Every knee surgeon has their own preferences when undertaking knee replacement surgery.
First published in 2009, and reviewed August 2023 by Dr Sheila Strover (Clinical Editor)
There are various different types and makes of total knee replacements.
Most surgeons would use a knee replacement design that they are best trained to do. It is much wiser to choose a surgeon and leave him to decide the type of prosthesis, than to choose a prosthesis and ask your chosen surgeon to do one.
Prosthesis design preferences
I personally choose a prosthesis called the 'Medial-Pivot knee' which is based on the normal anatomy of the knee. The ADVANCE Medial-Pivot knee features a medial ball-and-socket design like your normal knee and controls the movement of your thighbone on your shinbone actively reproducing the medial pivoting motion of a normal knee. Due to this design movement, bending and flexibility, feels more like a normal joint. This knee gives you a feeling of stability, stops the knee sliding or giving way and makes you feel like you have a stable knee.
Computer assisted knee replacement
Traditionally total knee replacements are done by surgeons using a mechanical jig to align the cutting block which cuts the top of your shinbone and the end of your thighbone so that the metallic prosthesis fits. This jig can easily be placed outside your bone or inside it. More recently surgeons have used computer-assisted surgery in order to improve the accuracy of doing the knee replacement. I started doing computer navigation surgery in 2005, and this does improve the accuracy of doing knee replacements. Not all knees may be suitable for this technology and a level-headed discussion should be had with your treating surgeon. If you are having a total knee replacement using computer navigation, your surgeon would give you an information leaflet to read about the technological stuff - at surgery you would have pins inserted into your thighbone and shinbone to attach the computer tracker which is identified by the computer equipment. Your surgeon, while doing your operation, would define your anatomy which is registered in the computer. The computer then helps the surgeon to cut your bones in the most accurate way.
When the cuts are made, the surgeon can check for accuracy and make modifications if required. Computer-assisted surgery may take slightly longer than traditional surgery but with experience the extra time is reduced dramatically and at times may be limited to an additional five to ten minutes on top of the usual operating time. I feel this time is best spent inside the theatre.
Computer-assisted surgery is particularly indicated when patients have large deformities or have had fractures of their thighbone or shinbone. If you do have computer-assisted surgery, care should be taken to not engage in impact activity before a recommended period of time as there is a mild risk of fracture of the long bones.
Custom jigs for total knee replacement
I started using this new technology in July 2010. Patients have an MRI scan of their legs including the knees prior to their total knee replacement. The scans are sent to the implant manufacturering company who, based on your anatomy, prepare a patient- and side-specific jig which is then used by your surgeon to do the bony cuts and help him during knee repalcement.
This technology again helps your surgeon to do a knee replacement using modern techniques. There is additional expense involved if this technology is used and this may not be available readily on the NHS. Some insurance companies may not accept to pay the excess and it is important for you to discuss this with your insurance company if required.
No matter what technology and how your knee replacement is done, the hard work that is required following knee replacements does not change. Complications may still occur even when the best of technologies are used and hence active participation in your rehabilitation, optimising your health before the knee replacement and understanding the procedure is of vital importance.
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