Knee catching, or knee locking, is a sensation where the knee momentarily gets stuck, hesitates, or feels like it is giving way during movement. This can range from a brief feeling to a mechanical blockage preventing full movement. It may include a popping or clicking sound, or a feeling of physical obstruction. Understanding the causes can help address the issue.
Understanding Why Knees Catch
Several conditions can lead to the sensation of a knee catching or locking, often involving mechanical interference within the joint. One frequent cause is a meniscus tear, which involves the C-shaped cartilage pads that cushion the knee joint. If a piece of this cartilage tears, a fragment can become lodged in the joint, blocking the knee’s full range of motion. This can happen due to forceful twisting or rotation of the knee, or from gradual wear and tear over time.
Loose bodies within the knee joint can also cause catching. These are small fragments of bone or cartilage that detach and float freely in the joint fluid. When these fragments get caught between the moving surfaces of the knee, they can hinder smooth movement, leading to a sudden catching or locking sensation. Such loose bodies can result from injuries, or from conditions like osteoarthritis, which causes cartilage and bone breakdown.
Plica syndrome occurs when a normal fold of tissue in the knee, called a plica, becomes inflamed or irritated. This inflamed tissue can get pinched or caught during knee movement, resulting in pain, clicking, and a catching sensation. It might also make the knee feel unstable.
Another reason for knee catching relates to patellar tracking issues, where the kneecap, or patella, does not move correctly within its groove on the thigh bone. If the kneecap shifts or tilts out of alignment as the leg bends or straightens, it can lead to a popping, grinding, or catching feeling. Weak thigh muscles, tight or loose tendons, or structural abnormalities of the knee bones can contribute to this improper movement.
Osteoarthritis, a degenerative joint disease, is a common cause of knee catching, particularly in older individuals. This condition involves the breakdown of cartilage that normally provides a smooth surface for joint movement. As cartilage wears away, the bones can rub together, leading to pain, stiffness, and the formation of bone spurs. These uneven surfaces or bony growths can interfere with joint motion, causing the knee to catch or feel stuck.
When to See a Doctor
While some instances of knee catching might be minor, certain signs indicate the need for professional medical evaluation. Seek medical advice if you experience:
- Persistent or worsening pain that does not improve with rest.
- Inability to bear weight on the affected knee, or a feeling that the knee is unstable.
- Noticeable swelling or bruising around the knee, especially if it develops rapidly after an injury.
- A visible deformity of the knee joint.
- Recurrent or complete locking where the knee cannot be straightened, or a catching sensation accompanied by a distinct popping sound at the time of injury.
- Knee catching that interferes with daily activities, such as walking or climbing stairs, or disrupts sleep.
Ways to Support Knee Health
For minor instances of knee catching and to promote overall knee health, several practical strategies can be helpful. Applying the RICE method—Rest, Ice, Compression, and Elevation—can help manage acute flare-ups. Resting the knee allows it to recover, while applying ice for 15-20 minutes at a time can reduce swelling and pain. Compression with an elastic bandage can help minimize fluid buildup, and elevating the leg above the heart encourages fluid drainage.
Maintaining gentle movement and stretching is beneficial for preserving knee range of motion, but it is important to avoid forcing movement if it causes pain. Incorporating strengthening exercises for the muscles supporting the knee, such as the quadriceps and hamstrings, can enhance joint stability. Examples include straight-leg raises, gentle squats, and lunges, but consulting a professional for specific exercises is advisable if pain persists.
Managing body weight plays an important role in knee health. Excess weight increases the load on the knee joints, accelerating wear and tear and contributing to pain. Even a modest weight loss can substantially reduce the pressure on the knees, as each pound lost can decrease the load on the knee by four pounds. This reduction helps alleviate discomfort and can slow the progression of joint issues.
Choosing proper footwear also impacts knee alignment and support. Shoes with good arch support, cushioning, and stability can help distribute weight evenly and absorb shock, reducing stress on the knees. Avoiding high heels and worn-out shoes, which can lead to misalignment and increased knee strain, is also recommended. Modifying activities to avoid repetitive stress on the knees can prevent irritation and support long-term joint well-being.