Knee Replacement Surgery
During a knee replacement, surgical instruments are used to resurface the ends of the femur and tibia. The knee cap (patella) may or may not be relined. This is done after making a vertical incision over the front of the knee to gain access to the joint surfaces. Computer navigation is often used in surgery to increase the accuracy of the placement of the knee replacement, although different surgeons use different methods to achieve this.
The decision to proceed with knee replacement surgery should only be made after discussion with your surgeon and when you feel you have got enough information to make a good decision. The decision is yours and does not need to be rushed.
Types of Knee Replacement
There are a few varieties of knee replacement which are commonly used to treat your pain. Depending on the type of arthritis you have, some methods of knee replacement will be better suited to you than others. It’s important to remember there are different opinions regarding the use of each of these knee replacements, so you should ask your surgeon if you have any queries about one preference over another.
Total Knee Replacement – this is the most common type of knee replacement performed to treat arthritis. In this procedure, both the inside and outside portions of the knee are replaced to resurface the knee. A metal prosthesis replaces the bone and cartilage surfaces, with a polyethylene (plastic) insert in between to allow for smooth movement between the two surfaces. Replacing the knee cap is sometimes done with this procedure, although not always.
Unicompartmental Knee Replacement – this is less commonly performed than total knee replacement, as often the arthritis is too far gone and not isolated to one area of the knee. In this procedure, only the one side of the knee is replaced (the inside or the outside). Again, a metal prosthesis is used to resurface the knee and a plastic liner is inserted in between to allow for smooth movement. There are some benefits to having a unicompartmental knee replacement, although there are pros and cons to this surgery and your surgeon will discuss these issues with you in person.
Patellofemoral Replacement – this is a relatively rare procedure as the arthritis in the knee commonly involves other areas and a total knee replacement is often used. Still, in some instances where arthritis is only present between the knee cap and femur, this area is replaced. You surgeon will explain this procedure in more detail should they think it is appropriate for you.
Post Operative Care
Wherever possible it is important to have a support person or network around you when recovering from your knee replacement. You will need help getting to and from hospital, travelling to and from appointments and with general help around the house and during your activities of daily living.
With improved techniques and pain relief, patients are able to go home earlier and earlier. Hospital stay can be anywhere from 3-7 days. Some patients will be transferred to a rehabilitation centre after surgery for more care – this is simply organised during your inpatient stay, however most patients can go directly from hospital to home provided they have the right care.
You will be encouraged to get out of bed and walk with the aid of crutches or a walker straight after surgery. We encourage you to use the crutches or a walker for stability until you have good control of your leg and your pain is under control, as it is important to avoid falls in the first weeks after surgery.
It is important to try to regain the range of motion in your knee after surgery. Initially this will feel difficult but improves with time. Your knee will swell after surgery, so it is important to ice your knee every 1-2 hours and elevate your knee – this means lying down and elevating your knee above your heart. Swelling can last up to 12 weeks after surgery, although it will steadily decrease with time.
Your hospital will have an excellent team of physiotherapists who will see you each day and go through your post-operative exercises with you. They will also provide you with exercises to continue with at home and can help with physiotherapy once discharged if you wish.
First 2 Weeks
Your goals in the first 2 weeks after surgery are:
- increase your comfort level with your new knee and pain relief
- decrease swelling
- work on the range of movement in the knee
- regain function of your leg muscles, particularly your quads muscle at the front of your thigh
- Beginning to walk on your new knee with the aid of crutches or a frame
You will be reviewed in the rooms approximately 2 weeks after surgery. If you are unsure of your follow-up appointment, please call our rooms.
First 3 Months
This is focussed at improving your function and comfort levels:
- reducing the use of crutches and frames
- further improvements in range of motion and swelling
- increased strength
- hydrotherapy and stationary cycling
This is a period of gradual improvement in knee function, where the benefits gained on a day to day basis will be less noticeable. However, over the longer term you will still be gaining benefits in your knee function, becoming more comfortable with more strenuous activities. Generally complete recovery takes at least 12 months, sometimes longer.
There will be some heavier bandages wrapped around your knee which are generally taken down the day after your surgery. Overlying the surgical incision is an adhesive dressing, which if clean and dry can just be left in place. The nursing staff in hospital will help you with any questions you have regarding your dressings, and the healing of your wound will be checked at your follow-up appointment approximately 2 weeks after surgery.
Knee replacement surgery has traditionally been painful, although with current techniques patient comfort is improving all the time. Our surgeons use a number of different modalities to help with pain relief, and your Anaesthetist will talk you through these. Once discharged from hospital, you will have pain relief tablets you can take that will help with your comfort levels. In general you will require some regular pain relief each day, consisting of regular paracetamol, anti-inflammatories (if tolerated) and then a stronger type of pain relief. For periods of increased pain during the day (breakthrough pain), you will have a faster acting pain reliever to take. Some of these pain relievers can have side effects such as nausea, stomach upset or sedation. They can be tailored to try and reduce these side effects to keep you as comfortable as possible. It might be necessary to avoid certain activities (ie driving) if you are taking these types of pain killers.
