Why Your Knee Bone Pops When Getting Up & Your Leg Is Stiff

Hearing a popping sound from your knee and feeling stiffness in the knee joint upon arising is a common experience, and may happen for a variety of reasons.

Escaping Gases

• Synovial fluid, which serves a a lubricant for the joints, contains oxygen, nitrogen and carbon dioxide gases. When the joint capsule is stretched, a popping sound occurs as the gas is rapidly released.

Movement

• Movement causes a tendon to change position, and a snapping sound may be heard as it returns to the original position. Also, knee and ankle ligaments commonly tighten upon movement, causing a cracking noise.

Rough Surfaces

• When knee joints become arthritic, cartilage is lost and the joint surface is rough, which may cause popping sounds upon movement.

Stiffness

• According to MayoClinic.org, stiffness in the knee is a common symptom of osteoarthritis, the most prevalent form of arthritis. The stiffness is usually felt in the morning or after activity, and can be accompanied by pain, swelling, and creaking and popping sounds from the knee joint.

Danger

• The Johns Hopkins Department of Orthopaedic Surgery says that such popping noises are usually harmless and do not require treatment. However, patients should consult a doctor if their knee sounds are accompanied by pain or swelling, or if they are losing motion in the knee joint.