Performed by – Khalid Al-Hourani, Alastair Davidson, Richard Hargrove, Azal Jalgaonkar, Zuhair Nawaz,  Andrew Perry, James Singleton, Seb Sturridge

As arthritis deteriorates the pain can become debilitating and then surgery is considered. In some types of arthritis of the knee, only the medial (inside) part of the joint is affected. In this situation it is possible to replace the damaged part of the knee without resorting to a total knee replacement (TKR). This is called a unicompartmental knee replacement (UKR). The surgeons at Joint Reaction use the Oxford UKR which has the longest pedigree and best results. This preserves all the knees ligaments and thus mimics the function of a normal knee as best possible. The ‘Signature’ option is an MRI scan-based technology that plans individualised surgical planning with customised cutting blocks.

What happens in surgery?
The surgery involves removing a small thickness of damaged bone from the inside part of the knee. Less bone is removed than in a Total Knee Replacement and only from one side of the knee. The Unicompartmental Knee Replacement fits inside this prepared space. The Operation takes about an hour and involves a smaller surgical incision and a faster recovery. This is often described as ‘mini-invasive surgery’. This small incision does not involve cutting any muscle or tendons (as with a Total Knee Replacement), thus enabling quicker recovery from surgery.

The component parts of the UKR
The UKR comes in three parts. The femoral component is made of metal, is curved and highly polished. The tibial component is made of the same metal and has a flat upper surface. A plastic component, which is curved on the top and flat on the underside, sits on the flat tibial surface and can slide backwards and forwards. This mimics the meniscal cartilage in the normal knee. The upper part of this plastic insert articulates with the femoral component. This type of knee replacement is called a meniscal bearing and has the advantage of sharing the load through the knee over a large surface area, which helps to reduce wear and hence make the knee replacement last longer.

After a Unicompartmental knee replacement
The day after the operation your exercise regime begins. With the aid of a physiotherapist you will get out of bed and begin to exercise your new knee replacement. With perseverance, you should be able to climb stairs by day 2 or 3 and go home the following day. You will need to continue attending physiotherapy as an outpatient. This can be done closer to your home with one of our recommended group of physiotherapists. For most people it will take a month or so to be walking reasonably. After three months you should be able to walk well without pain, climb stairs (leading with your operated leg) and be capable of a range of movement with your new knee from 0 degrees to at least 120 degrees.

What can I do with my new knee?
It is important to remember that a unicompartmental knee replacement will not give you a normal knee. However, it will give excellent pain relief, very good function and range of movement, which will be better than a TKR. Biomechanical studies suggest a UKR allows the most normal knee function of any type of joint replacement.

You will be able to walk a good distance and play recreational sports such tennis, golf, cycle or swim. We would not recommend running after a UKR.

Lifespan of a UKR
Studies suggest that a UKR has a better than 90% chance of surviving for more than 10 years. The small amount of bone removed means that it is easy to revise it to a Total knee replacement if the UKR wears out. Revising a worn TKR is a much more complex procedure. UKR is therefore a good option for younger more active patients.