Osteoarthritis is a degenerative joint disease, which is always characterized by both, the degeneration of articular cartilage and simultaneous proliferation of new bones, cartilage, and connective tissue. It is not a single disease rather it is the result of various joint failure. The proliferative responses result in some degree of remodeling of the joint contour. Inflammatory changes in the synovium are usually minor and secondary. It is characterized by a slow and progressive focal erosion, and later more extensive destructive of the articular cartilage, followed by subchondral sclerosis and the formation of large body spurs as protrusions (osteophytes) at the margin of the affected joints.
This disease is uncommon before the age of 40 years. It affects both male and female and is more generalized and more severe in elder women. If affects mainly the articular cartilage of the big weight-bearing joints like spine, knee, and hip. The small joints of the hands and feet are also often involved. The osteophytes may contribute to the pain and disability, but they never fuse to cause ankylosis of the joint. When they occur at the distal interphalangeal joint, they are called Heberden's osteoarthritis.
Types of Osteoarthritis:
1. Primary Osteoarthritis: In this type, there is no obvious predisposing cause evident. There is a presumptive abnormality of chondrocyte metabolism, but it is essential to nature obscure. A familial pattern is apparent in some cases.
2. Secondary Osteoarthritis: In this, there is a clear association with some predisposing conditions, which may be virtually any abnormality of the joint as follows:
Classification of Osteoarthritis:
A) Localized Osteoarthritis:
B) Generalized Osteoarthritis: When the affected joint include three or more of the area listed above, it is known as generalized osteoarthritis.
B) Congenital Development:
E) Calcium Deposition Disease:
Differential Diagnosis of Joint Disorders:
Epidemiology and Risk Factors of Osteoarthritis
Osteoarthritis is one of the most common joint diseases. In developing countries, knee osteoarthritis is the leading cause of chronic disability among the elders. Age is one of the risk factors for osteoarthritis. In a radiographic survey of women less than 45 years old, only 2 % had osteoarthritis, between the ages of 45 to 65 years it was 30 % and those above 65 years it was 68 %. In males, the figure was similar but somewhat lower in older age group.
In general population, osteoarthritis is not very common at any of these sites. In contrast, vocational activities such as those performed by jackhammer operation, cotton mill and shipyard worker and coal miner may lead to osteoarthritis in the joint which is rapidly exposed due to occupational use. Obesity is a risk factor for knee osteoarthritis. For those in the highest quintile for body mass index at baseline examination, the relative risk of developing knee osteoarthritis by 36 years was 1.5 for men and 2.1 for women. In obesity, the relative risk rose to 1.9 for men and 3.2 for women suggesting that obesity plays a large role in the etiology of the most serious case of knee osteoarthritis. Further, a more obese individual who has not yet developed osteoarthritis can reduce the risk. A weight loss of 5 kg was found to be associated with 50 % reduction in the acts of developing symptomatic knee osteoarthritis.
Pathology of Osteoarthritis
It is not a disease of a single tissue, but the synovial joint as a whole is affected. The morphologic change in osteoarthritis is mostly seen in the articular cartilage of the weight bearing bones. The cardinal pathologic feature of osteoarthritis is a progressive loss of articular cartilage.
Changes in Articular Cartilage:
In the beginning, there is a loss of cartilaginous matrix (proteoglycans) resulting in progressive loss of normal metachromasia. This is followed by focal loss of chondrocyte and at other place proliferation of chondrocyte forming clusters. Further progression of the process causes loosening, flaking, and assuring of the articular cartilage resulting in breaking of pieces of cartilage exposing subchondral bones. Radiologically, this progressive loss of cartilage is apparent as narrowed joint space.
Changes in the Bone:
The denuded subchondral bone appears like polished ivory. There is a death of superficial osteocytes and increase osteoblastic activity causing rarefaction, microcyst formation, and occasionally microfracture of the subjacent bones. This changes result in remodeling of bones and changes in the shape of the joined surface leading to flattering and mushroom like an appearance of the articular end of the bones. The margins of the joints respond to cartilage damage by osteophytes or spur formation, these are cartilaginous outgrowth at the joint margin that later gets ossified. Osteophytes give the appearance of lipping of the affected joint loosened, and fragmented osteophytes may form free joint mice or loose bodies.
