Artificial Knee Replacement (Knee Arthroplasty) Animated Tutorial
Knee Anatomy
A Patient’s Guide to Knee Anatomy
Introduction
To better understand how knee problems occur, it is important to understand some of the anatomy of the knee joint and how the parts of the knee work together to maintain normal function.
First, we will define some common anatomic terms as they relate to the knee. This will make it clearer as we talk about the structures later.
Many parts of the body have duplicates. So it is common to describe parts of the body using terms that define where the part is in relation to an imaginary line drawn through the middle of the body. For example, medial means closer to the midline. So the medial side of the knee is the side that is closest to the other knee. The lateral side of the knee is the side that is away from the other knee. Structures on the medial side usually have medial as part of their name, such as the medial meniscus. The term anterior refers to the front of the knee, while the term posterior refers to the back of the knee. So the anterior cruciate ligament is in front of the posterior cruciate ligament.
In addition to reading this article, be sure to watch our Knee Anatomy Animated Tutorial Video.
This guide will help you understand
- what parts make up the knee
- how the parts of the knee work
Important Structures
The important parts of the knee include
- bones and joints
- ligaments and tendons
- muscles
- nerves
- blood vessels
Bones and Joints
The knee is the meeting place of two important bones in the leg, the femur (the thighbone) and the tibia (the shinbone). The patella (or kneecap, as it is commonly called) is made of bone and sits in front of the knee.
The knee joint is a synovial joint. Synovial joints are enclosed by a ligament capsule and contain a fluid, called synovial fluid, that lubricates the joint.
The end of the femur joins the top of the tibia to create the knee joint. Two round knobs called femoral condyles are found on the end of the femur. These condyles rest on the top surface of the tibia. This surface is called the tibial plateau. The outside half (farthest away from the other knee) is called the lateral tibial plateau, and the inside half (closest to the other knee) is called the medial tibial plateau.
The patella glides through a special groove formed by the two femoral condyles called the patellofemoral groove.
The smaller bone of the lower leg, the fibula, never really enters the knee joint. It does have a small joint that connects it to the side of the tibia. This joint normally moves very little.
Articular cartilage is the material that covers the ends of the bones of any joint. This material is about one-quarter of an inch thick in most large joints. It is white and shiny with a rubbery consistency. Articular cartilage is a slippery substance that allows the surfaces to slide against one another without damage to either surface. The function of articular cartilage is to absorb shock and provide an extremely smooth surface to facilitate motion. We have articular cartilage essentially everywhere that two bony surfaces move against one another, or articulate. In the knee, articular cartilage covers the ends of the femur, the top of the tibia, and the back of the patella.
Ligaments and Tendons
Ligaments are tough bands of tissue that connect the ends of bones together. Two important ligaments are found on either side of the knee joint. They are the medial collateral ligament (MCL) and the lateral collateral ligament (LCL).
Inside the knee joint, two other important ligaments stretch between the femur and the tibia: the anterior cruciate ligament (ACL) in front, and the posterior cruciate ligament (PCL) in back. The MCL and LCL prevent the knee from moving too far in the side-to-side direction. The ACL and PCL control the front-to-back motion of the knee joint.
The ACL keeps the tibia from sliding too far forward in relation to the femur. The PCL keeps the tibia from sliding too far backward in relation to the femur. Working together, the two cruciate ligaments control the back-and-forth motion of the knee. The ligaments, all taken together, are the most important structures controlling stability of the knee.
Two special types of ligaments called menisci sit between the femur and the tibia. These structures are sometimes referred to as the cartilage of the knee, but the menisci differ from the articular cartilage that covers the surface of the joint.
The two menisci of the knee are important for two reasons: (1) they work like a gasket to spread the force from the weight of the body over a larger area, and (2) they help the ligaments with stability of the knee.
Imagine the knee as a ball resting on a flat plate. The ball is the end of the thighbone as it enters the joint, and the plate is the top of the shinbone. The menisci actually wrap around the round end of the upper bone to fill the space between it and the flat shinbone. The menisci act like a gasket, helping to distribute the weight from the femur to the tibia.
Without the menisci, any weight on the femur will be concentrated to one point on the tibia. But with the menisci, weight is spread out across the tibial surface. Weight distribution by the menisci is important because it protects the articular cartilage on the ends of the bones from excessive forces. Without the menisci, the concentration of force into a small area on the articular cartilage can damage the surface, leading to degeneration over time.
In addition to protecting the articular cartilage, the menisci help the ligaments with stability of the knee. The menisci make the knee joint more stable by acting like a wedge set against the bottom of a car tire. The menisci are thicker around the outside, and this thickness helps keep the round femur from rolling on the flat tibia. The menisci convert the tibial surface into a shallow socket. A socket is more stable and more efficient at transmitting the weight from the upper body than a round ball on a flat plate. The menisci enhance the stability of the knee and protect the articular cartilage from excessive concentration of force.
Taken all together, the ligaments of the knee are the most important structures that stabilize the joint. Remember, ligaments connect bones to bones. Without strong, tight ligaments to connect the femur to the tibia, the knee joint would be too loose. Unlike other joints in the body, the knee joint lacks a stable bony configuration. The hip joint, for example, is a ball that sits inside a deep socket. The ankle joint has a shape similar to a mortise and tenon, a way of joining wood used by craftsmen for centuries.
Tendons are similar to ligaments, except that tendons attach muscles to bones. The largest tendon around the knee is the patellar tendon. This tendon connects the patella (kneecap) to the tibia. This tendon covers the patella and continues up the thigh.
There it is called the quadriceps tendon since it attaches to the quadriceps muscles in the front of the thigh. The hamstring muscles on the back of the leg also have tendons that attach in different places around the knee joint. These tendons are sometimes used as tendon grafts to replace torn ligaments in the knee.
Muscles
The extensor mechanism is the motor that drives the knee joint and allows us to walk. It sits in front of the knee joint and is made up of the patella, the patellar tendon, the quadriceps tendon, and the quadriceps muscles. The four quadriceps muscles in front of the thigh are the muscles that attach to the quadriceps tendon. When these muscles contract, they straighten the knee joint, such as when you get up from a squatting position.
The way in which the kneecap fits into the patellofemoral groove on the front of the femur and slides as the knee bends can affect the overall function of the knee. The patella works like a fulcrum, increasing the force exerted by the quadriceps muscles as the knee straightens. When the quadriceps muscles contract, the knee straightens.
The hamstring muscles are the muscles in the back of the knee and thigh. When these muscles contract, the knee bends.
Nerves
The most important nerves around the knee are the tibial nerve and the common peroneal nerve in the back of the knee. These two nerves travel to the lower leg and foot, supplying sensation and muscle control. The
large sciatic nerve splits just above the knee to form the tibial
nerve and the common peroneal nerve. The tibial nerve continues down
the back of the leg while the common peroneal nerve travels around the
outside of the knee and down the front of the leg to the foot. Both of
these nerves can be damaged by injuries around the knee.
Blood Vessels
The major blood vessels around the knee travel with the tibial nerve
down the back of the leg. The popliteal artery and popliteal vein are the largest blood supply to the leg and foot. If the popliteal artery is damaged beyond repair, it is very likely the leg will not be able
to survive. The popliteal artery carries blood to the leg and foot.
The popliteal vein carries blood back to the heart.
Summary
The knee has a somewhat unstable design. Yet it must support the body’s full weight when standing, and much more than that during walking or running. So it’s not surprising that knee problems are a fairly common complaint among people of all ages. Understanding the basic parts of the knee can help you better understand what happens when knee problems occur.
ACL Hamstring Tendon Graft Reconstruction
A Patient’s Guide to Hamstring Tendon Graft Reconstruction of the ACL
Introduction
When the anterior cruciate ligament (ACL) in the knee is torn or injured, surgery may be needed to replace it. There are many different ways to do this operation. One is to take a piece of the hamstring tendon from behind the knee and use it in place of the torn ligament. When arranged into three or four strips, the hamstring graft has nearly the same strength as other available grafts used to reconstruct the ACL.
This guide will help you understand
- what parts of the knee are treated during surgery
- how surgeons perform the operation
- what to expect before and after the procedure
Anatomy
What parts of the knee are involved?
Ligaments are tough bands of tissue that connect the ends of bones together. The ACL is located in the center of the knee joint where it runs from the backside of the femur (thighbone) to the front of the tibia (shinbone).
The ACL runs through a special notch in the femur called the intercondylar notch and attaches to a special area of the tibia called the tibial spine.
The hamstrings make up the bulk of the muscles in back of the thigh. The hamstrings are formed by three muscles and their tendons: the semitendinosus, semimembranosus, and biceps femoris. The top of the hamstrings connects to the ischial tuberosity, the small bony projection on the bottom of the pelvis, just below the buttocks. (There is one ischial tuberosity on the left and one on the right.)
The hamstring muscles run down the back of the thigh. Their tendons cross the knee joint and connect on each side of the tibia. The graft used in ACL reconstruction is taken from the hamstring tendon (semitendinosus) along the inside part of the thigh and knee. Surgeons also commonly include a tendon just next to the semitendinousus, called the gracilis.
The hamstrings function by pulling the leg backward and by propelling the body forward while walking or running. This movement is called hip extension. The hamstrings also bend the knees, a motion called knee flexion.
Related Document: A Patient’s Guide to Knee Anatomy
Related Document: A Patient’s Guide to Anterior Cruciate Ligament Injuries
Rationale
What does the surgeon hope to accomplish?
The main goal of ACL surgery is to keep the tibia from moving too far forward under the femur bone and to get the knee functioning normally again.
There are two grafts commonly used to repair a torn ACL. One is a strip of the patellar tendon below the kneecap. The other is the hamstring tendon graft. For a long time, the patellar tendon was the preferred choice because it is easy to get to, holds well in its new location, and heals fast. One big drawback to grafting the patellar tendon is pain at the front of the knee after surgery. This can be severe enough to prevent any pressure on the knee, such as kneeling.
For this reason, a growing number of surgeons are using grafted tissue from the hamstring tendon. There are no major differences in the final results of these two methods. When it comes to symptoms after surgery, joint strength and stability, and ability to use the knee, either method is good. However, with the hamstring tendon graft, there are generally no problems kneeling and no pain in the front of the knee.
Related Document: A Patient’s Guide to Patellar Tendon Graft Reconstruction of the ACL
Preparation
What do I need to know before surgery?
You and your surgeon should make the decision to proceed with surgery together. You need to understand as much about the procedure as possible. If you have concerns or questions, you should talk to your surgeon.
