Main symptoms of osteoarthritis

In most cases, the patient cannot accurately indicate the time and cause when the first symptoms of osteoarthritis appear. For a fairly long time, the disease, even in the presence of pathohistological changes and radiographic signs, is asymptomatic.

The most common early sign of the disease is diffuse, intermittent joint pain, usually occurring during or immediately after exertion on the joint. Osteoarthritis is also characterized by morning stiffness lasting no more than 30 minutes. Sometimes there is slight soreness in the periarticular tissues (mainly muscles). Gradually and, as a rule, imperceptibly, the range of motion in the joint decreases. For example, the patient may complain that recently (a year/several years) it has become increasingly difficult for him to bend over to put on socks due to a feeling of stiffness in the hip joint.

In rare cases, the first symptoms of osteoarthritis develop quickly (within days or weeks) after the injury. In this case, the injury probably acts as a "trigger" for the clinical manifestation of changes in the joint that have been asymptomatic for a long time.

Main signs and symptoms of osteoarthritis (according to Dieppe PA, 1995, with changes)

Symptoms

• “Mechanical” nature of pain (occurs/intensifies with load on the joint, in the evening; subsides at rest, at night)
• Morning stiffness (< 30 min)
• Limitation of range of motion
• Decreased functional ability (difficulty putting on socks, etc.)

Signs

• Painful points along the edge of the joint space (pain when palpating periarticular tissues)
• The appearance of dense thickenings along the edge of the joint space
• Coarse crepitations (clicking or jamming)
• Moderate signs of inflammation ("cold effusion")
• Limited, painful movements
• Feeling of "tightness" in the joint
• Instability (signs of severe bone/joint destruction)

Factors that may influence the outcome of osteoarthritis

• Age at onset, race and gender
• Obesity and other factors associated with osteoarthritis
• Overuse of the relevant joints
• The degree of development of periarticular muscles and innervation
• Joint stability
• Reaction of bone and synovial tissue
• Crystal deposition
• Psychological and social factors
• Drug and other therapy

Osteoarthritis is a disease that does not have systemic manifestations, so complications are always associated with the affected joint/joints. Local complications include the development of secondary periarticular syndromes (bursitis, tendovaginitis, etc.), tunnel syndromes caused by the formation of large osteophytes or joint deformation. Severe deformations of the affected joints can cause secondary fractures and aseptic bone necrosis.

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Pain

The most important symptom of osteoarthritis is undoubtedly pain. Comparative studies have demonstrated differences in the quantitative and qualitative characteristics of pain in osteoarthritis and rheumatoid arthritis. Osteoarthritis is characterized by "mechanical" pain, i.e. arising/increasing during stress on the joint and subsiding at rest. Pain usually occurs some time (minutes/hours) after the onset of stress on the joint (less often - immediately after stress) and can continue for several hours after it stops. The nature of the pain syndrome is one of the main differential diagnostic signs of osteoarthritis: for inflammatory processes in the joints (arthritis, including rheumatoid arthritis), in contrast to degenerative processes, the "inflammatory" nature of pain is characteristic (arising/increasing at rest and at night, subsiding with joint movements). Patients with osteoarthritis rarely complain of pain at rest and at night, but at the same time they are usually also bothered by pain in the joint during physical stress, i.e. "mechanical pain".

Pain in manifest osteoarthrosis is not as pronounced as in arthritis, it is more local, although as the disease progresses it becomes persistent. To a certain extent, the severity of the disease as a whole can be determined by the nature of pain and its persistence in osteoarthrosis. For example, at first, pain in a specific joint is associated with movement and disappears when it stops. Later, pain in the joint (joints) bothers at rest, increasing with load. Finally, the pain bothers the patient at night. And although clinically pain in the joint is perceived unambiguously, in reality the mechanisms of pain in osteoarthrosis are associated not only with synovitis, as in arthritis. With synovitis, pain occurs when getting out of bed with a feeling of stiffness ("gel") in the affected joint, subsequently the pain intensifies with load. Pain with certain movements in the joint may be due to the involvement of periarticular tissues, and pain caused by periosteal detachment due to the development of osteophytes is local in nature, increasing with palpation of the joint. In addition, with osteoarthritis, pain may be due to muscle pathology, increases with increasing anxiety and depression, as well as due to impaired motor activity, etc.

