X-ray signs of diseases of bones and joints

Radiation diagnosis of diseases of the musculoskeletal system is an exciting and at the same time very complex area of knowledge. Over 300 diseases and anomalies in the development of bones and joints have been described. Each disease is characterized by a certain dynamics - from the initial manifestations, often elusive in the radiation study, to gross deformations and destruction. In addition, the pathological process can develop both in the entire skeleton, and almost in any of the 206 constituent bones. Symptoms of the disease affect the age-related features of the skeleton, the properties of the pathogen, numerous regulatory, including endocrine effects. In connection with the foregoing, it is clear how heterogeneous the radiographs of each patient are, how thoughtfully the doctor should consider a set of anamnestic, clinical-x-ray and laboratory data in order to make the correct diagnosis.

Systemic and common lesions

Systemic and common lesions are based on one of 5 pathological conditions:

1. anomalies in the development of the osteoarticular apparatus;
2. disorder of protein, vitamin or phosphoric-calcium metabolism;
3. defeat of other organs and systems (endocrine glands, blood system, liver, kidneys);
4. generalized tumor processes;
5. exogenous intoxications (including iatrogenic effects, for example, steroid hormone treatment).

Congenital developmental disorders occur in utero. After birth, they can progress, but mostly as long as the growth and differentiation of the osteoarticular system continues. Some of these anomalies are hidden, and they are accidentally detected during X-ray examination, others cause pronounced disorders of skeletal functions. Systemic anomalies affect the condition of the entire osteoarticular apparatus, but the most pronounced lesion is those or other departments. If the developmental disorder occurred during the formation of the connective tissue skeleton, then there are various variants of fibrous dysplasia, and if during the formation of the cartilaginous skeleton - cartilaginous dysplasia (dyschondroplasia). Many anomalies are associated with disorders occurring during the replacement of the cartilaginous skeleton with bone (bone dysplasia). These include isolated and associated defects of the endochondral, periosteal and endosteal ossification.

X-ray symptoms of systemic and common anomalies are diverse. Among them, there are changes in the size, shape and structure of bones. For example, for such cartilaginous dysplasia as chondrodystrophy, disproportionately short and dense bones of extremities with metaphysexes and massive epiphyses expanded in the form of funnels are characteristic. With such a defect as arachnodactyly, on the contrary, the tubular bones are unreasonably elongated, thin. With multiple cartilaginous exostoses, bizarre protrusions appear on the surface of the bones of the limbs, consisting of bone and cartilaginous tissue. With chondromatosis of bones on radiographs, various forms of cartilaginous inclusions are defined in the extended metaphysis of long tubular bones.

Anomalies of endosteal ossification are often expressed in the compaction of bone tissue. The observer is struck by a marble disease; with her bones of the skull, vertebrae, pelvic bones, proximal and distal sections of the femurs are very dense, in the pictures they seem made of ivory and structureless. And with such a blemish as osteopoxia, almost in all bones, multiple islets of a compact bone substance are determined.

Endocrine and metabolic disturbances manifest themselves in the delay or change in the normal growth of bones in length and systemic osteoporosis. Rachitis is a classic example of such disorders. Bones with it are very thin and often curved, as they can not withstand the usual load. Metaphyseal sections of bones are widened in the form of saucer, their ends facing toward the epiphysis, have the appearance of fringe. Between the metaphysis and the epiphysis there is a wide light band, representing the sum of the germ cell cartilage and osteoid substance, which was not subjected to calcification in time. Exogenous intoxications most often lead to systemic osteoporosis, but when a heavy metal baby enters the body in the distal part of the metaphyses, a transverse intense darkening band is found. A peculiar picture can be observed with prolonged penetration into the body of fluoride compounds: in the pictures there is a systemic sclerosis of bones resembling a marble disease. In the clinic, systemic lesions of the skeleton are most often observed in tumor lesions: metastases of cancer in the bone, myeloma, leukemia, lymphoblastoma, including lymphogranulomatosis. With all these diseases, tumor foci can form in the bone marrow, which lead to the destruction of bone tissue. While the destruction is small, they can be detected mainly through osteoscintigraphy. When the foci increase, they are determined on radiographs in the form of sites of destruction. Such foci are called osteolytic.

