| Knee replacement in young patients | | | | that has been used successfully for knee & hip |
| Dr.A.K.Venkatachalam | | | | implants. It is a metal with a coating of ceramic. In |
| Consultant orthopedic surgeon | | | | the manufacturing process, prosthetic components |
| Chennai | | | | made of Zirconium are heated and infused with |
| Unheard of until recently, this is now becoming a hot | | | | oxygen to create a ceramic surface on metal. This |
| subject of deliberation amongst patients and | | | | ceramic surface is more durable than normal metals. |
| orthopedic surgeons. Normally the typical patient for | | | | This material received FDA approval in 1996. After |
| a knee replacement would be a patient in their golden | | | | rigorous testing, this material received approval for |
| years of life. Surprisingly now increasingly large | | | | use in knees. |
| number of young patients, plagued by end stage | | | | Advantages of Zirconium knees |
| arthritis from various causes, are now seeking an end | | | | The significant advantage of a Zirconium knee implant |
| to their constant pain and stiffness by demanding a | | | | is that it is considerably harder. On testing it lasts 85 |
| total knee replacement. The number of patients less | | | | times longer in tests that simulate the stresses inside |
| than 65 years old seeking a knee replacement is | | | | the actual knee. |
| increasing. According to a national sample survey in | | | | Additional advantages are scratch resistance. When it |
| the US done in 2005, about 9660 patients less than | | | | is wet, ceramic can glide smoothly along plastic, |
| 45 years underwent a primary total knee | | | | making for smoother motion than with |
| replacement. This figure is expected to touch 108000 | | | | metal-on-plastic. As a result, the Oxinium total knee |
| by 2030. To quote some figures, 27 percent of TKR | | | | replacement will not generate the quantity of plastic |
| recipients are between 18 and 64 years. This is | | | | wear debris that cobalt chrome will, and the implants |
| setting a new trend in orthopedic surgery. | | | | should last considerably longer. |
| At present Knee replacement is advised for elderly | | | | Zirconium is one of the six most biocompatible |
| patients. Whenever orthopedic surgeons come across | | | | elements know to man. So, your immune system will |
| younger patients less than 65 years, they generally | | | | more easily tolerate your new implant. |
| advise exhaustion of conservative measures before | | | | Lastly, patients who are allergic to nickel, the metal |
| proceeding to a total knee replacement. As the | | | | most often used in the current implants, cannot |
| above figures show, more and more younger | | | | currently receive total knee replacements. The |
| patients are likely to demand a total knee | | | | ceramic implant, however, can be implanted safely in |
| replacement in years to come. | | | | patients with nickel allergies, since it uses a zirconium |
| Younger patients live a more active life style and | | | | alloy with no nickel. Implants made of Oxinium have |
| joint replacement is likely to result in early failure if | | | | been implanted in larger number of patients in the UK |
| standard approaches are adopted. | | | | Australia and the US with great success. |
| The purpose of this article is to inform readers | | | | Who would benefit most from an Oxinium total knee |
| particularly the younger ones about some of the | | | | replacement? |
| advances in Joint replacement for the young patient | | | | Three types of patient have been identified as the |
| with knee arthritis. | | | | "best" candidates for an Oxinium total knee |
| Conditions | | | | replacement. |
| The conditions leading to end stage arthritis in the | | | | "Younger" patients: Because Oxinium knee implants |
| young are rheumatoid arthritis, post traumatic | | | | offer significantly less wear compared to cobalt |
| arthritis, ankylosing spondylitis, post infective arthritis | | | | chrome implants, they are expected to last |
| hemophilic arthritis and osteoarthritis in the genetically | | | | considerably longer. In the past, orthopedic surgeons |
| predisposed young patient. | | | | have advised patients less than 65 years of age to |
| Survivorship of standard knee replacements | | | | wait to have knee replacement surgery because the |
| Conventional knee prostheses are made of an alloy | | | | life span of the cobalt chrome knee implants is only |
| of Cobalt, Chromium, Molybdenum & Nickel and | | | | 10-15 years. Now, surgeons have a viable option for a |
| Titanium. The plastic component is high density poly | | | | younger patient who previously would not be a |
| ethylene. The survivorship is such that 1 % of every | | | | candidate for a total knee replacement because the |
| 100 knees fail every year, so that after 15 years, 85 | | | | Oxinium knee implants should last much longer. |
| % of knees implanted on day one are expected to | | | | Therefore, a patient under the age of 65 who has |
| survive or remain intact without loosening. This | | | | advanced arthritis of the knee no longer has to |
| excludes loosening due to faulty insertion and | | | | suffer for years until he reaches an appropriate age |
| infection. So in the elderly patient, a reasonable | | | | for total knee replacement surgery. |
| outcome is expected with the prosthesis expected | | | | "Active" patients: Patients, who desire to return to an |
| to outlive the person. | | | | active lifestyle, including sports, dancing, gardening, or |
| In the young however the situation is different. | | | | other strenuous activities, may also benefit from an |
| Historically, total knee replacements are known to | | | | Oxinium knee replacement. As a result of their high |
| have poor outcomes in the young due to their higher | | | | activity level, this patient population will put more |
| activity levels compared to older patients. Hence | | | | "wear and tear" on their knee replacement, which can |
| surgeons are reluctant to place them in younger | | | | cause the implants to wear more quickly. An Oxinium |
| patients as they are bound to outlive their implants. | | | | knee is better able to tolerate this high activity level |
| Better materials | | | | and last longer that the traditional cobalt chrome |
| With the advent of newer materials and designs of | | | | knee. |
| knee prostheses, these perceptions are about to | | | | Metal allergy patients: Because Oxinium is one of the |
| change. The biggest advance is the availability of | | | | most biocompatible materials known to man; It is the |
| newer materials like Ceramic for knee replacements. | | | | only choice for patients who exhibit metal allergies. |
| Pure ceramic or ceramic coatings on metal are the | | | | Patients who have needed total knee replacement |
| latest in technology. | | | | surgery, but could not tolerate the cobalt chrome |
| Titanium carbide has been used for dental implants | | | | implants due to their nickel content, can now have |
| but its use as a bearing surface in hip & knee | | | | the surgery they need to return to an active lifestyle |
| prostheses is not widespread. Knees made of | | | | without the fear of an allergic reaction. |
| ceramic are in restricted use. Implantation of pure | | | | Three designs are available, the Genesis knee, |
| ceramic knees requires specialized instrumentation. | | | | Journey knee and the Deuce knee, according to the |
| Oxinium or Oxidised Zirconium is the wonder material | | | | manufacturer, Smith & Nephew. |