Why Does My Knee Hurt Without Injury?
Knee pain can significantly diminish your quality of life, making even basic tasks like walking a challenge.
Joint pain – particularly in the knees – can interfere with your ability to perform everyday activities, but there are many things you can do to treat and prevent this condition.
Whether you're dealing with severe pain or mild discomfort, continue reading to discover what to do when sudden knee pain strikes and how to prevent these episodes.
What Does Sudden Knee Pain Feel Like?
Sudden knee pain can arise quickly and unexpectedly, often without any clear event or injury to trigger it.
The sensations associated with sudden knee pain can vary widely, ranging from mild discomfort to severe pain.
Knee pain may be described as:
Sharp
Stabbing
Burning
Throbbing
Aching
If the pain appears suddenly and eases just as quickly, it may not be cause for concern.
However, persistent pain without relief may indicate more serious knee problems that require medical attention.
What Can Cause Knee Pain Without Injury?
Knee osteoarthritis (OA)
Osteoarthritis is the most common form of arthritis, characterized by the degeneration of smooth cartilage within the joints. This wear and tear often leads to knee problems, especially in joints that bear weight, like the knees and hips.
Causes include genetic factors, mechanical issues (primary osteoarthritis), or secondary conditions affecting cartilage.
As the cartilage breaks down, irritation, pain, and inflammation can disrupt daily activities.
Osteoarthritis affects about 25% of adults. Men under 50 are more likely to develop it, while women are at higher risk after 50. Being overweight increases the risk by adding strain to weight-bearing knee joints.
Rheumatoid arthritis (RA)
Rheumatoid arthritis is an autoimmune disorder that primarily affects the joints, specifically targeting the synovium — the lining of the joints — and its fluid.
Unlike the body's normal inflammatory response, which aims to eliminate harmful substances, rheumatoid arthritis misdirects this response, causing the immune system to attack healthy joint tissue.
RA leads to knee pain due to the inflammation it causes. An inflamed knee joint may feel swollen, stiff, sore, and warm to the touch.
Risk factors for developing rheumatoid arthritis include environmental factors like air pollution, a family history of the condition, and being female.
Statistics indicate that women under 50 are four to five times more likely to develop rheumatoid arthritis than men.
Gout
Knee pain from gout is a result of acute joint inflammation caused by the buildup of monosodium urate crystals, which form from uric acid found in foods like red meat, alcohol, and seafood.
These tiny crystals, shaped like sharp needles, trigger severe pain and inflammation in the knee joint, making gout-related knee pain particularly intense.
Gout is more common in people with other health conditions like high blood pressure, diabetes, high cholesterol, and heart problems, as well as in older adults.
Septic arthritis (SA)
Septic arthritis is a joint infection that can develop in a vulnerable joint during surgery, recovery, or when there's a wound, prosthetics, or metal implants involved. It can also spread to a joint through the bloodstream.
Knee pain associated with SA is caused by inflammation, often accompanied by swelling, stiffness, and sharp pain in the joints.
This condition is a medical emergency, as it can rapidly deteriorate the joint, leading to permanent damage.
Around 20,000 people in the United States are affected by SA each year, with the condition being most prevalent in children.
Lupus
Lupus — also known as systemic lupus erythematosus (SLE) — is an autoimmune disease in which the body's immune system mistakenly attacks its own organs and tissues, including the liver, lungs, skin, muscles, and joints.
This can cause sudden knee pain due to inflammation and other symptoms such as headaches, rashes, fever, hair loss, and fatigue.
Tendinopathy
Tendinopathy is a broad term that covers various conditions affecting the tendons. One common form is tendonitis, where a tendon becomes inflamed.
Since tendons connect muscles to bones, tendonitis always involves a muscle. In the knee joint, several muscles, including the quadriceps, hamstrings, and gastrocnemius, are connected by tendons that can become inflamed.
This inflammation can result from factors such as strain, chronic steroid use, disease, overuse, or irritation.
The most common type of knee tendinopathy is patellar tendinopathy — this causes pain located in the front of the knee. It occurs when repetitive strain or overload on the quadriceps muscles causes tension and compression of the patellar tendon.
Patellofemoral pain syndrome (PFPS)
Patellofemoral pain syndrome (PFPS) affects the kneecap (patella), its tendon, and the way it moves. It’s typically felt as pain at the front of the knee.
Normally, when you bend and straighten your knee, the kneecap glides smoothly along a groove in the lower leg bone (tibia).
However, if the kneecap moves out of this groove, it increases friction, leading to irritation and inflammation of the patellar tendon.