Once you decide on surgery, you need to take several steps. Your surgeon may suggest a complete physical examination by your regular doctor. This exam helps ensure that you are in the best possible condition to undergo the operation.
You may also need to spend time with the physical therapist who will be managing your rehabilitation after surgery. This allows you to get a head start on your recovery. One purpose of this preoperative visit is to record a baseline of information. Your therapist will check your current pain levels, your ability to do your activities, and the movement and strength of each knee.
A second purpose of the preoperative visit is to prepare you for surgery. Your therapist will teach you how to walk safely using crutches or a walker. And you’ll begin learning some of the exercises you’ll use during your recovery.
On the day of your surgery, you will probably be admitted to the surgery center early in the morning. You shouldn’t eat or drink anything after midnight the night before.
Surgical Procedure
What happens during the operation?
Most surgeons perform this surgery using an arthroscope, a small fiber-optic TV camera that is used to see and operate inside the joint. Only small incisions are needed during arthroscopy for this procedure. The surgery doesn’t require the surgeon to open the knee joint.
Before surgery you will be placed under either general anesthesia or a type of spinal anesthesia. The surgeon begins the operation by making two small openings into the knee, called portals. These portals are where the arthroscope and surgical tools are placed into the knee. Care is taken to protect the nearby nerves and blood vessels.
An incision is also made along the inside edge of the knee, just over where the hamstring tendons attach to the tibia. Working through this incision, the surgeon takes out the semitendinosus and gracilis tendons. Some surgeons prefer to use only the semitendinosus tendon and do not disrupt the gracilis tendon.
The tendons are arranged into three or four strips, which increases the strength of the graft. The surgeon stiches the strips together to hold them in place.
Next, the surgeon prepares the knee to place the graft. The remnants of the original ligament are removed. The intercondylar notch (mentioned earlier) is enlarged so that nothing will rub on the graft. This part of the surgery is referred to as a notchplasty.
Once this is done, holes are drilled in the tibia and the femur to place the graft. These holes are placed so that the graft will run between the tibia and femur in the same direction as the original ACL. The graft is then pulled into position through the drill holes. Screws or staples are used to hold the graft inside the drill holes.
To keep fluid from building up in your knee, the surgeon may place a tube in your knee joint. The portals and skin incisions are then stitched together, completing the surgery.
Complications
What can go wrong?
As with all major surgical procedures, complications can occur. This document doesn’t provide a complete list of the possible complications, but it does highlight some of the most common problems. Some of the most common complications following hamstring tendon graft reconstruction of the ACL are
- anesthesia complications
- thrombophlebitis
- infection
- problems with the graft
- problems at the donor site
Anesthesia Complications
Most surgical procedures require that some type of anesthesia be done before surgery. A very small number of patients have problems with anesthesia. These problems can be reactions to the drugs used, problems related to other medical complications, and problems due to the anesthesia. Be sure to discuss the risks and your concerns with your anesthesiologist.
Thrombophlebitis (Blood Clots)
View animation of pulmonary embolism
Thrombophlebitis, sometimes called deep venous thrombosis (DVT), can occur after any operation, but is more likely to occur following surgery on the hip, pelvis, or knee. DVT occurs when blood clots form in the large veins of the leg. This may cause the leg to swell and become warm to the touch and painful. If the blood clots in the veins break apart, they can travel to the lung, where they lodge in the capillaries and cut off the blood supply to a portion of the lung. This is called a pulmonary embolism. (Pulmonary means lung, and embolism refers to a fragment of something traveling through the vascular system.) Most surgeons take preventing DVT very seriously. There are many ways to reduce the risk of DVT, but probably the most effective is getting you moving as soon as possible after surgery. Two other commonly used preventative measures include
- pressure stockings to keep the blood in the legs moving
- medications that thin the blood and prevent blood clots from forming
Infection
Following surgery, it is possible that the surgical incision can become infected. This will require antibiotics and possibly another surgical procedure to drain the infection.
Problems with the Graft
After surgery, the body attempts to develop a network of blood vessels in the new graft. This process, called revascularization, takes about 12 weeks. The graft is weakest during this time, which means it has a greater chance of stretching or rupturing. A stretched or torn graft can occur if you push yourself too hard during this period of recovery. When revascularization is complete, strength in the graft gradually builds. A second surgery may be needed to replace the graft if it is stretched or torn.
Problems at the Donor Site
Problems can occur at the donor site (the area behind the leg where the hamstring graft was taken from the thigh). A potential drawback of taking out a piece of the hamstring tendon is a loss of hamstring muscle strength.
The main function of the hamstrings is to bend the knee (knee flexion). This motion may be slightly weaker in people who have had a hamstring tendon graft to reconstruct a torn ACL. Some studies, however, indicate that overall strength is not lost because the rest of the hamstring muscle takes over for the weakened area. Even the portion of muscle where the tendon was removed works harder to make up for the loss.
The hamstring muscles sometimes atrophy (shrink) near the spot where the tendon was removed. This may explain why some studies find weakness when the hamstring muscles are tested after this kind of ACL repair. However, the changes seem to mainly occur if both the semitendinosus and gracilis tendons were used. And the weakness is mostly noticed by athletes involved in sports that require deep knee bending. This may include participants in judo, wrestling, and gymnastics. These athletes may want to choose a different method of repair for ACL tears.
The body attempts to heal the donor site by forming scar tissue. This new tissue is not as strong as the original hamstring tendon. Because of this, there is a small chance of tearing the healing tendon, especially if the hamstrings are worked too hard in the early weeks of rehabilitation following surgery.
After Surgery
What should I expect after surgery?
You may use a continuous passive motion (CPM) machine immediately afterward to help the knee begin moving and to alleviate joint stiffness. The machine straps to the leg and continuously bends and straightens the joint. This continuous motion is thought to reduce stiffness, ease pain, and keep extra scar tissue from forming inside the joint. The CPM is often used with a form of cold treatment that circulates cold water through hoses and pads around your knee.
Most ACL surgeries are now done on an outpatient basis. Many patients go home the same day as the surgery. Some patients stay one to two nights in the hospital if necessary. The tube placed in your knee at the end of the surgery is usually removed after 24 hours.
Your surgeon may also have you wear a protective knee brace for a few weeks after surgery. You’ll use crutches for two to four weeks in order to keep your knee safe, but you’ll probably be allowed to put a comfortable amount of weight down while you’re up and walking.
Rehabilitation
What will my recovery be like?
Patients usually take part in formal physical therapy after ACL reconstruction. The first few physical therapy treatments are designed to help control the pain and swelling from the surgery. The goal is to help you regain full knee extension as soon as possible.
The physical therapist will choose treatments to get the thigh muscles toned and active again. Patients are cautioned about overworking their hamstrings in the first six weeks after surgery. They are often shown how to do isometric exercises for the hamstrings. Isometrics work the muscles but keep the joint in one position.
As the rehabilitation program evolves, more challenging exercises are chosen to safely advance the knee’s strength and function. Specialized balance exercises are used to help the muscles respond quickly and without thinking. This part of treatment is called neuromuscular training. If you need to stop suddenly, your muscles must react with just the right amount of speed, control, and direction. After ACL surgery, this ability doesn’t come back completely without exercise.
Neuromuscular training includes exercises to improve balance, joint control, muscle strength and power, and agility. Agility makes it possible to change directions quickly, go faster or slower, and improve starting and stopping. These are important skills for walking, running, and jumping, and especially for sports performance.
When you get full knee movement, your knee isn’t swelling, and your strength and muscle control are improving, you’ll be able to gradually go back to your work and sport activities. Some surgeons prescribe a functional brace for athletes who intend to return quickly to their sports.
Ideally, you’ll be able to resume your previous lifestyle activities. However, athletes are usually advised to wait at least six months before returning to their sports. Most patients are encouraged to modify their activity choices.
You will probably be involved in a progressive rehabilitation program for four to six months after surgery to ensure the best result from your ACL reconstruction. In the first six weeks following surgery, expect to see the physical therapist two to three times a week. If your surgery and rehabilitation go as planned, you may only need to do a home program and see your therapist every few weeks over the four to six month period.
Lumbar Spine Anatomy
A Patient’s Guide to Lumbar Spine Anatomy
Introduction
Knowing the main parts of your low back and how these parts work is important as you learn to care for your back problem.
Two common anatomic terms are useful as they relate to the low back. The term anterior refers to the front of the spine. The term posterior refers to the back of the spine. The section of the spine that makes up the low back is called the lumbar spine. The front of the low back is therefore called the anterior lumbar area. The back of the lower spine is called the posterior lumbar area.
In addition to reading this article, be sure to watch our Lumbar Spine Anatomy Animated Tutorial Video.
This guide gives a general overview of the anatomy of the low back. It should help you understand
- what parts make up the low back
- how these parts work
Important Structures
The important parts of the lumbar spine include
- bones and joints
- nerves
- connective tissues
- muscles
- spinal segments
This section highlights important structures in each category.
Bones and Joints
The human spine is made up of 24 spinal bones, called vertebrae. Vertebrae are stacked on top of one another to form the spinal column. The spinal column is the body’s main upright support.
From the side, the spine forms three curves. The neck, called the cervical spine curves slightly inward.
The middle back, or thoracic spine curves outward. The outward curve of the thoracic spine is called kyphosis. The low back, also called the lumbar spine curves slightly inward. An inward curve of the spine is called lordosis.
The lumbar spine is made up of the lower five vertebrae. Doctors often refer to these vertebrae as L1 to L5. The lowest vertebra of the lumbar spine, L5, connects to the top of the sacrum, a triangular bone at the base of the spine that fits between the two pelvic bones. Some people have an extra, or sixth, lumbar vertebra. This condition doesn’t usually cause any particular problems.
Each vertebra is formed by a round block of bone, called a vertebral body. The lumbar vertebral bodies are taller and bulkier compared to the rest of the spine. This is partly because the low back has to withstand pressure from body weight and from movements such as lifting, carrying, and twisting. Also, large and powerful muscles attaching on or near the lumbar spine place extra force on the lumbar vertebral bodies.
A bony ring attaches to the back of each vertebral body. This ring has two parts. Two pedicle bones connect directly to the back of the vertebral body. Two lamina bones join the pedicles to complete the ring. The lamina bones form the outer rim of the bony ring. When the vertebrae are stacked on top of each other, the bony rings form a hollow tube that surrounds the spinal cord and nerves. The laminae provide a protective roof over these nerve tissues.
