Joint Replacement Surgery

Introduction

Arthritis is a very common condition that affects mainly the weight bearing joints prominently the hip and the knee. The cushoning surface on the ends of the bones wears off and the bones start rubbing against each other . This results in pain, swelling and stiffness. This gradually increases with activity and age.

Total Knee replacement is a surgical procedure to replace the damaged surfaces of the knee joint to relieve pain and disability. The damaged surfaces are replaced with metal and plastic components shaped to allow continued motion of the knee.

It is a very common tendency amongst Indian population to tide over the pain temporarily using analgesics and other non-surgical modalities .These modalities can be beneficial only in the initial stage when the physical damage is minimal. As the arthritis worsens , the mobility decreases and it becomes difficult to perform daily activities as well . This results in weakening of the muscles and deformities.

Analgesics with guided physiotherapy definitely helps in controlling the pain but this should be done with proper consultation of the orthopaedic surgeon from the first stage itself. The key to successful surgery is timely intervention before advanced osteoarthritis for optimum results.

TYPES OF JOINTS

Total knee replacement implants are not one size fits all or even one style fits all. Prosthetic implants may vary greatly by design, fixation and materials.

The choice of implant will ultimately be made by your surgeon, based upon your physical situation, your age and lifestyle and the surgeon’s experience

Femoral component

The femoral component is generally made of metal and curves around the end of the femur(your thigh bone). There is a groove down the center of this part of the implant which allows the patella (knee cap) to move up and down as the knee bends and straightens.

Tibial Component

The tibial component is a flat metal platform with a polyethylene (plastic) insert or spacer. This component varies in structure, depending on which type of surgery is performed.

Patellar component

The patellar implant is a dome shaped piece of polyetylene that mimics the knee cap. This implant is used in some knee replacements, not in others

TYPES

1. Fixed Bearing Implants

The most common knee replacement implant is referred to as a fixed bearing implant, It is referred to as fixed because the polyethylene cushion of the the tibial component is fixed firmly to the metal platform base. The femoral component then rolls over this cushion. The fixed – bearing prosthesis provide a good range of motion and just as long-lasting as other implants for most patients. In some cases, excessive activity and or extra weight can cause a fixed bearing prosthesis to wear down more quickly. This wear can cause loosening of the implant causing pain and joint failure though this is not common

2. Mobile Bearing Implants

If you are younger, more active, and /or overweight, your doctor may recommend a rotating platform/mobile bearing knee replacement. These implants are designed for potentially longer performance with less wear. Fixed bearing implants and mobile bearing implants use the same three components. In a mobile-bearing knee, however, the polyethylene insert in the tibial component can rotate short distances inside the metal tibial tray. This rotation allows patients a few degrees of greater rotation to the medial (inner)and lateral (outer) sides of their knee. Because of this mobility, mobile bearing knee implants do require more support from the ligaments surrounding the knee. If the soft tissues are not strong enough, though, the knee is more likely to dislocate. Mobile bearing implants may also cost a bit more than fixed bearing implants.

3. Medial Pivot Implants

The Medial-Pivot knee replicates the rotating, twisting, bending, flexion and stability of your natural knee, so it feels more like your natural knee. A normal knee actually pivots on its medial (inner side) condyle. When the knee flexes, that lateral (outer side) rolls back while the medial side rotates in one place. This design is more stable during normal knee motion. But these may cost more than the fixed bearing implants.

4. Posterior Cruciate Ligament(PCL) Retaining or substituting

The Posterior Cruciate Ligament is one of the major ligaments in the knee. It provides support and stable movement of the knee, preventing the femur from rolling back on the top of the tibia when flexed ( folded). Depending upon its condition, the type of knee implant and the surgical approach, this ligament can be kept or removed during total knee replacement surgery.

PCL Retaining

TheIn PCL retaining designs, the rearward movement of the tibia continues to be resisted by an intact PCL, which creates stability. The femoral and tibial prosthesis have notches to accommodate the ligament and the plastic insert also has a flat central surface.