Epidemiological and clinical studies have found significant differences in pain intensity in different groups of patients with osteoarthritis.

The severity of changes detected on radiographs of the affected joints is associated with an increased probability of clinical manifestation of osteoarthritis. At the same time, the authors of this study note that even significantly pronounced changes on radiographs can be asymptomatic. J. Cashnaghan (1991) indicates that women with osteoarthritis have a more intense pain syndrome than men. The results of the study by MN Summers et al. (1988) indicate the presence of a direct correlation between pain and anxiety/depression in patients with osteoarthritis.

The study of pain characteristics in patients with osteoarthritis has been the subject of several studies. F. A. Hart (1974) described six types of pain sensations in osteoarthritis. The results of a detailed study of pain in 500 patients with osteoarthritis of the peripheral joints confirmed these data. Thus, the most common variant was pain during joint movements or weight-bearing on the limb (use-related pain). Such pain, according to the authors, usually arose within a few seconds/minutes after the onset of static or dynamic loading and could persist for several hours after its cessation. Some patients complained of inconstant sharp pain, precisely coinciding with certain movements in the joints or wearing loads; others - of a constant nature of pain, while they found it difficult to accurately indicate its localization. While almost all patients with manifest osteoarthritis complained of pain associated with joint movements or weight-bearing on the limb, only half of them indicated the presence of pain at rest and about 30% - pain occurring at night. Only in a small number of subjects did the intensity of pain in the affected joints make daily activities difficult or cause insomnia. As a rule, in these cases, radiographs of the joints showed significant and rapidly progressing changes, often involving the subchondral bone.

Joint pain in osteoarthritis is often accompanied by a feeling of pain when palpating the joint area. The patient may indicate the presence of several pain points located along the joint space and in the area of adjacent skeletal muscles.

The mechanism underlying the pain syndrome in osteoarthritis is still a subject of debate. Factors influencing the occurrence of pain in osteoarthritis can be divided into local, systemic and CNS factors.

Changes in the contours of the articular surfaces, osteophytosis and other local mechanical factors may be the cause of abnormal loading of the ligaments, joint capsule and other innervated structures. Such a mechanism may play an important role in the development of periarticular pain and acute pain in the joint during movement.

Factors influencing the severity of pain in osteoarthritis and possible causes of its occurrence (according to Dieppe PA, 1995)

Factors Affecting the Severity of Pain in OA	Possible Causes of OA Pain
Radiographic stage Pop (women experience more pain than men) Age (pain is less pronounced in young and old people) Localization (pain is less pronounced in osteoarthritis of the joints of the hands, more pronounced in coxarthrosis) Psychological factors (anxiety, depression)	Increased intraosseous pressure Synovitis Changes in periarticular tissues (stretching of the capsule, ligaments, tendons, etc.) Thickening of the periosteum Changes in periarticular muscles Fibromyalgia Changes in the central nervous system

It is known that with osteoarthrosis, intraosseous pressure in the subchondral bone increases due to the difficulty of venous outflow. A decrease in intraosseous pressure reduces pain in osteoarthrosis. It is assumed that this mechanism is responsible for the pronounced pain syndrome - long-term, occurring at rest at night. Perhaps one of the sources of pain in osteoarthrosis is the periosteum, which thickens as a result of the appearance of osteophytes and chondrophytes.

Moderate synovitis often accompanies osteoarthritis, especially in the later stages, and may contribute to increased pain. This mechanism is supported by the reduction in pain in osteoarthritis in response to NSAID treatment.

