Osteoarthritis of the knee
Total knee replacement:
The artificial implant that is used to replace damaged areas of the knee joint is called a knee prosthesis. The procedure is also called prosthetic knee replacement surgery. The total knee prosthesis is made up of 4 pieces: tibial and femoral (metallic) components, polyethylene (between the two metallic pieces), and a patellar button.
Total knee prosthesis
This operation has considerably improved the quality of life of patients suffering from advanced osteoarthritis, who are no longer relieved by medical treatments, or by inflammatory diseases such as polyarthritis. Advances in implants as well as improved surgical techniques and post-operative pain management have significantly contributed to the quality of current results in knee function and pain. The lifetime of a prosthesis is now on average 15 to 18 years.
The duration of hospitalization is approximately 3 to 5 days. Rehabilitation of the operated knee as well as walking are started from the first or second day after the operation and is continued for approximately 2 months after discharge. Usually the recovery time for a correct function is around the 3rd month post-operatively and a steady situation is achieved between the 6th and 12th month postoperatively.
Partial prostheses (uni-compartmental prosthesis) are reserved for arthritis limited to one compartment of the joint, most often the internal compartment of the knee.
Partial knee prosthesis (hemi-prosthesis)
Early post-operative complications:
• Infection is a feared complication because it is potentially serious. It is a uncommon, and occurs in, less than 1% of cases based on currents studies. All precautions must be taken (compliance with aseptic measures, a thorough preoperative assessment aimed at finding any infectious sources on the patient in order to eradicate them before the intervention).
• Deep vein thrombosis. This complication is potentially serious because it can develop into a pulmonary embolism. Prevention is with post-operative anticoagulants.
• Hematoma. This can be normal (mild and of small volume) or much larger corresponding to active bleeding and sometimes requires re-intervention for evacuation
• Algodystrophy is a rare and unexplained complication that can cause stiffness, pain, and edema which ultimately slow down functional recovery. It is a dysregulation of the autonomic nervous system and the available treatments are not very affective. Algodystrophy can last for several months and disappears spontaneously. During this period, no aggressive knee treatment or surgical intervention will be undertaken, except in emergent cases
• Knee stiffness can occur after any knee surgery, and in particular after a total knee prosthesis. Adhesions can form in the joint leading to mobility restrictions. Various causes of stiffness include postoperative pain, hematoma, infection (rare), inappropriate rehabilitation, inflammation, or algodystrophy. By nature, everyone reacts differently to tissue scarring after knee surgery and some patients will develop these kinds of complications slowing recovery. Knee mobilization under anesthesia may be necessary to improve mobility and pain. The goal is to break down scar tissue at the latest a few weeks after the intervention.
Midterm and long term complications:
These include late infections, chronic stiffness, and loosening of the prosthesis:
• Late infection is very rare and occurs most often secondary to a distant infection which subsequently spreads to the prosthesis. Examples of this include a dental abscess, urinary tract infection, digestive tract infection, skin infection etc..It is therefore important that any patient with a knee prosthesis be treated adequately for any infection and followed by a doctor who is aware of the patient’s implant. The treatment of these late infections may require re-intervention to replace the prosthesis and a long course of antibiotic therapy
• Chronic stiffness is rare and difficult to treat.
• loosening of the prosthesis leads to more pain or pain that is less well tolerated. This is often associated with wear of the prosthesis and increases with age of the prosthesis and the degree of stress imposed on it (heavy physical activity, overweight). On average, loosening occurs approximately 18 years after the operation and may require reoperation for replacement of the prosthesis.