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UniSpacer May Delay TKR for Patients with Early Osteoarthritis
July 31, 2003
By Julia Yuo for Knee1
Reviewed by Dr. James Lubowitz
Are you suffering from stiff and painful knee joints? Are you apprehensive about the possibility of having total knee replacement surgery?
Over 300 orthopedic surgeons in the United States are now performing less invasive surgery: the UniSpacer™. The UniSpacer (Centerpulse Orthopedics, Inc.) was introduced to the orthopedic community in 2002 to provide a simpler alternative to total knee replacement surgery for the relief of pain resulting from osteoarthritis of the knee joint. When performed on patients who are the correct candidates for the procedure, the UniSpacer procedure may postpone the need for total knee replacement surgery for up to ten years. In the best-case scenario, UniSpacer could allow certain patients to avoid knee replacement altogether.
The UniSpacer procedure is minimally invasive surgery with less risk of major complications compared with total knee replacement. In addition, the UniSpacer requires no bone cuts and no cement: patients have less pain and faster rehabilitation as compared to patients having total knee replacement. Preservation of bone stock is an issue especially pertinent to younger or more active patients.
Healthy knee cartilage has the ability to absorb stress by providing a smooth surface for the gliding movements of the bones in the knee joint. In the case of osteoarthritis, however, as the cartilage wears away and cracks due to strenuous exercise or overuse, the body is unable to repair itself fully. Early symptoms include stiffness and aching in the joint. Over time, a patient may feel pain as the bones of the joint start to rub against each other without normal cushioning.
Candidates for UniSpacer surgery are patients with early stages of osteoarthritis with worn or cracked cartilage of the medial compartment (the inside) of the knee joint. As the cartilage wears away in the medial compartment, a patient may experience pain, deformity (bowlegged or varus malalignment), and limitation of function.
The UniSpacer is a small, lightweight, C-shaped cup that requires neither screws nor cement to hold it in place. The UniSpacer is inserted between the femur (thigh bone) and tibia (leg bone) to fill the space where the cartilage has worn away. During surgery, an orthopedic surgeon makes a small incision, slightly bends the knee, and slides the device into the medial compartment. The leg is then straightened and surgery is complete.
By correcting leg deformity (malalignment), the UniSpacer restores normal ligament tension that is lost when - bones collapse due to cartilage loss. By replacing the missing cartilage, the UniSpacer restores the smooth surface allowing the bones in the joint to move without severe arthritis pain. Since the device is not attached to the bone, it is free to move within the knee joint. By moving with the knee, rather than against it, the UniSpacer is an effective substitute for the lost cartilage.
Patients who have already exhausted the use of drugs and arthroscopy and who are looking for alternatives for total knee replacement surgery should consult their orthopedic surgeon to see if the UniSpacer is right for them. The UniSpacer is not intended yet for patients who suffer from knock-knee (valgus) condition due cartilage damage to the lateral compartment (outsides) of the knee.
This minimally invasive surgery takes about one hour to complete. Recovery time is about 8 to 12 weeks where a leg brace is generally worn. About 6 to 8 weeks of physical therapy will follow.
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