For a three variable system of equations to be consistent, the equations formed by the equations must meet two conditions: 1  All three planes have to parallel. 2  Any two of the planes have to be parallel and the third must meet one of the planes at some point and the other at another point.
Osteoarthritis affects 20 million Americans, occurring most often in women and adults older than 45. Osteoarthritis can affect any joint, but it most often occurs in the knees, hips, spine and fingers. At first it may affect only one joint, but if the joint is in the fingers, multiple hand joints may become affected.
They include pain, tenderness in the knee, stiffness when standing or walking, loss of flexibility, and grating sensations that can be heard when the knee joint is used. Osteoarthritis in the knee begins with the gradual deterioration of cartilage. Without the protective cartilage, the bones begin to rub together, causing pain, loss of mobility, and deformity. It affects approximately 16 million people. The majority of arthritis cases involving the knee are osteoarthritic cases.