PCL Substituting

PCL substituting knees (also called posterior stabilised knees) have raised surface on the tibial component cushion with a raised sloping post which compensates for the missing PCL to give your knee stability in the absence of this ligament. This post mimics the normal function of the PCL by limiting the forward roll of the femur over the tibia and supporting backward movement of the femur as you bend or flex your knee.

MEET THE EXPERTS

Dr. Yogesh R. Vaidya

Dr Yogesh vaidya is a consultant knee replacement surgeon at Pinnacle Orthocentre specialising in “ Computer-assisted Knee Joint Replacement”.

Dr yogesh Vaidya has done his MBBS from LTMGH Hospital, Sion, Mumbai and completed his MS-Orthopaedics from KEM Hospital and Seth G. S Medical College in the year 2003.

Dr Yogesh Vaidya brings with him wealth of experience as a knee replacement surgeon since 2003, having done over 2000 hip and knee replacement surgeries over the past 14 years.

Dr Yogesh Vaidya has attended the Biomet Visiting Surgeons Programme at New Albany Hospital, Ohio, USA under Dr Adolf Lombardi and Dr Keith Barand.He has completed a certified course in Total Hip Replacement at Chula Long Corn Hospital, Thailand.

This experience enables him to offer surgeries for Total knee replacement using muscle preserving techniques with no compromise on alignment and balance

FAQ's

The knee is the largest joint in the body and having healthy knees is required to perform most everyday activities. The knee is made up of the lower end of the thigh bone(femur), the upper end of the shin bone (tibia) and the kneecap (patella). The ends of these three bones where they touch are covered with articular cartilage, a smooth substance that protects the bones and enables them to move easily. The menisci are located between the femur and tibia.

These C shaped wedges act as “shock absorbers” that cushion the joint. Large ligaments hold the femur and tibia together and provide stability. The long thigh muscles give the knee strength. All remaining surfaces of the knee are covered by a thin lining called the synovial membrane.

This membrane releases a fluid that lubricates the cartilage, reducing the friction to nearly zero in a healthy knee. Normally all these components work in harmony. But disease or injury can disrupt this harmony resulting in pain , muscle weakness and reduced function.

The most common cause of chronic knee pain and disability is arthritis. Although there are many types of arthritis , most knee pain is caused by just three types:

  • Osteoarthritis: This is an age related wear and tear type of arthritis. It usually occurs in people 50 years of age and older, but may occur in younger people too. The cartilage that cushions the bones of the knee softens and wears away. The bones the rub against one another, causing knee pain and stiffness.
  • Rheumatoid arthritis: This is a disease in which the synovial membrane that surrounds that joint becomes inflammed and thickened causing cartilage loss, pain and stiffness.
  • Post-traumatic arthritis: This can follow a serious knee injury. Fractures of the bones surrounding the knee , tears off the knee ligaments damaging the articular cartilage over time causing knee pain and limiting knee function.

A knee Replacement (Arthroplasty) is a surgical procedure in which a damaged joint is removed and replaced by metal and plastic implants. There are four basic steps to a knee replacement procedure.

  • Prepare the bone: The damaged cartilage surfaces at the ends of the femur and tibia are removed along with a small amount of underlying bone.
  • Position with metal implants: The removed cartilage and bone is replaced with metal components that recreate the surface of the joint. These metal parts may be cemented or press fit into the bone.
  • Resurface the patella: The undersurface of the patella (kneecap) is cut and resurfaced with a plastic button.This step is optional and many surgeons do not prefer to do it.
  • Insert a spacer: A medical grade plastic spacer is inserted between the metal components to create a smooth gliding surface.

There are several reasons why your doctor may recommend knee replacement surgery. People who benefit from total knee replacement often have:

  • A knee that has become bowed as a result of severe arthritis.
  • Severe knee pain or stiffness that limits your everyday activities, including walking, climbing stairs and getting in and out of chairs. You may find it hard to walk more than a few blocks without significant pain and you may need to use a cane or a walker.
  • Moderate or severe knee pain while resting, either day or night.
  • Chronic knee inflammation and swelling that does not improve with rest or medications.
  • Failure to substantially improve with other treatments such as anti-inflammatory medications, cortisone injections, lubricating injections, physical therapy or other surgeries.

