If you suffer with frequent or chronic knee pain, you’re in good company.
According to Dr. Colin Cooper with New England Orthopedic Surgeons, knee pain is the second most common reason people go to see a doctor (FYI, skin disorders is #1).
“The largest joint in the body, your knee is vulnerable to injury and damage due to repeated stress,” says Cooper. “With every step you take, your knee takes on 3-6 times your body weight. It’s really no wonder that, over time, the structures of the knee can start to break down.”
Anatomy of the Knee
Knowing the anatomy of the knee can help you understand what might be causing pain.
The knee is made up of bones, cartilage, ligaments, tendons, and other tissues. Here’s a quick look at each:
Bones
These include the femur (thigh bone), patella (kneecap), and tibia (shin bone).
Cartilage: there are two types found in the knee.
- Articular cartilage forms a smooth layer over the ends of bones which allows them to glide smoothly over each other when the knee is in motion.
- Meniscus is a rubbery, c-shaped pad of cartilage that acts as a shock absorber between your shin and thigh bones.
Ligaments
These are the short bands of elastic tissue that holds the knee together and provide stability.
Tendons
These connect the knee bones to the leg muscles that move the knee joint.
While pain can be experienced in any part of the knee, the most common causes of pain are related to aging, injury, or repeated stress on the knee. Although sprained or strained ligaments and tendonitis are quite common, Dr. Cooper says the most frequently diagnosed causes of knee pain are osteoarthritis and tears of or injury to the meniscus.
Understanding the cause can help you and your doctor figure out how to relieve your knee pain.
Osteoarthritis Symptoms and Risk Factors
Osteoarthritis (OA) is the most common type of arthritis that affects the knee. OA is a degenerative process where the articular cartilage in the joint gradually wears away. In severe cases, you can lose all the cartilage causing the bones to painfully rub against each other. Without the cushion and shock absorption that cartilage provides, natural movements and even standing can become difficult.
Most frequently diagnosed in middle-age and older adults, signs of OA include:
- Pain or aching
- Stiffness
- Decreased range of motion
- Swelling
Dr. Cooper says, “In the early stages, these symptoms may come and go, often being more apparent with shifts in the weather. As the disease progresses, the intensity of pain tends to increase while the range of motion decreases.”
The greatest risk factor for developing OA—or any kind of arthritis—says Dr. Cooper, is age. “As many as 75% of adults aged 65 and older reporting persistent pain from arthritis. Because of the weight-bearing nature of our knees and the daily use they get throughout our lives, the wear and tear take a toll.”
Other risk factors for osteoarthritis include:
- Gender: Women are 40% more likely to develop knee osteoarthritis than men.
- Obesity: The more weight you carry on your knees, the more likely arthritis is to develop.
- Joint injuries and overuse: Injury or overuse, such as knee bending and repetitive stress on a joint, can damage a joint and increase the risk of developing OA.
- Family history: People who have family members with OA are more likely to develop OA.
- Bone deformities: often occurring because of damage to or erosion of the cartilage in the knee, bone deformities such as bone spurs can increase the risk of developing OA.
- Certain metabolic diseases
Osteoarthritis Diagnosis and Treatment
Diagnosing OA typically involves a physical exam, imaging, and lab tests.
“In addition to asking about overall health and family history,” says Dr. Cooper, “I’ll examine the knee looking for swelling, tenderness, and flexibility. Depending upon what’s learned, an x-ray may be ordered to determine the extent of the OA and to rule out other causes of pain.”
While there's no cure for OA, we can usually manage symptoms successfully. The first course of action is cold therapy and painkillers. Prescription and over-the-counter medications such as acetaminophen, nonsteroidal anti-inflammatory medicines (like aspirin, ibuprofen, or naproxen) can be taken in pill form or as a topical cream.