On the formation of tumor nodes, bone tissue sometimes responds with a pronounced osteoblastic reaction. In other words, around the nodules of cancer, a zone of sclerosis is formed. Such foci determine on the radiographs not defects, but foci of compaction in the bones, which are called osteoblastic metastases. They are not difficult to distinguish from developmental anomalies, in which dense osteosclerotic islets form in the bone tissue: the latter, in contrast to tumor metastases, do not concentrate RFP in osteoscintigraphy. 

It is advisable to mention another disease, which often assumes a systemic nature, about deforming osteodystrophy (Paget's disease). Its characteristic manifestation is the restructuring of the bone structure, primarily a kind of thickening and at the same time the breaking of the cortical layer: it is, as it were, divided into coarse bone plates. Tubular bones are deformed, the medullary canal of them is blocked by the image of bent and thickened bony beams intersecting in different directions. In the bones of the skull and pelvis, usually thickened, there are formless areas of sclerosis, sometimes alternating with defects in bone tissue. The cause of this disease is not established, but its radiological picture is typical and usually serves as a reliable basis for diagnosis.

Osteoporosis is one of the most common and at the same time important systemic diseases of the skeleton. He first described the clinical picture of osteoporosis and isolated it from the osteomalacia of Rotter in 1885. However, it was only in 1940, after works by the famous American osteologist F. Albright and representatives of his school, that the disease became known to a wide range of physicians. Osteoporosis acquired a particular urgency in the 1960s as a result of a significant increase in the number of elderly people and, no less important, due to the development of methods for radiation diagnosis of this disease. Especially great is the social significance of osteoporosis, since it is the most common cause of fractures in middle-aged and especially elderly people. Thus, 17% of men and 32% of women at the age of 80 have hip fractures, 20% of them die, 25% become disabled.

Systemic osteoporosis is a condition of the skeleton, characterized by a decrease in bone mass and microarchitectural disorders of bone tissue, leading to increased fragility of bones and the risk of fractures.

Most likely, osteoporosis should be considered not as a separate nosological form, but as a uniform response of the skeleton to the effects of various endogenous and exogenous factors.

First of all, it is necessary to clearly distinguish primary osteoporosis (it is also called senile, or involutive). One of its varieties is postmenopausal (presenil) osteoporosis of women. Occasionally, juvenile idiopathic osteoporosis (a disease of the "fish" vertebrae) occurs. Secondary osteoporosis occurs as a result of various diseases or some types of medication.

From osteoporosis, both primary and secondary, it is necessary to distinguish osteomalacia (demineralization of the skeleton due to the influence of various factors with the preserved structure of the organic matrix of the bone), hypostases (insufficient formation of bone tissue during skeletal development), and physiological age atrophy.

Risk factors for the development of osteoporosis include family predisposition to the disease, female sex, late menstruation, early-onset or surgically induced menopause, lack of calcium in food, caffeine and alcohol addiction smoking corticosteroids, anticoagulants, anticonvulsants, methotrexate, multiple treatment hunger for weight loss ("dietary weight loss"), hypermobility. There is a special type of "osteoporotic people" - these are short, thin women with blue eyes and blond hair, freckles and hypermobility of the joints. Such women seem prematurely old.

In the understanding of osteoporosis as a pathological condition of the skeleton, it is important to study the dynamics of bone mineralization throughout the life of a person. As is known, in both sexes, bones are formed up to about 25 years, but in women, the bone mass is 13% less than in men. Beginning at the age of 40, cortical bone mass decreases in men by an average of 0.4%, in women by 1% per year. Thus, the total loss of compact substance by the age of 90 reaches 19% in men and 32% in women. The dynamics of the spongy substance is different: its loss begins much earlier than the compact one, from 25-30 years, with the same speed in men and women - an average of 1% per year. The total loss of spongy substance by the age of 70 reaches 40%. Especially fast decreases the mass of bone substance in women in the postmenopausal period.

Radiographic diagnosis of osteoporosis includes a number of research methods. First of all, it is necessary to perform a radiograph of the spine in two projections, pelvic bones, skull and hands. X-ray signs of osteoporosis are an increase in the transparency of bones and deformation of the vertebrae, ranging from mild to severe ("fish vertebrae"). It should be noted, however, that the visual evaluation of bone transparency according to the radiograph is highly subjective: the human eye is able to assess the change in the transparency of the radiograph only when the bone mass is reduced by at least 30-40%. In this regard, more important are the various quantitative methods for assessing bone mineral density.

