Severe knee pain can lead to inflammation and mobility problems. Anyone suffering from knee pain should uncover the exact cause so that it can be treated properly. To understand the common causes of severe knee pain, it helps to know a little about how the knee works.
The knee is the joint between the bones of the upper leg and the bones of the lower leg. It allows the leg to bend and provides stability to support the weight of the body. The knee supports motions such as walking, running, crouching, jumping, and turning.
Several parts help the knee to do its job, including:
Any of these parts are susceptible to disease and injury which can lead to severe knee pain.
The common causes of severe knee pain can be broken down into five categories: trauma, infection, metabolic, degenerative, and connective tissue disorders.
The Arthritis Foundation list the knee as one of the joints most prone to injury. The knee's overall structure and components put the knee at risk for certain types of injuries which can cause pain and stop it from working properly.
This diagram of the knee shows where two of the main ligaments can be found.
Common knee injuries are due to tears in one of the three main ligaments of the knee, tissues that hold the knee together. These are the anterior cruciate ligament (ACL), medial collateral ligament (MCL), and posterior cruciate ligament (PCL). These types of injury are common in athletes.
A sudden twisting motion or change in direction can lead to an injury of the ACL, the most common cruciate ligament to be injured. The PCL is generally injured due to direct impacts, such as a car crash or from being tackled while playing football. A direct blow to the knee can lead to MCL damage. These types of injuries often require surgery.
Tendon injuries can occur if the tendon is overworked or overstretched. Inflammation, tendinitis, or ruptures can cause knee pain. Engaging in activities that require use of the tendons, such as running, jumping, and lifting heavy items, can cause tendon injuries.
Patellar tendinitis is the term used to describe irritation and inflammation of the patellar tendon in the knee. A ruptured tendon can require surgical repair. Less severe cases can be treated with a rigid support called a splint to keep the knee in a fixed position.
Knee bursitis is caused by an injury that produces inflammation in the bursae. These are small fluid-filled sacs that cushion the outside of the knee joint and make it possible for tendons and ligaments to glide easily over the joints.
The bursae can become injured by a sudden blow to the front of the knee, or if people spend a lot of time on their knees without protection. If the bursae are injured, an individual may experience swelling, warmth, pain, and stiffness in the knee area.
Therapy and oral medications such as nonsteroidal anti-inflammatory drugs (NSAIDs) are often used to treat the problem. Therapy can include rest, ice, elevation, and splinting.
Serious cases may require steroid injections. Patients normally make a full recovery with proper management and treatment.
Trauma from a fall or collision can cause fractures in the bones of the knee. The knee contains several bones which can be broken, including the patella, also known as the kneecap.
Individuals with osteoporosis or other degenerative bone disorders that cause bones to weaken can fracture their knee simply by stepping off a curb in the wrong way. Serious fractures require surgery, but physical therapy is often all that is needed.
Some injuries can cause the kneecap to move out of place. Often, a doctor can simply pop the kneecap back into place without any problems. An X-ray is usually required to look for a fracture. The individual may have to use a splint to allow the soft tissue around the patella to heal properly and regain its strength.
A dislocated knee is a rare but dangerous injury. It takes a very powerful blow to cause this type of damage. Though this can be reversed, the actual dislocation of the knee is very painful. If the knee has not been put back in place, the doctor must reduce the dislocation and ensure that there are no further injuries.
Injuries to the nerves and blood vessels about the knee are very common with this injury, making this a medical emergency.
Degenerative tissue disorders
Osteoarthritis often occurs due to aging. Severe cases can be treated with a knee replacement.
Degenerative tissue disorders such as osteoarthritis are a common type of knee complaint. Osteoarthritis causes damage to the cartilage and surrounding tissues of the knee. It can produce pain, stiffness, and prevent the joint from working properly.
Osteoarthritis is most commonly due to aging and affects almost all people by the age of 80.
Though there is no cure for this degenerative disease, it can be treated with exercise and medications that reduce pain and improve function.
Severe damage may require joint replacement or other forms of surgery. Initially, a doctor will order an X-ray to see the extent of the damage and decide on the best course of treatment.
Connective tissue disorders
Rheumatoid arthritis (RA) is an inflammatory autoimmune disorder that affects the joints of the body. It causes the immune system to attack its own body tissues in error.
Unlike degenerative tissue disorders, RA and other connective tissue disorders affect the lining of the joints. The result is a painful swelling in the knee joints. If untreated, RA can lead to bone erosion and even joint deformity.
Even though the pain may only be in the knee area, RA can also damage other parts of the body. It is important for an individual to talk to a doctor regarding treatment options.
Currently, there is no cure for RA, but medication and treatment options are available. Nonsteroidal anti-inflammatory drugs, steroids, and biological agents are just a few of the available treatments.
Metabolic causes are those that occur alongside a disease that affects the several parts of the body, such as gout. Gout is one of the most common metabolic causes of knee pain.
Gout is caused by a buildup of uric acid crystals in the joints. Gout is a form of arthritis and can be very painful. It causes the knee to become swollen and inflamed, and can even affect the knee's range of motion.
A doctor will often recommend anti-inflammatory medications or other treatments that assist in the breakdown of the chemicals that lead to crystal formation.
Pseudogout is a similar condition and is commonly mistaken for gout. It causes calcium-containing crystals to develop in the fluid of the joint, causing the knee to swell. Treatment for gout and pseudogout are often similar.
The knee area can become infected by bacteria. This can lead to severe knee pain.
Cellulitis is a very serious bacterial skin infection that can affect the knee area. Even a simple scrape on the knee can become infected if it is left untreated. Symptoms often include redness in the affected area and skin that feels hot and extremely tender to the touch.
The infection can spread to other areas of the body, including the lymph nodes and bloodstream. Such an infection can be life-threatening if it is not treated. It is important to pay close attention to any scrapes or bruises, especially if they don't seem to be healing properly.
In most cases, cellulitis can be cleared up with antibiotics. Signs and symptoms normally disappear within a few days following treatment.
It is also possible for the joints in the knee to become infected. This condition is called septic arthritis and causes swelling, pain, and redness. Some individuals also complain of a fever. If caught early, it can be treated easily, but any infection not properly medicated can lead to permanent damage to the cartilage of the knee.
Talk to a doctor
These are just a few of the common causes of knee pain. Any knee pain should be evaluated by a trained medical professional who can perform tests to determine the direct cause of pain.
A medical professional could ask the following questions about a patient's knee pain:
- When did the pain start?
- How did the pain start?
- Is the pain linked to an injury?
- How severe is the pain?
- How has the pain changed over time?
- What makes the pain worse and what makes it better?
- What treatment has been used so far?
- Has this ever happened before?
Learn more about the causes of severe knee pain here.