Dr. Cooper cautions, “NSAIDs can be very effective but long-term use can lead to serious side effects include stomach pain, heart burn, ulcers, and bleeding. With the exception of aspirin, NSAIDs may also increase the risk of heart attack and stroke. If you have a heart condition or history of stroke, be sure to speak to your doctor before taking them.”
In cases where NSAIDs are ineffective, cortisone injections may be used to reduce swelling. But like NSAIDs, Dr. Cooper notes, cortisone is not without risk. “Injection can only be given a maximum of 3 to 4 times per year as too much cortisone may cause further damage to the knee. And because it can elevate blood sugar and blood pressure, cortisone is not an option for everyone.”
Two more recent injection options for OA of the knee include Hyaluronic Acid and Platelet Rich Plasma (PRP).
Dr. Cooper explains, “Hyaluronic acid is a naturally occurring gel-like fluid found in the knee that acts as a lubricant. The idea is to ‘replenish’ the fluid in the knee to create better movement. It can be safely paired with cortisone but does require insurance approval.”
PRP, which is not covered by insurance and can run $500-1000, involves drawing a patient’s blood and putting it in a centrifuge to concentrate the platelet-rich plasma. The plasma contains proteins that are thought to be helpful in healing injuries. Injected into the knee, PRP can provide relief to mild- to moderate-grade OA of the knee.
In cases where the noted treatments fail to bring relief, a full knee replacement may be recommended.
Meniscus Tear or Damage
Injuries to the meniscus are very common, often resulting from an injury usually occurring during an activity that causes you to forcefully twist or rotate your knee. However, tears to the meniscus may also be the result of the aging and the wearing down of meniscal cartilage. This type of tear, referred to as a degenerative meniscus tear occurs gradually, often with no symptoms.
Torn Meniscus Symptoms
The most common symptoms include:
- Swelling
- Difficulty bending and straightening the leg
- Sensation of the knee giving way
- A feeling that your knee is locked or catching
- Inability to bear weight on the knee
- Pronounced limping
Meniscus tears can happen to anyone at any age but people who participate in contact sports like football as well as noncontact sports, such as soccer and volleyball, that involve a lot of quick turns and jumping are at greatest risk of injury. Very often, patients experience a popping sensation at the time of injury. And because the meniscus weakens with age, older athletes and adults with OA of the knees are also at special risk for injury.
Both acute injury and degenerative (weakening or worsening over time) tears may vary in degrees from partial to full. In most cases, a tear can be identified through a physical exam. Your doctor might move your knee and leg into different positions, watch you walk, and ask you to squat to help pinpoint the cause of your signs and symptoms.
“Typically, an examine is followed with some imaging, most often an MRI that will provide images of both hard and soft tissue in the knee,” says Dr. Cooper. “The type of tear revealed will dictates the best treatment option. In some cases, a tear can heal on its own while more serious tears may require surgery.”
Torn Meniscus Treatment
In the case of a minor injury, conservative treatment options—such as rest, ice, and medication—are often enough to relieve the pain of a minor injury and allow for healing. As with OA, prescription and over-the-counter NSAIDs should not be used long-term use due to potential side effects.
Surgical repairs are performed on an outpatient basis with patients able to walk on crutches immediately after. Recovering typically takes several weeks with regularly icing of the area and use of prescribed pain medication. Physical therapy may or may not be recommended as part of the recovery.
Preventing Knee Pain and Injuries
Both OA and tears to the meniscus are a result of using your knees. While you can’t full prevent either from occurring, there are steps you can take to reduce your risks.
These include:
- Maintain a healthy body weight that doesn’t overstress your knees
- Strengthen the muscles that support and stabilize your knee
- Work up slowly to more intense exercise activity
- Wear a knee brace if you know your knee is unstable or weak
- Wear appropriate footwear for whatever activity you’re doing
Learn More or Find a Doctor
Baystate Health’s orthopedic surgeons treat conditions from osteoporosis to arthritis, joint pain, and hip and knee problems. Learn more about orthopedic care at Baystate.