According to the American Osteopathic Association, knee pain is the second major cause of chronic pain. More than one-third of people in the U.S. suffer from it. If you’re suffering from chronic knee pain, though, know that knee pain isn’t normal. And, it’s not an unavoidable part of aging. In this post, we discuss the ten major causes of knee pain, as well as treatment options that can help you get back to a life without pain.
What causes chronic knee pain?
Classified as a hinge joint, the knee is made up of two main bones that meet to make up the hinge, the femur and tibia. Protected by the patella, otherwise known as the knee cap, this joint gains its support, flexibility, and range of motion from its supporting tendons and ligaments. The knee is the largest joint in the body and while it may seem simple, it is actually one of the most complex joints in the body. Additionally, the knee is the most common injury reported during exercise and among professional athletes.
The following video gives a brief overview of common chronic knee pain causes and treatments.
How does the knee’s anatomy contribute to pain?
There are four main ligaments that are responsible for the connection of the knee:
- The anterior cruciate ligament, known as the ACL
- The posterior cruciate ligament, known as the PCL
- The medial collateral ligament, known as the MCL
- The lateral collateral ligament, known as the LCL
The ACL and PCL, if injured, often are unable to heal without surgical intervention, due to a low blood supply. Another oft-injured part of the knee is the meniscus, or the plural menisci. The menisci are two pieces of cartilage in the knee that works to distribute the weight of the body across the knee joint. Shaped like two half moons, the menisci are susceptible to injury, especially to athletes both professional and recreational. If the knee is twisted and force is applied, the menisci can tear.
There are also muscles supporting and surrounding the knee. These include the quadriceps and the hamstrings. A group of four distinct muscles, the quadriceps or quads form the quadriceps tendon, which works to connect this muscle group to the knee cap, or patella. This connection is what allows the knee to extend, or raise directly in front of a person. The hamstrings work to aid in the flexion of the joint, as well as provide additional support and stability.
Where does your knee hurt?
You may be experiencing knee pain in certain areas of your knee or leg. Pay attention specifically to how your pain feels and where you’re feeling pain or sensation. By doing this, you can better help your doctor figure out the cause of your pain. Knee pain may present as:
- Pain behind knee
- Pain in back of knee
- Inside knee pain
- Pain on outside of knee
- Knee pain when bending
- Pain below knee cap
- Pain above knee
Further, pay attention to how long you’re experiencing pain. Pain that lasts longer than three months is considered chronic knee pain that may require additional treatment strategies. Acute knee pain that has a sudden onset may be related to an injury or other trauma.
10 common causes of chronic knee pain
The cause of your knee pain will depend on where you’re feeling your pain, but it may also depend on some key risks factors you may have. Knee pain can be caused by:
- Wear and tear conditions
- Mechanical issues
There are several injuries that can result in knee pain, including:
- Torn ACL: Athletes who move from side to side or anyone who has a sudden change of direction can suffer from a tear in the anterior cruciate ligament.
- Torn meniscus: This injury to the cartilage of the knee occurs when the knee is suddenly twisted when it is bearing weight.
- Bursitis: Bursitis is inflammation in the bursae, the fluid-filled sacs that cushion the knee. This can be caused by another injury or infection elsewhere in the body.
- Tendonitis: Located specifically in the patella, an injury to the patellar tendon is common in athletes or active people who use their quadriceps muscles in their activity. Skiers, cyclists, and anyone who plays a sport with repeated jumping and use of the quadriceps can be susceptible to inflammation of this tendon that attaches the quadriceps muscle to the shinbone.
Any of these injuries, if left untreated, can become worse over time and develop into chronic knee pain.
Wear and tear
Wear-and-tear and other degenerative conditions of the knee is one of the most common causes of chronic knee pain.
Arthritis of the knee can occur over time. Due to contributing factors including age, weight and mechanical wear and tear, arthritis of the knee affects millions of people in the U.S. Pain from arthritis can be treated conservatively with medications, injections, and physical therapy, but advanced cases may require a full knee replacement.
Two other specific types of arthritis can occur:
- Osteoarthritis: This chronic knee pain condition occurs over time as the cartilage in the knee wears out with years of repeated use.
- Rheumatoid arthritis: An autoimmune condition that can affect every joint in the body, rheumatoid arthritis (RA) can be debilitating. Although chronic, RA symptoms can vary from day to day and may sometimes recede or intensify.
Knee injury can also be due to wear-and-tear, resulting in the following conditions:
- Gout: When uric acid crystals build up in joints, a condition called gout occurs. This should not be confused with pseudogout, a condition that also causes knee pain but due to calcium build-up. Treatments for these two conditions can be different, so proper diagnosis is important.
- Septic arthritis: This condition can appear with no warning when the knee joint becomes infected and swells. This is generally accompanied by fever.
Finally, certain mechanical issues can lead to knee pain, including:
- Illiotibial (IT) band syndrome: Common in runners, this type of knee pain occurs when the IT band that stretches from the outside of the pelvic bone to the outside of the tibia becomes so tight that it rubs against the femur bone.
- Bone chips: Pieces of bone in the knee can be chipped due to injury or wear and tear and float into the spaces of the knee joint, causing pain. Many people do not realize this has happened until the loose chip gets stuck and the joint will not move, much like a piece of debris caught in a door hinge, not allowing it to close.
- Dislocated patella: A dislocated patella is easy to see; the bone actually slips to one side or the other, generally to the outside. This can occur easily in women who are pregnant, as joints become more lubricated and move more easily, or it can occur when walking down the street.
Again, these types of knee pain may start as acute (less than three months) incidents that then progress to chronic knee pain if you don’t take the time to diagnose the issue correctly and treat it before it gets worse.
Risk factors for knee pain
Finally, there are several important factors that increase a person’s chances of suffering knee pain at some point in their life, including:
- Being overweight: Taxing the joint by adding extra weight increases the risk of knee pain.
- Mechanical problems: Other mechanical issues such as having one leg longer than the other or a spinal issue such as scoliosis put a person at higher risk because the body will compensate for that condition and potentially misuse the knee.
- Lack of strength or flexibility: Muscles help support the knee joint, and lack of muscle means less support. Tight tendons also contribute to knee pain.
Treating knee pain
Depending on the injury and severity, your knee can be treated with a variety of methods. Conservative treatments can start with the use of non-steroidal anti-inflammatory medications (NSAIDs) such as ibuprofen and aspirin. Hot and cold compresses can also be applied depending on whether the injury is inflammatory or involves deep muscle pain or spasms. Physical therapy and acupuncture also can be included as conservative treatments for injuries of less severity.
Knee joint injections are minimally invasive and can be highly effective. Consisting of a corticosteroid injection administered directly into the joint, this method can reduce inflammation and decrease pain caused by the injury. The following video shows how this procedure is done.
In severe cases, surgery may be advisable. If a meniscus tear is the cause of pain and debilitation, laparoscopic surgery may be an option. Consisting of surgery done through a small incision and using a scope, this surgery is preferred over full open knee surgery because it is less invasive and involves a shorter recovery and rehabilitation period. Full knee replacements may be warranted due to either degeneration due to arthritis, or severe injury.
If you suffer from chronic knee pain, remember that your pain isn’t normal and it’s not an unavoidable part of getting older. There are pain doctors who can help diagnose the cause of your pain and suggest treatment options that could work for you. Click the button below to get started.