Approximately 10 million Americans suffer from knee pain, with pain behind the knee being the leading cause of disability for the middle aged and elderly populations.
Causes of Pain behind the Knee
Occasional knee pain is common for people of all age groups, but a chronic pain behind the knee is typically caused by either overusing or placing too much stress on the knee joints.
The main causes of pain behind the knee joints include:
1. Leg Cramps
A leg cramp may disguise itself as a knee problem, but it really has to do with a brief tightening of the muscle. The cramps often occur below the knee, most frequently in the calves, although they can occur in the quads and hamstring, too.
Leg cramps are common among pregnant women and active people. Additional causes may include:
- Neuropathy, or nerve damage
- Infections like tetanus
- Liver disease
- Heavy metals in the blood (e.g. mercury, lead, arsenic)
Cramps come on quickly and strongly and can be quite painful. The rapid muscle contractions (spasms) will typically last a few seconds and up to 10 minutes. Stretching the muscle may help, as can drinking water or pickle juice.
The area may remain sore for several hours following the spasm.
2. Hamstring Injuries
The muscles that run down the back of the leg between your buttocks and knee are called hamstrings. They allow you to bend your knee, and they consist of a network of three muscles (semitendinosus, semimembranosus, and biceps femoris).
These muscles can be injured—known as a hamstring strain—when pulled too far.
The biceps femoris muscle, in particular, can cause pain in the back of the knee if it becomes injured. This injury is known as biceps femoris tendinopathy.
Typically occurring in athletes who use their legs in an explosive fashion, this injury may also be marked by:
- Weakness in the back of the leg
3. Calf Strain
Your calves are made up of two main muscles: the gastrocnemius and the soleus. The gastrocnemius is just below the knee, and if it’s injured or strained, it can lead to posterior knee pain. The injury is known as gastrocnemius tendonitis.
An injury here will lead to sudden pain, along with:
- Swelling in the calf
- Difficulty standing on toes or pointing toes
At the ends of each of your bones, there is cartilage that protects them from rubbing together. This cartilage, however, can wear down over time.
Overuse, ongoing age-related disintegration, arthritis, and poor nutrition can lead to cartilage breakdown. When it happens in the knee joint, you can experience pain from the bones rubbing together. This condition is called chondromalacia.
It’s marked by a dull ache or pain behind the kneecap and may become more intense when climbing stairs or after an extended period of sitting. Additional symptoms can include:
- Limited range of motion in the knee joint
- Weakness in the joint
- Buckling in the knee
- A cracking or grinding sensation in the region
5. Deep Vein Thrombosis (DVT)
A blood clot that forms deep inside the leg is called deep vein thrombosis. It will cause severe pain when you stand up, and will also:
- Lead to swelling in the leg
- Produce warmth around the area
- Trigger reddening of skin
This can be a fatal condition and should be examined and treated by a doctor as quickly as possible.
6. Runner’s Knee
Runner’s knee is another term for cartilage breakdown. This is common in people who run, and is marked by a dull, aching pain in the back of the leg, behind the knee. Additional symptoms are similar to those of chondromalacia.
7. Ligament Injury
Athletes or individuals who attend the gym on a regular basis often develop pain behind the knee joints due to ligament tears.
The MCL (medial collateral ligament), ACL (anterior cruciate ligament), and PCL (posterior cruciate ligament) are the most common ligaments that tear when the knee is injured.
Depending on the severity of the injury, treatment may include surgery or rehabilitation.
MCL (Medial Cruciate Ligament) Injury
On the inner part of the knee, though outside of the actual joint, is the medial cruciate ligament, or MCL. It is responsible for holding the bones together and providing stability in the joint. It connects at the top of the shin (tibia) and bottom of the thigh (femur).
An MCL sprain occurs when the ligament is stretched too far or torn, and typically occurs from a direct impact to the knee. Symptoms may include:
- A popping sound during impact (when the injury occurs)
- Pain and tenderness along the inner part of the knee
- Swelling at the joint
- Instability (i.e. feeling the knee will give out)
- Locking or catching at the joint
ACL (Anterior Cruciate Ligament) Injury
The ACL ligament runs along the front of your knee. It connects the same bones as the MCL, just at the anterior. Injuries to the ACL typically happen if you change speeds or direction, or stop quickly while running. It can also be injured on a jump landing or from a direct impact.
This is quite a painful injury, and symptoms can include:
- A popping sound when the tear occurs
- Swelling, typically quite severe and occurring hours after the injury takes place
- Sharp pain, especially when walking, twisting, or turning the leg
PCL (Posterior Cruciate Ligament) Injury
The PCL connects the same bones as the ACL and MCL; however, this ligament is at the back of the knee. A PCL injury will often accompany an injury to one of the other knee ligaments, and it’s often the result of a direct impact to the area.
One specific cause of PCL injury is knee hyperextension, which may occur when jumping. It can also happen if the knee is knocked out of place while flexed or bent.
Symptoms may include:
- Tenderness at the back of the knee
- Difficulty walking
8. Patellar Tendonitis
If the patellar tendon—the tendon that starts at the lower portion of the kneecap and ends just below the knee—becomes inflamed or is not treated properly, it can lead to patellar tendonitis, or jumper’s knee. This is common for athletes who don’t stretch or warm up before exercising.
- Mobility limitations
- Pain below the kneecap
9. Meniscal Tear
This is also known as knee cartilage injury. A meniscal tear is usually a result of a sports injury, which can often lead to pain behind the knee joint.
Some studies have indicated that obesity and excess body weight can also contribute to an increased risk of meniscal tears and injuries; however, results are inconclusive. Other reviews have shown no difference in the risks of obese people and those of normal weight.
The meniscus is a piece of cartilage that stabilizes the knee, and there is one (menisci) on each side. They can be torn when the knee is twisted during a squatting position.
