Knee Replacement and Reconstruction

Unicompartmental/Partial Knee Arthroplasty

Unicompartmental knee replacement is a minimally invasive surgery in which only the damaged compartment of the knee is replaced with an implant. It is also called a partial knee replacement. The knee can be divided into three compartments: patellofemoral, the compartment in front of the knee between the knee cap and thigh bone, medial compartment, on the inside portion of the knee, and lateral compartment which is the area on the outside portion of the knee joint.

Traditionally, total knee replacement was commonly indicated for severe osteoarthritis of the knee. In total knee replacement, all worn out or damaged surfaces of the knee joint are removed and replaced with new artificial parts. Partial knee replacement is a surgical option if your arthritis is confined to a single compartment of your knee.

Disease Overview

Arthritis is inflammation of a joint causing pain, swelling (inflammation), and stiffness.

Osteoarthritis is the most common form of knee arthritis in which the joint cartilage gradually wears away. It most often affects older people. In a normal joint, articular cartilage allows for smooth movement within the joint, where as in an arthritic knee the cartilage itself becomes thinner or completely absent. In addition, the bones become thicker around the edges of the joint and may form bony “spurs”. These factors can cause pain and restricted range of motion in the joint.

Causes

The exact cause is unknown, however there are several factors that are commonly associated with the onset of arthritis and may include:

  • Injury or trauma to the joint
  • Fractures of the knee joint
  • Increased body weight
  • Repetitive overuse
  • Joint infection
  • Inflammation of the joint
  • Connective tissue disorders

Symptoms

Arthritis of the knees can cause knee pain, which may increase after activities such as walking, stair climbing, or kneeling.

The joint may become stiff and swollen, limiting the range of motion. Knee deformities such as knock-knees and bow-legs may also occur.

Diagnosis

Your doctor will diagnose osteoarthritis based on the medical history, physical examination, and X-rays.

X-rays typically show a narrowing of joint space in the arthritic knee.

Surgical procedure

Your doctor may recommend surgery if non-surgical treatment options such as medications, injections, and physical therapy have failed to relieve the symptoms.

During the surgery, a small incision is made over the knee to expose the knee joint. Your surgeon will remove only the damaged part of the meniscus and place the implant into the bone by slightly shaping the shin bone and the thigh bone. The plastic component is placed into the new prepared area and is secured with bone cement. Now the damaged part of the femur or thigh bone is removed to accommodate the new metal component which is fixed in place using bone cement. Once the femoral and tibial components are fixed in proper place the knee is taken through a range of movements. The muscles and tendons are then repaired and the incision is closed.

Post-Operative Care

You may walk with the help of a walker or cane for the first 1-2 weeks after surgery. A physical therapist will advise you on an exercise program to follow for 4 to 6 months to help maintain range of motion and restore your strength. You may perform exercises such as walking, swimming and biking but high impact activities such as jogging should be avoided.

Risks and Complications

Possible risks and complications associated with unicompartmental knee replacement include:

  • Knee stiffness
  • Infection
  • Blood clots (Deep vein thrombosis)
  • Nerve and blood vessel damage
  • Ligament injuries
  • Patella (kneecap) dislocation
  • Plastic liner wears out
  • Loosening of the implant

Advantages

The advantages of Unicompartmental Knee Replacement over Total Knee Replacement include:

  • Smaller incision
  • Less blood loss
  • Quick recovery
  • Less post-operative pain
  • Better overall range of motion
  • Feels more like a natural knee

Patellofemoral Knee Replacement

Patellofemoral Knee Replacement surgery may be recommended by your surgeon if you have osteoarthritis contained to the patellofemoral compartment and you have not obtained adequate relief with conservative treatment options.

Traditionally, a patient with only one compartment of knee arthritis would undergo a partial Knee Replacement surgery. Patellofemoral Knee Replacement is a minimally invasive surgical option that preserves the knee parts not damaged by arthritis as well as the stabilizing anterior and posterior cruciate ligaments, ACL and PCL. This less invasive bone and ligament preserving surgery is especially useful for younger, more active patients as the implant placed more closely mimics actual knee mechanics than does a total knee surgery.

Surgical procedure

Your doctor may recommend surgery if non-surgical treatment options such as medications, injections, and physical therapy have failed to relieve the symptoms.

During the surgery, a small incision is made over the knee to expose the knee joint. Your surgeon will remove only the damaged part of the meniscus and place the implant into the bone by slightly shaping the shin bone and the thigh bone. The plastic component is placed into the new prepared area and is secured with bone cement. Now the damaged part of the femur or thigh bone is removed to accommodate the new metal component which is fixed in place using bone cement. Once the femoral and tibial components are fixed in proper place the knee is taken through a range of movements. The muscles and tendons are then repaired and the incision is closed.

