Knee Replacement – What you need to know
Damage to the knee may happen due to wear and tear from age and sport activities, or physical traumas like fractures causing ligament injuries to the knee. In some of these cases, the damage might be severe enough to affect one's daily mobility and quality of life, and does not heal on its own. In these cases, knee replacement should be considered to minimize the disruptions to daily activities as well as the pain associated with it.
In this article, we share with you what you need to know about Knee Replacements.
Table of contents:
- Understanding the Knee
- When is Knee Replacement necessary?
- Understanding Knee Replacement
- Revision Surgery for worn-out Knee Replacements
- Understanding Revision Knee Replacement
Understanding the Knee
The knee is an important joint for almost any leg movements and plays an integral part in a person's mobility. Because of the relative complexity of the knee joint, it is susceptible to many different types of injuries like anterior cruciate ligament (ACL) tears, posterior cruciate ligament (PCL) tears, meniscus tears and more. Knee injuries can greatly affect one's performance of daily activities and causes difficulty to move from place to place.
The knee joint is formed by the lower end of the femur (thigh bone) and the upper end of the tibia (shin bone). The surfaces of the joint are covered by a smooth elastic soft tissue called cartilage.
The cartilage allows the joint surfaces to glide smoothly and painlessly against each other. Damage to the cartilage and bone within the knee joint is called osteoarthritis of the knee joint, or knee arthritis. This can result from:
- Wear and tear (degenerative conditions)
- Trauma (fractures and ligament injuries)
- Avascular necrosis (depletion of the blood supply to the bone)
- Inflammatory disorders (such as rheumatoid arthritis)
Symptoms and Diagnosis of Osteoarthritis
Patients who develop osteoarthritis of the knee joint can present with symptoms like:
- Knee pain and stiffness
- Joint deformity
- Not being able to walk as fast as they used to
This can sometimes be severe enough to affect one's daily mobility and quality of life, such as simple activities like walking and climbing stairs. The diagnosis of knee osteoarthritis is made after a thorough clinical assessment of the knee joint. X-rays and MRI scans are also done to further confirm the diagnosis, since these knee symptoms are widely shared with other knee injuries such as ACL, PCL and meniscus tears. Occasionally, additional blood tests may be done to find out the underlying cause of the osteoarthritis.
When is Knee Replacement necessary?
Most knee pain tend to go away on its own after a few days after the inflammation subsides. However if the pain persists, or it's significant enough to affect your daily activities, you might want to consider contacting a orthopaedic clinic like us, where we have highly experienced orthopaedic surgeons ready to help you and find out the root cause of your knee pain and recommend the appropriate treatment.
A thorough diagnosis of knee pain and condition will be carried out. Patients with early osteoarthritis and mild symptoms may be treated non-surgically with a course of rehabilitation by our physical therapist. However, patients with severe symptoms and advanced osteoarthritis may be candidates for surgical treatment, in the form of knee replacement surgery.
Understanding Knee Replacement
Knee replacement surgery involves replacing the worn out surfaces of the knee joint with prosthetic devices which are made of cobalt-chromium, titanium and polyethylene (medical grade plastic).
If only one compartment of the knee is involved, then partial knee replacement may be performed. In this procedure, only the affected part of the knee surface is replaced by prosthetic components.
If more than one compartment of the knee is affected by osteoarthritis, then total knee replacement is carried out. In this case, all the surfaces of the knee are replaced by prosthetic components.
Such surgery is usually performed under general anaesthesia and may take about 2 hours to perform. A 3-4 day stay in hospital is usually required and for a few weeks after the surgery, about 2-6 weeks of walking aid-assisted ambulation may be advised until full recovery.
The rehabilitation process after the surgery is generally supervised by a physiotherapist, and consists of progressive range of motion exercises, muscle strengthening exercises, and functional therapy. The whole rehabilitation process may last to 3-6 months following the procedure. The success rate of knee replacement surgery has been reported to be 90%. The complications of this procedure include deep vein thrombosis, infection and prosthetic wear.
Revision Surgery for worn-out Knee Replacements
However, in some patients, the knee replacement may loosen, wear out or develop instability overtime. Patients who develop such complications may experience symptoms such as pain, stiffness and difficulty walking.
The diagnosis of a malfunctioning knee replacement is made after a thorough clinical assessment of the knee joint. X-rays, CT scans and specialized MRI scans may also be needed to confirm the diagnosis and to look for associated problems such as bone loss around the knee replacement.
Understanding Revision Knee Replacement
In patients who develop a malfunctioning knee replacement, revision surgery may be necessary to reduce pain and restore mobility. The surgery involves replacing one or more components of the knee replacement, which have failed. At the same time, areas of bone loss may need to be restored with bone graft from the patient himself (autograft) or from a donor (allograft), or replaced with metal blocks.
Revision knee replacement is a technically demanding procedure and should be carried out by surgeons who are trained and experienced. Such surgery is usually performed under general anaesthesia and may take about 2-3 hours to perform. A 3-4 stay in hospital is usually required after the surgery and 2-6 weeks of walking aid-assisted ambulation may be advised until full recovery.
The rehabilitation (or physical therapy) process after revision knee replacement is often slower and longer compared to that following primary knee replacement. It may last up to 6-12 months following the revision procedure. The success rate of revision hip replacement has been reported to be approximately 80%. The complications of this procedure include deep vein thrombosis, infection and loosening of the new prosthesis.
Most knee pain will go away on its own, but if it is severe enough to affect your daily activities, seek medical help from an orthopaedic surgeon like us, and we'll help you to diagnose and recommend the right treatment for your knee condition and other orthopaedic conditions.