Knee locking occurs when your knee feels jammed, preventing you from fully straightening or bending it. This experience can be unsettling and painful, significantly impacting daily activities. This article explores common conditions that cause the knee to feel stuck.
Understanding Common Causes of Knee Locking
A frequent cause of knee locking is a meniscus tear. The menisci are two C-shaped pieces of cartilage that act as cushions between the thigh and shin bones. If a torn fragment displaces and gets caught within the joint, it obstructs smooth movement. This mechanical blockage, sometimes called a “bucket handle tear,” prevents full knee extension. Such tears can result from forceful twisting motions or gradual wear over time.
Loose bodies, fragments of bone or cartilage, can also cause knee locking. These pieces break off due to injury, trauma, or arthritis. Once dislodged, they float within the joint’s synovial fluid and can wedge between joint surfaces, causing a sudden, painful inability to move the knee. Removing them is often necessary to restore full motion.
Problems with the kneecap (patella) can cause the knee to catch or lock. Patellar instability occurs when the kneecap moves out of its normal groove, either partially (subluxation) or completely (dislocation). This improper tracking can lead to a feeling of the knee “giving way” or catching. Patellofemoral pain syndrome, or “runner’s knee,” involves pain around or behind the kneecap and can cause a catching sensation due to cartilage stress from overuse or poor alignment.
Other Factors Contributing to a Stuck Knee
Other conditions can also cause a stuck knee. Plica syndrome involves an inflamed or thickened fold of the synovial membrane, the knee joint’s lining. This irritated plica can get pinched or caught during knee movement, resulting in pain, clicking, and a sensation of locking.
Arthritis, particularly osteoarthritis and rheumatoid arthritis, can cause knee locking. In osteoarthritis, cartilage wear can lead to bone spurs (osteophytes) forming around the joint. These bony growths interfere with normal joint mechanics and physically block movement. Rheumatoid arthritis, an autoimmune condition, causes inflammation and swelling of the joint lining, restricting motion and leading to stiffness or a locking sensation.
A Baker’s cyst, a fluid-filled sac behind the knee, can create a feeling of blockage or stiffness. While it typically doesn’t cause true mechanical locking, a large cyst can exert pressure and restrict the knee’s ability to bend or straighten fully, leading to a stuck sensation.
When to Consult a Professional
If you experience persistent or recurring knee locking, it is advisable to seek medical evaluation. Severe pain, an inability to bear weight, or significant swelling and bruising around the knee warrant prompt attention. A fever or redness around the knee, which could suggest an infection, also necessitates medical consultation. Consult a healthcare provider if knee locking is a new symptom or appears to be worsening over time.
Approaches to Diagnosis and Treatment
Diagnosis typically begins with a physical examination and review of your medical history. Imaging tests visualize internal knee structures. X-rays identify bone spurs, fractures, or joint alignment issues. Magnetic Resonance Imaging (MRI) is useful for assessing soft tissue structures like the meniscus, ligaments, and cartilage to detect tears or damage.
Treatment varies depending on the underlying cause. Conservative management is often the initial strategy, including rest, ice, and elevation to reduce swelling and inflammation. Pain medication, like NSAIDs, may alleviate discomfort. Physical therapy strengthens knee muscles, improves flexibility, and restores range of motion to stabilize the joint and reduce locking.
If conservative methods fail or a mechanical obstruction exists, surgery may be considered. Arthroscopic surgery is a common minimally invasive procedure. During arthroscopy, a surgeon uses small incisions, a camera, and instruments to remove loose bodies, repair meniscal tears, or address patellar alignment. This approach effectively eliminates the physical impediment causing locking.