Can’t Bend Knee Without Pain

Can't Bend Knee Without Pain

For many of us, running is an essential component of our physical and mental health regimens.

There are many benefits to running, including stronger bones, stronger muscles, and better cardiovascular health. 

Unfortunately, running on a regular basis also comes with risks. One of the main problems runners encounter in regard to their health and mobility is knee pain.

Because running is a high-impact activity, it places strain on the joints, especially in the knees, which can eventually lead to injury. 

There are various causes of knee pain in runners, but taking note of movements that trigger the pain will help to narrow down the diagnosis.

If you’re a runner and have noticed that you can’t bend your knee without pain, read on to find out what might be causing it and what you can do. 

Why You Can’t Bend Your Knee Without Pain 

Runner’s Knee 

One of the main causes of knee pain in runners is a condition appropriately named ‘runner’s knee’. The scientific name for this injury is Chondromalacia patella. 

This is where the cartilage under your kneecap gets worn down, eventually causing pain at the front of (and sometimes around) the knee joint, especially when flexing or bending. 

Luckily, with rest, icing, and proper support, runner’s knee should resolve before too long. Sometimes, anti-inflammatory medication may be prescribed to reduce pain and swelling. 

Muscle Strain

If you’re unable to bend your knee without pain after a run, it might be that you’ve strained a muscle in your knee. 

Treatment for a muscle strain of this kind will depend on the severity. If the strain is mild, you can probably treat the problem yourself at home with rest, ice packs, compression, and elevation.

However, more severe strains might require mobility aids such as crutches and physical therapy to repair the damage. 

Torn Meniscus 

The meniscus is a piece of cartilage in the knee. Its role is to absorb shock that travels up the shin into the thigh, which is very important.

Unfortunately, this piece of cartilage can be damaged or torn if you twist your knee awkwardly while bearing weight.

These kinds of injuries are called meniscus tears. Meniscal tears can be quite painful, especially when bending the knee. 

Depending on the location and severity of the tear, your doctor might send you home with instructions to rest, put ice on the injured knee, and take over-the-counter pain relievers.

However, some meniscus tears are unable to heal themselves in this way, so physical therapy might be recommended, followed by surgery if the meniscus tears do not resolve.

ACL Injury 

ACL Injury 

The ACL is one of the most important, yet vulnerable ligaments in a runner’s body.

Its purpose is to stabilize the knee joint, but it can be torn if you suddenly change direction while running or come to a stop too quickly.

This is one of the most common knee injuries seen in runners. 

If you have only torn your ACL slightly, you might not need surgery to correct it.

Instead, you may be able to rely on rest and swelling-reducing treatments such as ice and anti-inflammatory pain medication.

However, if the ACL has been completely torn, it will not heal without surgery, so if you suspect this may be the problem, seek medical attention as soon as possible. 


Osteoarthritis is a condition that causes painful, stiff joints, and this can occur in the knees as well as other parts of the body.

While osteoarthritis is not directly connected to running, it can definitely make it more difficult for you to run at your usual pace. 

This condition is characterized by pain, swelling, stiffness, and tenderness in the joints. Sometimes, sufferers may feel a sensation that feels like parts of the joint are grinding against one another.

Although there is no cure for osteoarthritis, the symptoms can be managed through diet, physiotherapy, and pain relief, which means that you don’t have to stop running as a result of this condition. 

Patellar Tendinitis 

The tendon that connects your kneecap to the bone of your shin is called the patella, and patellar tendinitis is where this tendon gets injured in some way.

This can make it painful to bend your knee or put weight on it. 

This condition usually resolves itself in a few weeks to a few months, but until then, you can apply ice, elevate your knee, and take over-the-counter pain medication to manage the discomfort.

You should also do some exercises to improve the flexibility in your knee joints so that this does not happen again in the future. 


A severe injury that can occur as a result of any type of exercise is a dislocation.

If you dislocate your knee, you may experience pain on bending the knee, but this will probably not be the most noticeable symptom of your injury, partly because your knee will already be stuck in a bent position.

Dislocation is incredibly painful, and you will most likely find that you are unable to put any weight at all on the injured knee.

Straightening your leg will be impossible, and in addition to the severe pain, you are likely to notice sudden and significant swelling. 

Sometimes, a knee dislocation will require surgery to fix.

Other times, you may be able to recover with the help of crutches, a knee brace, and regular physiotherapy. This regimen helps to heal most dislocated knees within six weeks.

A knee dislocation is considered an emergency, so if you suspect that your kneecap is out of place, you should visit your nearest emergency room as soon as possible. 

Final Thoughts 

As a runner, there are many reasons why you might not be able to bend your knee without pain.

Some of these injuries, such as a mild muscle strain, are less serious, while others, such as an ACL injury or dislocation, are more serious and may require surgical intervention. 

For injuries that cause mild pain or discomfort, you may wish to try taking medications such as ibuprofen while icing, compressing, and elevating the affected knee.

However, if bending your knee is causing you significant pain, or you are experiencing other symptoms such as an inability to put weight on your leg or a grinding feeling, you should see your doctor.

Megan Rinzel
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