There are quite a few things to consider when asking the question of what causes weak knees.
Knees can be very sensitive and can cause issues for many people. Essentially, the knee is a hinge joint made up of three bones:
- Femur, or thigh bone;
- Tibia, or shin bone;
- Patella, or knee cap.
These bones create the tibiofemoral and patellofemoral joints, which form what we know as the knee joint.
Multiple muscles, tendons, and ligaments surround the knee to provide support, stability, and mobility of the knee. The knee joint also includes cartilage, menisci, synovial fluid, and other soft tissue structures necessary for smooth movement at the knee joint.
So, you need to understand the basics of knee anatomy to figure out the potential underlying cause of weak knees and knee pain. Then once you know the cause, it will be easier to treat weak or painful knees.
What Causes Weak Knees
Muscle Weakness and Deconditioning
A lack of regular exercise and a sedentary lifestyle can result in various knee problems, including the gradual weakening of the knees due to easily fatigued muscles. Weak knees may or may not be accompanied by pain, which typically develops slowly rather than from a specific injury.
When the muscles surrounding the knees are not functioning at their best to support the joints, it can lead to issues within the joint itself, potentially causing instability. Key muscles involved in knee movement and strength include the quadriceps, hamstrings, and calf muscles.
To avoid weak knees and prevent knee pain, it is crucial to keep the surrounding muscles properly stimulated. This can help maintain the strength and stability of the knees and overall joint health. Paying attention to these muscle groups and incorporating regular exercise into your routine can go a long way in promoting strong, healthy knees.
Arthritis
Arthritis is a significant contributor to knee weakness and the heightened risk of knee injuries.
The most prevalent form is osteoarthritis, which has been closely linked to abnormalities in knee joint function.
Other arthritis types to consider are Rheumatoid arthritis, Psoriatic arthritis, and Gout, some of which may have autoimmune or inflammatory components.
Although not classified as arthritis, conditions like lupus and fibromyalgia can also lead to knee joint pain and weakness.
When a joint’s quality is in question, it impacts its movement mechanics and the surrounding soft tissues like muscles, tendons, and ligaments. This can result in decreased support for the joint. If your knee lacks support and causes pain during movement, it can lead to reduced activity levels, increasing muscle weakness, and overall knee weakness.
Orthopedic Knee Injury
Knee injuries, especially when related to sports injuries, are a common cause of weak knees.
While a wide range of injuries can occur, common knee injuries include but are not limited to the following:
- Sprained or torn ligaments
- Strained muscles and tendons
- Tendon tears
- Meniscus tears
- Fracture
- Torn cartilage
- Overuse injury, like patellar tendonitis
The list could go on and on!
Orthopedic knee injuries can create more of a sudden pain onset and sudden knee weakness because of their usual traumatic onset.
Tendonitis is one type of injury that may have more of a gradual onset as it is an overuse injury commonly caused by continuous repetitive motions.
More Serious Conditions to Consider
Weakness in the knees may not always be related to deconditioning or an orthopedic issue. Other medical conditions can be an underlying cause for this issue. Some of these medical conditions are considered chronic, while others are considered more of an emergency.
Various neurologic conditions can create weakness in the knees. Some examples include the following:
- Multiple sclerosis
- Stroke
- Amyotrophic lateral sclerosis
- Neuropathy in the legs
- Spinal cord compression
- Myasthenia gravis
- Spinal nerve root compression
While all of these conditions are serious and need to be addressed immediately by a medical professional, the last three conditions mentioned (spinal cord compression, spinal nerve root compression, and stroke) are considered medical emergencies, especially if they have created a sudden weakness in the knees that wasn’t there before.
I hope this article has helped you to learn more about your knees and what causes weak knees.
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I enjoyed reading your post,
It was interesting to learn what can cause knee issues even if you are not of an age that is commonly known of issues with knees. The most common reason of a constant knee pain or weakness would be arthritis once you are old however it is useful to know that there are other reasons too especially if it is all of a sudden or if you are young.
Thanks for this information, have a great day!
Not getting enough exercise or getting the wrong exercise are part of the problem with people having weak knees. Another contributing factor is a person’s weight; if a person is significantly overweight, then there is added pressure on the knees. You have to consider proper nutrition as well. If your diet is not getting the proper vitamins and minerals to help the cartilage retain its elasticity, you could have problems.
Jerry