The knee is formed by the femur, tibia, fibia and the patella. These bones are protected and cushioned by cartilage in your knee. There are two wedge-shaped pieces of cartilage found in both knees that are called the meniscus, which act as shock absorbers. The meniscus also serves to protect the articular cartilage and help distribute weight evenly across the knee. 

When affected by osteoarthritis or rheumatoid arthritis, inflamed cartilage in the knee can make it difficult to complete basic movements like walking or climbing steps. Some symptoms that may indicate that you have arthritis in your knee are: 

• Inability to bend or straighten the knee
• Pain and swelling, especially in the morning or after sitting for a long period of time
• Exacerbated pain after vigorous activity
• Locking or clicking sound during movement
• Weakness or buckling in the knee

The hip is the largest ball-and-socket joint in the body and is held together by various muscles, tendons and cartilage. Cartilage in the hip, such as the labrum, serves to protect and cushion your bones, enabling them to move easily and without pain. 

When arthritis deteriorates cartilage of the hip, your bones can rub against each other, resulting in damaged bones. These bones sometimes extend outwards, forming bone spurs that cause pain or stiffness in the affected joint. The following factors increase the likelihood of developing arthritis in the hip:

• Age (55+)
• Family history 
• Previous injury to hip
• Obesity 
• Improper formation of the hip at birth

Without a properly functioning hip, your body may become increasingly unstable and can lose its range of motion.

Your shoulder is made up of numerous complex structures like the rotator cuff, the bursa and the labrum, along with three bones: 

• Upper arm bone (humerus)
• Shoulder blade (scapula)
• Collarbone (clavicle)

There are two joints in the shoulder that can be affected by arthritis. One joint is the glenohumeral joint, where the humerus meets the scapula. The other joint is called the acromioclavicular joint, where the clavicle is connected to the scapula. 

As arthritis progresses, the cartilage protecting your bones is damaged more and more, eventually leading to bone-on-bone traction in the joint. This can result in severe pain, stiffness, or a grinding or clicking in the shoulder.