Partial Knee Replacement
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During your knee replacement surgery in Melbourne, damaged bone and cartilage is resurfaced with metal and plastic components. In unicompartmental knee replacement (also called "partial" knee replacement) only a portion of the knee is replaced. This procedure is an alternative to total knee replacement for patients whose disease is limited to just one area of the knee. Because a partial knee replacement surgery is a more limited procedure, patients spend less time in the hospital and return to normal activities quicker than total knee replacement patients.
In knee osteoarthritis, the cartilage protecting the bones of the knee slowly wears away. This can occur throughout the knee joint or just in a single area of the knee.
Your knee is divided into three major compartments:
Medial compartment (the inside part of the knee)
Lateral compartment (the outside part)
Patellofemoral compartment (the front of the knee between the kneecap and thighbone)
Only part of the knee is arthritic
Advanced osteoarthritis that is limited to a single compartment may be treated with a unicompartmental knee replacement. During this procedure, the damaged compartment is replaced with metal and plastic. The healthy cartilage and bone, as well as all of the ligaments are preserved.
Part of the knee is replaced with artificial components
Advantages of Partial Knee Replacement
Multiple studies show that a majority of patients who are appropriate candidates for the procedure have good results with unicompartmental knee replacement.
The advantages of partial knee arthroplasty over total knee replacement include:
Quicker recovery
Less pain after surgery
Less blood loss
Also, because the bone, cartilage, and ligaments in the healthy parts of the knee are kept, many patients report that a unicompartmental knee replacement feels more natural than a total knee replacement. A unicompartmental knee may also bend better.
Disadvantages of Partial Knee Replacement
The disadvantages of partial knee replacement compared with total knee replacement include:
Slightly less predictable pain relief
Potential need for more surgery. For example, a total knee replacement may be necessary in the future if arthritis develops in the parts of the knee that have not been replaced.
An advantage of partial knee replacement over total knee replacement is that healthy parts of the knee are preserved, which helps to maintain more "natural" function of the knee.
Candidates for Partial Knee Replacement
If your osteoarthritis has advanced and nonsurgical treatment options are no longer relieving your symptoms, Surgeons may recommend knee replacement surgery.
In order to be a candidate for unicompartmental knee replacement, your arthritis must be limited to one compartment of your knee. In addition, if you have any of the following characteristics, you may not be eligible for the procedure:
Inflammatory arthritis
Significant knee stiffness
Ligament damage
With proper patient selection, modern unicompartmental knee replacements have demonstrated excellent medium- and long-term results in both younger and older patients.
Advantages of Robotic Partial Knee Replacement
These allow highly accurate placement of the knee replacement, and fine tuning in three dimensions in real time your knee function. These should allow for longer lasting knee replacements with better function.
Recovery
After your operation you will spend time in the recovery room, where you will be closely monitored before being transferred back to your room. You will have a large amount of local anaesthetic injected at the time of operation around your knee joint, so most patients are very comfortable post operatively.
You will be able to get up from Day 1 with the use of crutches for balance and start walking on your new knee with the guidance of our physiotherapy team. Some minor discomfort is to be expected during the first week or two, and this will settle gradually over time. We will review you at two weeks to check your wounds and monitor your rehabilitation. In most cases by week 4-6 patients are comfortable walking unassisted with the use of crutches. An exercise bike is recommended from 2 weeks post operatively and hydrotherapy from 4 weeks post operatively. Walking for exercise is encouraged from 8 weeks post operatively. Patients continue to improve with strength, walking and balance up to 1-year post surgery.
Risks and Complications Of Partial Knee Replacement
Partial knee replacement surgery overall is highly effective and rarely has complications. Our orthopedic surgeons take extensive precautions to prevent complications at every step of your journey, however, complications can still occur with any surgery. Your surgeon will get you to see a specialist physician prior to your knee replacement to optimize your overall medical condition and prevent medical complications.
Risks related to partial knee replacement surgery include:
- Progression of the Arthritis: over time arthritis can spread to the other areas of the knee, which may mean replacing your partial knee replacement with a total knee replacement.
- Wear/Loosening: over time the plastic within the knee replacement can wear out and may require changing, similarly to the tyres on a car. Occasionally the replacement itself may come loose and need to be replaced.
- Infection: Infection may occur in the wound or deep around the prosthesis, this even occur years later. Minor infections in the wound area are generally treated with antibiotics. Major or deep infections may require more surgery. Any infection in your body can spread to your joint replacement. Our surgeons give all patients antibiotics before and during the operation to prevent infections occurring.
- Blood clots (DVT): Blood clots in the leg veins can be life-threatening if they break free and travel to your lungs. VBJS surgeons utilize a range of preventative measures to stop these occurring which include medications, compression stockings, pneumatic compression devices, and early mobilization.
- Stiffness: scarring occurs around any place that you undergo surgery, in the knee this scarring causes stiffness and prevents it bending properly. It is essential to move your knee early and take sufficient painkillers to allow you to perform your range of exercises daily. If stiffness is an ongoing problem sometimes further surgery is required to remove the scar tissue.
- Continued Pain: A small number of patients continue to have pain after a knee replacement. This complication is rare, however, and the vast majority of patients experience excellent pain relief following knee replacement.
- Nerve/Blood Vessel Damage: While extremely rare, injury to the nerves or blood vessels around the knee can occur during surgery.
- Numbness: Our surgeons use a lateral incision which aims to prevent numbness at the front of the knee, however a small group of patients still experience numbness at the side of the knee, this normally settles over 6-12months.
- Swelling: some patients can get recurrent swelling in the knee, this can be due to a variety of causes, but normally settles over time.
FAQs (Frequently Asked Questions)
When can I walk after a partial knee replacement?
Full weight-bearing and walking is allowed immediately after total knee replacement. Initially, this will be aided by crutches. We get all patients mobilising Day 1 after their operation on crutches.
When can I drive after partial knee replacement?
You should not drive for at least 48 hours after an anaesthetic. After 48 hours, your ability to drive will depend on the side you had your operation, left or right, the type of vehicle you drive, manual or automatic and what type of pain relief you are taking. It is generally reasonable to drive when you are confident with walking and can fully weight-bear on your affected side. The usual recommendation is 6 weeks.
When can I work after partial knee replacement?
Your return to work will vary depending on the type of work you are engaged in. Most people can return to office work within 4-6 weeks. More strenuous manual work may require 3-6 months before returning to duties.
When can I play sports after partial knee replacement?
Low impact activities, such as cycling (exercise bike) and hydrotherapy, can be commenced from week 2. Walking for exercise can be commenced from week 6. More strenuous activities such as tennis takes 3-4 months. Note, this is highly variable and intended as a rough guide only.
How long will I take to heal after partial knee replacement?
The wounds take 7-10 days to heal. Most patients improve dramatically in the first 6-12 weeks. Occasionally, there are periods where the knee may become sore and then settle again. The knee may be swollen for some time post-surgery. This is part of the normal healing process. Continued improvements may be gained up to 1-year post-surgery.
How much pain will I experience after partial knee replacement?
Some discomfort is to be expected after knee surgery. A local anaesthetic is injected around the wound during the procedure to minimise any pain you may experience.
Will I beep going through metal detectors at airports?
Maybe. It depends upon the settings of the metal detector in use, some countries have higher sensitivities than others, so whilst you may not set them off in Australia you may do so overseas. Normally it is not an issue if you tell them in advance you have had a knee replacement.