In recent years, radionuclide and X-ray densitometric absorption methods for determining bone density have been introduced into clinical practice. In this case, several main indicators are distinguished.

• The content of mineral salts in the bone (IUD - bone mineral content), measured in grams per 1 cm (g / cm).
• Bone mineral density (BMD - bone mineral density), measured in grams per 1 cm ² (g / cm ² ).
• Bone mineral density (BMVD - bone mineral volume density), measured in grams per 1 cm ³ (g / cm ³ ).

The most accurate indicator is the Navy. However, the BMD index is more important, since it better coincides with an increased risk of fractures, therefore it has a greater prognostic value. BMVD is currently used comparatively rarely, since it requires a computed tomography with a very complex and expensive data processing program.

In accordance with the recommendations of the WHO, the following division of osteoporosis and osteopenia was adopted.

• Norm. Parameters of BMC and BMD are not higher than 1 SD - the standard quadratic deviation obtained by examining the reference group of young subjects.
• Reduction of bone mass (osteopenia). IUD and BMD values range from 1 to 2.5 SD.
• Osteoporosis. IUD and BMD values exceed 2.5 SD.
• Severe (stable) osteoporosis. BMC and BMD values go beyond 2.5 SD, with a single fracture or multiple fractures of the bones.

At present, there are several quantitative methods for determining the mineralization of the skeleton. When one-photon absorptiometry is used as the radiation source, ¹²⁵ I, having a gamma-ray energy of 27.3 keV, for two-photon absorptiometry, ^l53 Gd with a photon energy of 44 and 100 keV is used as a radiation source . However, one-photon X-ray absorptiometry is the most popular. This study is carried out on special compact X-ray prefixes: they study the distal part (cortical bone 87%) and the epiphysis (trabecular bone content 63%) of the forearm bones.

The most perfect and widespread method is two-photon X-ray absorptiometry. The essence of the method is a comparative analysis of two peaks of X-ray energy (usually 70 and 140 keV). Using a computer, the BMC and BMD parameters are determined in separate "areas of interest" - usually in the lumbar vertebrae, forearm bones and proximal femur. Currently, this method is the main diagnostic test in organizing screening to identify involuntary osteoporosis in the elderly and women in the pre- and post-menopausal period. The detection of a reduced mineralization of the skeleton allows for timely therapy and reduces the risk of fractures.

Quantitative computed tomography is used to determine the mineralization of the skeleton, mainly the spine, forearm and tibia. A principal feature of the method is the possibility of determining the mineralization of spongy bone, which, as is known, is most readily absorbed in osteoporosis. A new direction of CT was volumetric analysis of skeletal mineralization, the most indicative index - BMVD (g / cm ³ ) being used as the unit of measurement . This greatly increased the accuracy of the measurement, especially in the vertebrae and neck of the thigh.

Quantitative measurement of the mineralization of the skeleton with the help of ultrasonic biolocation allows to determine the unique parameters of bone, in particular its architectural properties, such as elasticity, fatigue of the trabecula, anisotropy of the bone structure. The new areas of MRI include obtaining a high-resolution magnetic resonance imaging of the trabecular bone structure. The main advantage of this study is a unique opportunity to study the architectonics of trabecular bone substance with the establishment of a number of important parameters: the ratio of trabeculae and bone marrow spaces, the total length of trabeculae in a unit of bone surface, the quantitative characteristic of the degree of anisotropy of bone pattern,

Focal lesions of bones

A large group of focal lesions are local changes in bones caused by an inflammatory process of a different nature. Among them, osteomyelitis and tuberculosis as well as arthritis are of particular practical importance.

Osteomyelitis is an inflammation of the bone marrow. However, starting in the bone marrow, the inflammatory process passes to the surrounding bone tissue and periosteum, i.e. Includes both ostitis and periostitis. Depending on the origin of the disease, hematogenous and traumatic (including gunshot) osteomyelitis are distinguished.

