The Efficacy of TGF for Treating Osteoarthritis of the Knee: A Randomized Double-blind Controlled Trial

Introduction Knee osteoarthritis is a common disease of joint degeneration. Chronic inflammation is the major cause of this disease. One-third of the people over 65 years of age have Knee OA and the prevalence in women is more than in men. One-third of the people over 65 years of age have Knee OA and the prevalence in women is more than in men. The risk factors include age, weight, genetic factor, sex, bone density, and the past history of trauma or work. The more important risk factors are age and weight. These multiple factors make the change of knee joint, like chronic inflammation, joint remodeling and loss of function that make the change of joint homeostasis.

The diagnosis criteria of knee OA is based on two groups. In 1957, Kellgren and Lawrence established the criteria of radiological assessment and in 1986, Altman's group created the criteria of classification of idiopathic knee OA. In the beginning, only four pictures presented the four grade of knee OA without description. In 1963, Lawrence wrote the original description. Altman and his team used clinical signs combined with laboratory or radiography to established the diagnosis criteria. Now, the most used method is clinical and radiographic examination. In the clinical part, the patient should have knee pain with at least one of three items: age over than 50 years, the time of morning stiffness is less than 30 minutes or crepitus. In the radiography, the patient's X ray should show the definite osteophytes. The sensitivity can reach 91 percent and the specificity can reach 86 percent.

Knee joint is a diarthrodial joint. Two adjacent bones are covered by a layer of specialized articular cartilage and are encased in a connective tissue capsule lined by a synovial membrane, consisting of a thin cell layer of macrophages and fibroblasts. The main structural elements of knee include the articular cartilage (with chondrocytes), tidemark (separating the calcified and articular cartilage), calcified cartilage, and subchondral cortical and trabecular bone. The advanced osteoarthritic changes characterized by fissuring and fragmentation of the articular cartilage, chondrocyte proliferation and hypertrophy, duplication and advancement of the tidemark, expansion of the zone of calcified cartilage, thickening of the subchondral cortical plate and vascular invasion of the bone and calcified cartilage.

The signaling of cytokine is an important part of progression of knee OA. The initial is inflammation, maybe from cartilage or synovium. Then the hypertrophic chondrocyte and the macrophage of synovium will secret IL-1, 4, 13, TNF-α,β, MMP1,13 and ADAMTS 4, 5. The major function of MMP and ADAMTS is to degrade the articular cartilage.

The treatment of knee OA by OARSI (Osteoarthritis Research Society International) has one core treatment and four recommend treatment by different OA types. The core treatment includes strength training and exercise, weight management and education. The recommend treatment includes NSAIDs by oral or topical, acetaminophen, corticosteroid and duloxetine.