OA is one of the most common diseases in the world, whose frequency increases progressively with age, although the mechanisms by which this correlation occurs are not fully understood yet. In fact it affects 80% of people over the age of 65 and therefore represents the most frequent cause of disability.
According to observational studies on population, 52% of adults in Western nations, have a minimum or a major radiological change of OA in the hands, feet , or both conditions with moderate to severe OA for an additional 21%. However, from studies in many populations is clear that over 50% of individuals that show radiographic changes, have no symptoms.
OA affects all people regardless of race, geographic location or climate. However, the course of the disease can vary in different ethnic groups. For example, the disease of the hip is less common in people of Chinese origin and/or Asian compared to those of Western origin.
This condition occurs when one or more causes associated with each of them activate a slow, progressive and irreversible alteration of the bearing structures of the joint, in particular cartilage and subchondral bone.
There are several risk factors that may contribute to the onset of this disease and are divided into:
A strong genetic component seems to be present, especially among women. The rate of OA is approximately double in first-degree relatives of people with OA compared to the population. From studies on twins it is estimated that the genetic influence is 35-65%.
It is closely associated with the risk of OA. The prevalence of OA increases almost exponentially after 50 years since the articular cartilage undergoes physiological aging and tends to wear out.
The OA is more frequent in women than in men. This frequency is more evident after age 55 in women, while up to 45 years most commonly affects men. In the latter, the precocious onset can be traced in employment, whereas in women most often after the age of 50 could be due to alterations in bone metabolism due to hormonal changes. In fact, there is evidence that women undergoing hormone therapy have fewer hip and knee OA than those who do not follow it.
They are certainly factors that favor the onset of OA especially in load-bearing joints. The frequency of cases of OA among obeses increases with age to a greater extent than the increase of cases in the normal population. It is probably that obesity leads to an alteration of cartilage metabolism which can promote the onset of arthritic damage.
The individuals with congenital malformations (eg, abnormal alignment of the knees) or acquired (injury to the meniscus or ligaments as a result of accidents or surgical procedures) perform movements not correct for the articulation and have more likely to develop OA. In fact, there is evidence that a previous fracture is a risk factor for OA. Even an excessive load on the joints because of a job or a too intense sport over time can cause the onset of OA. It has been estimated that at least half of all cases of knee OA is probably caused by obesity, injury, by work or by a combination of these factors.
Many factors appear to be associated with the beginning of the pathological process, while others are involved in the progression of the disease.
Osteoarthritis initially occurs with regressive lesions of the joints (loss of cartilage that covers the articular heads) caused by different factors and by enzymes that attack the cartilage through a metabolically active process that involves all the structures of the cartilage. During the early stages of the disease anabolic repair processes are predominant, wich offset the damage of cartilage, then the balance tilts in favor of degenerative catabolic processes.
The first alteration that can be detected is the loss of elasticity. The cartilage softens and its surface becomes irregular and jagged called “fibrillation”. These changes are then reflected in a loss of cartilage matrix which causes an increased friction when the joint surfaces rub against each other during movement. Tis friction in turn can lead to the formation of cracks which are the first step towards the total destruction in that area. When the cartilage breaks down completely on both surfaces, it has the rubbing of bones during movement that determines considerable pain and functional limitation. The deterioration of the cartilage at the end of the bones also causes a weakening of the muscles, tendons and ligaments that support the joint. Chondrocytes, the cells that produce cartilage tissue, decrease and the detritus formed by the degeneration of the tissue are phagocytosed by osteoclasts, which release substances that induce a local inflammation that goes further damage to the cartilage until its total disappearance. We have therefore changes in the surrounding bone, periarticular osteophytes, dystrophies. The process can be accelerated by overweight, joint injury, inadequate diet and poor or inadequate exercise. The cartilage being devoid of blood vessels, is normally nourished by the synovial fluid produced by the synovial membrane, the inner lining of the joint capsule, highly vascularized. In case of OA may be thickening and inflammation of the synovial membrane with increased production of this fluid that can cause swelling of the joint. This fluid is more diluted and less viscous and rich of cartilage fragments decomposed and molecules that promote inflammation, which constitute real biological marker of the pathological process.
The clinical condition of osteoarthritis is characterized by its polymorphism. Pain, functional limitation and morning stiffness are the most characteristic clinical manifestations. The occurrence of episodes of acute inflammation may then be the result of microtrauma, functional overload and/or a concomitant pathology by microcrystals (eg . Gout). The clinical evidence of Osteoarthritis appears with pain that is initially mild, more frequent in the hours following the awakening (due to immobility) and in those that precede the rest (due to joint fatigue). The pain is not derived from the joint, which is devoid of nerve endings, but from inflammation of the synovial membrane, from stretching of the ligaments and joint capsule, from bone micro-fractures etc. The symptoms are exacerbated with the progression of the disease, causing continuous pain and reduction or inhibition of motor abilities. In the early stages of the disease the functional limitation is closely linked to pain and the resulting degree of disability is of particular importance when the weight-bearing joints (hip and knee) are affected. Morning stiffness is generally of short duration and is characterized by a feeling of weakness, subsidence and insecurity at the beginning of the movement after a more or less prolonged period of rest, typical expression of osteoarthritis of the weight-bearing joints.