A bony knob projects out at the point where the two lamina bones join together at the back of the spine. These projections, called spinous processes, can be felt as you rub your fingers up and down the back of your spine. Each vertebra also has two bony knobs that point out to the side, one on the left and one on the right. These bony projections are called transverse processes. The projections in the low back are broader than in other areas of the spine because many large back muscles attach and impart powerful forces on them.
Between the vertebrae of each spinal segment are two facet joints. The facet joints are located on the back of the spinal column. There are two facet joints between each pair of vertebrae, one on each side of the spine. A facet joint is made of small, bony knobs that line up along the back of the spine. Where these knobs meet, they form a joint that connects the two vertebrae. The alignment of the facet joints of the lumbar spine allows freedom of movement as you bend forward and back.
The surfaces of the facet joints are covered by articular cartilage. Articular cartilage is a smooth, rubbery material that covers the ends of most joints. It allows the ends of bones to move against each other smoothly, without friction.
On the left and right side of each vertebra is a small tunnel called a neural foramen. (Foramina is the plural term.) The two nerves that leave the spine at each vertebra go through the foramina, one on the left and one on the right. The intervertebral disc (described later) sits directly in front of the opening. A bulged or herniated disc can narrow the opening and put pressure on the nerve. A facet joint sits in back of the foramen. Bone spurs that form on the facet joint can project into the tunnel, narrowing the hole and pinching the nerve.
Nerves
The hollow tube formed by the bony rings on the back of the spinal column surrounds the spinal cord. The spinal cord is like a long wire made up of millions of nerve fibers. Just as the skull protects the brain, the bones of the spinal column protect the spinal cord.
The spinal cord extends down to the L2 vertebra. Below this level, the spinal canal encloses a bundle of nerves that goes to the lower limbs and pelvic organs. The Latin term for this bundle of nerves is cauda equina meaning horse’s tail.
Between vertebrae, two large nerves branch off the spinal cord, one on the left and one on the right. The nerves pass through the neural foramina of each vertebra. These spinal nerves group together to form the main nerves that go to the organs and limbs. The nerves of the lumbar spine (cauda equina) go to the pelvic organs and lower limbs.
Connective Tissues
Connective tissues are networks of fiber that hold the cells of the body together. Ligaments are strong connective tissues that attach bones to other bones. Several long ligaments connect on the front and back sections of the vertebrae. The anterior longitudinal ligament runs lengthwise down the front of the vertebral bodies. Two other ligaments run full-length within the spinal canal. The posterior longitudinal ligament attaches on the back of the vertebral bodies. The ligamentum flavum is a long elastic band that connects to the front surface of the lamina bones (just behind the spinal cord). Thick ligaments also connect the bones of the lumbar spine to the sacrum (the bone below L5) and pelvis.
A special type of structure in the spine called an intervertebral disc is also made of connective tissue. The fibers of the disc are formed by special cells, called collagen cells. The fibers may be lined up like strands of nylon rope or crisscrossed like a net.
An intervertebral disc is made of two parts. The center, called the nucleus, is spongy. It provides most of the shock absorption in the spine. The nucleus is held in place by the annulus, a series of strong ligament rings surrounding it.
Muscles
The muscles of the low back are arranged in layers. Those closest to the skin’s surface, the superficial layer, are covered by a thick tissue called fascia. The middle layer, called the erector spinae, has strap-shaped muscles that run up and down over the lower ribs, chest, and low back. They join in the lumbar spine to form a thick tendon that binds the bones of the low back, pelvis, and sacrum. The deepest layer of muscles attaches along the back surface of the spine bones, connecting the low back, pelvis, and sacrum. These deepest muscles coordinate their actions with the muscles of the abdomen to help hold the spine steady during activity.
Spinal Segment
A good way to understand the anatomy of the lumbar spine is by looking at a spinal segment. Each spinal segment includes two vertebrae separated by an intervertebral disc, the nerves that leave the spinal column at each vertebra, and the small facet joints that link each level of the spinal column.
The intervertebral disc separates the two vertebral bodies of the spinal segment. The disc normally works like a shock absorber. It protects the spine against the daily pull of gravity. It also protects the spine during heavy activities that put strong force on the spine, such as jumping, running, and lifting.
The spinal segment is connected by two facet joints, described earlier. When the facet joints of the lumbar spine move together, they bend and turn the low back.
Summary
Many important parts make up the anatomy of the back. Understanding the regions and structures of the lumbar spine can help you be more involved in your health care and better able to care for your back problem.
Artificial Joint Replacement of the Hip, Anterior Approach
A Patient’s Guide to Artificial Joint Replacement of the Hip, Anterior Approach
Introduction
A hip that is painful as a result of osteoarthritis (OA) can severely affect your ability to lead a full, active life. Over the last 25 years, major advancements in hip replacement have improved the outcome of the surgery greatly. Hip replacement surgery (also called hip arthroplasty) is becoming more and more common as the population of the world begins to age.
There are several different ways of entering the hip joint to perform surgery on the hip; these are referred to by orthopaedic surgeons as “approaches” to the hip. The two most common approaches used in the past to perform artificial hip replacement are the “posterior” approach and the “anterolateral” approach. A new, less invasive approach to the hip joint that was pioneered over the last 20 years is being used more frequently today. Each approach has its own benefits, but the newer anterior approach is felt by many to be the best option today. In this document, we will be discussing the anterior approach.
In addition to reading this article, be sure to watch our Artificial Hip Replacement Anterior Approach (Hip Arthroplasty) Animated Tutorial Video.
This guide will help you understand
- what your surgeon hopes to achieve
- the benefits of the anterior approach
- what happens during the procedure
- what to expect after your operation
Anatomy
How does the hip normally work?
The hip joint is one of the true ball-and-socket joints of the body. The hip socket is called the acetabulum and forms a deep cup that surrounds the ball of the upper thigh bone, known as the femoral head. The thick muscles of the buttock at the back and the thick muscles of the thigh in the front surround the hip.
The surface of the femoral head and the inside of the acetabulum are covered with articular cartilage. This material is about one-quarter of an inch thick in most large joints. Articular cartilage is a tough, slick material that allows the surfaces to slide against one another without damage.
Related Document: A Patient’s Guide to Hip Anatomy
Rationale
What does the surgeon hope to achieve?
The main reason for replacing any arthritic joint with an artificial joint is to stop the bones from rubbing against each other. This rubbing causes pain. Replacing the painful and arthritic joint with an artificial joint gives the joint a new surface, which moves smoothly without causing pain. The goal is to help people return to many of their activities with less pain and greater freedom of movement.
Over the last decade, many surgeons have begun using smaller and smaller incisions to perform surgeries that once required larger incisions. This has been made possible due to the development of better tools and techniques to perform the procedures, as well as the use of computer assisted imaging. This trend is sometimes referred to as minimally invasive surgery.
There are many benefits to using smaller incisions including less damage to normal tissue and less blood loss. The anterior approach does not require the cutting of any muscles or tendons around the hip joint. Patients tend to recover quicker and are able to leave the hospital sooner after surgery. In the case of artificial hip replacement, using a smaller incision can result in less damage to the ligaments around the hip that provide stability to the joint. This means that the risk of dislocation of the artificial joint during recovery after surgery is lessened.
Many surgeons have adopted the anterior approach to the hip joint in order to utilize these minimally invasive techniques. Many research studies show that the risk of dislocation after surgery when using the anterior approach is significantly less that other approaches. The anterior approach is considered to be the most stable of all the approaches to the hip.
Related Document: A Patient’s Guide to Osteoarthritis of the Hip
Preparation
How should I prepare for surgery?
The decision to proceed with surgery should be made jointly by you and your surgeon only after you feel that you understand as much about the procedure as possible.
Once the decision to proceed with surgery is made, several things may need to be done. Your orthopedic surgeon may suggest a complete physical examination by your medical or family doctor. This is to ensure that you are in the best possible condition to undergo the operation. You may also need to spend time with the physical therapist who will be managing your rehabilitation after the surgery.
One purpose of the preoperative physical therapy visit is to record a baseline of information. This includes measurements of your current pain levels, functional abilities, and the movement and strength of each hip.
A second purpose of the preoperative therapy visit is to prepare you for your upcoming surgery. You will begin to practice some of the exercises you will use just after surgery. You will also be trained in the use of either a walker or crutches. Whether the surgeon uses a cemented or noncemented approach may determine how much weight you will be able to apply through your foot while walking.
This procedure requires the surgeon to open up the hip joint during surgery. This puts the hip at some risk for dislocation after surgery. To prevent dislocation, patients follow guidelines about which hip positions to avoid (called hip precautions). Your therapist will review these precautions with you during the preoperative visit and will drill you often to make sure you practice them at all times for at least six weeks. Some surgeons give the OK to discontinue the precautions after six to 12 weeks because they feel the soft tissues have gained enough strength by this time to keep the joint from dislocating. Finally, the therapist assesses any needs you will have at home once you’re released from the hospital.
Related Document: A Patient’s Guide to Artificial Hip Dislocation Precautions
You may be asked to donate some of your own blood before the operation. Because of the trend towards newer minimally invasive techniques, hip replacement surgery today results in much less blood loss during surgery. You probably will not be asked to donate blood and probably will not require a blood transfusion after surgery. But, if your surgeon feels the surgery may be more complex and require a blood transfusion after surgery, this blood can be donated three to five weeks before the operation. During the time before the operation, your body will make new blood cells to replace the loss. At the time of the operation, if you need to have a blood transfusion you will receive your own blood back from the blood bank.
Surgical Procedure
Before we describe the procedure, let’s look first at the artificial hip itself.
The Artificial Hip
There are two major types of artificial hip replacements:
- cemented prosthesis
- noncemented prosthesis
A cemented prosthesis is held in place by a type of epoxy cement that attaches the metal to the bone. An noncemented prosthesis bears a fine mesh of holes on the surface that allows bone to grow into the mesh and attach the prosthesis to the bone.
Both are still widely used. In some cases a combination of the two types is used in which the ball portion of the prosthesis is cemented into place, and the socket not cemented. The decision about whether to use a cemented or noncemented artificial hip is usually made by the surgeon based on your age and lifestyle, and the surgeon’s experience.
Each prosthesis is made of two main parts. The acetabular component (socket) replaces the acetabulum. The acetabular component is made of a metal shell with a plastic inner liner that provides the bearing surface. The plastic used is so tough and slick that you could ice skate on a sheet of it without much damage to the material.