Acute hematogenous osteomyelitis begins suddenly. The patient has a high body temperature, chills, frequent pulse, headache and vague pain in the area of the affected bone. The clinical picture is supplemented by neutrophilic leukocytosis in the peripheral blood and an increase in ESR. Despite the pronounced clinical picture, no changes in the bones are detected on the radiographs during this period. To confirm the clinical data and timely treatment, it is necessary to use other radiotherapy methods. In the first hours of the disease, radionuclide research of the skeleton shows an increased accumulation of RFP in the affected area. When sonography is relatively early can be found the presence of fluid (pus) under the periosteum, and later - an abscess in soft tissues. Clinical and radiological data are the basis for conducting early antibiotic therapy in large doses. New prospects in the diagnosis of osteomyelitis opens an MRI. On the tomograms, bone marrow damage is directly detected.

With successful treatment, changes in bones on radiographs may not appear at all and the process ends with recovery. However, in most cases, hematogenous osteomyelitis is accompanied by severe x-ray symptoms, which are found mainly at the end of the 2nd week after the acute onset of the disease (in children, by the end of week 1). If the site of inflammation is located in the depth of the bone, the earliest X-ray signs are local osteoporosis and small foci of destruction of bone tissue (destructive foci). Initially, they can be found on computer and magnetic resonance tomograms. On radiographs in the spongy bone tissue of the metaphysis of a tubular bone or in a flat bone, enlightenments are defined, a kind of "nostrils" with vague, uneven outlines.

If the site of inflammation is localized subperiosteally, the first radiologic symptom is periosteal stratification. Along the edge of the bone at a distance of 1-2 mm from its surface a narrow strip of calcified periosteum emerges. The outer contour of the cortical layer in this region becomes uneven, as if eaten.

Subsequently, small destructive foci merge into larger ones. In this case, bone fragments of different sizes and shapes separate from the edges of the collapsing bone, float into pus, necrotic and turn into sequesters, which in turn support inflammation. Periostalnye stratifications grow, their outlines become uneven (fimbriated periostitis). Consequently, in the acute phase of the disease processes of destruction, necrosis and suppurative inflammation of the tissues predominate. Their x-ray reflection is destructive foci, sequesters and periosteal stratifications.

Gradually, signs of reactive inflammation around the necrotic areas, delimitation of inflammation and symptoms of reparative osteoblastic process appear in the radiographic picture. The destruction of the bone is suspended, the edges of the destructive foci become sharper, around them arises the zone of osteosclerosis. Periostalnye stratifications merge with the surface of the bone (assimilation of these layers cortical layer). The course of osteomyelitis changes into chronic.

Purulent masses often find an outlet on the surface of the body - a fistula is formed. The best way to study fistula is its artificial contrasting - fistulography. In the external fistula a contrast medium is injected, followed by radiographs in two mutually perpendicular projections and, if necessary, computer tomograms. Fistulography makes it possible to establish the direction and course of the fistula, the source of its formation (sequestrum, purulent cavity, foreign body), the presence of branches and purulent fouling.

Unfortunately, chronic osteomyelitis can not always be cured by a single operation. The disease is prone to relapse. They are signaled by renewed pains, fever, changes in blood. Radionuclide research is an effective method of detecting relapse. On radiographs, new destructive foci and "fresh" periosteal layers are identified.

The radiological picture of gunshot osteomyelitis is more diverse and more difficult to interpret. On the radiographs produced after the injury, a gunshot fracture of the bone is determined. Within 10 days after injury, the fracture gap increases, regional osteoporosis is noted, but these symptoms are observed after any fracture and can not be the basis for establishing the diagnosis of osteomyelitis. Only at the beginning of the third week and especially at the end of the fragments, there are small foci of destruction, which can be distinguished from local osteoporosis because of their uneven distribution, diffuse outlines, and the presence of small sequestration in the center of the foci. Purulent inflammation leads to necroticisation and separation of bone sites. The size and shape of the sequesters are different: small pieces of spongy bone tissue, elongated laminae of compact bone substance, part of the epiphysis or diaphysis can separate. Against the background of osteoporosis, sequestrants stand out as denser areas that have lost touch with the surrounding bone.

