Several things can cause knee pain without any clear injury.
Age and weight-related stress, lower-leg medical conditions, biomechanical problems like flat feet and knee instability, systemic factors like inflammatory conditions… there’s quite a list!
Let’s explore the 11 most common non-traumatic knee pain causes, and find out: How can my knee hurt without an injury!?
When I consult with patients with new knee pain, the first questions I ask are about medical history, i.e
- trauma and injury history
- recent or past illness
- if knee problems run in the family
- recent blood test information
Weight-bearing joints like the knees are especially vulnerable to developing knee arthritis like OA, a degenerative joint disease. Osteoarthritis occurs when the cartilage that cushions and protects the ends of bones breaks down.
This deterioration can be caused by age, repetitive stress on the joint, or previous injury. Therefore, it’s a consideration – even if you are not elderly. Read our full post about bone on bone knees.
Patellofemoral pain syndrome
Patellofemoral pain syndrome (PFPS) is one of the most common causes of knee pain. It occurs when the patella (knee cap) rubs against the femur (thighbone), causing irritation and inflammation.
PFPS is often seen in young athletes, but it can also affect people of any age who have kneecap instability, muscle imbalance or pelvis, leg and foot alignment problems.
Bursitis can be caused by overuse, repetitive stress, or trauma to the knee area. Poor knee mechanics and muscle weakness can contribute too.
There are 3 major knee bursae, and one to note is the pes anserine.
What is pes anserine bursitis?
Pes anserine bursitis is a condition that causes inflammation of the bursa, which is a small sac of fluid that acts as a cushion between the tendons and bones in the knee.
The pes anserine bursa is located at the point where the tendons of three muscles (the sartorius, gracilis, and semitendinosus) attach to the shinbone.
This occurs when a nerve exiting from the spinal cord in the lower back is compressed or pinched.
The cause may be a disc bulge or degenerative bony spurs. This can cause:
- Intense pain that radiates from the low back into the buttock and down the leg
- Numbness, tingling, or weakness in the leg or foot
If you have lumbar radiculopathy, you may also have difficulty straightening your leg or knee. I usually suggest a CT or MRI scan in suspected lumbar radiculopathy cases, because an x-ray cannot pick up soft tissue structures like a spinal disc. Check how much a knee MRI in your area costs here.
Iliotibial band syndrome
Iliotibial band syndrome (ITBS) is a condition that causes inflammation of the iliotibial band – thick tissue that runs from the hip to the fibula via the outer side of your knee.
ITBS is a common injury in runners and other athletes who repetitively flex and extend their knees. It can also be caused by prolonged sitting and driving, or incorrect form during exercise.
Congenital conditions causing knee pain
There are numerous congenital conditions (present from birth) that can cause knee pain without injury. Just to name a few as examples:
This condition is also known as “knock-knee.” It occurs when the knees point inwards, and the ankles point outwards. This can put stress on the knees and lead to pain.
This condition is also known as “bow-leggedness.” It occurs when the ankles point inwards, and the knees point outwards. This can also lead to knee pain.
This is a condition that affects the growth of the shinbone. It can cause the shinbone to curve inwards, which can put pressure on the knees and lead to pain.
A Baker’s cyst is a fluid-filled sac that forms behind the knee. It’s usually the result of another condition, such as arthritis or meniscus tears.
Baker’s cysts can cause pain and stiffness, especially when bending the knee.
[Read the full list of reasons for pain behind your knee.]
Osgood-Schlatter disease usually affects young adults, typically those heavily involved in sports with a lot of running.
The condition is characterized by pain and swelling at the bump of bone on the upper shin (tibia), just below the knee joint. Here are some facts about Osgood-Schlatter disease:
- The pain is usually worse when the knee is flexed, such as when squatting, climbing stairs, or running. In some cases, the pain may be severe enough to limit participation in sports.
- Caused by overuse or sometimes trauma to the front area of the knee.
- Treatment for Osgood-Schlatter disease generally involves ice packs and rest, followed by a gradual return to activity. Generally resolves on its own once the child/teen gets older.