The femoral component (stem and ball) replaces the femoral head. The femoral component is made of metal. Sometimes, the metal stem is attached to a ceramic ball.
The Operation
Some type of anesthesia is necessary to perform a hip replacement. The procedure can be performed under general anesthesia or using some type of spinal anesthesia, such as an epidural or spinal. General anesthesia means that you are put completely asleep and a tube inserted into your windpipe to breathe for you while you are under the anesthesia. With a spinal type of anesthetic, you will be numb from the waist down after receiving an injection of anesthetic medication into your spinal canal. You will probably also be given medications to make you unaware of what is going on around you, but you will not have a tube inserted into your windpipe – you will breathe on your own. You should plan on discussing your options with your surgeon and anesthesiologist.
The surgeon begins by making an incision on the side of the thigh to allow access to the hip joint. Several different approaches can be used to make the incision. The choice is usually based on the surgeon’s training and preferences. For the anterior approach, an incision is made on the side of the thigh. This incision is usually around 4 to 6 inches but may be lengthened if more room is needed to complete the operation.
Once the skin incision is made, the muscles below the skin are separated to allow access to the hip joint. The nerves and blood vessels that run down the thigh in front of the hip joint are protected with special metal retractors. The anterior hip capsule that covers the front of the hip joint is opened by making an incision in the joint capsule.
Once the hip joint is entered, the surgeon dislocates the femoral head from the acetabulum. Then the femoral head is removed by cutting through the femoral neck with a power saw.
Attention is then turned toward the socket. The surgeon uses a power drill and a special reamer (a cutting tool used to enlarge or shape a hole) to remove cartilage from inside the acetabulum. The surgeon shapes the socket into the form of a half-sphere. This is done to make sure the metal shell of the acetabular component will fit perfectly inside. After shaping the acetabulum, the surgeon tests the new component to make sure it fits just right.
In the noncemented variety of artificial hip replacement, the metal shell is held in place by the tightness of the fit or by using screws to hold the shell in place. In the cemented variety, a special epoxy-type cement is used to anchor the acetabular component to the bone.
To begin replacing the femur, a drill is used to create the initial space to begin the process of preparing the femoral canal. Once the drilling is complete special rasps (filing tools) are used to shape the hollow femur to the exact shape of the metal stem of the femoral component. Once the size and shape are satisfactory, the stem is inserted into the femoral canal.
Again, in the noncemented variety of femoral component the stem is held in place by the tightness of the fit into the bone (similar to the friction that holds a nail driven into a hole that is slightly smaller than the diameter of the nail). In the cemented variety, the femoral canal is enlarged to a size slightly larger than the femoral stem, and the epoxy-type cement is used to bond the metal stem to the bone.
The metal ball that makes up the femoral head is then inserted. The hip is relocated and tested for range of motion and stability. The surgeon literally moves the leg in a full range of motion while watching the ball move in the plastic socket. The purpose of this step is to make sure that the hip moves well through the normal range of motion and does not tend to dislocate.
Once the surgeon is satisfied that everything fits properly, the incision is closed with stitches. Several layers of stitches are used under the skin, and either stitches or metal staples are then used to close the skin. A bandage is applied to the incision, and you are returned to the recovery room.
Complications
What might go wrong?
As with all major surgical procedures, complications can occur. This document doesn’t provide a complete list of the possible complications, but it does highlight some of the most common problems. Some of the most common complications following hip replacement surgery include
Anesthesia Complications
Most surgical procedures require that some type of anesthesia be given during surgery. A very small number of patients have problems with anesthesia. These problems can be reactions to the drugs used, problems related to other medical complications, and problems due to the anesthesia. Be sure to discuss the risks and your concerns with your anesthesiologist.
Thrombophlebitis (Blood Clots)
Thrombophlebitis, sometimes called deep venous thrombosis (DVT), can occur after any operation, but it is more likely to occur following surgery on the hip, pelvis, or knee. DVT occurs when the blood in the large veins of the leg forms blood clots. This may cause the leg to swell and become warm to the touch and painful. If the blood clots in the veins break apart, they can travel to the lung, where they lodge in the capillaries and cut off the blood supply to a portion of the lung. This is called a pulmonary embolism. (Pulmonary means lung, and embolism refers to a fragment of something traveling through the vascular system.) Most surgeons take preventing DVT very seriously. There are many ways to reduce the risk of DVT, but probably the most effective is getting you moving as soon as possible. Two other commonly used preventative measures include
- pressure stockings to keep the blood in the legs moving
- medications that thin the blood and prevent blood clots from forming
Infection
Infection can be a very serious complication following artificial joint replacement surgery. The chance of getting an infection following total hip replacement is probably around one percent. Some infections may show up very early, even before you leave the hospital. Others may not become apparent for months, or even years, after the operation. Infection can spread into the artificial joint from other infected areas. Your surgeon may want to make sure that you take antibiotics when you have dental work or surgical procedures on your bladder or colon to reduce the risk of spreading germs to the joint.
Dislocation
Just like your real hip, an artificial hip can dislocate if the ball comes out of the socket. There is a greater risk just after surgery, before the tissues have healed around the new joint, but there is always a risk. Once of the reasons that surgeons choose the anterior approach is that the risk of dislocation is much less than other approaches. But, there is still a small risk of dislocation even after using the anterior approach. The physical therapist will instruct you very carefully how to avoid activities and positions which may have a tendency to cause a hip dislocation. A hip that dislocates more than once may need to have another operation to make it more stable.
Loosening
The main reason that artificial joints eventually fail continues to be the loosening of the metal or cement from the bone. Great advances have been made in extending how long an artificial joint will last,but any artificial joint may eventually loosen and require a revision. A “revision” is the term used to describe removing the old artificial joint parts and replacing them with new parts. Today you can expect 15 to 20 years of service from an artificial hip, but in some cases the hip will loosen earlier than that. A loose hip is a problem because it causes pain. Once the pain becomes unbearable, another operation will probably be required to revise the hip.
Related Document: A Patient’s Guide to Revision Arthroplasty of the Hip
After Surgery
What happens after surgery?
After surgery, your hip will be covered with a padded dressing. Special boots and stockings are usually placed on your feet and legs to help prevent blood clots from forming.
If your surgery was performed under general anesthesia, a nurse or respiratory therapist will visit your room to guide you in a series of breathing exercises. You’ll use an incentive spirometer to improve breathing and avoid possible problems with pneumonia.
Physical therapy treatments are scheduled one to three times each day as long as you are in the hospital. Your first treatment is scheduled soon after you wake up from surgery. Your therapist will begin by helping you move from your hospital bed to a chair. By the second day, you’ll begin walking longer distances using your crutches or walker. Most patients are safe to put comfortable weight down when standing or walking. However, if your surgeon used a noncemented prosthesis, you may be instructed to limit the weight you bear on your foot when you are up and walking. Your therapist will review exercises to begin toning and strengthening the thigh and hip muscles. Ankle and knee movements are used to help pump swelling out of the leg and to prevent the formation of blood clots.
Patients are usually able to go home after spending one to four days in the hospital. You’ll be on your way home when you can demonstrate a safe ability to get in and out of bed, walk up to 75 feet with your crutches or walker, go up and down stairs safely, and consistently remember to use your hip precautions. Patients who still need extra care may be sent to a rehabilitation unit until they are safe and ready to go home.
Most orthopedic surgeons recommend that you have checkups on a routine basis after your artificial joint replacement. How often you need to be seen varies from every six months to every five years, according to your situation and what your surgeon recommends.
Patients who have an artificial joint will sometimes have episodes of pain, but if you have a period that lasts longer than a couple of weeks you should consult your surgeon. During the examination, the orthopedic surgeon will try to determine why you are feeling pain. X-rays may be taken of your artificial joint to compare with the ones taken earlier to see whether the joint shows any evidence of loosening.
Rehabilitation
What should I expect during my recovery?
After you are discharged from the hospital, your therapist may see you for one to six in-home treatments. This is to ensure you are safe in and about the home and getting in and out of a car. Your therapist will review your exercise program, continue working with you on your hip precautions, and make recommendations about your safety. These safety tips include using raised commode seats and bathtub benches, and raising the surfaces of couches and chairs. This keeps your hip from bending too far when you sit down. Bath benches and handrails can improve safety in the bathroom. Other suggestions may include the use of strategic lighting and the removal of loose rugs or electrical cords from the floor.
You should use your walker or crutches as instructed. You surgeon will advise you and your therapist how fast you can increase the weight you place through your leg. Most patients progress to using a cane in two to four weeks. In some cases, you may allowed to bear full weight almost immediately.
You may have your sutures or staples removed ten days to two weeks after surgery. Patients are usually able to drive within three weeks and walk without a walking aid by six weeks. Upon the approval of the surgeon, patients are generally able to resume sexual activity by one to two months after surgery.
The need for physical therapy usually requires a few visits in outpatient physical therapy. More visits may be needed for patients who have problems walking or who need to get back to heavier types of work or activities. Therapists sometimes treat their patients in a pool. Exercising in a swimming pool puts less stress on the hip joint, and the buoyancy lets you move and exercise easier. Once you’ve gotten your pool exercises down and the other parts of your rehab program advance, you may be instructed in an independent program. When you are safe in putting full weight through the leg, several types of balance exercises can be chosen to further stabilize and control the hip.
Finally, if your surgeon feels additional physical therapy is necessary, a select group of exercises can be used to simulate day-to-day activities, such as going up and down steps, squatting, and walking on uneven terrain. Specific exercises may then be chosen to simulate work or hobby demands.
Many patients have less pain and better mobility after having hip replacement surgery. But, you will need to follow some guidelines to help keep your new joint healthy for as long as possible. This may require that you adjust your activity choices to keep from putting too much strain on your new hip joint. Heavy sports that require running, jumping, quick stopping and starting, and cutting are discouraged. Patients may need to consider alternate jobs to avoid work activities that require heavy demands of lifting, crawling, and climbing.
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//Document link: A Patient’s Guide to Rehabilitation After Total Hip Replacement; rehab_thr.txt]
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Transcutaneous Electrical Stimulation (TENS) for Chronic Lumbar Spine Pain
A Patient’s Guide to Transcutaneous Electrical Stimulation (TENS) for Chronic Lumbar Spine Pain
Introduction
Low back pain due to musculoskeletal disorders, is the largest cause of time off work. The most commonly prescribed intervention is rest, pain medications, and a referral to physical therapy.
Physicians and physical therapists commonly recommend the use of a transcutaneous electrical nerve stimulation (TENS) unit as part of a pain management strategy for controlling low back pain. TENS is used primarily for chronic pain.
This guide will help you understand
- who may benefit from a TENS unit
- how a TENS unit works
- what to expect with a TENS unit
Who may benefit from a TENS?
TENS can be used for relief of pain associated with a wide variety of painful conditions. This may include back pain caused by spine degeneration, disc problems, or failed back surgery. Nerve pain from conditions such as chronic regional pain syndrome (CRPS) and neuropathies caused by diabetes or as a side effect of cancer treatment may also be managed with TENS.
TENS has been used for people suffering from cancer-related pain, phantom-limb pain (a chronic pain syndrome following limb amputation), and migraine or chronic tension-type headaches.
TENS can also be used for muscle soreness from overuse, inflammatory conditions, and both rheumatoid and osteoarthritis. Athletes with painful acute soft tissue injuries (e.g., sprains and strains) may benefit from TENS treatment.
Sometimes it is used after surgery for incisional or post-operative pain from any type of surgery (e.g., joint replacement, cardiac procedures, various abdominal surgeries, cesaerean section for the delivery of a baby). Studies show that TENS can significantly reduce the use of analgesics (pain relievers, including narcotic drugs) after surgery.
TENS is usually used along with other forms of treatment and pain control such as analgesics, relaxation therapy, biofeedback, visualization or guided imagery, physical therapy and exercise, massage therapy, nerve block injections, and/or spinal manipulation.
The effectiveness of TENS remains controversial. The American Academy of Neurology (AAN) findings published in Dec. 30, 2009 issue of Neurology claims it is not effective and cannot be recommended. But, many patients find TENS effective for pain relief, easy to use, and with very low side effects. It may be worth a try for those who suffer from chronic low back pain. It can be discontinued easily if it doesn’t work. TENS cannot correct an underlying problem; it is only used for temporary relief of symptoms.
TENS is a noninvasive way to override or block signals from the nerves to the spinal cord and brain. Pain messages may be altered enough to provide temporary pain relief. Besides controlling pain, this type of electrical stimulation can also improve local circulation and reduce or eliminate muscle spasm.
To summarize, the benefits from TENS treatment can include:
- pain relief
- increased circulation and healing
- improved sleep pattern
- decreased use of pain relievers or other analgesic drugs
- increased motion and function
How does a TENS work?
TENS produces an electrical impulse that can be adjusted for pulse, frequency, and intensity. The exact mechanism by which it works to reduce or even eliminate pain is still unknown. It is possible there are several different ways TENS works. For example, TENS may inhibit (block) pain pathways or increase of the secretion of the pain reducing substances (e.g., endorphins, serotonin) in the CNS.
Electrical stimulation has been shown to enhance tissue healing by improving circulation. This effect may alter pain perception.
Some integrative medicine practitioners also believe that it’s possible that the flow of energy through the meridian system modifies the sensation of pain. These practitioners believe that meridians are interconnected channels of energy throughout the body that are closely linked with the central nervous system (brain and spinal cord) as well as the peripheral nervous system (spinal nerves). These practitioners suggest that the electrical stimulation from the TENS unit is able to open up any blocked areas of energy flow bringing pain relief.
Recent research has also shown that autosuggestion or the placebo effect is a powerful way many people experience pain relief or improvement in symptoms. Simply by believing the treatment (any treatment, including TENS) will work has a beneficial effect on the nervous system. Many studies have shown that people get pain relief through the placebo effect alone.
How do I use my TENS unit
You will be shown how to use your TENS device by your healthcare provider trained in the set-up and use of this modality. Round or square rubber electrodes are applied to the skin over or around the painful area. Usually four electrodes (two pairs) are used to get maximum benefit from this treatment.
The electrodes are self-adhesive with a protective layer of gel built in to prevent skin irritation or burning. The unit is battery-operated with controls you manipulate yourself to alter the strength of the electrical signal. The unit can be slipped into a pocket or clipped to your belt. You may use two or four electrodes.
The electrodes will be placed on your body at positions selected by a physician or physical therapist. The electrode placement is determined based on the location of the involved nerves and/or the location of your pain.
The first place to try the electrodes is either directly over the painful area or on either side of the pain. You will slowly turn up the intensity of the unit until you feel a buzzing, tingling, or thumping sensation strong enough to override the pain signals.
If that doesn’t work, you may get better results putting the electrodes over the area where the spinal nerve root exits the vertebra. Sometimes it takes a bit of trial and error to find the right settings and best electrode placement for you.
Be sure and let your healthcare provider know if you experience increased pain. Electrodes placed below the level of a peripheral nerve impairment might actually block the input from the TENS unit and cause increased pain. Or placement over an area of scar tissue from surgery can cause increased skin resistance and decreased transmission of the electrical impulses.
Another way to use TENS is over spots in the muscles that trigger pain called trigger points (TrPs). Trigger points are areas of hyperirritability in the muscles that can cause chronic pain. The healthcare provider will identify any TrPs present during your exam. Usually TrPs are taken care of with a treatment designed to eliminate them. In some patients they are chronic and don’t go away or come back easily. In such cases, TENS may be helpful.
Your health care team will guide you through the trial-and-error process for finding the best electrode placement for you and make any changes needed in the program.
When you should NOT use TENS
1.If you have loss of skin sensation or even decreased sensation, you should not use TENS. With altered sensation, there is a risk of turning the unit up too high and causing injury or harm.
2.The use of TENS is not recommended for older adults with Alzheimer’s, dementia, or other cognitive problems.
3.If you have a cardiac pacemaker, you should not use TENS as the electrical signals could interfere with your pacemaker. Cardiac patients should not use TENS without their physician’s approval.
Some guidelines when using TENS
- Before applying the electrodes, it is important to remove all lotions, oils, or other applications to the skin. You may want to shave hair from the local area where the electrode will be applied.
- Daily use of TENS for several hours at a time is recommended. You should not wear the unit for long periods of time (e.g., 24 hours) or during extended sleep time (napping is okay but TENS should not be used while sleeping at night or for more than a couple of hours).
- Never place an electrode over an open wound or area of skin irritation. Report any skin problems or burns immediately.
- Do not place electrodes near your eyes or over your throat.
- Do not use TENS in the shower or bathtub.
- Move the electrodes a bit each time you put them on to avoid skin irritation.
- You should experience a comfortable tingling sensation that is comfortable enough to allow you to complete daily tasks and activities.
- You may want to keep a daily journal of your pain levels, the settings you use, and a record of the medications you are taking for pain relief. By reviewing your notes, you may find the best combination of electrode placement and unit settings that gives you the most pain relief.
What can you expect with TENS
You should feel a mild to moderately strong tingling or buzzing sensation. Some people experience a more unpleasant sensation described as burning or prickling. Depending on the intensity and duration of your pain, you may or may not get results right away.
It can take several days to even several weeks to get the desired results. Differences in results may occur based on properties of skin resistance, type of pain, and individual differences in the mechanism of pain control. Be patient and persistent. Do not hesitate to contact your healthcare provider as often as it takes to get the desired results.
Many patients do report good-to-excellent results, first with pain control, then pain relief, and finally reduction in the use of medications. Although it doesn’t happen for everyone, some chronic pain patients are “cured” permanently from their pain.
As each of these benefits from the TENS treatment occur, you may find yourself increasing your activity level – either with the same level of TENS usage or even with reduced frequency of use, intensity of signal, or duration (length of time the unit is turned on).
If for any reason your pain starts to increase in frequency, duration, or intensity, don’t assume the treatment isn’t working for you. First, check the TENS unit for any malfunction, need to recharge, or replace the electrodes with new ones. If your unit is battery-operated, you may find it necessary to turn the intensity up to obtain the same sensation when the batteries are low. This should alert you to the need for battery replacement.
Finally, be aware that some patients experience “breakthrough pain,” referring to a situation in which you get pain relief at first but then even with the TENS unit, you start to have pain once again. Turning the intensity up high enough to cause muscle contraction is an indication of breakthrough pain.
Sometimes a different setting for the stimulator may be needed when this happens. Most units have a setting that allows for random pulse frequency, duration, and amplitude. The use of this setting helps keep the nervous system from getting used to a specific amount of stimulation and ignoring it. This phenomenon is called habituation or adaptation.
Summary
TENS is an effective method of pain control for chronic pain when you want to maintain your normal routine of daily activities that would otherwise be hampered by too high of pain levels. TENS helps many people reduce and sometimes even eliminate the use of pain medications, thus avoiding side-effects of long-term drug use.
Even without complete pain relief, TENS makes it possible to stay active and participate in work, family, and even recreational activities. There are no significant adverse effects from the use of TENS. The ability of this treatment technique to moderate pain and reduce the use of pain medications is a real benefit — especially with the potential for serious or adverse effects from long-term use of pain relievers.
Transcutaneous Electrical Stimulation (TENS) for Cervical Spine Pain
A Patient’s Guide to Transcutaneous Electrical Stimulation (TENS) for Cervical Spine Pain
Introduction
Neck (cervical spine) pain due to musculoskeletal disorders, is the second largest cause of time off work – low back pain being first. It is generally worse in the morning and evening. The most commonly prescribed intervention is rest and analgesics, and often a referral to physical therapy. Among the rehabilitation intervention treatments for neck pain is the transcutaneous electrical nerve stimulation (TENS) unit.
Electrical nerve stimulation is a treatment for pain that is used primarily for chronic pain. The electrical stimulation is delivered through electrodes or patches placed on the skin. The technique and the device used is called transcutaneous electrical stimulation or TENS for short.
TENS is a noninvasive way to override or block signals from the nerves to the spinal cord and brain. Pain messages may be altered enough to provide temporary or even long-lasting pain relief. Besides controlling pain, this type of electrical stimulation can also improve local circulation and reduce or eliminate muscle spasm.
This guide will help you understand
- who may benefit from a TENS unit
- how a TENS unit works
- what to expect with a TENS unit
Who may benefit from a TENS unit
TENS can be used for relief of pain associated with a wide variety of painful conditions. This may include back pain caused by spine degeneration, disc problems, or failed back surgery. Nerve pain from conditions such as chronic regional pain syndrome (CRPS) and neuropathies caused by diabetes or as a side effect of cancer treatment may also be managed with TENS.
TENS has been used for people suffering from cancer-related pain, phantom-limb pain (a chronic pain syndrome following limb amputation), and migraine or chronic tension-type headaches.
TENS can also be used for muscle soreness from overuse, inflammatory conditions, and both rheumatoid and osteoarthritis. Athletes with painful acute soft tissue injuries (e.g., sprains and strains) may benefit from TENS treatment.
Sometimes it is used after surgery for incisional or post-operative pain from any type of surgery (e.g., joint replacement, cardiac procedures, various abdominal surgeries, cesaerean section for the delivery of a baby). Studies show that TENS can significantly reduce the use of analgesics (pain relievers, including narcotic drugs) after surgery.
TENS is usually used along with other forms of treatment and pain control such as analgesics, relaxation therapy, biofeedback, visualization or guided imagery, physical therapy and exercise, massage therapy, nerve block injections, and/or spinal manipulation.
The effectiveness of TENS remains controversial. The American Academy of Neurology (AAN) findings published in Dec. 30, 2009 issue of Neurology claims it is not effective and cannot be recommended. But, many patients find TENS effective for pain relief, easy to use, and with very low side effects. It may be worth a try for those who suffer from chronic low back pain. It can be discontinued easily if it doesn’t work. TENS cannot correct an underlying problem; it is only used for temporary relief of symptoms.
TENS is a noninvasive way to override or block signals from the nerves to the spinal cord and brain. Pain messages may be altered enough to provide temporary pain relief. Besides controlling pain, this type of electrical stimulation can also improve local circulation and reduce or eliminate muscle spasm.
To summarize, the benefits from TENS treatment can include:
- pain relief
- increased circulation and healing
- decreased use of pain relievers or other analgesic drugs
- increased motion and function
How does TENS work?
TENS produces an electrical impulse that can be adjusted for pulse, frequency, and intensity. The exact mechanism by which it works to reduce or even eliminate pain is still unknown. It is possible there are several different ways TENS works. For example, TENS may inhibit (block) pain pathways or increase of the secretion of the pain reducing substances (e.g., endorphins, serotonin) in the CNS.
Electrical nerve stimulation is a treatment for pain that is used primarily for chronic pain. The electrical stimulation is delivered through electrodes or patches placed on the skin. The technique and the device used is called transcutaneous electrical neurostimulation or TENS for short.
TENS is a noninvasive way to override or block signals from the nerves to the spinal cord and brain. Pain messages may be altered enough to provide temporary or even long-lasting pain relief. Besides controlling pain, this type of electrical stimulation can also improve local circulation and reduce or eliminate muscle spasm.
Recent research has also shown that autosuggestion or the placebo effect is a powerful way many people experience pain relief or improvement in symptoms. Simply by believing the treatment (any treatment, including TENS) will work has a beneficial effect on the nervous system. Many studies have shown that people get pain relief through the placebo effect alone.
How do I use my TENS unit?
You will be shown how to use your TENS device by your healthcare provider trained in the set-up and use of this modality. Round or square rubber electrodes are applied to the skin over or around the painful area. Usually four electrodes (two pairs) are used to get maximum benefit from this treatment.
The electrodes are self-adhesive with a protective layer of gel built in to prevent skin irritation or burning. The unit is battery-operated with controls you manipulate yourself to alter the strength of the electrical signal. The unit can be slipped into a pocket or clipped to your belt. You may use two or four electrodes.
The electrodes will be placed on your body at positions selected by a physician or physical therapist. The electrode placement is determined based on the location of the involved nerves and/or the location of your pain.
The first place to try the electrodes is either directly over the painful area or on either side of the pain. You will slowly turn up the intensity of the unit until you feel a buzzing, tingling, or thumping sensation strong enough to override the pain signals.
If that doesn’t work, you may get better results putting the electrodes over the area where the spinal nerve root exits the vertebra. Sometimes it takes a bit of trial and error to find the right settings and best electrode placement for you.
Be sure and let your healthcare provider know if you experience increased pain. Electrodes placed below the level of a peripheral nerve impairment might actually block the input from the TENS unit and cause increased pain. Or placement over an area of scar tissue from surgery can cause increased skin resistance and decreased transmission of the electrical impulses.
Another way to use TENS is over spots in the muscles that trigger pain called trigger points (TrPs). Trigger points are areas of hyperirritability in the muscles that can cause chronic pain. The healthcare provider will identify any TrPs present during your exam. Usually TrPs are taken care of with a treatment designed to eliminate them. In some patients they are chronic and don’t go away or come back easily. In such cases, TENS may be helpful.
Your health care team will guide you through the trial-and-error process for finding the best electrode placement for you and make any changes needed in the program.
When you should NOT use TENS
- If you have loss of skin sensation or even decreased sensation, you should not use TENS. With altered sensation, there is a risk of turning the unit up too high and causing injury or harm.
- The use of TENS is not recommended for older adults with Alzheimer’s, dementia, or other cognitive problems.
- If you have a cardiac pacemaker, you should not use TENS as the electrical signals could interfere with your pacemaker. Cardiac patients should not use TENS without their physician’s approval.
Some guidelines when using TENS
- Before applying the electrodes, it is important to remove all lotions, oils, or other applications to the skin. You may want to shave hair from the local area where the electrode will be applied.
- Daily use of TENS for several hours at a time is recommended. You should not wear the unit for long periods of time (e.g., 24 hours) or during extended sleep time (napping is okay but TENS should not be used while sleeping at night or for more than a couple of hours).
- Never place an electrode over an open wound or area of skin irritation. Report any skin problems or burns immediately.
- Do not place electrodes near your eyes or over your throat.
- Do not use TENS in the shower or bathtub.
- Move the electrodes a bit each time you put them on to avoid skin irritation.
- You should experience a comfortable tingling sensation that is comfortable enough to allow you to complete daily tasks and activities.
- You may want to keep a daily journal of your pain levels, the settings you use, and a record of the medications you are taking for pain relief. By reviewing your notes, you may find the best combination of electrode placement and unit settings that gives you the most pain relief.
What you can expect with TENS
You should feel a mild to moderately strong tingling or buzzing sensation. Some people experience a more unpleasant sensation described as burning or prickling. Depending on the intensity and duration of your pain, you may or may not get results right away.
It can take several days to even several weeks to get the desired results. Differences in results may occur based on properties of skin resistance, type of pain, and individual differences in the mechanism of pain control. Be patient and persistent. Do not hesitate to contact your healthcare provider as often as it takes to get the desired results.
Many patients do report good-to-excellent results, first with pain control, then pain relief, and finally reduction in the use of medications. Although it doesn’t happen for everyone, some chronic pain patients are “cured” permanently from their pain.
As each of these benefits from the TENS treatment occur, you may find yourself increasing your activity level – either with the same level of TENS usage or even with reduced frequency of use, intensity of signal, or duration (length of time the unit is turned on).
If for any reason your pain starts to increase in frequency, duration, or intensity, don’t assume the treatment isn’t working for you. First, check the TENS unit for any malfunction, need to recharge, or replace the electrodes with new ones. If your unit is battery-operated, you may find it necessary to turn the intensity up to obtain the same sensation when the batteries are low. This should alert you to the need for battery replacement.
Finally, be aware that some patients experience “breakthrough pain,” referring to a situation in which you get pain relief at first but then even with the TENS unit, you start to have pain once again. Turning the intensity up high enough to cause muscle contraction is an indication of breakthrough pain.
Sometimes a different setting for the stimulator may be needed when this happens. Most units have a setting that allows for random pulse frequency, duration, and amplitude. The use of this setting helps keep the nervous system from getting used to a specific amount of stimulation and ignoring it. This phenomenon is called habituation or adaptation.
Summary
TENS is an effective method of pain control for chronic pain when you want to maintain your normal routine of daily activities that would otherwise be hampered by too high of pain levels. TENS helps many people reduce and sometimes even eliminate the use of pain medications, thus avoiding side-effects of long-term drug use.
Even without complete pain relief, TENS makes it possible to stay active and participate in work, family, and even recreational activities. There are no significant adverse effects from the use of TENS. The ability of this treatment technique to moderate pain and reduce the use of pain medications is a real benefit — especially with the potential for serious or adverse effects from long-term use of pain relievers.
Transcutaneous Electrical Stimulation (TENS)
A Patient’s Guide to Pain Management: Transcutaneous Electrical Stimulation (TENS)
Introduction
Electrical nerve stimulation is a treatment for pain that can be used for acute pain (e.g., during labor or after surgery) or for chronic pain. It is a form of electrical energy sent in various wave forms to the nerves. When it is delivered through electrodes or patches placed on the skin, it is called transcutaneous electrical stimulation or TENS for short.
TENS is a noninvasive way to override or block signals from the nerves to the spinal cord and brain. Pain messages may be altered enough to provide temporary or even long-lasting pain relief. Besides controlling pain, this type of electrical stimulation can also improve local circulation and reduce or eliminate muscle spasm.
This guide will help you understand
- who may benefit from a TENS unit
- how a TENS unit works
- what tto expect with a TENS unit
Who may benefit from a TENS?
TENS can be used for relief of pain associated with a wide variety of painful conditions. This may include back pain caused by spine degeneration, disc problems, or failed back surgery. Nerve pain from conditions such as chronic regional pain syndrome (CRPS) and neuropathies caused by diabetes or as a side effect of cancer treatment may also be managed with TENS.
TENS has been used for people suffering from cancer-related pain, phantom-limb pain (a chronic pain syndrome following limb amputation), and migraine or chronic tension-type headaches.
TENS can also be used for muscle soreness from overuse, inflammatory conditions, and both rheumatoid and osteoarthritis. Athletes with painful acute soft tissue injuries (e.g., sprains and strains) may benefit from TENS treatment.
Sometimes it is used after surgery for incisional or post-operative pain from any type of surgery (e.g., joint replacement, cardiac procedures, various abdominal surgeries, cesaerean section for the delivery of a baby). Studies show that TENS can significantly reduce the use of analgesics (pain relievers, including narcotic drugs) after surgery.
TENS is usually used along with other forms of treatment and pain control such as analgesics, relaxation therapy, biofeedback, visualization or guided imagery, physical therapy and exercise, massage therapy, nerve block injections, and/or spinal manipulation.
To summarize, the benefits from TENS treatment can include:
- pain relief
- increased circulation and healing
- improved sleep pattern
- decreased use of pain relievers or other analgesic drugs
- increased motion and function
How does a TENS work?
TENS produces an electrical impulse that can be adjusted for pulse, frequency, and intensity. The exact mechanism by which it works to reduce or even eliminate pain is still unknown. It is possible there are several different ways TENS works. For example, TENS may inhibit (block) pain pathways or increase of the secretion of the pain reducing substances (e.g., endorphins, serotonin) in the CNS.
Electrical nerve stimulation is a treatment for pain that is used primarily for chronic pain. The electrical stimulation is delivered through electrodes or patches placed on the skin. The technique and the device used is called transcutaneous electrical neurostimulation or TENS for short.
TENS is a noninvasive way to override or block signals from the nerves to the spinal cord and brain. Pain messages may be altered enough to provide temporary or even long-lasting pain relief. Besides controlling pain, this type of electrical stimulation can also improve local circulation and reduce or eliminate muscle spasm.
Recent research has also shown that autosuggestion or the placebo effect is a powerful way many people experience pain relief or improvement in symptoms. Simply by believing the treatment (any treatment, including TENS) will work has a beneficial effect on the nervous system. Many studies have shown that people get pain relief through the placebo effect alone.
How do I use my TENS unit
You will be shown how to use your TENS device by your healthcare provider trained in the set-up and use of this modality. Round or square rubber electrodes are applied to the skin over or around the painful area. Usually four electrodes (two pairs) are used to get maximum benefit from this treatment.
The electrodes are self-adhesive with a protective layer of gel built in to prevent skin irritation or burning. The unit is battery-operated with controls you manipulate yourself to alter the strength of the electrical signal. The unit can be slipped into a pocket or clipped to your belt. You may use two or four electrodes.
The electrodes will be placed on your body at positions selected by a physician or physical therapist. The electrode placement is determined based on the location of the involved nerves and/or the location of your pain.
The first place to try the electrodes is either directly over the painful area or on either side of the pain. You will slowly turn up the intensity of the unit until you feel a buzzing, tingling, or thumping sensation strong enough to override the pain signals.
If that doesn’t work, you may get better results putting the electrodes over the area where the spinal nerve root exits the vertebra. Sometimes it takes a bit of trial and error to find the right settings and best electrode placement for you.
Be sure and let your healthcare provider know if you experience increased pain. Electrodes placed below the level of a peripheral nerve impairment might actually block the input from the TENS unit and cause increased pain. Or placement over an area of scar tissue from surgery can cause increased skin resistance and decreased transmission of the electrical impulses.
Another way to use TENS is over spots in the muscles that trigger pain called trigger points (TrPs). Trigger points are areas of hyperirritability in the muscles that can cause chronic pain. The healthcare provider will identify any TrPs present during your exam. Usually TrPs are taken care of with a treatment designed to eliminate them. In some patients they are chronic and don’t go away or come back easily. In such cases, TENS may be helpful.
Your health care team will guide you through the trial-and-error process for finding the best electrode placement for you and make any changes needed in the program.
When you should NOT use TENS
- If you have loss of skin sensation or even decreased sensation, you should not use TENS. With altered sensation, there is a risk of turning the unit up too high and causing injury or harm.
- The use of TENS is not recommended for older adults with Alzheimer’s, dementia, or other cognitive problems.
- If you have a cardiac pacemaker, you should not use TENS as the electrical signals could interfere with your pacemaker. Cardiac patients should not use TENS without their physician’s approval.
Some guidelines when using TENS
- Before applying the electrodes, it is important to remove all lotions, oils, or other applications to the skin. You may want to shave hair from the local area where the electrode will be applied.
- Daily use of TENS for several hours at a time is recommended. You should not wear the unit for long periods of time (e.g., 24 hours) or during extended sleep time (napping is okay but TENS should not be used while sleeping at night or for more than a couple of hours).
- Never place an electrode over an open wound or area of skin irritation. Report any skin problems or burns immediately.
- Do not place electrodes near your eyes or over your throat.
- Do not use TENS in the shower or bathtub.
- Move the electrodes a bit each time you put them on to avoid skin irritation.
- You should experience a comfortable tingling sensation that is comfortable enough to allow you to complete daily tasks and activities.
- You may want to keep a daily journal of your pain levels, the settings you use, and a record of the medications you are taking for pain relief. By reviewing your notes, you may find the best combination of electrode placement and unit settings that gives you the most pain relief.
What can you expect with TENS
You should feel a mild to moderately strong tingling or buzzing sensation. Some people experience a more unpleasant sensation described as burning or prickling. Depending on the intensity and duration of your pain, you may or may not get results right away.
It can take several days to even several weeks to get the desired results. Differences in results may occur based on properties of skin resistance, type of pain, and individual differences in the mechanism of pain control. Be patient and persistent. Do not hesitate to contact your healthcare provider as often as it takes to get the desired results.
Many patients do report good-to-excellent results, first with pain control, then pain relief, and finally reduction in the use of medications. Although it doesn’t happen for everyone, some chronic pain patients are “cured” permanently from their pain.
As each of these benefits from the TENS treatment occur, you may find yourself increasing your activity level – either with the same level of TENS usage or even with reduced frequency of use, intensity of signal, or duration (length of time the unit is turned on).
If for any reason your pain starts to increase in frequency, duration, or intensity, don’t assume the treatment isn’t working for you. First, check the TENS unit for any malfunction, need to recharge, or replace the electrodes with new ones. If your unit is battery-operated, you may find it necessary to turn the intensity up to obtain the same sensation when the batteries are low. This should alert you to the need for battery replacement.
Finally, be aware that some patients experience “breakthrough pain,” referring to a situation in which you get pain relief at first but then even with the TENS unit, you start to have pain once again. Turning the intensity up high enough to cause muscle contraction is an indication of breakthrough pain.
Sometimes a different setting for the stimulator may be needed when this happens. Most units have a setting that allows for random pulse frequency, duration, and amplitude. The use of this setting helps keep the nervous system from getting used to a specific amount of stimulation and ignoring it. This phenomenon is called habituation or adaptation.
Summary
TENS is an effective method of pain control for chronic pain when you want to maintain your normal routine of daily activities that would otherwise be hampered by too high of pain levels. TENS helps many people reduce and sometimes even eliminate the use of pain medications, thus avoiding side-effects of long-term drug use.
Even without complete pain relief, TENS makes it possible to stay active and participate in work, family, and even recreational activities. There are no significant adverse effects from the use of TENS. The ability of this treatment technique to moderate pain and reduce the use of pain medications is a real benefit — especially with the potential for serious or adverse effects from long-term use of pain relievers.
Bipartite Patella in Children
A Patient’s Guide to Bipartite Patella in Children
Introduction
Bipartite patella is a congenital condition (present at birth) that occurs when the patella (kneecap) is made of two bones instead of a single bone. Normally, the two bones would fuse together as the child grows. But in bipartite patella, they remain as two separate bones. About one per cent of the population has this condition. Boys are affected much more often than girls.
This guide will help you understand
- what parts of the knee are involved
- how this condition develops
- how doctors diagnose this condition
- what treatment options are available
Anatomy
What is the patella and what does it do?
The knee is the meeting place of two important bones in the leg, the femur (the thighbone) and the tibia (the shinbone). The patella (kneecap) is the moveable bone that sits in front of the knee. This unique bone is wrapped inside a tendon that connects the large muscles on the front of the thigh, the quadriceps muscles, to the lower leg bone.
Related Document: A Patient’s Guide to Knee Anatomy
Causes
What causes this condition?
The patella starts out as a piece of fibrous cartilage. It turns into bone or ossifies as part of the growth process. Each bone has an ossification center. This is the first area of the structure to start changing into bone.
Most bones (including the patella) only have one primary ossification center. But in some cases, a second ossification center is present. Normally, these two centers of bone will fuse together during late childhood or early adolescence. If they don’t ossify together, then the two pieces of bone remain connected by fibrous or cartilage tissue. This connective tissue is called a synchondrosis.
The most common location of the second bone is the supero-lateral (upper outer) corner of the patella. But the problem can occur at the bottom of the patella or along the side of the kneecap.
Injury or direct trauma to the synchondrosis can cause a separation of this weak union leading to inflammation. Repetitive microtrauma can have the same effect. The cartilage has a limited ability to repair itself. The increased mobility between the main bone and the second ossification center further weakens the synchondrosis resulting in painful symptoms.
Symptoms
What does bipartite patella feel like?
Most of the time, there are no symptoms. Sometimes there is a bony bump or place where the bone sticks out more on one side than the other. If inflammation of the fibrous tissue between the two bones occurs, then painful symptoms develop directly over the kneecap. The pain is usually described as dull aching.There may be some swelling.
Movement of the knee can be painful, especially when bending the joint. Atrophy of the quadriceps and malalignment of the patella can lead to patellar tracking problems. Squatting, stair climbing, weight training, and strenuous activity aggravate the knee causing increased symptoms. For the runner, running down hill causes increased pain, tenderness, and swelling.
Diagnosis
How will my doctor diagnose this condition?
Most of the time, this condition is seen on X-rays of the knee that are taken for some other reason. This is referred to as an “incidental finding”. A radiolucent line is observed across the superior-lateral corner of the patella. This represents the extra ossification center and is seen most often in children between the ages of eight and 12. Sometimes, it is mistaken for a fracture of the patella. But since the problem usually affects both knees, an X-ray of the other knee showing the same condition can confirm the diagnosis.
MRIs or bone scans are useful when a fracture is suspected but doesn’t show up on the X-rays. The presence of fibrocartilaginous material between the two bones helps confirm a diagnosis of bipartite patella. An MRI can show the condition of articular cartilage at the patellar-fragment interface. The lack of bone marrow edema helps rule out a bone fracture. CT scans will show the bipartite fragment but are not as helpful as MRIs because bone marrow or soft tissue edema does not show up, so it’s still not clear from CT findings whether the symptoms are from the fragment or fracture.
Treatment
What treatment options are available?
Most of the time, no treatment is necessary. Most people who have a bipartite patella, probably don’t even know it. But if an injury occurs and/or painful symptoms develop, then treatment may be needed.
Nonsurgical Treatment
Conservative care involves rest, over-the-counter nonsteroidal antiinflammatory drugs (NSAIDs) such as ibuprofen, and activity modification. Avoiding deep flexion such as squatting, excess use of the stairs, and resisted weight training are advised.
Separation of the synchondrosis can be treated with immobilization for four to six weeks. The knee is placed in full extension using a cylinder cast, knee immobilizer, or dynamic patellar brace. An immobilizer is a removable splint. It’s usually only taken off to wash the leg and remains in place the rest of the time. The dynamic brace immobilizes the knee in an extended (straight-leg) position with limited flexion (up to 30 degrees). The brace reduces pain by decreasing the pull on the patella from the quadriceps muscle. Once healing occurs and the cast or brace is no longer needed, then stretching exercises of the quadriceps muscle are prescribed.