Pain caused by inflammation has long been the subject of serious attention, and currently the mechanisms of pain associated with inflammation are actively studied. It has been shown that any peripheral pain is associated with an increase in the sensitivity of specialized neurons - nociceptors, creating a signal recognized as pain. Increased sensitivity of the primary nociceptor in the affected peripheral tissue leads to an increase in the activity of neurons sending a signal to the spinal cord and CNS, but it should be emphasized that spontaneous electrical activity can be generated in the inflammation focus, causing persistent pain syndrome. Such a powerful inducer of pain sensitivity are proinflammatory components: bradykinins, histamine, neurokinins, complement, nitric oxide, which are usually found in the inflammation focus. In recent years, more and more attention has been paid to prostaglandins, the accumulation of which correlates with the intensity of inflammation and hyperalgesia. However, prostaglandins themselves are not pain mediators, they only increase the sensitivity of nociceptors to various stimuli. They seem to "switch on" normal ("silent") nociceptors in a state where they are easily excited by various influences.

Violation of biomechanics in the affected joint contributes to the development of secondary periarticular syndromes - bursitis, tenosynovitis, etc. When collecting anamnesis and examining a patient with osteoarthritis, it is necessary to determine what causes the pain - directly due to damage to the joint or inflammation localized in the joint bags and synovial sheaths.

Patients with osteoarthritis often complain of pain in the periarticular muscles upon palpation. It is assumed that weakness of the muscles that perform movements in the joint may be one of the causes of pain. This is supported by the reduction of pain in patients with gonarthrosis who perform exercises to strengthen the quadriceps muscle of the thigh.

J. H. Kellgren (1939) pointed out the "direction" of pain and tenderness upon palpation from the affected joints to the muscles that perform movements in the joints. This phenomenon may explain the frequent occurrence of pain "near" the affected joint.

Patients with osteoarthritis may have signs of fibromyalgia. In addition, MN Summers et al (1988) point to the importance of central neurogenic mechanisms in the genesis of pain in osteoarthritis.

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Stiffness

A feeling of stiffness in the joints is a common complaint of patients. Stiffness is usually characterized by difficulty in the first movements, the phenomenon of a "frozen" joint after a period of rest, and a limitation of the range of motion in the affected joint. Stiffness in osteoarthritis usually lasts for several minutes (rarely up to 30 minutes) and occurs only in the affected joint.

The cause of stiffness in osteoarthritis remains unknown. Complaints of "frozen" joints after a period of rest can be explained by simple mechanical causes (thickening of the joint capsule, etc.). Long-term (up to 30 min) morning stiffness observed in some patients with osteoarthritis may occur as a result of the development of synovitis (similar to morning stiffness in rheumatoid arthritis).

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Limitation of range of motion

Limited range of motion is a common complaint of patients with osteoarthrosis. It is usually accompanied by complaints of pain during joint movements, with the maximum pain noted at the height of limited motion. Chondrophytosis and osteophytosis, joint remodeling, and thickening of the joint capsule contribute to the limited range of motion in a joint affected by osteoarthrosis. The latter may also explain the difficulty in performing the available range of motion in the affected joint.

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Dense thickening of the articular edges

Dense thickenings of the articular margins are often easily palpated and may be painful. Along with coarse crepitations that are felt during movements in the affected joints, dense thickenings of the articular margins are an important differential diagnostic sign of osteoarthrosis. Crepitations are detected during palpation of the affected joint; in the late stages of osteoarthrosis, they can be heard at a distance. A probable cause of crepitations in osteoarthrosis, along with the formation of gas bubbles in the synovial fluid that “burst” during movements in the joint, is the roughness of the articular surfaces of the affected joint. It is necessary to differentiate crepitations and the sensation of a coarse crunch during movements in normal joints. The latter, as a rule, is always audible at a distance and is one or more inconstant individual sound phenomena during movement in the joint. Crepitations are felt (less often they can be heard) in the joints always and throughout the entire movement in the joint.