In the first weeks of the disease, as in hematogenous osteomyelitis, the processes of necrosis, destruction and melting of tissues predominate. The formation of the bone callus is severely impaired, as a result of which the consolidation of the fragments is delayed, under false circumstances a false joint can form. However, timely antibiotic therapy and surgical intervention prevent such an outcome. When acute inflammatory phenomena subsided, proliferative processes intensify. Destructive foci gradually decrease and disappear, in their place sclerosis sites are detected. Periostalnye stratifications become even, breaks in them are eliminated. In the end, these stratifications merge with the bone, which as a result thickens. The ends of the fragments are fixed with a callus. Usually on radiographs it is possible to detect enlightenments in the sclerotized bone. Some of them are fringed by a thin closing plate and are fibrous-osteoid fields, others are surrounded by a sclerotized bone and are immured in the sclerosis zone by residual cavities. They can cause a relapse of osteomyelitis.

Tuberculous bone damage arises from the transfer of mycobacterium tuberculosis from the primary focus to the bone marrow in the lung or, more rarely, in the intestine. In the bone marrow is formed a tuberculous granuloma, which leads to resorption and destruction of bone beams. Such a granulation focus is formed in the epiphysis and usually is not clinically manifested or its symptoms are poorly expressed. On the radiographs, he determines a single area of enlightenment or a group of nearby foci with irregular shapes. If the flow is favorable, the granulation tissue becomes fibrous and subsequently replaced by a bone. With curdled necrosis with calcification of bone, a dense focus can be found.

Under less favorable circumstances, the expanding granulation tissue replaces the bony beams, one or more large destructive foci are identified. In the center of such a focus, a spongy bone sequestrum is often visible. Gradually, the edges of the foci become denser, and they turn into bone cavities. In contrast to hematogenous osteomyelitis caused by staphylococcus or streptococcus, with tuberculous osteomyelitis, reparative phenomena develop slowly. This, in particular, is due to the location of the focus in the epiphysis. Periosteal stratifications are weakly expressed, since in this area the periosteum is thin and weak.

Due to the localization of the pituitary gland, the tubercular process very often passes to the joint. Until this time, the disease is in the so-called preartritic phase, but the spread of granulation tissue along the synovial membrane leads steadily to the development of tuberculous arthritis (the arthritic phase of the disease), undoubtedly, the main stage of tuberculous lesion.

Clinically entering the arthritic phase is marked by a gradual disruption of the function of the joint, the appearance or strengthening of pain and slowly progressing muscle atrophy. Osteoscintigraphy and thermography make it possible to establish the involvement of the joint in the pathological process even before the appearance of X-ray symptoms. The first of them is osteoporosis. If tuberculous osteomyelitis osteoporosis has a local character and is determined only in the emerging tuberculosis foci, then it becomes regional in arthritis. This means that osteoporosis captures an entire anatomical area - the joint ends and the adjacent parts of the bones.

Direct signs of arthritis are narrowed X-ray joint gap and destructive foci. The latter are more often found as small usuras at the points of attachment of the joint capsule and ligaments to the osseous part of the epiphysis. The contours of the end plates of both epiphyses become uneven, locally thin, sometimes sclerotized. Foci of destruction cause disruption of nutrition in the areas of the epiphysis, which necrosis and are separated.

The fading of tuberculous arthritis is indicated on radiographs by replacing small destructive foci with bone tissue, tightening and sclerotic delimitation of large foci. The x-ray joint gap remains narrowed, but the contours of the endoplasmal plates are restored and become continuous. Gradually the disease passes into the postartritic phase (metatuberculous osteoarthritis), when the stabilized tissue changes. It can be resistant for many years. Osteoporosis persists, but acquires new features: according to the new load conditions, the bony beams thicken in the bones. They stand out sharply against the background of a dilute bone. Such an osteoporosis is called reparative. The cortical layer of the bones thickens.

Among focal inflammatory lesions, one can not ignore the panaritium - acute purulent inflammatory processes in the tissues of the fingers. Radiographs are extremely important to exclude or confirm the development of bone or bone-joint panaritium and distinguish it from isolated soft tissue damage. With bone felony already after 5-8 days after the onset of the disease, osteoporosis of the bone phalanx is determined and small destructive foci begin to appear. To this can join small sequesters. At the edges of the affected phalanx, a narrow strip of exfoliated periostitis emerges. Foci of destruction develop mainly at the sites of attachment of the joint capsule, which is why the process often passes to the interphalangeal joint. Its slit narrows, and in the other joint end there are also foci of destruction of bone tissue.