The exact time until you return to driving is variable depending on your recovery and the leg you had operated on. The Australian Orthopaedic Association recommends a period of at least 6 weeks before you should consider recommencing driving. For more information, please read the Arthroplasty Society of Australia’s statement on return to driving after hip and knee replacement.
Return to Work
This will vary depending on the nature of work you do, and your surgeon can provide some more specific guidance to you. At a bare minimum, you should have a least 2 weeks off to allow the incision to heal and your pain levels to reduce, although most patients will require more time off work.
A physiotherapist will visit you twice per day whilst in hospital, but it is important to perform exercises and activities on your own to enhance your recovery. Once discharged, it is recommended that you see a physiotherapist on a regular basis until you have recovered to a satisfactory level. Your surgeon can help you with some advice on appropriate physiotherapists, however if you already have an existing relationship with one then sometimes it is better to continue with this.
Dental Work and Knee Replacements
If you have dental work or any other surgery, let your dentist or surgeon know. It is common to take some antibiotics during this surgery to help reduce the risk of a deep infection in the knee. This needs to happen on a permanent basis after your knee replacement. If you have a significant amount of dental work planned or any dental problems, these should be attended to prior to your knee replacement where possible.
The risk of infection around the prosthesis is about 1 patient in every 100. This can happen anytime after surgery, as the infection can spread to your knee from any part of your body. In the event you do have a deep infection, it is important to seek treatment as soon as possible. Simple tablet antibiotics will not treat this problem and you will require surgery to wash the knee joint out. Infrequently if you have a resistant infection, you may require a surgery where the existing knee replacement is removed and a new replacement inserted after a period of antibiotics. This is known as a Revision Knee Replacement.
If you are concerned about an infection, please contact the rooms as soon as possible. During business hours the best point of contact is to call. After hours, please contact the hospital where you had your surgery, and ask them to get in touch with your surgeon. Failing this, present to your local emergency department.
This is also not common, although can occur. This is usually an infection just within the skin of the lower leg. It is important to contact your surgeon if this is the case, as it will need treatment to prevent infection spreading to the knee joint, and in addition it is important to accurately detect the difference between a deep and a superficial infection by an experienced doctor or surgeon.
If the joint was extremely stiff before surgery, you may have difficulties with stiffness after surgery. Rarely, the knee replacement can become extremely stiff, requiring a manipulation of the knee replacement or even revision surgery.
Most patients get some numbness over the front of their knee after surgery, although it is rarely a big problem.
Foot and Ankle Swelling
This is normal to an extent, and generally reflects the effects of gravity on the swelling around your knee.
Blood clots can form in the deep veins of the calf or leg, or occasionally these clots can travel to your lungs (pulmonary embolus), affecting your breathing. During your inpatient stay we use blood thinners to help prevent this, although there is no method that is 100% effective. In the event you do have a large clot in your legs (DVT) or in your lungs, you will need to go on to longer term blood thinning medication until it has resolved.
Prosthesis wear and revision surgery
For most people, the knee replacement will last for the remainder of their life. We know from experience that, at 10-15 years after surgery, 95 out of 100 knee replacements are still functioning well. However, if the prosthesis wears out or breaks, revision surgery will be required to remove the existing prosthesis, and insert a new one. Revision surgery is more complex than the initial surgery, recovery takes longer and functional outcomes can be decreased.
Damage to structures inside the knee
Fortunately this is very rare, but there have been instances of damage to the bones, arteries, nerves and veins in the leg. Some of these require repair during surgery, and other instances will improve with time.
When to Report to Your Surgeon
- temperature higher than 38.5 degrees or chills
- severe pain or tenderness
- heavy bleeding from incisions
- redness around an incision that is spreading
- nausea or vomiting
- worsening flexibility or inability to bend the knee
- loss of mobility after a fall
- any concerns you may have after surgery
Costs of Treatment
In general, there are three areas that draw fees for surgery:
Surgeon – You will be provided with a quote prior to surgery.
Anaesthetist – Once you have booked your surgery you will given the Anaesthetist’s contact details, so you can have the opportunity to discuss any costs you might receive from the Anaesthetist.
Hospital – Depending on your health insurance policy you may have an excess fee on the hospital admission or no excess. The cost of the prosthesis and surgical costs are built in to the hospital fees. Your insurer in conjunction with the hospital, will be able to give you the details of any hospital costs you might expect to receive.