Grade 4 arthritis is categorized as osteoarthritis, or OA, whichis a joint disease that affects thecartilage that allows bone joints to function easily. Grade 4 osteoarthritis is categorized as the most severe level of the disease causing particular difficulty when walking, according to the Steadman Clinic.
There are five grades ofOA, the first being 0, a normal, healthy joint. The highest grade, 4, is measured as the most severe form of OA according to Healthline.Grade 4 OAaffects the cartilage in bone joints making walking especially difficult. The disease stiffens the joint space between the bones which is diminished. With very little cartilage left, the joint becomes rigidand in some cases immobile. The disease also reduces the amount of lubrication, called synovial fluid, causingfriction between the joints, as stated in Medicinenet.
The treatment for OA is surgery and is usually performed on the knee, making walking easier. The procedure, called an osteotomy, reduces the length of the bone, cutting above or below the knee. The goal is to change the alignment of the joint and shift body weight away from the damaged area according to Healthline.
Another surgery option to treat Grade 4 OA is an arthroplasty or total knee replacement. For this procedure the damaged joint is removed and replaced with an artificial device made from plastic or metal.