Total knee replacement surgery removes the worn surfaces of the thigh bone and shin bone and, in most patients, the kneecap surface, and replaces them with metal and plastic implants. It is considered for advanced knee arthritis or other joint damage that causes pain limiting daily life after non-surgical treatment has been tried.
What is total knee replacement?
The knee joint is where the thigh bone (femur), the shin bone (tibia) and the kneecap (patella) meet. Each is covered with smooth cartilage. In total knee replacement, also called total knee arthroplasty, the worn surfaces of these bones are removed and replaced with a metal cap on the thigh bone, a metal tray with a plastic spacer on the shin bone and, in Dr. Aman's practice, usually a plastic button on the kneecap.
A partial replacement treats only one compartment of the knee. The comparison of total and partial knee replacement explains the difference.
Why is knee replacement needed?
Knee replacement is considered when pain from joint damage limits walking, stairs or sleep, and treatment without surgery has not been enough. Common causes are:
- osteoarthritis, where cartilage wears away and bone rubs on bone
- inflammatory arthritis such as rheumatoid arthritis
- avascular necrosis (AVN), where the bone loses its blood supply and collapses
- arthritis after an old fracture or ligament injury
Other knee operations
Knee replacement is only one of several knee operations. Keyhole knee surgery through small cuts, called arthroscopy, treats problems such as meniscus tears. A torn ligament may need ligament reconstruction. In some people, a joint-preserving operation called osteotomy is an option. Replacement is usually kept for advanced wear, and your surgeon will tell you which operation fits your knee.
The knee replacement surgery procedure, step by step
The details differ between patients and surgeons, and the general path is the same.
- Anaesthesia. The anaesthetist decides the type after assessment; in Dr. Aman's practice knee replacement is most often done under spinal anaesthesia.
- Exposure. A cut over the front of the knee gives access to the joint.
- Shaping the bone. The worn surfaces are removed with cuts planned so the implants sit correctly. Instruments, or in some cases a robotic arm under the surgeon's control, guide the cuts.
- Trial and balance. Trial components are fitted and the knee is tested through bending and straightening, so the ligaments are balanced.
- Final implants. The final components are fixed in place with bone cement, which is the usual method in Dr. Aman's practice.
- Closure. The wound is closed and a dressing applied. Physiotherapy begins soon after.
Mako robotic-arm assisted knee replacement is also available at Mahavir Health Campus, for both total and partial replacement. In Dr. Aman's practice a CT scan is done before Mako surgery, usually the day before, and robotic registration adds about 20 minutes of theatre time; conventional replacement remains a very good option for an uncomplicated knee. What it does and does not do is explained on the robotic knee replacement page.
Preparing for total knee replacement
Before surgery you will have an examination, X-rays and sometimes further scans, plus blood tests and a check of your heart, diabetes and blood pressure if relevant. Infections in the teeth, urine or skin are treated first. Bring a list of all medicines, and follow instructions on which to pause. A pre-operative assessment is done so that risk can usually be anticipated, and surgery is sometimes not advised for a patient who is medically unfit. Strengthening the thigh muscles beforehand, with pre-operative physiotherapy for some patients, and arranging help at home for the first weeks make recovery smoother.
Recovery in brief
You will usually get out of bed with a physiotherapist within a day or two and stay in hospital for 2 to 3 days in Dr. Aman's practice, or up to about 5 days when other medical conditions need attention. Walking aids are used for some weeks, and many people reach their functional level over three to six months. After a partial knee replacement the hospital stay is usually 1 to 2 days, and in most patients early recovery is quicker than after a total replacement. The stages are described in detail in our guide to knee replacement recovery time.
Risks of total knee replacement
The main risks of knee replacement are infection, blood clots in the leg or lung, stiffness, and persistent pain or swelling. Less often there is bleeding, injury to a nerve or blood vessel, kneecap problems or a reaction to the anaesthetic. Over the years the implants can wear or loosen, and that may need revision surgery. Your surgeon goes through the risks that apply to you before you decide.
Implants and cost
Knee implants differ in design, materials and fixation, and the choice of implant is one of the things that changes cost. These are covered in the knee implant guide, and no figures are given here. Cost factors are on the knee replacement cost page.
When to see a doctor about your knee
See an orthopaedic surgeon if knee pain limits walking, stairs or sleep for several weeks, if the knee is becoming more deformed, or if there is night pain. A hot, swollen knee with fever needs same-day medical attention.
The knee replacement in Surat page covers the surgery in more detail, and the clinic and hours page lists OPD timings.