Post-Operative Care

You may walk with the help of a walker or cane for the first 1-2 weeks after surgery. A physical therapist will advise you on an exercise program to follow for 4 to 6 months to help maintain range of motion and restore your strength. You may perform exercises such as walking, swimming and biking but high impact activities such as jogging should be avoided.

What is new in Knee Replacement

For a patient considering knee replacement surgery, there are new developments under study which can help enhance their quality of life. These include:

  • Use of cementless parts that allow new bone to grow into a porous prosthesis and hold the parts in place, creating a biologic fixation
  • Use of bioactive joint surfaces such as hydroxyapatite
  • The use of mobile-bearing knee replacement in which a polyethylene insert creates a dual-surface articulation by articulating with the femoral as well as tibial components. This will enhance the life of the implant by reducing wear.
  • Development of systems with improved kinematics
  • Better fixation

Use of navigation- guided surgery that involves use of navigation –guided instruments with smaller incisions and less tissue damage. Only suitable trained surgeons with various measures offer this procedure.

A total knee replacement surgery is the last resort to relieve pain and restore function in knee damaged by arthritis or an injury when non-surgical treatments do not relieve the condition. The procedure involves replacing the damaged surfaces of the articulating bones with the artificial implant. Most of these implants wear with use. Thus, the risk of need for revision surgery is high in young and active people if the implant must last the lifetime of the patient. The life of the implant can be extended by precise alignment of the implant and this can be achieved using computer navigation for total knee replacement surgery.

Computer navigation provides the surgeon with the real time 3-D images of the mapped patient’s knee and the surgical instruments during surgery. Thus, the surgery is done by the surgeon only. Computer navigation is just a tool to guide the surgeon and improve the outcome of the surgery. It cannot replace the skills of an experienced surgeon.

Total Knee Replacement

Total knee arthroplasty, is a surgical procedure in which the worn out or damaged surfaces of the knee joint are removed and replaced with artificial parts. The knee is made up of the femur (thigh bone), the tibia (shin bone), and patella (kneecap). The meniscus, the soft cartilage between the femur and tibia, serves as a cushion and helps absorb shock during motion. Arthritis (inflammation of the joints), injury, or other diseases of the joint can damage this protective layer of cartilage, causing extreme pain and difficulty in performing daily activities. The knee can be divided into three compartments:

  • Patellofemoral – the compartment behind the kneecap
  • Medial compartment – the compartment on the inside of the knee
  • Lateral compartment – the area on the outside of the knee joint

Indications

Total knee replacement surgery is commonly indicated for severe osteoarthritis of the knee. Osteoarthritis is the most common form of knee arthritis in which the joint cartilage gradually wears away. It often affects older people.

In a normal joint, articular cartilage allows for smooth movement within the joint, whereas in an arthritic knee the cartilage itself becomes thinner or completely absent. In addition, the bones become thicker around the edges of the joint and may form bony “spurs”. These factors can cause pain and restricted range of motion in the joint.

Your doctor may advise total knee replacement if you have:

  • Severe knee pain which limits your daily activities (such as walking, getting up from a chair or climbing stairs).
  • Moderate to severe pain that occurs during rest or awakens you at night.
  • Chronic knee inflammation and swelling that is not relieved with rest or medications
  • Failure to obtain pain relief from medications, injections, physical therapy, or other conservative treatments.
  • A bow- legged knee deformity

Causes

The exact cause of osteoarthritis is not known, however there are several factors that are commonly associated with the onset of arthritis and may include:

  • Injury or trauma to the joint
  • Fractures at the knee joint
  • Increased body weight
  • Repetitive overuse
  • Joint infection
  • Inflammation of the joint
  • Connective tissue disorders

Diagnosis

Your doctor will diagnose osteoarthritis based on the medical history, physical examination, and X-rays.

X-rays typically show a narrowing of the joint space in the arthritic knee.

Procedure

The goal of total knee replacement surgery is to relieve pain and restore the alignment and function of your knee.

The surgery is performed under spinal or general anesthesia. Your surgeon will make an incision in the skin over the affected knee to expose the knee joint. Then the damaged portions of the femur bone are cut at appropriate angles using specialized jigs. The femoral component is attached to the end of the femur with or without bone cement. The surgeon then cuts or shaves the damaged area of the tibia (shinbone) and the cartilage. This removes the deformed part of the bone and any bony growths, as well as creates a smooth surface on which the implants can be attached. Next, the tibial component is secured to the end of the bone with bone cement or screws. Your surgeon will place a plastic piece called an articular surface between the implants to provide a smooth gliding surface for movement. This plastic insert will support the body’s weight and allow the femur to move over the tibia, like the original meniscus cartilage. The femur and the tibia with the new components are then put together to form the new knee joint. To make sure the patella (knee cap) glides smoothly over the new artificial knee, its rear surface is also prepared to receive a plastic component. With all the new components in place, the knee joint is tested through its range of motion. The entire joint is then irrigated and cleaned with a sterile solution. The incision is carefully closed; drains are inserted and a sterile dressing is placed over the incision.

