If your knee is affected by severe arthritis or injury it may be difficult to perform simple activities such as walking, climbing stairs or sitting comfortably for prolonged periods. You may even feel the pain lying down. In India 1 in 5 patients over the age of 65 has some form of arthritis and in 1 in 20 patients the knee is the most severely affected joint.
HOW THE NORMAL KNEE WORKS
The knee is the largest joint in the body and each knee carried half the body weight. It is the articulation between the lower part of the thigh bone (femur) and the upper part of the leg bone (tibia). These are covered by a smooth layer of cartilage called articular cartilage. There is rotation and hinge activity between these two bones. In addition the kneecap or patella is covered by articular cartilage on its under surface and slides in the groove on the front of the femur. There are two large ligaments joining the two bones together, reinforced by strong muscles and tendons at the back and the front of the joint.
The initial treatment includes drugs to reduce pain and inflammation, changing activity levels, using walking supports and physiotherapy, and injections. Occasionally keyhole surgery is advised to clean out any damaged areas. However, if these are not successful in curing the symptoms, a total knee replacement may be considered. This operation resurfaces the knee joint removing diseased bone and cartilage from the lower end of the thigh bone, the upper end of the shin bone and the back of the kneecap (patella). These surfaces are replaced with metal and plastic implants which allow natural knee motion and function and at the same time relieve pain and correct any deformity, enabling you to resume a greater range of normal activities.
Knee replacement was developed following the success of hip replacement. The early knee replacements in the 1960s and 70s were fairly basic and the results were mixed. Improvements in surgical materials and techniques have greatly increased the effectiveness so that knee replacement surgery today has a high rate of success in relieving pain and restoring mobility.
When is Surgery necessary?
You may be offered knee replacement surgery if:
THE DECISION TO HAVE TREATMENT
This should only be made after discussion with the Orthopaedic Surgeon whose team is going to carry out the operation. The Surgeon will discuss benefits and risks of treatment, and will emphasise that surgery cannot be guaranteed to meet all expectations. There must be a realistic expectation by the patient about what the operation can achieve and, whilst over 90% of patients have dramatic reduction in pain, the operation will not allow a high level of athletic activities and in particular some high impact sports will be excluded from normal activities.
THE ORTHOPAEDIC ASSESSMENT
This consists of several components:
Knee replacement can be performed under a general or spinal anaesthesia, which numbs the lower limbs but you remain awake.
Most patients are admitted the day prior to surgery. The operation usually takes place with a tourniquet around the thigh to reduce the amount of bleeding and enable the components to be fitted accurately into position. The incision can be anything from 10 to 20cm in length depending on the type of approach and the size of the leg. The components may be implanted by shaping the bone to form a tight fit with the prosthesis, which is coated with a special material which allows bone to grow on to the surface and provide fixation (uncemented prosthesis); alternatively bone cement may be used to hold the prosthesis in place (cemented). The wound is closed with internal stitches to keep all the ligaments and muscles securely together, and clips, sutures or special tape on the skin.
Following the total knee replacement you will be transferred from the operating theatre into the Recovery area.
An exercise programme is an important part of recovery. This starts with gentle exercises in bed. Patients are normally advised to get out of bed with the help of physiotherapy on the second day.
Most patients can begin physical therapy immediately after surgery. A frame, crutches or a stick may be needed for up to 6 weeks.
Report to the Doctor or Medical Staff any of the following: