Knee pain: Causes & treatments

Knee pain is a common complaint with a prevalence of 10-12%. It is the second most common reason for visiting a primary care physician after low back pain.

About 800,000 knee replacements are performed every year in the United States with the expectation that a well-maintained knee implant could last up to 15 years. However, knee replacements are increasing as the population ages and obesity rates rise.

Most knee pain can be treated without surgery. Only 5-10% of people with knee pain will ever need a knee replacement. There are many different treatment options available depending on the underlying cause of your knee pain.

What is the knee joint?

The knee joint is by definition a complex hinge joint that allows the leg to bend and straighten. The knee joint is made up of the following parts:

• Tibia (shin bone)
• Fibula (smaller bone next to the tibia)
• Patella (kneecap)
• Femur (thigh bone)

These bones are held together by ligaments, which are strong bands of tissue that keep the bones in place. The knee joint is also surrounded by a fluid-filled sac called the bursa, which helps to cushion the joint. Tendons are also attached to the knee joint, and these help to move the muscles of the leg.

Injuries or disease processes that affect any of the structures can cause knee pain. The knee is a weight-bearing joint and any condition that alters the alignment or biomechanics can lead to knee pain.

What are the signs & symptoms of knee pain?

The most common symptom of knee pain is, not surprisingly, sharp pain. This pain can be dull and achy or sharp and intense. It may be worse when you move your knee or put weight on it. You may also notice swelling, stiffness, clicking or popping, and warmth around the joint.

What are the causes of knee pain?

The most common cause of knee pain is knee osteoarthritis, which affects approximately 30% of adults over the age of 60. This occurs when the knee cartilage that cushions your joints breaks down over time. This can lead to joint pain and stiffness. Causes of knee problems can be divided into three main categories:

1. Injuries
2. mechanical problems
3. types of arthritis

Injuries leading to knee pain

Injuries to the knee are common and can involve the structures of the knee joints: Bones, ligaments, cartilage, tendons, bursae, and muscles. Examples include:

• ACL injury. A tear of the anterior cruciate ligament (ACL) — one of four ligaments that connects your shin and femur are common in sports when there is a sharp change in direction.
• Meniscus tear. The meniscus is a tough, rubbery cartilage in your knee joint acting as a shock absorber. If you twist your knee while bearing weight it can tear eg high-impact activities.
• Fractures. Often fractured with trauma although if weakened by disease eg osteoporosis or other medical conditions can fracture by a simple misstep.
• Knee bursitis. Bursae are small sacs of fluid cushioning the outside of your knee joint allowing tendons and ligaments to glide smoothly over the joint. Bursae inflammation leads to pain.
• Patellar tendinitis.  Tendon can become inflamed eg from overuse or injury. This is called tendonitis. This inflammation can happen when there's an injury to the patellar tendon, which runs from the kneecap (patella) to the shinbone and allows you to kick, run and jump.

Mechanical problems

Some examples of mechanical problems that can cause knee pain include:

• Dislocation. Injury can make bones slip out of place. Commonly the patella (the kneecap) slips out of place, usually to the outside of your knee.
• Hip or foot pain.  If you have pain in your hip or foot you may change your gait to relieve pain. But this change in the way you walk may put stress on your knee joint causing pain.
• Iliotibial band syndrome.  There is a tough band of connective tissue running from the hip to the outside of the knee called the iliotibial band. With overuse, this can become tight and cause pain.
• Loose body. Injuries or degeneration can lead to a piece of bone or cartilage. If this loose body restricts movement it may cause pain

Types of arthritis

There are more than 100 different types of arthritis. Commonly affecting the knee are:

• Osteoarthritis. Wear and tear, degenerative arthritis - the most common type of knee arthritis.
• Rheumatoid arthritis. An auto-immune chronic disease can vary in severity and time course: coming and going.
• Gout.  Uric acid crystals accumulate in the knee (but usually in the big toe)
• Pseudogout a gout mimic results from calcium salt crystals (not uric acid) and is usually in the knee.,

Septic arthritis. Infection causes the joint to become hot, inflamed, and painful. The infection can be quickly destructive to joints and is a medical emergency.