Surgery
If conservative care with immobilization is not successful in alleviating swelling and pain, then surgery may be suggested. When the bipartite fragment is small, then the surgeon can simply remove the smaller fragment of bone. When the bipartite fragment is larger and also contains part of the joint surface, the surgeon may decide to try and force the two fragments to heal together or fuse. The connective tissue between the two fragments is removed first and the two bony fragments are then held together or stabilized with a metal screw or pin. This is called internal fixation. The two fragments of bone heal together or fuse, creating a solid connection between the two fragments. Although successful in reuniting the patella, the procedure may require several weeks of immobilization. As a result, knee stiffness may occur. This usually requires physical therapy once the bones have healed to regain strength and motion.
Another potential treatment option is a procedure called a lateral retinacular release. It may be beneficial to remove the constant pull of the vastus lateralis tendon (a part of the large quadriceps muscle of the thigh) where it attaches to the bone of the bipartite fragment of the upper, outer patella. Simply cutting this attachment reduces the constant pull on the bony fragment. Healing of the two fragments may occur as a result.
Rehabilitation
What should I expect after Treatment?
Nonsurgical Rehabilitation
Most patients respond well to activity modification and immobilization. When the X-ray shows complete ossification of the two bone fragments, then you’ll be able to return to your regular activities. If there is no improvement after three months of conservative care, then surgery is considered.
After Surgery
Usually, the removal of a bipartite patella is a simple surgery with prompt relief of pain and quick recovery. Athletes can expect full range of motion, a stable knee, and a fairly rapid return to normal activity (one to two months). But runners and other athletes who have had an extended time of immobility, muscle weakness and atrophy, loss of normal joint motion, and patellar tracking problems may require a special rehab program. A physical therapist will prescribe and monitor a rehabilitation program starting with range of motion and quadriceps strengthening exercises.
Athletes will be progressed quickly to restore full motion and strength. An aerobic program to improve cardiovascular endurance is often needed after so many months of inactivity. Proprioception and functional activities are added in order to prepare the individual to return to full sports participation. Proprioceptive exercises help restore the joint’s sense of position. Proprioceptive activities are needed to restore normal movement and prevent further injury.
Pigmented Villonodular Synovitis of the Knee
A Patient’s Guide to Pigmented Villonodular Synovitis (PVNS) of the Knee
Introduction
Pigmented villonodular synovitis of the knee (PVNS) is a very rare disease. Pigmented villonodular synovitis is most often painless inflammation or swelling, and overgrowth of the lining of a joint. The growth can invade the nearby bone.
Eighty per cent of the time pigmented villonodular synovitis affects just one joint of the body, primarily the knee joint. The hip, shoulder, and the smaller joints in the hands and feet can also be affected.
Pigmented villonodular synovitis occurs in less than two persons per million per year. It occurs in both men and women commonly between the ages of 20 and 45 years.
This guide will help you understand
- what parts of the knee are involved
- how this condition develops
- how doctors diagnose this condition
- what treatment options are available
Anatomy
What parts of the knee are affected?
There are several types of joints in the body, but pigmented villonodular synovitis (PVNS) generally affects the synovial joints. Synovial joints are the most common joints in the body (90 percent). They are the most mobile of the joints.
The knee joint is a synovial joint. It is surrounded by synovial tissue which is tough. It is not stretchy or elastic. The synovial tissue forms a covering called a joint capsule around the joint. The joint capsule helps stabilize the joint. The soft padding on the ends of the bones is called articular cartilage. This helps the joint move smoothly. Ligaments and tendons help hold the joint together.
Related Document: A Patient’s Guide to Knee Anatomy
Causes
What causes this condition?
Villous means hair-like. In pigmented villonodular synovitis, the tissue that is affected may look frayed or hair-like. The synovial tissue can also appear folded. Sometimes the tissue will have round bumps or nodules. The nodular type is usually seen in tendons. Tissue affected by pigmented villonodular synovitis can contain deposits of fat. Pigmented means colored. The synovium and its fluid is often a brown color instead of clear. This is because blood, which contains iron, is deposited in the fluid.
Pigmented Villonodular Synovitis (PVNS) at one time was thought to be a form of malignant cancer. It is now considered a benign, or non-cancerous, inflammatory process.
It is not known if PVNS is due to injury. Patients have reported injury at some time to the affected joint, others do not. There does not seem to be a genetic cause. It happens in both men and women generally between the ages of 20 and 45 years. It occurs in less than two persons per million per year.
The exact cause is unknown. Some doctors believe it’s caused by abnormal metabolism of fat. Others think it may be caused by repetitive inflammation. Some feel that blood within the joint may cause the inflammatory change.
Symptoms
What are the symptoms?
Symptoms of pigmented villonodular synovitis (PVNS) of the knee include inflammation, swelling, stiffness, and tenderness around the joint. The pain can come and go.
Symptoms may feel like arthritis. The pain comes on slowly in the joint. There may be swelling, tenderness, and limited movement of the knee. The symptoms can come and go. Eighty per cent of the time PVNS affects the knee.
Sometimes a popping feeling is felt in the knee. Tenderness in the front part of the knee near the knee cap is usually noticed. The symptoms are rather “non-specific”, meaning that they can act like other problems. PVNS of the knee can easily be mistaken for a torn meniscus, or problems with the patella (knee cap).
There are two types of pigmented villonodular synovitis (PVNS). When it occurs in one large synovial joint of the body, such as the knee, it is considered diffuse. This is because the inflammation is more widespread within the joint. The synovial capsule, bursa, and tendon sheaths around the joint can all be involved. Even the bones in the knee joint can be affected.
The other type of pigmented villonodular synovitis is localized, or focal. This form is rare. It usually affects just the tendon sheaths around smaller joints in the hands and feet. This means there will be localized swelling and likely some tenderness along the tendons.
Diagnosis
How will my doctor diagnose this condition?
Your doctor will want to do a physical examination. He/she will want to measure range of motion of the knee joint. Your doctor will also want to determine if there is any swelling, nodules, tenderness, or fluid in the joint. Swelling in your knee may feel warm and be somewhat tender to palpation.
Imaging plays an important role in the diagnosis of pigmented villonodular synovitis (PVNS). Often, X-rays will be normal. Sometimes there will be cysts in the bone at the joint caused by the invasion of PVNS. There are usually no wear and tear changes like with arthritis.
MRI does not use x-rays. It uses magnetic waves. It allows the doctor to
see your tissues and bones in thin slices. You will need an MRI with
contrast. This means that you will have to have an IV inserted. The contrast
material is called gladolinium. The gladolinium will go where cells are more
active in your body. Cells tend to be more active in areas where there is
inflammation, and in tumors.
If PVNS has invaded the bone, your doctor will likely want you to have a computed tomography (CT) scan. This is a special form of xray. Like the MRI, it takes pictures in slices. This will require the injection of intravenous contrast so that tissues can be better evaluated.
Your doctor may want to remove (aspirate) fluid from the joint that is affected. This is called arthrocentesis. The fluid is taken out with a needle. The fluid is then tested in the lab. If PVNS is the cause of the symptoms, most of the time the fluid will contain blood.
A contrast material may be injected into the joint after aspiration which will enhance the imaging studies. The contrast material will show irregular and nodular defects in imaging studies. This testing is called an arthrogram.
A biopsy of the affected tissue may be suggested. This can certainly confirm the diagnosis of PVNS. Computed tomography is used to perform the biopsy. Pictures are taken while your doctor is placing the needle in the tissue to be removed and tested. The tissue that is removed is then looked at in the lab. If pigmented villonodular synovitis (PVNS) is present, the synovium will be thickened. It will likely have both villous and nodular extra growth. Inflammation cells called giant cells are usually present. The synovium and fluid will be a brown color. This is due to deposits of iron in the blood.
Treatment
What treatment options are available?
Nonsurgical Treatment
There is no nonsurgical treatment. Because the PVNS can grow and invade bone, surgery is the recommended treatment.
Surgery
Since PVNS can invade the joint, the most effective treatment is surgery. Removing the synovium and involved tissue is necessary. Since PVNS can grow back, sometimes radiation is recommended. Sometimes joint replacement may be needed.
The recommended treatment for PVNS is removal of all the affected tissue. The surgery is called a synovectomy. Most of the time this surgery can be done with an arthroscope. Your surgeon makes tiny cuts in the skin over your joint. A thin tube with a tiny camera is used so your surgeon can see inside the joint. Instruments for cutting, smoothing, and removing tissue are passed through another thin tube. Arthroscopy is done as a “same day” surgery, meaning you can go home the same day.
Sometimes the synovectomy is done by opening the knee joint. In diffuse pigmented villonodular synovitis (PVNS), all the tissue, including any bone that seems to be affected is removed. Grafting, or replacing the bone with transplanted bone may be necessary to maintain the joint. In some instances, a total joint replacement of the knee is necessary.
Diffuse PVNS grows back in nearly 50 percent of cases. If your surgeon is concerned that not all of the affected tissue was removed, you may have to have radiation therapy. It is also used if there is recurrence (return) of PVNS after it has been removed.
Radiation therapy is determined by a specialist called a radiation oncologist. A machine that emits radiation waves may be used to treat the affected area. Other times, radiation pellets can be inserted in the area that needs to be treated. This helps to keep the radiation contained, so that it harms as little as possible of the normal tissue.
Rehabilitation
What should I expect after Treatment?
After Surgery
Rehabilitation usually involves physical therapy. Range-of-motion exercises are important and may be started right away. Strengthening and conditioning exercises will allow you to return to your previous level of activity. When surgery involves the leg, walking with a walker or crutches may be recommended at first.
If knee joint replacement is required, you will likely be hospitalized for three to five days. A continuous passive motion (CPM) machine may be used while in the hospital or started when you return home. Your leg will rest in the machine that is plugged into a wall outlet. The machine slowly bends you knee. This allows range of motion for several minutes or hours at a time. Pain will need to be treated for several weeks. You will need to be careful about keeping your incision clean, and monitor closely for infection.
Use of cold packs will help minimize swelling from surgery for the first several days. You may need pain medication if over the counter anti-inflammatories or acetaminophen (Tylenol®) do not control your pain.
After treatment, your doctor will want you to follow up with him periodically. Repeat MRI is needed to evaluate possible return of the PVNS.