The joint sites that may be affected by OA are numerous. In general it appears that, in relation to age, some joints are affected with a particular frequency. Under the age of 30 is early affected the vertebral column; after the age of 30 is more affected the knee joint; after the age of 40 are more affected hand, hip and foot joints.
It is the site most affected by OA because of the load that is subject to joint. The knee becomes stiff, swollen and painful, making walking difficult. If left untreated it can lead to disability. In severe cases, prosthetic replacement is required
It cause pain (hip, groin, gluteal, knee and inner thigh) stiffness and severe disability. When the pain becomes unbearable and not relieved through other methods the prosthetic replacement is required.
It affects mostly the elderly population. It causes pain in the joint and muscles affected more intense in the morning, which is attenuated during rest. The functionality is however limited.
It seems to be related to hereditary factors. It affects more men than women, especially after menopause. Small protuberances or nodules are formed on the ends of the fingers that cause pain and stiffness.
It causes stiffness and pain in the neck or in the lumbar region, with tiredness and numbness of arms and legs. In more severe cases, surgery is used to restore functionality.
Usually, little attention is devoted to early diagnosis of osteoarthritis and to the identification of pre-arthritic conditions that may occur many years before the real disease through the identification of a well-defined symptoms (muscle hypotonia, painful joint laxity, tendon alterations, easy fatigue, overweight, widespread myalgias etc.). There is the attitude to accept osteoarthritis as an almost obvious and inevitable component of aging. In the case of weight-bearing joints, however, it would be appropriate that early diagnosis became a prime target for the doctor and the patient in order to develop prevention strategies whose effectiveness is obviously subject to the timeliness of their adoption.
The diagnosis of osteoarthritis is based in each case on the simultaneous presence of clinical and radiological expressions indicative of pathology. So far, in fact, are not found abnormalities of laboratory data useful for diagnostic purposes for the monitoring of the disease.
The main diagnostic methods are therefore:
It is able to put in evidence in the affected joints the main expressions of the arthritic process (joint space narrowing, presence of osteophytes, subchondral osteoclerosis, geoid etc.)
It is a method that can provide useful information for early diagnosis and for monitoring the evolution of osteoarthritis
They allows a reliable exploration of the articular cartilage
It is in first place because it can provide different pictures at the same joint
It may be useful to reveal the presence of synovitis
It can provide a useful contribution to the diagnosis of Osteoarthritis
It allows to have an accurate assessment of the state of the joint cartilage that appears as a thin and hyperdense line, but this procedure is still little used for the high costs
Currently there is no method to treat or stop the progression of osteoartthritis. However, the most effective solution is a multidisciplinary approach with the purpose of controlling pain, improve joint function and quality of life of patient, possibly trying to contain the side effects caused by the treatment itself.
Generally the treatment varies depending on the joint involved and the pathological stage reached.
They are often used as anti-inflammatory and to reduce pain. They represent a valuable method for the symptomatic treatment of osteoarthritis because they reduce pain, facilitate movement and reduce the progression of damage, but they should be used with caution because of their poor tolerability.
It has been observed that women who have used oral estrogen as hormone replacement therapy decrease the risk of developing OA. However, further studies are needed to confirm this.
They are an effective method for the treatment of osteoarthritis as locally potentiate the pharmacological action also decreasing the side effects, however, not all joints are simple to infiltrate. For many patients constitutes an interesting alternative to drug treatment or surgery, in particular in subjects at high risk of side effects to the use of NSAIDs or in which the surgery is contraindicated.
Through the insertion of needles into specific points on the body, there is probably the release of endorphinic natural substances that relieve pain. It may represent an additional treatment in the treatment of OA but has not yet been shown the effective utility.
Different studies have shown that certain nutrients such as glucosamine and chondroitin sulfate, components of normal cartilage, lead to an improvement of symptoms in patients with OA due to their chondroprotection activities.
Through adequate surgical instruments inserted into the joint, it allows the surgeon to look the joint structures without having to open or cut muscles or ligaments. It Therefore it allows to determine the structural damage and possibly also remove fragments of damaged tissue that may lead to blockage of the joint and cause pain.
This surgical technique allows to change the angle of the tibia and femur in the knee joint to reduce the load and consequently the pain. It is usually done in young subjects with OA at an early stage and allows to postpone replacement prosthetic surgery.
It allows to lock the joint in one position, eliminating the pain associated with movement but also excluding the joint functionality. It is little used after the development of replacement surgery (Prosthesis).
It allows to replace the damaged joint with an artificial one. Sometimes it represents the only method to restore the joint functionality in cases of advanced OA, and it is often an intervention that lasts a lifetime.
It consists in removing cells from a healthy part of the body and repositioning in the damaged area to increase its functionality. It is currently used for minor injuries or defects in cartilage.
A few simple precautions may be important to limit the evolution of joint damage and reduce the symptoms of osteoarthritis. These measures should be assessed for each case, in relation to the patient’s general conditions, the location and severity of the disease. These treatments indicated in cases of more moderate OA, have no contraindications and can reduce pain and improve muscle trophism, but has not yet been demonstrated their effectiveness on the evolution of the disease.