4. Dr Ashok Rajgopal.Cdr
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Review Journal of Clinical Orthopaedics 2017 Jan-June;2(1):10-13 What is New in Total Knee Replacement Ashok Rajgopal1, Vivek Dahiya1 Abstract Total knee replacement is a Gold standard for treatment of arthritis of knees. It has stood the test of time and has delivered excellent results. With time the number of knee replacement are increasing and the age of patients are decreasing. Technological advances have kept pace with the newer designs which have helped deliver better results to the patients Keywords: Total knee replacement, new updates, technology Background adhere to the age old nuances of “Let it cellophane, and many other materials The knee is the largest joint of the be , you are getting old”. In the past two have been used, but results were human body and it is involved in almost decades the average age of the patients disappointing. The use of metallic all the activities of daily living. It is undergoing knee replacement surgery interposition arthroplasty began in the prone to repetitive micro trauma leading has come down resulting in an increased late 1930s. Today implants are made of a to wear and tear of the cartilage which in demand on the knee joint [3]. The highly polished cobalt chrome alloy turn leads to osteoarthritis of the knee challenges for the Orthopaedics surgeon which is a very strong alloy well joint. Osteoarthritis makes a knee stiff, are manifold. Not only does he need to tolerated and accepted by the human painful to walk on and inhibits an correct the deformity, and enable the body. Zirconium implants (Fig.1) offer individual from performing activities of patient to get back to a normal life but another bearing surface akin to ceramics daily living. Exercises, physiotherapy also think about life of the prosthesis. with a very low coefficient of friction. and over the counter pain killers do help This increased demand has forced the The long term results of these implants initially but with time it becomes surgeons to deliberate and research are awaited and we shall then know if it imperative to think about knee extensively in order to overcome the is worth the high price [4]. The replacement. Total knee replacement is drawbacks of the older conventional polyethylene insert which is placed the gold standard for treatment of knee knee systems and also meet the between the two metal components is arthritis and has shown predictably challenges faced by them in their daily highly cross linked which prevents its excellent results over the past 20 years surgical practice. wear and tear. Sterilization methods [1,2]. In recent times due to increased Advances in the past two decades have have helped reduce the wear and tear awareness more and more patients are been able to give the surgeons the tools rate of the insert. Gamma sterilization in opting for this surgery not only to to satisfy their patients over the whole the past led to early catastrophic wear maintain but also to improve their spectrum. In this article we shall try to and breakdown of the insert. Now a quality of life. The patients hope to enumerate the recent advances in total days EtO sterilization has solved the participate in all the activities and be knee replacement and how they help the problem. Addition of vitamin E in the physically active. They don’t want to patients. substance of the insert is said to delay its As we know in 1860, Verneuil degradation [5,6]. proposed interposition Design of the knee implant has a 1 Fortis Bone & Joint Institute arthroplasty, involving the bearing on the result of the surgery-both Fortis Group of Hospitals, Delhi, NCR insertion of soft tissue to in the survivorship of the implant and in Address of Correspondence reconstruct the joint surface. Since terms of patient satisfaction. The knee Dr. Ashok Rajgopal email: [email protected] then, pig bladder, nylon, femoral joint has three bones that articulate with sheath, anterior bursa of the knee, each other. For the implant to be © 2017 by Journal of Clinical Orthopaedics | Available on www.jcorth.com | doi:10.13107/jcorth.2456-6993.185 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non- commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 10| Journal of Clinical Orthopaedics | Volume 2 | Issue 1 | Jan - June 2017 | Page 10-13 Rajgopal & Dahiya www.jcorth.com Figure 1: Zirconium Implants Figure 2: Persona Implants Figure 3: – asymmetric tibial component successful the components have to be for the ideal fit. The Persona implant is against the soft tissues and cause pain well synchronised with each other and also the most patella friendly implant [8]. The question as to resurface the also perform their own functions available. This allows for ease of gliding patella or to leave it alone is eternal. The independently. The femoral component of the patella on the femoral component proponents of either are numerous but (part of the lower thigh forming the helping to achieve a better and more so far no consensus has been formed knee) should be well fitting on the host efficient thigh muscle function. This in [9]. So has been the case for posterior bone, and should not over hang the turn leads to better knee joint range of cruciate ligament retention or bone otherwise it will rub with the soft motion and gait pattern. substitution. All implants are available tissues causing pain. It should also The Tibial component (part of the leg in cruciate retaining and posterior provide a good and friendly surface for bone which participates in the knee) is stabilized designs. the knee cap (patella) to glide on. also an important part of the knee. Modern designs take care of this aspect. Traditionally they were made Newer metals like Trabecular metal The Persona implant (Fig. 2) from symmetric whereas the normal human have in fact revolutionized the area of Zimmer has femoral components in 2 anatomy is asymmetric [7].(Fig.3) knee replacement. These metals are mm increments and each size comes What this means that the shape of the extremely porous and have elasticity of with a standard and a narrow option. tibial component should closely modulus approximating that of natural The number of sizes available are in 2 approximate the original anatomy of the bone. The porosity allows for growth of mm increments in both planes,a design bone. In the Persona Knee system the bone into the implant(Fig.4). This which helps in providing a better fit of tibial component comes in 9 sizes with helps in better integration of the implant the implant. No two individuals are 1mm increments again allowing the to the bone and thus increasing the life alike so why should two knees be the surgeon much more flexibility in of the implant [10,11]. Also there is no same? To facilitate this there are several choosing the exact size of the implant need to use bone cement to fix these permutations and combinations for the patient. As with the femoral implants to bone. It has found use in available to the surgeon which provide component overhang is going to rub revision surgery of the knee too. Figure 4: Trabacular Metal Implant Figure 5: I Assist 11| Journal of Clinical Orthopaedics | Volume 2 | Issue 1 | Jan - June 2017 | Page 10-13 Rajgopal & Dahiya www.jcorth.com Figure 6: eNDTrac Figure 7: Navio Revision surgery is needed when the in the USA. Conformist manufactures implants are at one end of the original total knee replacement fails and these implants. Individualized fit and spectrum. The other end is occupied by a new surgery is needed to address all bone conservation are their hallmarks. Big Data. The immense amount of data the myriad issues where trabecular These unfortunately are not available in and surgeon experience that is available metal cones are helpful to reconstruct India yet [13]. all around is being understood now. It the lost bone. They are used to build up Awareness is leading to younger will be used to fabricate protocols to the defect in bones and allow for the patients opting for knee surgery. Every increase the surgeons and hospitals host bone to grow into them to achieve knee arthritis does not need a total knee efficiency while dealing with total knee a more biological end result. replacement. In case only one replacement patients. Big data Computer assisted surgery has been in compartment is involved then only that combined with the joint registries will use for a long time. Earlier devices were part can be replaced. This is called help the surgeons to make an informed large in size (Brain Lab) and unicompartmental knee replacement. choice on their choice of implants, cumbersome to useresulting in an Unicompartmental knee replacement is surgical techniques, pain management increase in surgery time. Newer devices getting to be more widely used than protocols and postoperative are gravitating towards hand held before and is well accepted. It is a rehabilitation. devices such as the iASSIST smaller procedure, allows the patient to Experience and hospital management (Zimmer)(Fig 5) or eNdtrac recover faster and gives a more natural systems have helped us evolve faster (Stryker)(Fig 6). These are surgical feel of the knee. It also allows the rehabilitation programs. They consist of guidance systems engineered to patient to continue with a fairly patient education prior to surgery, improve the accuracy and alignment of aggressive life style. ultrasound guided nerve blocks to total knee replacement surgery.