Osteoarthritis or degenerative joint disease is defined as a form of arthritis in which one or many joints undergo degenerative changes, including subchondral bony sclerosis, loss of articular cartilage, and proliferation of bone spurs or osteophytes and cartilage in the joint, according to Mosby’s Medical Dictionary (Anderson, 2001). Bullock, on the other hand, defines osteoarthritis as destruction of the articular cartilage and subchondral bone with cyst and osteophyte formation (Bullock and Henze, 2000).
Osteoarthritis is the most common form of arthritis affecting more than 20 million people in the country (Shiel, 2008).
Osteoarthritis is usually acquired by the elderly (Smeltzer and Bare, 2004). In males, there is a greater chance of contracting osteoarthritis before the age of 45, while in females, the greater chance is after the age of 45 (Smeltzer and Bare, 2004). Osteoarthritis can be called primary osteoarthritis when there is no known cause, or it has an idiopathic etiology and it is called secondary osteoarthritis when it is caused by another underlying disease condition (Shiel, 2008).
Risk factors that can predispose an individual to developing this disease condition are an increased age, obesity, previous joint damage, trauma to joint due to repetitive use, occupations that involve carpet installation, construction working, farming and sports injuries, anatomic deformity, and genetic susceptibility (Kaplan, 2007). Osteoarthritis most often targets weight bearing joints at the hips, knees and cervical and lumbar spinal area; it also affects finger joints, most especially those at the proximal and distal regions (Smeltzer and Bare, 2004).
Osteoarthritis occurs when the articular cartilage matrix is depleted thus exposing the basic collagen structure (Bullock and Henze, 2000). Due to the stress of everyday usage of the affected joint, the articular cartilage matrix will try to spread this compression hydrostatically but will fail to do so. This will cause the collagen fibers to rupture and the articular cartilage will flake, fissure and erode (Bullock and Henze, 2000).
The exposed subchondral bone will crack and the synovial fluid will enter the cracks towards the marrow, and subchondral cysts are formed (Bullock and Henze, 2000). Since the subchondral bone is already exposed, there will be proliferation of fibroblasts in order to form new bone in this area. The periosteal bone growth increases at the joint margins and at the attachment sites of ligament or tendons and will develop into bone spurs or ridges called osteophytes (Bullock and Henze, 2000).
The development of osteophytes will lead to an increase in synovial capsule size which in turn causes limited movement (Bullock and Henze, 2000). Also, osteophyte formation will irritate nerve endings in the periosteum causing pain (Smeltzer and Bare, 2004). Both the pain and movement limitation causes functional impairment in and individual suffering from osteoarthritis (Smeltzer and Bare, 2004).
Clinical manifestations of osteoarthritis include the symptoms of pain, most specifically joint pain, possibly due to an inflamed synovium, stretching of the joint capsule or ligaments, irritation of nerve endings in the periosteum over the osteophytes, trabecular microfracture, intraosseous hypertension, bursitis, tendonitis, and muscle spasm (Smeltzer and Bare, 2004). There is stiffness which is usually experienced in the morning but has a less than fifteen minutes duration and can be lessened with movement (Gardner, 2005).
The patient’s functional impairment is due to pain on movement and his or her limited motion is due to the structural changes in the joints and is seen as Heberden’s and Bouchard’s nodes (Smeltzer and Bare, 2004). Physical assessment for osteoarthritis will reveal tender and enlarged joints (Smeltzer and Bare, 2004). Diagnostic tests of choice will be an x-ray of the affected area and it will show narrowing of the joint space due to progressive loss of the cartilage (Smeltzer and Bare, 2004). Osteoarthritis can be managed with conservative treatment, pharmacologic treatment, and surgical management.
Conservative treatment involves heat application, weight reduction if obese, joint rest and avoidance of overuse, use of orthotic devices to support the affected joints, and isometric and postural exercises (Smeltzer and Bare, 2004). Medications to give patients include an analgesic therapy and acetaminophen is the drug of choice, glucosamine and chondroitin can be given too, to improve tissue function (Smeltzer and Bare, 2004). Surgical management involves osteotomy, arthroplasty and tidal irrigation of the knee (Smeltzer and Bare, 2004).