Post-operative care

Rehabilitation begins immediately following the surgery. A physical therapist will teach you specific exercises to strengthen your leg and restore knee movement. After total knee replacement you will likely utilize a home based and outpatient physical therapy regimen. Immediately after surgery you will walk with the assistance of a walker, crutches or cane depending upon your needs.

Risks and complications

As with any major surgery, possible risks and complications associated with total knee replacement surgery include:

  • Knee stiffness
  • Infection
  • Blood clots (deep vein thrombosis)
  • Nerve and blood vessel damage
  • Ligament injuries
  • Patella (kneecap) dislocation
  • Plastic liner wears out
  • Loosening of the implant

If you find difficulty in performing simple activities such as walking or climbing stairs because of your severe arthritic knee pain, then total knee replacement may be an option for you. It is a safe and effective procedure to relieve pain, correct leg deformity, and help you resume your normal activities of daily living.

Revision Knee Replacement

Revision knee replacement surgery involves replacing part or all your previous knee prosthesis with a new prosthesis. Although total knee replacement surgery is successful, sometimes the procedure can fail due to various reasons and require a second surgery also referred to as revision surgery.

Disease Overview

The knee joints are lined by soft articular cartilage that cushion the joints and aid in smooth movement of the joint bones. Degeneration of the cartilage due to wear and tear leads to arthritis, which is characterized by severe pain.

Total Knee Replacement

During total knee replacement, the damaged cartilage and bone is removed from the knee joint and replaced with artificial components. Artificial knee joints are usually made of metal, ceramic or plastic and consist of the femoral component and the tibial component.

Indications

Revision knee replacement surgery may be advised to patients if they have one or more of the following conditions:

  • Trauma to the knee joint
  • Chronic progressive joint disease
  • Increased pain in the affected knee
  • Worn out prosthesis
  • Knee instability or a feeling of giving way while walking
  • Loosening of the prosthesis
  • Infection in the prosthetic joint
  • Weakening of bone around the knee replacement, a process known as osteolysis (bone loss)
  • Stiffness in the knee
  • Leg length discrepancy
  • Fracture

Surgical procedure

Revision knee replacement surgery may involve the replacement of one or all the components.

The surgery is performed under general anesthesia. Your surgeon makes an incision over the knee to expose the knee joint. The kneecap along with its ligament may be moved aside so that there is enough room to perform the operation. Then the old femoral component of the knee prosthesis is removed. The femur is prepared to receive the new component. In some cases, the damaged bone is removed and bone graft or a metal wedge may be used to make up for the lost bone.

Next the tibial component along with the old plastic liner is removed. The damaged bone is cut and the tibia is prepared to receive the new component. Like the femur, the lost bone is replaced either by a metal wedge or bone graft. Then, a new tibial component is secured to the end of the bone using bone cement. A new plastic liner will be placed on the top of the tibial component. If the patella (kneecap) has been damaged, your surgeon will resurface and attach a plastic component. The tibial and femoral components of the prosthesis are then brought together to form the new knee joint, and the knee muscles and tendons are reattached. Surgical drains are placed for the excess blood to drain out and the incision is closed.

Risks and complications

Like all major surgical procedures, there may be certain risks and complications involved with revision knee replacement surgery. The possible complications after revision knee replacement include:

  • Stiffness in the knee
  • Infection
  • Bleeding
  • Formation of blood clots in the leg veins
  • Injury to nerves or blood vessels
  • Prosthesis failure
  • Patella (kneecap) dislocation
  • Ligament injuries

Postoperative care

You can walk with crutches, walker or a cane. You will begin physical therapy immediately after surgery. A physical therapist will teach you specific exercises to strengthen your leg and restore range of motion to the knee. Your physical therapist will also provide you with a home exercise program to strengthen thigh and calf muscles. Sometimes revision surgery requires specific limitations depending on the surgery performed.

Robotic Assisted Partial Knee Surgery

Robotic assisted partial knee surgery is an innovative alternative to the conventional surgical procedure in patients suffering from degenerative knee diseases such as osteoarthritis. It is performed using robotic-arm technology that allows the surgeon to precisely perform the surgery through a smaller incision as compared to traditional surgery.

This procedure utilizes X-rays and CT scans to determine the damaged areas, of the joint, that need to be removed for the precise placement of the knee implant. The procedure may be used for partial knee surgery. In the partial knee resurfacing, only the diseased portion of your knee is removed, preserving the surrounding healthy bone and tissue. An implant is then secured over the prepared portion of your knee joint that results in resolution of symptoms and a natural knee movement. As it employs a minimally invasive technique the incidence of scarring and blood loss is very low.