Bone-joint panaritium is an example of how in typical cases any purulent arthritis looks. It is characterized by the following radiographic signs: narrowing of the x-ray joint gap (uneven and rapidly progressing), destructive foci in articular surfaces of the jointed bones, regional osteoporosis, increased joint volume. Increased concentration of RFP in osteoscintigraphy, signs of destruction of articular cartilage in sonography and CT complete this picture

In recent decades, rheumatoid arthritis - a chronic relapsing systemic disease that occurs with a predominant joint damage - has spread significantly. It is characterized by a progressive course and disorders in the body's immune system. In the blood of patients, there is a special immunoglobulin - a rheumatoid factor. To the group of focal lesions, rheumatoid arthritis can be attributed only conditionally, since x-ray changes can be determined in several joints.

In the initial period of the disease, impeccable X-ray diffraction patterns are indistinguishable from those in normal, so the other ray methods of research are clearly advantageous. Osteoscintigrams show increased accumulation of RFP in the region of affected joints. Sonograms reflect the thickening of the synovial membrane, the appearance of fluid in the joint, changes in articular cartilage, the development of synovial cysts, the degree of periarticular edema /

Later, x-ray symptoms of rheumatoid arthritis appear. First of all, it is a swelling of the soft tissues of the joint, osteoporosis and a slight narrowing of the joint space. Then, erosions (small marginal defects in the articular ends of bones) and rounded racemose glands in the epiphyses are added to this. These defects, as well as the violation of the integrity of the terminal bone plate, are earlier and more clearly revealed by means of radiography with a direct magnification of the image. As the process progresses, further narrowing of the joint gap, a significant increase in the severity of osteoporosis and new foci of destruction in the bone tissue of the epiphyses are observed, as a result of which severe destruction with subluxations and ugly deformation of the articular ends of bones can develop.

In the absence of rheumatoid factor, they speak of seronegative arthritis, to which many joint injuries are attributed. Some of them appear as a local manifestation of a systemic disease of connective tissue (systemic lupus erythematosus, nodular periarteritis, scleroderma, etc.) complications of liver and intestinal diseases, urine acid diathesis (gout) Others are special nosological forms: Reiter's syndrome, psoriatic arthritis, ankylosing spondylitis Bekhterev's disease). Their recognition and sometimes difficult differential diagnosis are based on a combination of clinical, laboratory and radiographic data. It is important to note that most often the most significant symptoms are revealed during the radiography of the affected joint, as well as small joints of the hands and feet, sacroiliac joints and spine.

It is advisable to pay attention to the very often observed lesions of ligaments and tendons. They are divided into fibroostosis (tendinosis) and fibroostitis (tendinitis). With fibroostosis, there is no increased accumulation of RFP in the lesion site, and on the roentgenograms, ossification of the attachment sites of the ligaments and bone protrusions (osteophytes) can be determined. These protrusions have smooth contours and a bone structure. Fibroostitis is a process of inflammatory nature. It often accompanies rheumatic diseases and seronegative spondylitis. The protrusions on the bones are irregular in shape, sometimes unsharply contoured. The edge defect can be determined at the attachment point of the bundle. RFP intensively concentrates in the affected area. Typical examples of tendinitis are humeropathy periarthritis and Achillesbursitis, as well as calcaneal fibroostitus of rheumatic nature.

Another large group of focal lesions of bones and joints is formed by dystrophic processes and aseptic necrosis. Dystrophic changes develop mainly in the joints and in essence represent a premature wear of the articular cartilage (in the spine - intervertebral cartilage). Loss of their normal state and necrosis particles of cartilage have antigenic properties and cause immunopathological changes in the synovial membrane. Overload of the joint leads to secondary, including compensatory, reactions in the bone tissue of the epiphyses.

The radiological picture of a dystrophic joint lesion is quite stereotyped. It consists of the following main symptoms: narrowing of the x-ray joint gap, densification and widening of the endoccipital bone of the epiphyses, sclerosis of the subchondral layer of the bone tissue (ie, the layer lying under the terminal bone plate), bone growth along the edges of the joint surfaces. In general, this process was called "deforming osteoarthritis."

