When these kind of symptoms become limiting on mobility and activities of daily living primary care practitioners (or General Practitioners) will make a referral to an orthopaedic specialist. The specialist, a consultant knee surgeon, will examine the knee, its movement and the strength of the muscles around the joint. An x-ray will be necessary to show the surgeon the extent of the osteoarthritic change and an MRI scan may be necessary.
When the arthritic changes occur to this extent it would indicate that a total knee replacement is required rather than a partial knee replacement, which is suitable only when single-compartment osteoarthritis is present.
The patellofemoral compartment is the part of the joint shown at the top in the illustrations beneath the patella (or kneecap) itself.
The two condyles, as they are called, extend down from the femur and are called the medial (in-side) and the lateral (outside) condyles. In each of these illustrations the medial condyle is on the left hand side and the lateral on the right hand side. The simple way to remember this is that the lateral compartment is above the fibula, the smaller bone in the lower leg. The large bone in the lower part of the leg is called the tibia on which the two condyles bear. Arthritic change and the inflammation it causes increases friction in the knee joint, wears away cartilage and is the primary cause of the symptoms leading to knee replacement.
Treatment - surgery for total knee replacement
Before a patient is admitted for knee replacement they will be asked to make a visit for a pre-operative assessment. This is a thorough examination and education process during which routine tests are carried out. It is a very good opportunity for patients or their relatives to ask any questions to address their concerns about the upcoming operation and preparing for it.
The knee replacement operation itself at the most basic level involves removing the arthritic bone and tissue and covering the medial and lateral condyle and the top of the tibia with new bearing surfaces. The operation normally takes around two hours and is performed under anaesthetic. It is possible to use either regional or general anaesthetic, the latter being used in most instances.
During surgery a midline incision is made over the patella which is moved aside along with muscles and connective tissues. The operation is carried out with the knee in a bent position allowing all parts of the joint to be exposed. Arthritic bone is removed from both the tibia and femur, preserving as much healthy bone and tissue as possible. The tibia is hollowed out enough for the tibial implant to be inserted in a stable position and once the femoral and tibial compartments are smoothed over the surgeon will carefully measure both for the prostheses (implants).
Once measured a precise amount of bone will be removed from each part of the knee joint to ensure a good fit with the prostheses in place. Once the implants are inserted, which can be done with or without cement, the surgeon will bend and rotate the knee to confirm that it moves properly and the implants are aligned.