There is absolute age or weight restrictions for total knee replacement surgery. Recommendations for surgery are based on a patients pain and disability, not age. Most patients who undergo total knee replacement are age 50 to 80, but orthopaedic surgeons evaluate patients individually.Ideal age being 50 to 65 years.Total knee replacements have been performed successfully at all ages, from the young teenager with juvenile arthritis to the elderly patients with degenerative arthritis.

An evaluation with an orhopaedic surgeon consists of several components:

  • A medical history- Your ortopaedic surgeon will gather information about your general health and ask you about the extent of your knee pain and your ability to function.
  • A physical examination: This will assess knee motion, stability, strength and overall leg alignment.
  • X-Rays: These images help to determine the extent of damage and deformity in your knee.
  • Other tests: occasionally blood tests , or advanced imaging such as a magnetic resonance imaging (MRI) scan, may be needed to determine the condition of the bone and soft tissues of your knee.

An important factor in deciding whether to have a total knee replacement surgery is understanding what the procedure can and cannot do.

More than 90% of the people who have total knee replacement surgery experience a dramatic reduction of knee pain and a significant improvement in the ability to perform common activities of daily living but total knee replacement will not allow you to do more than you could before you devloped arthritis.

With normal use and activity, every knee replacement implant begins to wear in its plastic placer. Excessive activity or weight may speed up this wear and may cause the knee replacement to loosen and become painful. Therefore most surgeons advise against high-impact activities such as running, jogging, jumping or other high-impact sports for the rest of your life after surgery.

Realistic activities following knee replacement include unlimited walking, swimming, golf, driving, light hiking, biking, ballroom dancing and other low-impact sports

With appropriate activity modifications, knee replacements can last for many years.

An important factor in deciding whether to have a total knee replacement surgery is understanding what the procedure can and cannot do.

More than 90% of the people who have total knee replacement surgery experience a dramatic reduction of knee pain and a significant improvement in the ability to perform common activities of daily living but total knee replacement will not allow you to do more than you could before you devloped arthritis.

With normal use and activity, every knee replacement implant begins to wear in its plastic placer. Excessive activity or weight may speed up this wear and may cause the knee replacement to loosen and become painful. Therefore most surgeons advise against high-impact activities such as running, jogging, jumping or other high-impact sports for the rest of your life after surgery.

Realistic activities following knee replacement include unlimited walking, swimming, golf, driving, light hiking, biking, ballroom dancing and other low-impact sports

With appropriate activity modifications, knee replacements can last for many years.

The complication rate following total knee replacements is low. Serious complications such as knee joint infections occur in fewer than 2% of patients. Major medical complications such as heart attack or stroke occur even less frequently. Chronic illnesses may increase the potential for complications. Although uncommon, when these complications occur they can prolong or limit full recovery.

Discuss your concerns thoroughly with your orthopaedic surgeon prior to surgery.

  • Infections: Infections may occur in the wound or deep around the prosthesis. It may happen while in the hospital or after you go home or may even occur years later. Minor infections in the wound area are generally treated with antibiotics. Major or deep infections may require more surgery and removal of the prosthesis. Any infection in your body can spread to your replaced joint
  • Blood clot: Blood clots in the leg veins are the most common complications of knee replacement. These clots can be life-threatening if they break free and travel to your lungs. Your orthopaedic surgeon will outline a prevention programme which may include periodic elevation of your legs, lower leg excercises to increase circulation, support stockings and medications to thin your blood.
  • Implant problems: Although implant designs and materials, as well as surgical techniques, continue to advance, implant services may wear down and the components may loose. Additionally, although 115 degrees of motion is anticipated after the surgery, scarring of the knee can occasionally occur and motion may be more limited particularly in patients with limited motion before sugery.
  • Continued pain: A small number of patients continue to have pain after a knee replacement. This complication is rare. The vast majority of patients experience excellent pain relief following knee replacement.

You may have to stay around 4-5 days in the hospital if single knee is operated in one stage and around 6-7 days if both the knees are operated in one stage.

