Osteoarthritis of the Knee & Knee Replacement

Osteoarthritis of the knee is one of the most common causes of knee pain in Western civilisation, particularly in middle aged and older patients. Early in the disease process it will often respond well to conservative measures, including non weight bearing exercise, weight reduction and anti-inflammatory medication. An arthroscopic debridement of the knee can sometimes be of benefit for acute inflammatory flare-ups of knee osteoarthritis. 

Total knee replacement should be considered as a treatment option when there is a failure to control symptoms with conservative treatment, or when symptoms become incapacitating. Knee replacement was first performed in 1968 and has revolutionised the treatment of this condition. A total knee replacement involves replacing the worn out ends of the distal femur (end of thigh bone) and the proximal tibia (top end of lower leg bone). The procedure is carried out with very precise instrumentation to allow careful resurfacing of the worn out ends of the bone. The femoral component consists of a cobalt chrome alloy and the tibial prosthesis is modular, consisting of a stemmed metal base plate and a polyethylene insert, which glides on the femoral prosthesis. The results of knee replacement today are excellent. There is over 90% of patients achieving excellent pain relief, correction of deformity and ease of movement. Most patients can expect the procedure to give life time pain relief. At 10 years after surgery most patients will have a good functioning knee, but a small percentage will require revision knee surgery either due to loosening of the prosthesis or wear of the polyethylene.

A knee replacement is a major undertaking and the patient needs to allow at least 6 to 8 weeks to recover from that procedure. In addition, every patient is a bit different in their recovery rate. It is usual to expect swelling of the knee for at least 8 to 12 weeks postoperatively. Although the procedure carries predictable success in most patients, complications can occur which can lead to a fair or poor outcome in a small percentage of patients. The potential complications associated with this procedure will be discussed at the time of your consultation.


Unicompartmental Knee Replacement

In approximately one third of cases of osteoarthritis of the knee the wear and tear is confined to one compartment of the knee (either medial or lateral). In these cases a unicompartmental knee replacement (see diagram) can be performed. It has several advantages, including a smaller incision, quicker recovery and allows the knee to move in a much more normal way than what occurs with a total knee replacement. The range of movement following a unicompartmental knee replacement is usually significantly better, and it is very unusual to need a blood transfusion, which is commonly required in a total knee replacement. The decision to perform a unicompartmental or total knee replacement is based on the localisation of the pain, the severity of the disease process and the degree of any knee deformity.
If you have any questions regarding knee replacement it is often a good idea to write them down prior to your consultation and use them as a memory jogger at the time of consultation.