Total Knee Replacement (TKR) is an operation where your arthritic knee is replaced in all compartments with an artificial prosthesis, made of metal (Titanium, and Cobalt and Chromium alloys), and medical polyethylene (plastic)  TKR is advised when knee pain, loss of mobility, impaired function and deformity severely affect the quality of a person's life. Usually medical treatments have been tried unsuccessfully. This includes modalities such as pain medications, anti-inflammatory drugs, intra-articular injections, physiotherapy, use of walking aids, lifestyle changes, weight reduction, and the use of knee braces.

Making the decision to have a TKR operation. The decision to have a TKR is made after discussion with your orthopaedic surgeon, and you should only proceed when you are satisfied that you understand what is involved with the operation, you have realistic expectations of what the operation can acheive for you, and you are aware of the potential risks and complications that might  possibly occur. A successful TKR will relieve pain from an arthritic joint, correct deformity due to abnormal alignment of the knee joint, and restore function and mobility. You TKR should be able to bend well beyond 90degrees, but stiffness due to fibrosis (Scar tissue), occasionally results, and limits this. (See Complicationsof TKR). You will be able to return painfree to most daily activites, including modest excercise, such as golf, walking, dancing, swimming, gardening and bowls. Kneeling may not be possible, about one third of patients who have had a TKR kneel subsequently.

Preparation for TKR surgery: TKR is a major operation, although most people now recover quickly, and uneventfully from this procedure. This is due to careful pre-operative assessment and prepararion before the operation. A thorough medical assessment by a specialist physician is usual, to treat any associated medical disorders such as high blood pressure, asthma or breathing disorders, heart disease, diabetes, sleep apnoea, obesity, kidney or liver disorders, etc., and any potential unexpected sources of infections, such as varicose leg ulcers, or carious teeth. This assessment is important, as there may be conditions found that you were not aware of, that can cause anaesthetic, surgical or rehabilitation difficulties if not treated first. Your medications will need to be reviewed, and some will need to be stopped before surgery, such as aspirin or anti-inflammatory pills, that cause increased bleeding at operation.

Our pre-admissions nurse will also see you pre-operatively to show you around the ward, and outline the procedures for you. She will also organise post operative aids, and occupational and physiotherapy that you may later need,  and arrange referral for rehabilitation when necessary. The pre-admissions nurse acts as a point of contact for you before your TKR operation.

Complications of TKR: Every effort is made to minimise the risk of complications after TKR surgery, but for any major operation, risks and complications cannot be completely eliminated, and occasionally occur. Serious complications occur rarely, less than 1% of operations. Some general complications that may occur include haemorrhage, anaesthetic difficulties with breathing or chest complications after operation, wound infections or wound healing difficulties, urinary infections, blood clots in the legs. The TKR may develop later problems, with pain due to wearing, loosening, or late infections. Mechanical problems may occur due to instability, or wear pain due to malalignment of the knee cap after operation, or deformity of the knee after TKR. Knee stiffness due to scar tissue formation occurs in 5% cases and will require further management. Injuries to arteries or nerves, causing numbness or weakness of movements occur rarely, but may be serious and permanent..Later complications need to be managed by an Orthopaedic surgeon experienced in assessing these problems, and re-operating (revision surgery) if required. Mr. Lowe and Mr. Lade both have expertise dealing with these difficult cases.

Knee Replacement Surgery

The steps involved in replacing the knee begin with making an incision on the front of the knee to allow access to the knee joint. There are several different approaches used to make the incision, usually based on the surgeon's training and preferences.

Shaping the Distal Femoral Bone: Once the knee joint is entered, a special cutting jig is placed on the end of the femur. This jig is used to make sure that the bone is cut in the proper alignment to the leg's original angles, even if the arthritis has made you bowlegged or knock-kneed. The jig is used to cut several pieces of bone from the distal femur so that the artificial knee can replace the worn surfaces with a metal surface.

Preparing the Tibial Bone: Attention is then turned toward the lower bone, the tibia. The top of the tibia is cut using another jig that ensures the alignment is satisfactory.

Preparing the Patella: The undersurface of the patella is removed.

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Placing the Femoral Component: The metal femoral component is then placed on the femur. When using an uncemented femoral component, the prosthesis is held on the end of the bone through a taper on the end of the bone. In addition, the metal prosthesis is cut so that it matches the taper almost exactly. Driving the metal component onto the end of the bone holds the component in place by friction. The stable implant will allow bone tissue to grow into the porous surface, providing long-term stability. With a cemented femoral component, an epoxy cement is used to attach the metal prosthesis to the bone.

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Placing the Tibial Components: The metal tray that will hold the polyethylene spacer is attached to the top of the tibia. The metal tray is either cemented into place, or may be held with screws if the component is uncemented. The screws are primarily used to hold the tibial tray in place until the bone grows into the porous coating. (The screws remain in place and are not removed.)

The plastic spacer is then attached to the metal tray of the tibial component. If this component wears out while the rest of the artificial knee is sound, it can be replaced.

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Placing the Patellar Component: The patella button is usually cemented into place behind the patella.

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The artificial knee replacement is now complete.

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Closing the Incision: There are several ways that orthopaedic surgeons can close the incision after performing an artificial joint replacement. Stainless steel staples are popular with many orthopaedic surgeons because they are easy to put in and easy to take out. This can reduce time in the operating room. The stainless steel staples are one of the most inert types of sutures, meaning they have a very low risk of allergic reaction by the patient.

Some surgeons prefer using sutures that dissolve on their own after several weeks. These stitches are normally put in just under the skin. The advantage of this type of closure is that you don't have to have your stitches taken out! Usually there are special tape closures (sometimes called "butterfly" tapes or "steri-strips") that are used to hold the edges of the skin closed for the first few days. If you see strips of tape across the incision, this is probably the type of closure that was done. This type of incision closure takes a bit more time in the operating room. There is also a small chance that you may have an allergic reaction to the stitch material that delays the healing of the incision, but this risk is pretty small.

Finally, many surgeons still use the old "tried and true" nylon stitches one at a time. Nylon has withstood the test of time and is nearly as inert as stainless steel. It is strong and holds well until it is removed (somewhere between 10 to 14 days after surgery).