Knee Replacement Revision Surgery

CORRECTING KNEE REPLACEMENTS THAT HAVE GONE WRONG
Joint replacement is one of the most successful operations in the whole of medical field and millions of people have benefitted from this procedure. The fact that almost one million joint replacements are done in the US alone each year and the numbers are steadily increasing each year stands testimony to the success of the procedure. In India, the number of joint replacements has been increasing steadily over the last decade with over 10% growth each year. While joint replacements are extremely successful and perform very well for about 15 -20 years, they may wear out with time. After 15-20 years, 10 to 20 % of joint replacements require a revision surgery as they get worn out. With current advances in the field of joint replacement, they are expected to last even longer.When they fail after having served their purpose, they may be corrected by revision surgery.

Why knee replacements fail

LOOSENING OF KNEE REPLACEMENT
With time, as the joint is loaded and used millions of time over many many years, they can become worn out. The smooth bearing surface of the artificial joint is lost. This may result in loss of the stable interface between the bone and the implant. Once loosening occurs, the joint may become painful and unstable. Implant loosening can be detected on Xrays. Some times other tests such as bone scans may be required to detect loosening. Once loosening occurs, the supporting bone may become weak. In such cases it is necessary to revise the implant to prevent further damage to the bone. With revision surgery, a new implant is generally fixed to the bone and one can expect to return to the state of well functioning joint replacement.

INFECTED KNEE REPLACMENT
Joint replacement is associated with a small risk of infection. With current surgical techniques, antibiotic regimens and operating theatre conditions, infection rate is about 0.5%. Infection can cause the prosthesis to loosen. Infection may manifest with swelling, pain, drainage or loosening of the joint. Infection is often confirmed by taking fluid from the knee for testing, in addition to certain blood tests. Infection of a joint replacement may require revision surgery.

INSTABILITY AFTER KNEE REPLACMENT
If you are having unexplained pain even after knee replacement, it may be due to instability. Instability after knee replacement is due to laxity of soft tissues in the joint. It may happen when the soft tissues are not balanced well at the time of surgery or if they fail after surgery. In such cases, Xrays are normal but the joint continues to be painful. This can be detected only by careful examination by a surgeon with experience in this field. Such cases are generally managed with bracing and exercise program. If this does not address the problem, surgery may rarely be required.

REVISION KNEE REPLACMENT
Revision of a knee replacement may involve simple change of the plastic insert, revision of the knee cap, or leg bone or thigh bone components or a combination of these. Similar to hip revision, knee revision is a technically challenging procedure that involves the use of specialised techniques and instruments that is best undertaken by someone with formal training in this field. Dr Arun Kannan's work in this field has been presented in the prestigious Journal of Arthroplasty published bythe American Academy of Hip and Knee Surgeons

Below is an example of complex knee revision surgeries undertaken by our doctor. A 65 year old lady who had a well functioning knee replacement for several years, developed an infection that required removal of implants. She was then placed on antibiotics to clear the infection.