The knee joint can feel stiff upon waking up or after a passive activity. This is common among people who do a lot of physical activity and older adults. Like any joint, the knee wears down and can be injured.
Arthritis can cause joint stiffness as well. The result is a lack of flexibility, muscular imbalances, and pain. By understanding what causes stiff knees, we can identify what can be done to mitigate, eliminate, and address these causes.
Here are the different causes of stiff knees:
Cause #1: Meniscus Tear
The meniscus is two ‘C’ shaped pieces of cartilage that sit in the knee joint. This is the shock absorber in the knee that form the joint. With sudden movements or twists, one can injure or damage the meniscus. A sudden movement like this would most often come from participating in physical activity or sport.
Furthermore, as we age, the meniscus wears down, increasing the risk of a tear. Although you may still be able to walk on the knee, you may also experience locking knee, have pain, swelling, lose range of motion, and not be able to trust your knee to fully support you. A stiff knee is certainly included in the symptoms of a meniscus tear.
Cause #2: Ligament Injury
In addition to the meniscus, the knee is also comprised of ligaments. These are bands of fibre that connect one bone to another bone. The ligaments running through the knee connect the thigh bone to the lower leg bone or, phrase it another way, from the femur to the tibia.
The knee ligaments can sprain, tear, or rupture. These stretch and tear injuries are common to blows to the knee, such as when playing a sport and experiencing trauma. Symptoms of a ligament injury include pain in the knee joint, instability in the knee, swelling, and stiffness. Ligament injuries take six weeks to heal, although more severe injuries can remain for months. Work with your chiropractor to create a recovery plan.
Cause #3: Arthrofibrosis
Arthrofibrosis is where an excessive scar tissue forms and builds around the knee, effectively locking it in. Arthrofibrosis is better known as stiff knee syndrome. This often happens after a knee replacement, anterior cruciate ligament surgery, or similar knee surgery. On average, 6% of people who undergo knee replacements will deal with stiff knee syndrome after the fact.
Symptoms can include knee pain that gradually worsens throughout the day, swelling around the knee, and walking with a bent knee. Mild forms can be treated with physical therapy, and more severe cases can be treated with a combination of a knee arthroscopy followed by physical therapy.
Cause #4: Osteoarthritis
Osteoarthritis comes from wear and tear of the cartilage in the knee between the bones. The cartilage slowly degrades with osteoarthritis in the knee, eventually causing the bones to rub together. As they rub against each other, this causes spurs. Those spurs cause the joint stiffness and pain that osteoarthritis is known for.
This most commonly occurs in people between 55-64 years. Lots can be done to treat osteoarthritis, each to varying degrees of success. Anti-inflammatory diets are often prescribed. Certain physical therapies and exercise, as well as weight loss, are helpful. A knee brace, corticosteroid or hyaluronic acid injections, and surgery may be recommended in some cases.
Cause #5: Rheumatoid Arthritis
Rheumatoid arthritis is different from osteoarthritis as it does not originate from wear and tear. Rheumatoid arthritis in the knee stems from an autoimmune disorder that causes the body to attack its tissue. This type of arthritis is often found in both knees simultaneously.
What you will normally see with this is swelling of the membrane covering the inner lining of the joint. This swells to such a degree that you get knee pain and stiffness.
Walking is the best medicine for resolving knee stiffness from rheumatoid arthritis. This stimulates blood flow and strengthens the knee muscles that support the joint. Exercise and stretching, including yoga, tai chi, and similar activities, can help resolve these symptoms.
Cause #6: Post-Traumatic Arthritis
Post-traumatic arthritis, aka PTA, is when repeated meniscus tears and ligament tears have caused an injury to the knee. This is common after an injury hears and is often a temporary issue, recovering in months. However, some instances of post-traumatic arthritis can last longer, eventually becoming a chronic condition.
Symptoms of PTA include knee stiffness, swelling in the knee joint, making it difficult to move the knee, moderate pain, weakness in the knee, worsening symptoms after physical activity, and worsening symptoms during wet weather. PTA should be treated with rest, applying an ice pack and heat at regular intervals, and wearing a knee brace for stability as with other knee injuries.