What are the risk factors?

Several risk factors can increase your chances of developing knee problems. These include:

• age (knee problems are more common as you get older)
• obesity (carrying excess weight puts extra strain on your knees)
• occupation (jobs that involve kneeling or squatting can put stress on the knees)
• repetitive impact activities (such as running or playing tennis)
• previous knee injury or surgery
• chronic health conditions (such as rheumatoid arthritis, gout or diabetes)

How do Imaging & Interventional Specialists evaluate and diagnose your knee pain?

An Imaging & Interventional Specialists' physician will take a detailed history and perform a physical exam of your knee. Many times this will usually provide enough information to diagnose the cause of your knee pain. Your doctor may also order one or more of the following tests for further evaluation:

• X-ray.  X-rays can show degenerative changes in the bones and joints, but cannot show soft tissue structures such as ligaments and tendons.
• CT scan. A CT scan can show degenerative and arthritic changes in the knee, as well as detailed information about bony structures.
• Magnetic resonance imaging (MRI).  An MRI uses powerful magnets and radio waves to create detailed images of your knee. This test can show problems with any of the structures in your knee, including ligaments, tendons, cartilage, and muscles.

Careful evaluation will also include blood tests and interacting with other members of your care team will help determine your diagnosis but developing an individualized treatment plan

What can you do to decrease knee pain?

Treatment for knee pain depends on the underlying cause. For osteoarthritis, treatments may include weight loss, exercise, physical therapy, joint protectants (such as glucosamine and chondroitin), and pain relief medications (both over-the-counter and prescription). If these conservative measures do not relieve your pain, your doctor may suggest injecting corticosteroids or other agents directly into the knee joint. In some cases, surgery may be necessary to provide relief and improve function.

For rheumatoid arthritis, treatments may include weight loss, exercise, physical therapy, splints or braces, medications (including disease-modifying anti-rheumatic drugs (DMARDs) and biologic agents), and in some cases, orthopedic surgery.

If you have gout, treatment may include medications to reduce uric acid levels in the blood (such as allopurinol) and to relieve pain (such as ibuprofen or colchicine). Your doctor may also recommend changes in your diet to help prevent gout attacks.

If you have septic arthritis, treatment will likely include antibiotics to clear the infection and joint drainage to remove any pus from the joint. You may also need physical therapy to help preserve range of motion in the affected joint.

In some cases, knee pain may be caused by a pinched nerve or other problems with the nervous system. Treatment for this type of knee pain may include medications, physical therapy, joint injections, and in some cases, surgery.

What lifestyle changes decrease pain?

In general, to decrease or prevent knee pain, you can:

Maintain a healthy weight.  Excess weight puts extra stress on your knees.

Exercise regularly.  Exercise strengthens the muscles around your knee joint, which can help to stabilize your knee and protect it from injury.

Wear comfortable, low-heeled shoes.  High heels can put extra strain on your knees.

Avoid repetitive impact activities, if possible.  If you play sports or participate in other activities that involve repetitive impact (such as running or playing tennis), take breaks often and be sure to stretch properly before and after activity.

What non surgical treatments are available?

Several nonsurgical treatments can be effective in treating knee pain. These include:

Physical therapy. Physical therapy can help improve range of motion and flexibility and also help to strengthen the muscles around your knee.

Joint protectants. Joint protectants such as glucosamine and chondroitin can help to protect the cartilage in your knee joint and reduce pain.

Pain relief medications. Over-the-counter pain relievers such as ibuprofen

Medications are tailored to the disease affecting your knee.

What surgical treatments are used for knee pain?

In some cases, surgery may be necessary to relieve knee pain. Surgery for knee pain may include:

Arthroscopy.  This is a minimally invasive surgical procedure in which your surgeon inserts a small camera into your knee joint. Arthroscopy can be used to diagnose and treat a variety of conditions that cause knee pain, including torn cartilage and ligaments, inflamed tissue, and removal of loose bodies from the joint space.