With age, the meniscus can degenerate, and the risk of a tear increases with virtually any twisting motion. You may notice a popping sound, and pain may not set in for a few days afterwards. Symptoms can include:
Arthritis can slowly wear away at the cartilage in your knee, and although pain usually comes on gradually, it can begin suddenly.
It’s likely noticeable in the morning or after long periods of inactivity. For instance, you may experience pain in the back of the knee after sitting for a while and then getting up.
Pain may also occur when climbing stairs or during a walk.
The risk of arthritis increases if you’ve experienced a previous knee injury like meniscus tear, ligament injury, or fracture. Symptoms of arthritis include:
- Swelling and tenderness (inflammation)
- Buckling and locking
- Cracking or popping sounds
- Poor range of motion
- Deformities at the joint
11. Baker’s Cyst
This cyst or swelling is caused by excessive pressure at the back of the knee joint; it can lead to the accumulation of fluid behind the knees. Arthritis or a knee injury can increase the risk of fluid buildup.
The symptoms of a Baker’s cyst include:
- Pain in or behind the knee
- Swelling behind the knee
- Stiffness and trouble flexing
Symptoms can worsen with increased activity, and if the cyst bursts, there will be a sharp pain in the knee.
12. Being Overweight
Being overweight can contribute to joint pain in the knee. There are multiple reasons why. The first is the added pressure placed on the joints. Over time, this can lead to enhanced cartilage reduction that can cause pain.
Furthermore, a diet that encourages obesity can also lead to systemic inflammation that contributes to joint pain. And new research is uncovering that the make-up of a person’s microbiome can influence joint pain.
Obese individuals tend to have an unhealthy microbial population, which may lead to inflammation and joint degradation. That said, more research needs to be completed on exactly how the microbiome influences joint health.
13. Sitting Cross-Legged
Crossing your legs at the knees for extended time periods puts pressure on a nerve that sits behind the knee joint—the peroneal nerve. This nerve allows sensation in your lower legs and feet.
Sitting cross-legged could potentially lead to pain in the back of the knee and calf, but you’re more likely to experience a temporary tingling sensation.
Complications of Pain behind the Knee
If left untreated, moderate to severe pain behind the knee can affect your everyday activities:
- You might have difficulty moving around, as pain behind the knees can cause limited mobility and stiffness
- Skin discoloration around the knee
- Tenderness or extreme soreness of the skin surrounding the knee—this may even spread to the entire lower limb
- Pain and swelling
Natural Treatments for Pain behind the Knee
1. Knee brace: A knee brace stabilizes the knee so you can continue with your day-to-day activities. The brace reduces the stress and strain on the knee.
2. Stretching exercises: Your joints need constant blood flow in order to properly heal—I recommend doing low-impact stretching exercises on a daily basis. You may find it useful to consult a fitness professional to avoid overexertion or injury.
3. Special shoes: The wrong choice of footwear can place enormous pressure on the knee joints—this can lead to deterioration in the connective tissues in the lower limbs. I recommend wearing comfortable footwear, especially if you’ll be on your feet for most of the day.
4. Lose weight: If you are overweight or obese, you are putting more pressure on your joints and limbs, especially if you experience drastic weight gain. Try to incorporate a healthy diet full of whole grains, fruits, and veggies to help manage your weight.
5. Tai chi: If the cause of your knee pain is arthritis, studies have shown tai chi may help with pain relief and range of motion.
6. Movement: If the cause of pain is arthritis, avoiding a sedentary lifestyle by staying active may also reduce pain.
7. Essential oils: Some suggest rubbing essential oils on the area to help provide short-term relief from joint pain. Peppermint, chamomile, and eucalyptus oils are thought to be effective options.
When to See a Doctor
If you experience moderate to severe knee pain, it’s best to seek consultation from your doctor as soon as possible to make sure the problem isn’t critical.
Some other symptoms that may indicate you should see a doctor include:
- Severe pain
- Sudden swelling or warmth
- Inability to bear weight on the leg
- Trouble breathing
- A change in the shape of the joint
Final Thoughts on Pain behind the Knee
If you’ve been experiencing pain behind the knee, a wide range of conditions and injuries could be to blame. Problems like muscle cramps or strains may resolve on their own. For more serious issues, such as ligament injuries, meniscal tears, and especially deep vein thrombosis, you’ll want to visit the doctor for an examination and take treatment from there.
Article Sources (+)
“Why weight matters when it comes to joint pain,” Harvard Health Publishing; https://www.health.harvard.edu/pain/why-weight-matters-when-it-comes-to-joint-pain, last accessed June 26, 2018.
Ford, G., et al, “Associations of body mass index with meniscal tears,” American Journal of Preventative Medicine, May 2005, DOI: 10.1016/j.amepre.2005.01.013; https://www.ncbi.nlm.nih.gov/pubmed/15831342, last accessed June 26, 2018.
Zini, S., et al., “Knee arthroscopic visibility alterations in obese and non-obese patients,” Arquivos Brasileiros de Cirurgia Digestiva, 2016, DOI: 10.1590/0102-6720201600S10019; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5064278/, last accessed June 26, 2018.
Boer, C., et al., “The role of the gut microbiome in osteoarthritis and joint pain,” Osteoarthritis and Cartilage, April 2017, DOI: https://doi.org/10.1016/j.joca.2017.02.033; https://www.oarsijournal.com/article/S1063-4584(17)30082-1/abstract, last accessed June 26, 2018.
Wang, C., et al., “Tai Chi is Effective in Treating Knee Osteoarthritis: A Randomized Controlled Trial” Arthritis and Rheumatology, Nov. 2009, DOI: 10.1002/art.24832; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3023169/, last accessed June 26, 2018