Benefits of Partial Knee Replacement Over Total Knee Replacement
This article provides information about the Oxford Partial Knee Replacement System.
Partial knee replacement is intended to preserve the healthy knee structures, and may restore normal knee motion and function. Unlike other components, the Oxford Partial Knee has a fully mobile bearing, which limits the forces and stresses seen by the implant that may often lead to loosening.
The Oxford Partial Knee is currently the fully mobile bearing partial knee system in the United States. Your orthopaedic surgeon has selected the Oxford implant specifically for you based on the unique design of the components, the proven clinical history of the system, and most importantly, your condition.
The traditional approach to knee reconstruction has been a total knee replacement, which replaces all three compartments of the knee. However, total knee replacement may not be necessary for every patient. Osteoarthritis often develops in only one compartment of the knee, while the other two compartments remain relatively healthy. Patients who have osteoarthritis in only one compartment may not need a total joint replacement. They may be candidates for a partial knee.
Minimally Invasive Technique for Rapid Recovery
With the Oxford minimally invasive technique, it is not necessary for your surgeon to make a large incision that would surgically expose healthy parts of the knee. With use of the Oxford proprietary instruments, the operation may be performed through a small incision. The system allows accurate balancing of the knee through this small incision avoiding disruption of the thigh muscles (quadriceps), which also contributes to a quicker recovery.
In addition to a less invasive surgery and a smaller incision, the procedure also removes less tissue from both the tibia and femur because only the damaged cartilage and bone is removed.
Moist patients walk on their Oxford Partial Knee the same day as surgery and can possibly be discharged within 24 hours. Some patients may need to use a walker or a cane for the first week. Your condition will determine when you will be discharged.
10 Frequently Asked Questions on Oxford Partial Knee Replacement
Who can benefit from partial reconstruction?
Adults who show one of more of these symptoms may benefit from this procedure:
- Pain while standing
- Pain while walking a short distance
- Pain changing position, such as sitting to standing
- Persistent knee swelling
- Giving out or locking of the knee
- Failure of the knee to respond to medication
What is the difference between a partial knee replacement and a total knee replacement?
Only part of the joint surface is replaced during a partial knee replacement. A total knee replacement involves resurfacing the entire knee.
Why would I have a partial knee replacement rather than a total knee replacement?
There may be several reasons. A partial knee replacement is typically used for patients who has osteoarthritis in limited parts of their knee. If you have osteoarthritis in more than one area of your knee, a total knee replacement is usually recommended. Of course, there may be other reasons for having a partial knee replacement – feel free to ask your surgeon.
Are there different types of partial knee replacement?
Yes, there are many different designs on the market. The most significant difference is whether the polyethylene (plastic) lining of the new knee is free to move or not. A moving plastic bearing (as in Oxford Knee) is known as a mobile bearing type. When the plastic cannot move, the replacement is a fixed bearing type.
Does a partial knee replacement last longer than a total knee replacement?
Not necessarily. All implants have a limited life expectancy depending on an individual’s age, weight, activity level, and medical condition. Research has shown that the newer types of partial knee replacements, particularly those with moving plastic bearings like, the Oxford Partial Knee, typically have exceptionally low wear rates, potentially giving them longer life expectancies. You can, of course, go on to have a total knee replacement after a previous partial knee replacement, should it become necessary.
What can I expect during and immediately after the surgery?
During surgery, your surgeon will remove small amounts of bone and then fix the Oxford Partial Knee components to your bone with bone cement. The operation usually lasts about one hour. The recovery time is usually much faster than a total knee replacement because the Oxford Partial Knee is inserted through a smaller opening in your knee. It is likely that you will be up and walking, although perhaps with some assistance, on the same day or the next day after the operation. Light activities, such as driving, can normally be resumed in a few weeks.
What activities can I expect to do after the surgery?
The amount of activity you will be able to perform will depend on several variables, including what activities you were able to perform before the operation. It will also depend on how much your surgeon allows. Always follow the advice given by your surgeon or rehabilitation professional.
What can I expect during rehabilitation?
You should follow the exercise program advised by your doctor. This may include visiting a physical therapist. Along with specific exercises to strengthen your knee joint, they will help you learn the best way to perform every day activities such as climbing stairs and rising from a chair.
What can I expect from the device?
Most Oxford Partial Knee recipients experience reduced pain and restored function of the knee. As with any artificial joint, this prosthesis will not restore your knee to normal, undiseased joint.
How do I prepare myself for surgery?
Your doctor will provide you with instructions regarding how to prepare for surgery.
The knee is a complex joint consisting of bones and soft tissues (Below Figure). The end of your thighbone (femur) can be compared to a rocking chair. It has two distinct surfaces called compartments, which rest on the shinbone (tibia). A third compartment is found behind the kneecap (patella), and all three compartments are covered with cartilage to help cushion and lubricate the bones during movement.
Knee cartilage is generally very durable, but susceptible to wear over time. As we age, old injuries can become more apparent with activity.
Osteoarthritis is a degenerative process that results in the wearing out of the cartilage that protects the joints. Over time, the cartilage slowly erodes until the underlying bone is exposed. The exposed bone can be painful when the joint moves and bears weight.
Purpose of the Device
The Oxford Partial Knee is intended for use in individual with osteoarthritis or avascular necrosis limited to the medical compartment of the knee and is intended to be implanted with bone cement.
The Oxford Partial Knee is unique in that the meniscal bearing is not fixed to the tibial component but free to move as your knee moves.
Description of the Device
The Oxford Partial Knee consists of three components: a femoral component, a tibial component, and a meniscal bearing.
The femoral component chosen for you is manufactured from a superalloy (cobalt chromium molybdeum). The component has a highly polished, spherical articular surface. A central peg assists in placement of the device in the femur.
The tibial component is also manufactured from cobalt chromium molybdenum. Separate components are designed for the left and right knee. The articular surface is flat and highly polished with a raised lip running the length of the inside edge. On the undersurface, there is a flat fin (keel) to locate the component during insertion.
The meniscal bearing is made of ultra high molecular weight polyethylene. The upper articular surface of the bearing is spherically concave and has the same radius as the femoral component. The lower articular surface is flat, to match the tibial component.
Not all patients are candidates for partial knee replacement. Only your orthopaedic surgeon can tell you if you’re a candidate for joint replacement surgery, and if so, which implant is right for your specific needs. You should discuss your condition and treatment options with your surgeon. The Oxford Meniscal Partial Knee is intended for use in individuals with osteoarthritis or avascular necrosis limited to the medial compartment of the knee and is intended to be implanted with bone cement. Potential risks include, but are not limited to, loosening, dislocation, fracture, wear and infection, any of which can require additional surgery. For additional information on the Oxford knee, talk to your surgeon.