Improper movement of the patella creates significant friction between the patellar tendon and the knee joint, leading to intense pain.
PFPS is especially common in runners, who are prone to muscle imbalances and biomechanical issues during training. It accounts for 25% to 40% of sports-related knee injuries.
Baker’s cysts (popliteal cyst)
Surrounding the knee joint is a protective structure called the joint capsule, which plays a key role in maintaining joint stability.
The inner lining of this capsule, known as the synovium, contains synovial fluid that cushions and lubricates the knee.
When some of this fluid leaks out of the joint capsule and collects behind the knee, it forms a Baker's cyst in the crease of your knee. This causes pain just like a large pimple would — fluid buildup creates pressure, leading to discomfort and pain.
In children, Baker's cysts occur spontaneously and often resolve on their own. However, in adults, they are usually linked to an underlying knee condition.
How Should I Treat Knee Pain that Occurs Suddenly?
Follow the PRICE principle immediately
After experiencing knee pain, you might find that it eases quickly, allowing you to walk it off.
However, if you're unable to bear weight on your knee, stand, or if the pain persists, follow the PRICE principle:
Protect: Sit down and take the weight off your knee joints. Position your leg comfortably to minimize the risk of further injury.
Rest: Avoid sports or any other strenuous activities to give your knee time to heal.
Ice: Place a cold pack or a bag of frozen vegetables on the area of your knee that’s causing you discomfort. This helps reduce immediate pain and inflammation.
Compression: Wrap your knee firmly with a bandage or use a knee guard to support the joint.
Elevate: Raise your leg and knee slightly above your torso to reduce swelling.
By following these steps, you can help manage your knee pain and protect your knee joints from further damage.
Medication
Over-the-counter (OTC) painkillers
Acetaminophen (Tylenol): This is effective for mild to moderate knee pain as it blocks pain signals without addressing inflammation.
Anti-inflammatories (Advil, Bayer, Ecotrin): NSAIDs reduce both pain and inflammation in the knee joint, which helps treat swelling.
Prescription medication
Steroids (Deltasone): These are powerful anti-inflammatories that can relieve knee pain but require medical supervision.
Prescription painkillers: Consult your doctor, as misuse of prescription painkillers can be dangerous.
Disease-modifying antirheumatic drugs (DMARDs): These drugs suppress the immune system, helping to reduce knee pain in conditions like lupus and RA.
Physical therapy
Many knee injuries and conditions can be effectively managed by physical therapists, who provide a conservative approach to relieve pain without the need for surgery.
Your specific treatment plan will depend on the underlying issue.
For example, with patellofemoral pain syndrome, which is caused by improper movement of the kneecap, a physical therapist can help balance the strength of the quadriceps muscles to prevent the kneecap from being pulled out of place.
Surgery
Knee surgery may be required depending on the severity of a knee injury or the specific condition affecting the knee.
Here are some common surgical options for treating knee injuries:
Arthroscopy: This minimally invasive diagnostic procedure is used to assess the joint and identify issues that may not be detected with X-rays or other scans.
Total knee replacement (TKR): This is the surgical removal of a damaged knee joint, followed by the implantation of a knee prosthetic to restore function and alleviate pain.
Aspiration: During this procedure, a needle and syringe are used to remove unwanted fluid from the knee joint, often to relieve pain and reduce swelling.
Incision and drainage (I&D): Involves making a small incision to drain fluid from the knee joint, typically to reduce swelling and prevent further complications.
Intra-articular injection: During this minimally invasive procedure medication is injected directly into the knee joint to treat pain and inflammation.
Tendon release or reconstruction: These surgical procedures aim to either release a tendon that has become too stiff to function properly or reconstruct a tendon that has been severely damaged due to a knee injury.
How to Prevent Knee Pain
Prevention is always better than cure and the same applies to knee pain. Here are some tips to prevent knee pain and keep your joints healthy as you age:
Keep fit: Focus on exercises that strengthen muscles, improve flexibility, and enhance conditioning.
Enjoy a balanced diet: Make sure your diet supports overall health and joint function.
Maintain a healthy weight: Losing excess weight helps reduce the strain on your knee joints.
Protect your joints: Avoid high-impact activities that can put unnecessary stress on your knees.
Schedule regular checkups: Regular visits to your doctor can help catch and address potential knee issues early.
Where Can I Learn More About Managing Knee Pain?
Whether you experience occasional knee pain or have persistent knee problems, LifeMD is here to help.
A doctor or nurse practitioner can provide valuable guidance on managing knee pain all from the comfort of your own home.
Make your appointment today to take control of your health.
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