Joint replacement
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Joint replacement consists of replacing painful, arthritic, worn or cancerous parts of the joint with artificial surfaces shaped in such a way as to allow joint movement.
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[edit] Timeline
Because of the major surgery a complete pre-anaesthetic work-up is required. In elderly patients this usually would include ECG, urine tests, haematology and blood tests. Cross match of blood is routine also as a high percentage of patients receive a blood transfusion. Pre-operative planning requires accurate Xrays of the affected joint. The implant design is selected and the size matched to the xray images (a process known as templating).
A few days hospitalization followed by several weeks of protected function, healing and rehabilitation. This may then be followed by several months of slow improvement in strength and endurance.
Early mobilisation of the patient is thought to be the key to reducing the chances of complications such as venous thromboembolism and Pneumonia. Modern practice is to mobilize patients as soon as possible and ambulate with walking aids when tolerated. Depending on the joint involved and the pre-op status of the patient the time of hospitalization varies from 1 day to 2 weeks with the average being 4-7 days in most regions.
Physiotherapy is used extensively to help patients recover function after joint replacement surgery. A graded exercise programme is needed. Initially the patients' muscles have not healed after the surgery; exercises for range of motion of the joints and ambulation should not be strenuous. Later when the muscle is healed the aim of exercise expands to include strengthening and recovery of function.
[edit] Risks and complications
[edit] Medical risks
The Stress of the operation may result in medical problems of varying incidence and severity.
- Heart Attack
- Stroke
- Venous Thromboembolism
- Pneumonia
- Increased confusion
- Urinary Tract Infection (UTI)
[edit] Intra-operative risks
- Mal-position of the components
- Shortening
- Instability/dislocation
- Loss of range of motion
- Fracture of the adjacent bone
- Nerve damage
- Damage to blood vessels
[edit] Immediate risks
- Infection
- Superficial
- Deep
- Dislocation
[edit] Medium-term risks
- Dislocation
- Persistent pain
- Loss of range of motion
- Weakness
- Indolent infection
[edit] Long-term risks
- Loosening of the components: the bond between the bone and the components or the cement may break down or fatigue. As a result the component moves inside the bone causing pain. Fragments of wear debris may cause an inflammatory reaction with bone absorption which can cause loosening. This phenomenon is known as osteolysis.
- Wear of the bearing surfaces: polyethylene is thought to wear in weight bearing joints such as the hip at a rate of 0.3mm per year. This may be a problem in itself since the bearing surfaces are often less than 10 mm thick and may deform as they get thinner. The wear debris may also cause problems.
There are many controversies. Much of the research effort of the orthopedic-community is directed to studying and improving joint replacement. The main controversies are
- The best or most appropriate bearing surface - metal/polyethylene, metal-metal, ceramic-ceramic
- Cemented vs uncemented fixation of the components
- Minimally invasive surgery
[edit] See also
[edit] Specific joint replacements
[edit] Related treatents
[edit] External links
- The KNEEguru - educational site packed with knee content with sections on knee joint replacement
- Patient Information from the American Academy of Orthopedic Surgeons
- Patient Information from the FDA
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