  • After Surgery , you will feel some pain, but your surgeon and nurses will provide medication to make you feel as comfortable as possible. Pain management is the important part of yor recovery. Walking and knee movement will begin soon after surgery , and when you feel less pain, you can start moving sooner and get your strength back more quickly.
  • Your orthopaedic surgeon may prescribe one or more measures to prevent blood clots and decrease leg swelling.These may include special support hose, inflatable leg coverings (compression pumps) and blood thinners.Foot and ankle movement also is encouraged immediately following surgery to increase blood flow in your leg muscles to help prevent leg swelling blood clots.
  • Most patients begin exercising their knee the day after surgery. A physical therapist will teach you specific exercises to strength your leg and restore knee movement to allow walking and other normal daily activities soon after your surgery..

To restore movement in your knee and leg, your surgeon may use a knee support that slowly moves your knee while you are in bed.The device called a continuous passive motion (CPM) exercise machine , decreases leg swelling by elevating your leg and improves your blood circulation by moving the muscles of the leg.

The success of your surgery will depend largely on how well you follow your orthopaedic surgeon’s instructions at home during the first few weeks after surgery

  • Wound Care: You will have stitches or staples running along your wound or a suture beneath your skin on the front of your knee. The stitches or staples will be removed several weeks after surgery. A suture beneath your skin will not require removal, The number of sutures or staples have no connection to the extent of surgery. Avoid soaking the wound in water until it has thoroughly sealed and dried. You may continue to bandage the wound to prevent irritation from clothing or support stockings.
  • Diet: Some loss of appetite is common for several weeks after surgery. A balanced diet, often with an iron supplement, is important to help your wound heal and to restore muscle strength.
  • Activity: Exercise is a critical component of home care, particularly during first few weeks after surgery. You should be able to resume most normal activities of daily living within 3 to 6 weeks following surgery. Some pain with activity and at night is common for several weeks after surgery.

Your activity programme should include:

  • A graduated walking programme to slowly increase your mobility, initially in your home and later outside.
  • Resuming other normal household activities, such as sitting, standing, and climbing stairs.
  • Specific exercises several times a day to restore movement and strengthen your knee. You probably will be able to perform the exercises without help, but you may have a physical therapist help you at home or in a therapy center the first few weeks after surgery. You will most likely be able to resume driving when your knees bend enough that you can enter and sit comfortably in your car and when your muscle control provides adequate reaction time for braking and acceleration. Most people resume driving approximately 4-6 weeks after surgery.
  • Avoiding Falls: A fall during first few weeks after surgery can damage your knee and may result in a need for further surgery. Stairs are a particular hazard until your knee is strong and mobile. You should use a cane, crutches, a walker, handrails, or have someone to help you until you have improved your balance, flexibility and strength.
  • Your surgeon and physical therapist will help you decide what assistive aides will be required following surgery and when those aides can safely be discontinued.

Improvement of knee motion is a goal of total knee replacement, but restoration of full motion is uncommon. The motion of your knee replacement after surgery can be predicted by the range of motion you have in your knee before surgery. Most patients can expect to be able to almost fully straighten the replaced knee and to bend the knee sufficiently to climb stairs and get in and out of the car. Kneeling is sometimes uncomfortable but it is not harmful.

Most people feel some numbness in the skin around your incision.You also may feel some stiffness, particularly with excessive bending activities.

Most people also feel or hear some clicking of the metal and plastic with knee bending or walking. This is normal. These differences often diminish with time and most patients find them to be tolerable when compared with the pain and limited function they experienced prior to surgery.

Your new knee may activate metal detectors required for security in airports and some buildings. Tell the security agent about your knee replacement if the alarm is activated.

Your new knee may activate metal detectors required for security in airports and some buildings. Tell the security agent about your knee replacement if the alarm is activated.

Currently, more than 90% of of modern total knee replacements are still functioning well 15 years after the surgery.Following your orthopaedic surgeon’s instructions after surgery and taking care to protect your knee replacement and your general health are important ways you can contribute to the final success of your surgery