Knee Replacement Implants

As people grow old, they also start experiencing several pains in different parts of the body. Most people start experiencing pains in their joints, which makes it difficult for them to perform various kinds of physical activities optimally. Some may experience excruciating pain in their knees, for which they may have to consult an orthopaedic doctor, who may prescribe certain medications, along with treatments such as physiotherapy, acupuncture, use of braces, etc. However, if the pain remains unmanaged despite taking the medicines, the doctor may recommend a knee replacement surgery, which helps reduce the pain and improve one's ability to move around. Through the surgery, the doctor removes a part or all of the knee joints and replaces the damaged parts with an artificial knee replacement implant made of metal and/or plastics. This article explains what knee replacement implants are, their components, and the most prevalent type of knee implant preferred by surgeons – the fixed bearing implant.

Knee Replacement Implants – An Introduction

Knee replacement is a surgical substitution of a knee joint in which the femur and the tibia bone meet, with the help of an artificial implant or joint. The surgeon repairs the damaged part of the bones that form the knee joints i.e. the femur, tibia and patella. While this procedure seems modern to most patients, it was first performed in the mid-1800s.

As more and more younger and active individuals started experiencing injuries in their joints (due to sports activities and every-day wear and tear), the need to develop a permanent or a semi-permanent solution increased. This lead to the birth of knee replacement implants.

The Need for Knee Implants

Doctors typically recommend knee replacement implants to patients experiencing chronic, unceasing pain in their knees and those who need to correct bone deformities such as varus and valgus deformities. A varus deformity is condition in which there is an excessive inward or medial angulation of the distal segment of a joint or a bone, whereas a valgus deformity is when an extreme outward or lateral angulation of the distal segment of the joint or bone is observed. Surgery may also be imminent if one's daily life is getting affected due to reduced mobility. Arthritis is another major factor for patients to consider knee replacement surgery. Other reasons to undergo knee replacement implants include knee pain while resting or sleeping and long-lasting inflammation in the knees that causes swelling, but doesn't get better despite taking medication.

Components of a Knee Implant

There are three essential components of knee implants. They are as under:

1. The tibial component

   The tibial component is a flat, two-piece metal and polyethylene or plastic part, which is attached to the tibia. The metal component is placed on top of the tibia. It also has a stem, which is inserted inside the tibia and is meant to provide stability to the knees. The plastic component, also known as the tibial spaces serves as the cushion between the metal tibial part and the second component, i.e. the femoral metal component. 

2. The femoral component

   The femoral component is a metal piece and the largest curved part which is attached to the end of the femur or the resurfaced thighbone. This component comes in various metal or ceramic options and is usually made up of cobalt-chromium alloys, which is considered the most durable. It also has a groove which enables the third component, i.e. the patellar component to smoothly slide up and down when the knee bends and straightens.

3. The patellar component

   The patellar component is a dome-shaped part that matches the resurfaced shape or form of the patella. It replaces the damaged knee cap, rubbing against the thighbone. Since the patella component essentially rests against the femur component, the alignment of the two components is crucial for the knee to function properly. The patella component is held in its place by the patellar and quadriceps tendon. The patellar component may not necessarily be used in all knee surgeries and is typically made up of polyethylene, which is a durable plastic.

Total Knee Replacement Surgery and Fixed Bearing Knee Replacement Implants

What is Total Knee Replacement Surgery?

Total knee replacement is defined as the restructuring of the bones within the three knee-joint compartments, i.e. the front compartment, the central compartment and the outer compartment of the knee. In this type of surgery, the surgeon either leaves the ligaments supporting the knee in its place or removes it, based on the patient's condition. FREEDOM ® Total Knee System is a high flexion knee implant used in total knee replacement surgeries. The implant is characterised by its unique design that provides complete flexibility and the surgeon replaces a damaged knee with an artificial one.

What is a Fixed Bearing Knee Replacement Implant?

The most popular type of knee replacement implant is the fixed bearing implant. The fixed bearing implants are best suited for patients who aren't overweight and those who do not have active lifestyles. Surgeons typically recommend this implant to elderly patients, who will avoid putting any serious wear-and-tear on their implant. Depending upon the precision achieved during the surgery, and the quality of the product, a fixed-bearing knee replacement implant can easily last for a period of 10-15 years, whereas advanced implants such as MERIL’s Opulent can last for 18-20 years.

Meril’s Curiate Retaining (CR) and Posterior Stabilised fixed bearing knee (with and without cruciate ligament retention) are high-quality knee implants. Meril’s patented new technology known as the OPULENT BIONIC GOLD KNEE IMPLANT is 2 times stronger and long-lasting implant as compared to other implants in the same category. The implant is made of a biocompatible and non-allergic surface material. It enables both, young and old patients to remain active due to its long-term, quality performance.

The Role of the Patient’s Body Frame in Knee Replacement Implants

Orthopaedic surgeons have reported that there are several anatomical differences between the body frames of patients who need knee replacement implants. The patient’s body structure plays an integral role in deciding the right type of implant. As such, surgeons cannot adopt the "one size fits all" approach when it comes to knee replacement surgeries. Instead, they have to modify the knee implant to suit the patient's gender, ethnicity, and body frame, thereby ensuring optimal performance.

Meril's FREEDOM ® Total Knee System is an optimised sizing matrix, designed to cater to the requirements of the global population, with varying requirements. Developed using advanced design engineering technologies and extensive clinical experience, this implant addresses the anatomical, physiological and lifestyle needs of today's patients. The implant enables patients to achieve optimal high-flexion motion and requires minimum bone cutting.

Final note: After undergoing a knee replacement implant, the body can take a few weeks to recover fully, but life does eventually return to normal. Upon recovery, the patient can resume their activities as usual. The pain also subsides in a few weeks, enabling patients to move about freely. If the patient takes proper post-surgery care, the surgery can cause long-lasting relief for many years. In fact, some patients may not experience any issues throughout their lifetime, post the surgery.  Patients can speak to their orthopaedic surgeons and consider the best course of action before undergoing knee replacement implants.