(Part & Total Knee Replacement)
(Part & Total Knee Replacement)
What is the aim of this surgery? Painful arthritis is a debilitating condition that can severely affect our lives, both physically and mentally. The aim of this surgery is to resurface the worn area(s) of the knee joint. Resurfacing procedures of the worn areas of the knee are excellent pain-relieving options. When smaller areas in only one part of the knee are affected then a partial resurfacing (known as unicompartmental replacement) is beneficial. When two or more areas are affected then a total resurfacing is preferred, also known as a total knee replacement.
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 of arthritis. We recommend this type of surgery in older patients (over 60) looking for a definitive long-lasting improvement in their painful symptoms.
Will I need to stay in hospital overnight? Yes. You will normally stay in hospital for two nights, though discharge after one night is common after partial knee resurfacing. Discharge is dependent on passing confidence and safety tests with the physiotherapists. You will also need to have a blood test and an X-ray. The surgery is typically performed under a spinal anaesthetic with supplementary local anaesthetic delivered into the knee itself during surgery (see other information regarding what to expect before surgery).
What does the procedure involve? You will come in to hospital on the morning of surgery and be admitted by the ward staff. Both the anaesthetist and I will then meet with you and go over any questions or concerns you have. There are lots of questions and checks that will need to be carried out and this will seem exhaustive but it is all done for your absolute safety. Once in theatre you will have your anaesthetic and I will position your knee optimally. A skin incision is made over the front of the knee. The length depends on many factors but is typically 6-8cm for partial knee and 12-15cm for total knee resurfacing.
For partial knee resurfacing the “good areas” of the knee will then be formally assessed as final confirmation that this is suitable. Sometimes the “good areas” can look more worn than expected from the X-rays and MRI scan and in these cases we would change plan to a total knee resurfacing instead. Specialised cutting guides are then used to shave only very thin cuts of the worn arthritis away. The new resurfacing components are then fixed in to place. The procedure takes approximately 1 hour. You will then go to recovery before having an X-ray and then arriving back on the ward. Your knee is safe to put weight on straight away, so once safe the physiotherapists will get you up and walking – often on the day of surgery.
What are the chances of an improvement in my symptoms: The outcome of knee resurfacing procedures depends on many factors but, overall, these are excellent pain-relieving operations with over 90% of patients reporting significant improvements in their pain and function. Approximately 10% of patients are less satisfied, however. For this reason we recommend knee replacement surgery for severe pain that is not responding to non-operative measures (as listed above and under conditions treated ) and significantly affects your life on at least 4 or more days of the week. Implant survival is constantly improving and we will only use implants with the best long term outcome data: The Lima ZUK partial knee resurfacing has 94% 10 year survival. The Stryker Triathlon total knee resurfacing has 96% 10 year survival.
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. Your knee will swell up and feel bruised and it is not uncommon for the bruising to track down the shin to the ankle. Keeping your leg elevated on a pillow when resting or in bed, as well as regular icing (8 times per day for 10 minutes) can help to alleviate both pain and swelling.
The implants are 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. 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). I never use clips in the skin so you will not need anything removed at your wound review 2 week visit. At 6 weeks you will be feeling more comfortable but knee resurfacing surgery improves month on month for up to a year or more so don’t be frustrated if the recovery seems slow – this is very normal.
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 further surgery may be required to wash out the wound or sometimes change the components.
Nerve and Blood vessel injury: It is rare (less than 0.1%) to damage the main nerves and blood vessels that supply the leg as these lie at the back of the knee. Damage to the nerves that lie just under the skin and bring sensation to the front of the leg is almost unavoidable, however, and it is common to have a numb patch over the shin following surgery. This numb patch will often shrink in size over the first year but may never go away completely.
Damage to ligaments and tendons: Again rare (0.1%), this is a potentially serious complication that can result in time spent in a brace following surgery and knee laxity or stiffness as a result.
Blood clots in legs or lungs: We worry about leg vein clots (Deep Vein Thrombosis or DVT) because they can dislodge and travel to the lung becoming a life-threatening problem (1:10,000). For this reason you will be given blood thinning injections or a tablet each day for 2 weeks until fully weight bearing. We follow national best evidence-based guidelines.
Anaesthetic risks: Modern anaesthesia is usually very safe, but there are small risks associated that the anaesthetist will be able to go through with you prior to the operation.
For further information on the risks, benefits and implications of Knee Resurfacing (Replacement) surgery please use the links below for the British Orthopaedic Association (BOA) consent form:-
For further information on Knee Arthritis and Knee Replacement Surgery click here for the American Academy of Orthopaedic Surgery (AAOS) information site.