Osteotomy.  This is a surgical procedure in which your surgeon cuts and repositions bones around the knee joint to relieve pressure and improve alignment. Osteotomy is often used to treat osteoarthritis of the knee.

Uni-compartmental (partial) knee replacement.  This is a surgical procedure in which only the damaged portion of your knee joint is replaced with an artificial implant. Uni-compartmental knee replacement is often used to treat osteoarthritis that is limited to one area of the knee joint.

Total knee replacement.  This is orthopedic surgery in which your entire knee joint is replaced with an artificial implant. Total knee replacement is often used to treat osteoarthritis that has damaged the entire knee joint.

What are some possible complications of surgery?

As with any surgery, there are risks associated with knee surgery. These risks include infection, blood clots, and nerve or blood vessel damage. Be sure to discuss these risks with your surgeon before having any type of knee surgery.

What are the advantages of delaying a knee replacement?

In many instances and knee replacements is necessary. Since a knee replacement may last 15 years it is often an advantage to find a way to deal with pain so that a knee replacement can be delayed 5 years or so. One advanced method that can deal effectively with pain is genicular artery embolization (also called geniculate artery embolization).

What are advanced methods to alleviate knee pain?

More and more people with pain are turning to a minimally invasive, same-day surgery called genicular artery embolization (or geniculate artery embolization). Genicular arteries are arteries located around the knee that supply blood to the knee joint. When there is inflammation these arteries can become enlarged and contribute to chronic knee pain.

Genicular artery embolization involves placing a small catheter (tube) into the enlarged genicular arteries and injecting tiny beads to block them off. This reduces blood flow to the knee joint and can provide significant pain relief.

Most people who undergo this procedure have significant pain relief within 24 hours with little to no downtime.

Who performs genicular artery embolization?

Genicular artery embolization is typically performed by an interventional radiologist, a type of doctor who specializes in minimally invasive procedures. Interventional radiologists use image guidance techniques such as fluoroscopy to precisely place the catheter into the genicular arteries.

If you are suffering from chronic knee pain and want a non-surgical alternative to relief, consider talking to Imaging & Interventional Specialists about genicular artery embolization.

How do I prepare for genicular artery embolization?

You will likely be asked to stop taking blood thinners such as aspirin or ibuprofen for a week before the procedure. You may also be asked to refrain from eating or drinking for six hours before the procedure.

What is genicular artery embolization?

Genicular artery embolization is a non surgical, minimally invasive procedure used to treat chronic pain in the knee. This procedure involves placing a small catheter into genicular arteries feeding the area of inflammation and pain. Injecting tiny beads to block blood flow to the knee joint provides significant pain relief with little to no recovery time.

What can I expect after genicular artery embolization?

After the procedure, you will likely be able to go home the same day. You may have some bruising and soreness around the catheter insertion site, but this should resolve within a few days.

You should start to notice pain relief within 24 hours after the procedure.

How do Imaging and Interventional Specialists determine whether I am a candidate for a non surgical, "pinhole", genicular artery embolization (GAE) for knee pain?

An Imaging and Interventional Specialist will meet with you and go through your medical history, perform a physical exam and evaluate your imaging if any. They may order blood tests as well as additional imaging which may include a CT scan or magnetic resonance imaging (MRI) study of your painful knee. They will also communicate with other members of your treatment team. In this way, they will evaluate whether you are a candidate for this new, "pinhole" procedure and give your clear explanations.

Why Imaging & Interventional specialists?

Imaging & Interventional Specialists are leaders in interventional radiology and experts in the non surgical, minimally invasive procedure - genicular artery embolization - that will cure or minimize your knee pain.

Using state-of-the-art equipment, our experienced board-certified specialists are focused on your best outcome.

At Imaging & Interventional Specialists board-certified physicians offer in-house testing for diagnosis and to develop an individualized treatment program for the management of your knee pain.