Disease State

Over 12 million Americans live with osteoarthritisOsteoarthritis
Arthritis typically with onset during middle or old age that is characterized by degenerative (gradual deterioration of joint) and sometimes abnormal growth in the bone and cartilage of one or more joints and a progressive wearing down of opposing joint surfaces with consequent distortion of joint position and is marked symptomatically especially by pain, swelling, and stiffness; abbreviation (OA) of the knee.¹  Osteoarthritis of the knee most commonly affects middle-aged and older adults with most diagnosed after the age of 45. Women are more affected than men, especially with OA of the fingers and knees. OA of the knee can cause chronic pain or discomfort during standing or walking, and may limit daily activities such as dressing and bathing.

Osteoarthritis can be defined as the gradual loss of articular cartilageArticular Cartilage
Cartilage that covers the articular surfaces of bones combined with thickening of subchondralsubchondral
Situated beneath cartilage bone, bone outgrowths (osteophytesOsteophyte
A bony outgrowth) at joint margins, and mild, chronic synovial inflammationChronic Synovial Inflammation
Inflammation of synovial fluid lasting for a long period of time or marked by frequent recurrence.²

In a healthy knee joint, the space between the bones is filled with joint fluidJoint Fluid
A transparent, lubricating fluid secreted by a membrane of an articulation (place of union between two or more joints) or bursa (a saclike body cavity between a tendon and bone) and the bones are covered with cartilageCartilage
A usually translucent somewhat elastic tissue that composes most of the skeleton. As the disease progresses, cartilage thins, becoming grooved and fragmented.³  The surrounding bones react by becoming thicker, grow outward and form spursSpurs
A sharp, bony outgrowth located at the end of a bone.³  The synoviumSynovium
The inner membrane of a joint capsule surrounding a freely movable joint. becomes thick and inflamed.³

Osteoarthritic joints have abnormal cartilage and bone with synovial capsular lesions.²  Osteoarthritis causes progressive damage to the joint cartilage causing bones to rub against each other and wear away.³  Normal activity becomes painful due to deformity.³