What is Grade 4 arthritis?
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.
Sources: healthline.com, thesteadmanclinic.com, medicinenet.com