The procedure is beneficial in patients with unicompartmental or bicompartmental knee disease. Robotic assisted partial knee surgery can be considered in patients with early to mid-stage osteoarthritis associated with symptoms such as knee pain, knee swelling, and knee locking. The procedure results in resolution of symptoms and a natural knee movement.

Benefits

The benefits of the robotic assisted partial knee surgery include:

  • Smaller incisions
  • Rapid recovery
  • Precise placement of the implant
  • Reduced injury to adjacent tissues
  • Increased longevity of the implant

Outpatient Total Knee Replacement

Total knee replacement is the surgical treatment for knee arthritis, where the damaged knee is removed and replaced with an artificial knee implant. Traditionally performed as an inpatient procedure, total knee replacement surgery is now being conducted on an outpatient basis, allowing patients to go home the same day of the surgery. This is made possible with recent advances such as improved perioperative anesthesia, minimally invasive techniques and initiation of rehabilitation protocols soon after surgery. Outpatient total knee replacement is considered when your vital signs are stable, such as heart and respiratory rate, blood pressure and temperature during your post-operative physical therapy session. Moreover, you need to be able to maintain pain control with oral medication and tolerate a regular diet before being discharged on the same day of surgery.

The outpatient procedure is performed using advancements in anesthetic techniques like a femoral regional block, which produces a centralized anesthetic effect and does not require a hospital stay for its effects to wear-off, like traditional general anesthesia.

For more details regarding the surgery please refer the Total Knee Replacement section above.

After Knee Replacement

Knee replacement is a surgery performed to replace parts of a diseased knee joint with an artificial prosthesis. The goal of knee replacement is to eliminate pain and return you to your normal activities. You can help in recovery and improve the outcomes of the procedure by following certain precautions and changing the way you carry out your daily activities.

After knee replacement surgery, once the anesthesia wears off, you will start to experience pain, for which your doctor will prescribe medication. You may have to remain in the hospital for a few days depending on your progress and overall health. Remember to get plenty of rest during this initial phase. Your surgical wounds should be monitored for swelling, inflammation and other changes and frequent dressing changes are performed. A continuous passive motion machine is applied to keep your knee moving, compression boots or elevation of your leg may be recommended to encourage circulation and prevent stiffness, clots and scar formation.

Rehabilitation begins within 24 hours of surgery, where a physical therapist will help you stand up and walk using crutches or a walker. Adhering to the goals of the rehabilitation program is important to help you recover and resume your normal activities. You will be guided to perform strengthening exercises daily and learn to get in and out of bed, and use a bedside commode. When you are discharged from the hospital, you will be encouraged to walk short distances with an assistive device, climb a few stairs, dress, bathe and perform other basic functions by yourself.

On reaching home, have a family member or caregiver assist you with your activities for a few weeks. Taking care of someone following knee replacement surgery requires compassion, awareness and patience. Basic points to follow by your caregiver:

Helping with basic movement and functions as well as emotional support

Having a clear understanding of your medication and ensuring they are administered in a timely manner

Keeping emergency numbers ready

Assisting you with household chores, paperwork and traveling to keep your appointments

Helping and motivating you to perform your rehabilitation exercises

Ensuring that furniture is rearranged so as not to interfere with your movement and cause falls.

To avoid bending or reaching out, items that you use frequently can be placed easily within reach.

Certain instructions that your doctor will brief you about are:

  • You may shower once the wound heals, but avoid soaking in a bathtub for at least six weeks.
  • Keep the wound clean and dry. Your doctor will let you know when you can shower or bathe.
  • Some amount of swelling is normal after knee replacement and may last for more than a month. It can be controlled by icing and elevating your leg for 30 to 60 minutes every day.

By week 3, you should be able to move with minimal assistance and significant reduction in pain. Your physical therapy program will gradually include new and more difficult exercises as you improve in strength and flexibility. By week 7, you should be able to walk independently. To reduce stress, use the opposite knee to lead when climbing stairs and the replaced knee to lead when descending. You will be able to drive a few weeks after surgery when you have sufficient pain control, improved strength and can easily enter and exit a car. Walking and exercising at least 2-3 times a day for 10-15 minutes is recommended for a faster recovery.

You and your caregiver must be aware of the signs of infection. Contact your doctor if you notice any abnormal wound changes or any changes in general health and mental state, or should you have persistent fever, drainage, excessive swelling or other signs of infection.

credibility

  • The American Board of Orthopaedic Surgery
  • American Medical Association
  • Medical Society of the State of New York (MSSNY)
  • CareMount Medical
  • Northern Westchester Hospital

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