in the first couple of days after the surgery. This may necessitate a change of dressings if they come loose. Bruising can be significant and will often track down the leg to the ankle and foot but will settle and does not cause long term problems. Elevating the operated leg when resting (including at night) on a pillow will help to minimise swelling in the first few weeks after surgery. Regular icing should also be used liberally – this improves swelling and pain after surgery. An ice pack for 10 minutes in every hour can be used.
Infection: This is a rare complication and occurs in 1-2% of cases. It is a potentially serious complication when it does happen, however. Usually the infection is superficial involving the skin and will settle with antibiotics but if it is a deeper infection, this will require further surgery to wash out the wound.
Nonunion: Failure of the bone to heal at all (non-union) or to heal slowly (delayed union) occurs in 1-2% of cases and 5% of cases in the literature. Smokers have a higher rate of nonunion (6-8%) making this procedure unsuitable unless stopped.
Under-correction & Over-correction: New technology minimises the risk but it is still a concern. An under-correction may not fully alleviate painful symptoms and over-correction typically leads to a knocked-knee’d appearance. The rate is approximately 1-2%.
Blood clots in legs or lungs: We worry about leg vein clots (Deep Vein Thrombosis or DVT) because clots can be dislodged and travel to the lung where they can become a life-threatening problem (1:10,000). For this reason you will be given blood thinning injections until fully mobile and weight bearing normally. This can range from 2 to 6 weeks following surgery.
Anaesthetic risks: Modern anaesthesia is usually very safe, but there are small risks associated with general anaesthetics including airway problems and unexpected allergic reactions. There are separate risks associated with receiving a nerve block. The anaesthetist will be able to go through these risks with you prior to the operation.
For further information on the risks, benefits and implications of Knee Osteotomy surgery please click here for the British Orthopaedic Association (BOA) consent form.