Deforming osteoarthritis is observed very often and can affect any joint. The most common were degenerative-dystrophic diseases of the spine, and among them - osteochondrosis. The ray semiotics of this state was described above. A significant group of patients are those with deforming arthrosis of the hip and knee joints, interphalangeal joints of the hand and the 1st metatarsophalangeal joint. In recent years, surgical methods for treating osteoarthritis have been widely used, in particular, replacement of the deformed joint end of the bone with a prosthesis.

The group of aseptic necrosis includes various pathological processes. They are brought together by three common features:

1. development of aseptic necrosis of bone substance and bone marrow;
2. chronic benign course;
3. a regular clinical and morphological evolution with a relatively favorable outcome.

An important role in the genesis of the disease is played by the overload of one or another part of the skeleton. If the overload touches the whole bone, then aseptic necrosis of the entire bone develops (for example, the scaphoid bone of the foot). If the entire epiphysis is overloaded, then necrosis of this epiphysis or its part occurs. An example is the most commonly observed form of aseptic necrosis - lesion of the head of the femur. Overload of a part of the diaphysis leads to the formation of a so-called zone of adjustment, and overload of the apophysis - to its necrosis.

The radiation picture of aseptic necrosis is conveniently described by the example of the head of the femur of the child (this kind of aseptic necrosis is called the osteochondropathy of the femoral head or Legg-Calve-Perthes disease). The child complains of mild pain. Restriction of joint function is noted. An early diagnosis is extremely important, but it is not visible on the radiographs of pathological changes. The main thing in this period is to apply special techniques. Osteoscintigraphy allows to reveal the increased accumulation of RFP in the head of the femur, and CT and MRI make it possible to directly detect a site of necrosis of bone substance and bone marrow.

Later, there are X-ray symptoms. The affected area of the bone is highlighted in the pictures as a denser focus, devoid of bone structure. This is mainly due to multiple fractures and compression of bone beams, which leads to deformation of the epiphysis - its flattening and uneven outlines.

In this phase, an important role is played by differential diagnosis of aseptic necrosis and joint tuberculosis, since at the latter end, necrosis of bone substance also arises at the articular end. However, the support points for demarcation are quite strong: with tuberculosis the joint gap narrows, and with aseptic necrosis in the child it expands. When tuberculosis affects the second joint end (in our example - the acetabulum), and with aseptic necrosis, it is long intact. In the future, the distinction is further simplified. With aseptic necrosis, the necrotic area is divided into several dense bone islets (fragmentation), the epiphyses are further flattened, the joint gap widens and a slight subluxation is observed.

The earlier the disease is recognized, the more favorable its consequences. The bony structure of the epiphysis is restored, it remains only slightly deformed. The joint gap is slightly widened. However, if the disease is detected late, the joint remains inadequate due to the deformations occurring in it.

In adults, aseptic necrosis of the part of the head, usually the most loaded, is observed. Upper-external part of the epiphysis. In these cases, the joint gap does not expand, subluxation does not occur, arthrosis always develops, fragments of necrotic cartilage or bones can penetrate into the joint cavity, turning into joint "mice". To frequently observed focal lesions of the skeleton are bone tumors. Conditionally they are divided into benign and malignant, although benign neoplasms almost always represent not true tumors, but local malformations.

Depending on the structure and tissue composition , bone, osteoma, connective tissue (fibroma), cartilage (chondroma), cartilage and bone tissue (osteochondromas), vessels (hemangiomas, lymphangiomas) are secreted among benign tumors.

Common signs of all these tumors are their slow development, relatively sharp contours and clear delimitation from surrounding tissues (lack of infiltrative growth), the correct structural pattern. The tumor does not destroy, but replaces the bone substance. It can lead to deformation of the bone with an increase in its volume.

X-ray detection of benign tumors rarely encounters serious obstacles. Compact osteoma clearly stands out in the photographs as a dense unstructured formation. Spongy osteoma retains the structure of the lamellar bone. Osteoma can be located in the depth of the bone or on its surface. Fibromas and chondromas cause a defect in the bone - a bright area with sharp outlines, and with the chondroma, the mottled shadows of calcareous and bony inclusions may appear on the background of the defect. Perhaps the most demonstrative of osteochondrosis: it has a wide base or foot and grows away from the bone. Cartilage areas are seen as enlightenment in the image of the tumor, and the bone beams form divergent rafters. Hemangioma also causes a defect in the bone tissue, but it often shows a lacy bony pattern or radially divergent bony plates. In the cranial cavity, hemangiomas are formed quite often. The tumor causes a rounded defect, delimited from the surrounding bone by a narrow band of sclerosis. The edges of the defect are sharp, can be slightly wavy. In the body of the vertebrae, hemangiomas cause numerous enlightenments, separated by coarse vertical bony beams. The body of the vertebra is swollen. Small enlightenments and serpentine strips can be determined in the arch of the affected vertebra. In these cases, computer and magnetic resonance tomograms are very important, since they make it possible to detect the extraosteal development of the vasculature (in particular, in the vertebral canal).

