Every knee replacement surgery is different and has its own set of needs.
Your knee is made of three parts – the inside, the outside, and underneath the knee cap. Each part can be replaced on its own, or they can all be replaced at the same time for a total knee replacement, according to the American Association of Hip and Knee SurgeonsOff Site Icon (AAHKS).
In general, X-rays and your description of where you feel pain are both used to determine whether you will need a partial or total knee replacement
The decision of which one will work best for you also depends on what caused the knee issues to begin with, for example: Was it an injury or was it arthritis? You and your doctor also need to consider the differences in recovery time and how long each type of knee replacement parts will last. These factors can be different for different patients depending on your current health and health history.
There are three compartments within the knee joint: the medial compartment (inner), lateral compartment (outer) and patellofemoral (middle). If your knee arthritis is limited to just one compartment, you may be a candidate for partial knee replacement. Partial knee replacement is less invasive than total knee replacement. It requires a smaller incision, uses smaller components, and has a shorter recovery time.
Total knee replacement is recommended for patients who have arthritis in more than one compartment of the knee. Total knee replacement is a more involved procedure, but it also lasts longer than partial knee replacement.
Three main sections (medial, lateral, and patellofemoral) make up the knee joint, and are joined by a complex system of ligaments, tendons, and muscles. While these connective tissues secure the joint and provide support, the bone surfaces are coated by a thin synovial membrane, which provides valuable friction-reducing lubrication. Within a healthy knee, abrasive contact is almost non-existent, allowing for movements to be pain-free and uninhibited.
Knee and cartilage damage may result from a traumatic injury, called post-traumatic arthritis, or emerge as the result of long-term wear and deterioration as in osteoarthritis or as the result of an inflammatory process such as rheumatoid arthritis. These have all been associated with the occurrence of progressive knee damage, and are associated with the need for both partial or total joint replacement.
Partial Versus Total Knee Replacement
Any or all of the three main joint sections may become damaged due to either wear-and-tear or injury. Common symptoms will include the development of progressive discomfort and restricted knee movement. If significant damage is present within all three sections, a total knee replacement most likely will be recommended; however, if only one requires intervention, a partial knee replacement may be considered. Determination of whether or not more than one compartment is involved will most often require careful examination and special testing, such as special X-rays and MRI examination.
For younger patients, and some older patients, the partial replacement procedure may be recommended, since only part of the joint may be damaged. Patients who undergo a partial knee replacement must understand that due to progressive damage in other compartments they will likely have to have another operation to convert the partial to a total knee replacement.
In cases of severe knee injury or advanced damage, a total knee replacement will be recommended for both the recovery of function and relief of pain. This procedure replaces only the surface of the three compartments, much like a cap on a tooth. It removes any damaged cartilage and therefore removes the arthritis.