Knee pain can develop immediately during an activity or come on gradually after sitting or kneeling for a long period. There are many structures that work together to make up the inside of the knee joint and a number of things can go wrong with any one of these tissues. It is important to seek professional help if home treatment does not reduce pain within seven days, according to MayoClinic.com.
Meniscus is a flexible tissue made up of cartilage. It is the shock absorber between the bones of the knee and allows for smooth movement in the joint. Meniscus injuries are the most common knee injury, especially in sports, according to the American Academy of Orthopaedic Surgeons. The meniscus can tear in many different ways and causes symptoms of catching and locking, a feeling of "giving way," pain, swelling and an inability to move the knee through the full range of motion.
Sprains, or tears in the ligament can happen to the ligaments inside the knee joint such as the ACL and PCL or to those on the outside of the joint such as the MCL or LCL. These ligaments all work together to attach bone to bone. A sudden twist or trauma to the side of the knee can cause any one of these ligaments to tear partially or completely. With the ACL or PCL, there is usually a loud pop associated with the tear and is followed by more immediate swelling and pain in the joint. St. Johns Providence Health System in Detroit indicates that these symptoms can take as long as six to 12 hours to set in. Complete tears require surgery to repair.
There are many types of arthritis, ranging from hereditary types such as rheumatoid arthritis to arthritis caused from degenerative and traumatic changes to the knee. All types of arthritis cause the smooth surfaces of cartilage to wear down. This can lead to bony spurring of the knee. The pain from this develops gradually and grows increasingly uncomfortable over time, with the pain usually being worse in the morning until the joint loosens up with movement, according to University of California San Francisco Medical Center.
Gout and Infection
While gout is a type of arthritis, it is caused by a diet too high in purine-rich foods such as sardines, animal organs and brewer’s yeast. This type of pain will set on rapidly, often at night, according to the Merck Manuals Online Medical Library. It leads to immediate redness, heat and swelling. It may appear to be an infection but will resolve after five to 10 days on its own or with the help of medication. An infection in the knee can be caused by trauma, an infection elsewhere in the body or after surgery. The redness and swelling and heat that the joint is giving off may be similar to that of a gout flare up but is often accompanied with a fever.
Loose bodies is a condition also known as joint mice. It occurs when a piece of torn cartilage chips off and floats around in the knee joint. If this "mouse" gets caught between two pieces of bone, it can cause immediate and sudden intense knee pain and an inability to move the joint altogether. A joint mouse can affect the knee for up to a year before symptoms are felt, according to St. Johns Providence Health System.