Changes in the Synovium:
Initially, there are no pathologic changes in the synovium, but in advanced cases, there is low-grade chronic synovial effusion associated with chronic synovitis.
Etiology of Osteoarthritis:
According to the etiology, there are two types of osteoarthritis.
Clinical Features of Osteoarthritis:
The joints most frequently involved are those of weight-bearing bones like spine, hips, knees, and hands. The disease is confined to one or only a few joints in the majority of patients. The clinical features of osteoarthritis vary as follows:
Primary Generalised Osteoarthritis:
It has a gradual onset. And the pain is deep aching, intermittent at first but becomes persistent afterward. The pain increased by joint use and decreases by rest. In advanced osteoarthritis, nocturnal pain may be seen which interferes with sleep. The causes of pain are:
Advanced Stage of Osteoarthritis May Have:
This is clinically from primary generalized osteoarthritis, which occurs predominantly. The affected joints are terminal interphalangeal joints of the finger with the development of generalized gelatinous cysts or bony outgrowth on the dorsal aspect of these joints (Heberden's nodes). It has an acute onset, with pain and swelling. Heberden's nodes seldom cause serious disability. The similar lesion may affect proximal interphalangeal joints called Bouchard's nodes. The disorder also frequently involves in the carpometacarpal joints of the thumb, the spinal epiphysial joints, the hip and the knees. A strong family history of Heberden nodes is usually single autosomal dominating gene. Patient with nodal primary generalized osteoarthritis is more susceptible to secondary osteoarthritis.
This is a more severe form of nodal primary generalized osteoarthritis. It has episodic symptoms and signs of local joint inflammation with development of destructive subchondral erosion and instability in the proximal and the distal interphalangeal joints.
Non-Nodal Primary Generalized Osteoarthritis:
It is characterized by an equal sex incidence and less prominent distal interphalangeal joint disease.
Osteoarthritis of the Knee Joint:
This is often associated with obesity. Isolated knee osteoarthritis may, however, be a consequence of various knee deformities associated with medial meniscectomy and dysplasia such as Blount's disease.
Isolated Hip Osteoarthritis:
This is frequently secondary to some predisposing causes such as inequality of leg length, preceding hip disease, acetabular dysplasia or occupational trauma. The superior pole hip is typically affected in such cases whereas hip disease in primary generalized osteoarthritis is usually medial or concentric.
Investigation of Osteoarthritis:
The diagnosis of osteoarthritis is usually based on clinical and radiographic features. Following are the investigation done to diagnosis osteoarthritis.
Radiological: X-ray of affected joint is the most significant investigation for osteoarthritis. The most important changes in the x-ray are:
Synovial fluid study:
Blood: Blood count and ESR (erythrocyte sedimentation rate) are characteristically normal. Isotope scintigraphy with 99 m TC bisphosphonate shows increased uptake of isotope in osteoarthritis joint that is destined to develop progressive damage.
Management of Osteoarthritis:
The treatment of osteoarthritis is aimed at reducing pain, maintaining mobility, minimizing disability, and thus improving the function of the joint. The patient education and encouragement of a positive approach are particularly important in osteoarthritis. The pathological changes of osteoarthritis are irreversible, the overall prognosis for maintaining function is generally good, and a great deal can be done to alleviate symptoms by the following.
Reduction of Joint Loading:
Osteoarthritis may be caused and aggravated by poor body mechanics. So following precautions are necessary.
Exercise should be designed to maintain range of motion as well as to strengthen muscles surrounding the joint.
Joint protection technique:
Incase of Obese Patient:
For more information consult an osteoarthritis specialist online --> https://www.icliniq.com/ask-a-doctor-online/orthopaedician-and-traumatologist/osteoarthritisLast reviewed at: 07.Sep.2018