There are a large number of different malignant tumors of bones and joints. Some of them are characterized by rapid growth and significant destruction of bone tissue, others develop relatively slowly and rather squeeze out surrounding tissues than infiltrate them. However, all malignant tumors are characterized by progressive course, increased pain, changes in peripheral blood (anemia, increased ESR), the appearance of regional or distant metastases.

The classic sign of a malignant tumor is the destruction of bone tissue. On radiographs, the defect is determined in it, most often with uneven and unsharpened contours. Moreover, what is very important for discrimination with inflammatory lesions, there is no sequestration and detached or fimbriated periostitis.

The unique form of the bone tumor is osteoblastoklastoma (it is also called a giant cell tumor). It develops in flat bones, vertebrae or epimetaphysis of the tubular bone, characterized by a relatively regular shape and a sharp delimitation from the surrounding bone tissue. In many osteoblastoklastomy, a large-cellular bone pattern is determined, which makes it possible to differentiate this tumor from other malignant neoplasms.

The most known malignant bone tumor is the osteogenic sarcoma. It grows rapidly and infiltrates the bone, on X-rays it appears as a site of bone destruction with uneven and unsharp shape. At the edges of the tumor, where it mixes the periosteum, calcified protuberances form - periosteal canopies. For this tumor is characterized by needle periostitis, in which perpendicular to the surface of the corroded cortical layer are located multiple bone needles - spicules.

Cells of osteogenic sarcoma are able to produce bone substance, so often in the tumor are found randomly scattered foci of ossification. Sometimes they cover the area of destruction with their own shadow. This variant of sarcoma is called osteoblastic as opposed to the first - osteolytic. However, on the border of the darkened bone mass, it is possible to discern the destruction of the cortical layer, periosteal canopies and spicules. Sarcoma is inclined to give early metastases to the lungs, so patients need to be given an X-ray examination of the thoracic cavity organs.

One of the relatively often observed variants of malignant tumors is Ewing's sarcoma, originating from bone marrow cells. In the pictures, it causes a group of destructive foci, mainly in the diaphyseal part of the bone. Let us emphasize, by the way, that the localization of the tumor has a certain differential-diagnostic significance. If osteoblastoclastoma is characterized by the spread of the tubular bone in the epiphysis, then for osteogenic sarcoma - localization in the metaphysis and the adjacent part of the diaphysis, and for Ewing's sarcoma - in the diaphysis. The cunning of the latter is that clinical symptoms and destructive foci may be similar to those in hematogenous osteomyelitis. Patients with fever, leukocytosis, pain in the limbs. However, with a tumor, there is no bone sequestration and detached periostitis. Changes in the periosteum for Ewing tumors are called onion, or layered, periostitis, in which the strips of the calcified periosteum are located along the surface of the affected bone in several rows.

The radiographic picture of generalized metastatic tumor lesion of the skeleton was described above. However, there are often single or few metastases. They also come in two types: osteolytic and osteoblastic.

The former cause destructive foci in the bone. At the second, the destruction can be invisible, since the surrounding osteosclerosis of the bone tissue in the images only the foci of compaction are visible. The nature of the lesion is easy to establish if the patient has a history of a malignant tumor or is found simultaneously with bone metastasis. If there is no relevant data, they are guided by radiation symptoms. In favor of metastases, the multiplicity of the foci, their destructive character, the absence of sequesters and periosteal reaction testify.

Osteoscintigraphy has acquired special significance. The increased accumulation of 99mTc phosphorus compounds in the lesion, which indicates the activity of metabolic processes, is characteristic of malignant neoplasms. It is important that radionuclide indications are detected long, sometimes for several months, until clear radiologic symptoms of bone destruction.

[1], [2], [3], [4]