Knee replacement surgery is offered to patients with advanced degenerative or inflammatory knee arthritis, who have not responded adequately to more than 6 weeks of supervised physiotherapy; and in whom knee pain and/ or disability is causing a significant impact over activities of daily living.
This procedure involves replacement of damaged cartilage with Metal components and High density polyethylene insert. Typically, the femoral components are made of Co-Cr alloy, tibial components are Ti-Al-Vn alloys, and polyethylene insert is highly cross-linked polymer to reduce frictional wear.
With the advent of latest technology, the success rates after knee replacement surgery have gone very high, with a patient satisfaction rate of more than 90 percent.
CUSTOM KNEE REPLACEMENT SURGERY
Custom Knee Replacement is the latest technology that can offer best alignment for an individual knee implants.
This technology utilizes patient’s MRI/ CT data to design special instruments that are specific for the patient’s anatomy.
- Each knee joint has a different anatomy and morphology. Custom made instruments help to restore the mechanical axis as close to the natural axis as possible. Technically, it helps to get the best size and fit for a knee replacement.
- Significant reduction in Surgery time, thereby reducing risk of infection, and other complications.
- The Surgeon can avoid making a hole in the Femoral canal for Intra-Medullary alignment, a technique used in traditional knee replacement surgery. This can significantly reduce the risk of embolism.
It adds to the cost of knee replacement by approximately 10 %.
In Custom knee replacement, the implants are designed for the individual knee.
In a Custom Knee Replacement surgery, the surgeon uses the same set of implants, as in a conventional surgery.
OXINIUM KNEE REPLACEMENT
Laboratory wear testing has indicated that OXINIUM total knee implants demonstrate the scratch and wear resistance necessary to be long lasting. The smooth, hard surface of an OXINIUM total knee implant is the result of a process that allows oxygen to absorb into zirconium metal, which changes only its surface from metal to ceramic. The ceramic surface makes OXINIUM implants 4,900 times more abrasion resistant than cobalt chrome and reduces friction between the implant and plastic surface. *Smith&Nephew
Unlike conventional cobalt-chromium implant, Oxinium implants are believed to be safe in patients suffering with metal sensitivity, as they do not contain significant levels of Nickel.
Author’s Disclaimer: Oxinium knee replacements have been done for past 10 years. So far, the results between Co-Cr alloy and Oxinium implants have been comparable. We do not have any clinical study to support the laboratory proven wear rates, and survival up to 30 years. However, the US-FDA has approved the use of Oxinium Knee Implants, and considering the lower likelihood of causing metal sensitivity, it remains a viable option in younger patients opting for Knee Replacement Surgery. The benefits/ limitations MUST be discussed with the patient before offering this implant.
HIGH FLEXION KNEE REPLACEMENT SURGERY
Conventional Knee replacement implants offer approx. 90 – 100 deg knee flexion. This range is sufficient to perform majority of activities of daily living.
However, In patients keen to sit on the floor after Surgery; there are some implant designs that allow up to 130 – 135 deg of knee flexion. Such designs may allow patients to sit cross legged on the floor.
Certain positions like squatting and kneeling should altogether be avoided by the patients, as it may lead of enhanced eccentric wear of the polyethylene component, thereby limiting the implant longevity.
Knee flexion after surgery depends upon a lot of factors, most important among which in the knee flexion before surgery. Good supervised physiotherapy also helps in achieving knee flexion.
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