Patellar tendinitis is an inflammation of the patellar tendon, which connects the kneecap (patella) to the tibia (shinbone). The condition is also known as jumper’s knee or patellar tendinopathy.
It is a common injury in athletes, especially with repeated knee bending, like for those who participate in jumping sports: basketball, volleyball, and track and field, for example.
Patellar tendinitis can also be caused by overuse, trauma, or repetitive stress on the tendon – even driving a lot for work.
Chondromalacia patella is a condition that causes the cartilage on the underside of the kneecap to soften and break down. The condition is also known as patellofemoral syndrome or runner’s knee.
CP is a common injury in athletes, especially those who participate in activities that put repetitive stress on the kneecap, such as running, cycling, and jumping.
Patellar subluxation is a condition in which the kneecap (patella) slides out of place. In the absence of any knee injury, it can be caused by overuse, or repetitive stress on the knee joint causing faulty patella movement.
Other types of arthritis causing gradual onset knee pain
A chronic, inflammatory autoimmune disease that affects the joints. It can cause pain, swelling, and stiffness in the joints. It can also lead to joint damage and deformity.
Rheumatoid arthritis is different from osteoarthritis, which is a more common, degenerative disease, affecting the cartilage in joints.
Arthritis that affects people with psoriasis. Psoriasis is a condition that causes raised, red, scaly patches on the skin.
The accompanying psoriatic arthritis can cause pain and swelling, and damage the knee joints over time.
Gout is technically a form of arthritis, but with different origins. Caused by the buildup of uric acid in the joints, this condition generates inflammation in the joints, and a tremendous amount of pain!
Gout often affects the big toe, but it can also affect the knee joint. A related but different joint problem is “pseudogout”.
How painful is gout?
Many people report the pain from gout as severe – a 9/10 or a 10/10 pain . It is typically described as a burning sensation in the joint that comes on suddenly.
There can be milder forms of gout, where the pain is more like a 5-6/10 but still very painful, especially if the joint is touched or bumped.
Gout vs. pseudogout
Both conditions are characterized by the presence of crystals in the joints, which leads to inflammation. However, in gout, these crystals are typically uric acid crystals, whereas, in pseudogout, they are typically calcium pyrophosphate crystals.
Gout usually develops without any prior injury to the joint, whereas pseudogout often develops following an injury or trauma to the joint.
What causes pseudogout flare-ups?
Pseudogout flare-ups can be caused by joint injuries, alcohol consumption, and stress. Additionally, people who are obese or have high blood pressure are at an increased risk for pseudogout flare-ups.
Knee Tumors, benign or malignant
What are the three most common cancers in the knee?
The three most common cancers that can develop in the knee are bone cancer, chondrosarcoma, and synovial sarcoma. Bone cancer is the most common type of cancer that starts in the bones of the leg or arm.
What are the three most common types of infections in the knee?
The three most common types of infections in the knee are septic arthritis, osteomyelitis, and patellar bursa infection.
Septic arthritis is an infection of the joint space, whereas osteomyelitis is an infection of the bone.
Patellar bursa infection affects the soft tissue sac that cushions the kneecap.
What are the traumatic knee pain injuries?
- medial collateral ligament: most common ligament injured in the knee
- anterior cruciate ligament: injured during sudden changes of direction, usually sports
- meniscus tear: the shock absorbers in the knee
- knee fracture: car accident, trauma, etc. Ouch!
- posterior cruciate ligament: often injured from a direct knee blow.
- Patellar dislocation: traumatic blow or twisting at the knee cap, lots of swelling.
Treatment for knee pain without injury
If rest and home treatments are not providing relief, or if the knee pain is getting worse, it is time to see your healthcare provider.
Depending on the type of knee pain, treatments include lifestyle changes, physical therapy, and medication (especially so with OA, poor knee biomechanics, or repetitive strain injury).
In some cases, surgery may be necessary to correct problems like severe OA – or even total knee replacement.
Have you had knee pain occur without any injury? Let us know in the comments if you have symptoms like those listed above.
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