The formation of dense ("bone") thickenings along the edge of the joint space is more characteristic of osteoarthrosis of the hands: the nodularity of the proximal interphalangeal joints is called Bouchard's nodes, and the distal interphalangeal joints are called Heberden's nodes. Less often, dense thickenings are found along the edge of the joint spaces of other joints, in particular the knees.

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Crepitations

Crepitations are one of the main differential diagnostic signs of osteoarthrosis. Crepitations in osteoarthrosis must be differentiated from crunching in the joint in a healthy person, which can be caused by gas bubbles in the synovial fluid that burst during movement.

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Synovitis

Most often, synovitis in osteoarthrosis occurs in the knee joints. In patients with synovitis, the nature of the pain changes: in some cases, it occurs immediately after putting weight on the leg and during normal (not long) walking. Such "starting" pain does not disappear completely at rest, and in some patients it acquires an indefinite rhythm (the patient cannot clearly determine the time of its greatest intensity). Synovitis in gonarthrosis can be subclinical, weak, moderate, significant; in prevalence - limited and diffuse; depending on the course - primary, recurrent and often recurrent. The presence and intensity of synovitis correlates with the radiographic stage of gonarthrosis.

Less often, synovitis occurs in the proximal and distal interphalangeal joints of the hands with the presence of Heberden's and/or Bouchard's nodes (manifested by pain, swelling, and hyperemia of the joints), which requires differential diagnosis with rheumatoid arthritis.

Signs of joint destruction

In the late stages of osteoarthritis, signs of destruction of cartilage, bone and surrounding soft tissues are detected: varus deformity of the knee joints (due to damage to the medial tibiofemoral part of the joint), weakness of the ligamentous apparatus, instability of the joints (often develops in the distal interphalangeal joints). Destruction of bone tissue in osteoarthritis of the hip joint can lead to shortening of the limb.

Clinical manifestations of synovitis

Symptoms of synovitis	Synovitis
	Subclinical	Weak	Moderate	Significant
Pain: intensity time of occurrence	Very weak Only when going down the stairs	Minor Only during long walks, disappears at rest	Moderate When walking, at rest it does not disappear immediately	Strong When leaning on the leg
Increased skin temperature over the joint: intensity localization	Very weak On a limited area of the inner surface	Weak Over the entire inner surface	Noticeable On the inner and outer surface	Moderate Whole joint
Pain: intensity, localization	-	Weak On the inside Surfaces	Noticeable Throughout the joint space	Moderate Entire joint surface
Swelling: intensity localization	-	Weak In the area of the inner surface of the joint	Noticeable On the inner surface and in the prepatellar region	Moderate Total joint
Effusion	-		Suspected effusion	Minor effusion

The course of osteoarthritis in different locations varies. In general, the disease progresses slowly. Most patients with osteoarthritis have periods of exacerbation (can last days/months), when the pain is particularly intense, the function of the affected joints is significantly impaired and joint effusion may appear, and periods of relative remission, when there is no pain or it is weakly expressed, the affected joints function fully or their function is slightly reduced and there is no effusion. Some patients diagnosed with osteoarthritis may not present any complaints for months or even years.

The most rapid progression of osteoarthrosis is observed in the joints of the hands, the slowest - in the knee joints, the defeat of the hip joints occupies an intermediate position. "Rapid" progression, meaning a change in clinical symptoms and radiographic signs over a short period of time, measured in months, occurs only in a small number of patients. Destruction of bone tissue is more common in elderly women. For osteoarthrosis of the joints of the hands and hip joints, the phenomenon of regression of not only clinical symptoms, but also radiographic signs has been described. Radiographic signs of changes in the anatomy of the joints do not always correlate with changes in the clinical symptoms of osteoarthrosis and the disability of patients.

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Features of osteoarthritis of various localizations

Most often, primary osteoarthrosis affects the joint groups that bear the greatest static (knee, hip joints, apophyseal joints of the spine) and dynamic (proximal and distal interphalangeal joints of the hands) load. Symptoms of osteoarthrosis vary significantly depending on the location of the lesion.

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