Osteotomy around the knee is a more major operation involving correcting the alignment of the leg by cutting one of the bones (osteotomy), changing the shape and then holding it in position with a plate and screws until the bone heals over 2 to 3 months. This technique is useful in those who have bow legs or knock-knees with arthritis affecting just one compartment of the knee. The most common form is a High Tibial Osteotomy (HTO), which is useful if only one side of the knee is worn out. It involves cutting the tibia and repositioning it to reduce the load on the worn inside compartment of the knee so that the the healthier outside can act as the main load-bearing surface.
Following surgery, you may be placed in a brace for comfort for the first 2 weeks. You are likely to be in hospital for 2-3 days. Skin staples will need to be removed after 10 days, and you will then be seen at approximately 6 weeks with a new X-ray.
You will be able to bear weight through the operated leg following surgery, using 2 crutches for support initially. You should be able to return to driving when you can control your vehicle and confidently perform an emergency stop. This is usually around 6 weeks.
What are the risks of osteotomy around the knee?
All operations come with attached risks. These can include:
Bleeding – a blood transfusion may be required but this is rare.
Infection – This is a potentially devastating complication and all efforts are taken to prevent this. These include the use of antiseptic skin preparations during surgery, ultra-clean air laminar flow operating theatres with every care taken to maintain sterility during surgery, and the use of antibiotics during and after surgery. Despite this infections can still occur. These may be superficial wound infections which can be successfully treated with antibiotics, but a severe deep infection is likely to need further surgery to wash out the operation site. The risk of a deep infection is less than 0.5%.
Blood clots – a blood clot in the leg (a deep vein thrombosis; DVT) or in the lung (a pulmonary embolus; PE) is a potentially serious complication. The risk is decreased by giving you blood thinning medication following surgery. The most important factor to reduce this risk is getting you mobile as quickly as possible. The risk of a DVT that causes symptoms is approximately 2%; the risk of a PE is 0.5%. If you are unfortunate enough to develop either of these, then blood thinning medication such as warfarin (or a newer alternative) is usually required for 3-6 months.
Knee stiffness – Although relatively uncommon following osteotomy, the knee may become stiff following surgery. Manipulation of the joint under general anaesthetic to bend the knee and break down scar tissue within the joint may be required. Early and regular exercises can reduce this risk.
Prominent metalwork – the metal plate used to fix the osteotomy can feel rather bulky under the scar. Normally this is not a problem, but if it is irritating, the plate and screws can be removed after the osteotomy has healed (usually 6 to 9 months following surgery).
Numbness – it is common to have some numbness over the outside of the knee. This is because the small skin nerves running across the knee are cut at the time of surgery. This numbness does not usually cause problems.
Progression of arthritis – The osteotomy is planned to keep your own knee joint functioning as long as possible. 85% of osteotomies are functioning at 10 years. If the remaining joint surfaces become worn and painful, then the osteotomy may need to be converted to a total knee replacement.
Outcomes of Osteotomy
It is very important to me that the outcomes of surgery are monitored so that we can monitor the progress of your recovery and drive research aimed at improving surgical performance. I will invite you to contribute to the national UK Knee Osteotomy Registry which will collect this data. Please rest assured that this information is held securely and any personally identifiable information will not be shared with anyone else. Any data used for research purposes will be anonymised.