Villezonodular synovitis is a rare proliferative disease of unknown etiology that affects the synovium. Pigmented villonodular synovitis does not produce atypical cells, although the presence of cytogenetic abnormalities has recently been shown. However, the presence of synovitis suggests an inflammatory process.

Cause

The etiology remains unclear. Regardless, it is characterized by inflammation and hemosiderin deposition in the synovium. This disease exists in three forms: an isolated variant involving the tendon sheath (giant cell tumor of the tendon sheath), a separate intra-articular node (localized villusonodular synovitis) and diffuse villous and pigmented changes in the synovium (diffuse villonodular synovitis). This chapter focuses on the latter two forms.

Symptoms

A typical onset of the disease is observed in a 20-40 year old patient who complains of swelling of one joint. In 80% of cases the knee joint is affected. Some patients may experience joint stiffness and local hyperthermia. Mechanical signs such as blockage and joint instability may develop, especially if the joint contains a large pedicle. Symptoms are usually episodic or slowly progressive. Laboratory results, such as erythrocyte sedimentation rate, are within normal limits and can help rule out infection and rheumatoid arthritis. Aspiration of the joint demonstrates brown, red, or yellow fluid.

Diagnostics

In the initial stages, non-contrast radiographs reveal swelling of the periarticular soft tissues, absence of synovial calcification, normal bone density and preservation of the joint space. Bone changes develop in later stages. Recent studies suggest that the expression of matrix metallolroteinases in villonodular synovitis may contribute to the development of bone and cartilage destruction. In joints with a small joint cavity volume (such as the hip joint), synovial villi may adhere to the bone and cause superficial erosions. As the villi grow, the pressure in the joint capsule increases. The villi then penetrate the bone and periarticular cysts form. If the disorder is not diagnosed and treated, joint destruction may follow.

Due to hemosidprin deposition, MRI usually reveals reduced nodular lesions. Additionally, a low signal during a fast-field echo study is useful in the diagnosis of villonodular synovitis. Articular effusion is detected, as well as bone erosions in the hip, ankle, elbow and wrist joints. In cases of localized villonodular synovitis, MRI will show a single nodule. MRI can also determine the extent of the disease, which helps plan appropriate treatment.

If the diagnosis remains in doubt, arthroscopy can show a macroscopic picture of the changes.

In the localized form, a single yellow node on a stalk is detected. The surface is often divided into lobules and has an “oily” appearance. It is often located in the anterior knee joint and resembles a giant cell tumor of the tendon sheath.

In the diffuse form, the thickened synovial membrane is covered with villi and nodes on a broad base or on a stalk. The entire joint appears to be covered in brown and orange algae. The nodules resemble bunches of grapes protruding into the joint cavity. They are usually loose and bleed with minimal damage. Some of the villi contain convex ends and look like a randomly protruding “beard”. Other hairs are finely tipped and fern-like. The villi may become embedded in the bone or, less commonly, extend beyond the joint capsule into the periarticular soft tissue.

A biopsy confirms the diagnosis. All three forms of villonodular syndrome have a similar histological picture, which is characterized by hypercellularity of the subsynovial connective tissue. The synovial membrane is represented by one to three layers and covers the nodules and villi. In some areas, the ends of the villi come together to form clefts. The subsynovial stroma contains fibroblasts that form collagen and phagocytic histiocytes. These polygonal cells contain pale nuclei and abundant cytoplasm.

They proliferate and can be seen in the mitotic stage. Some histiocytes will phagocytose hemosiderin; others merge to form multinucleated cells; others will form foam cells. Lipid-filled macrophages (foam cells) produce the yellow color that is dominant in the localized form. Foam cells and hemosiderin-laden macrophages are mainly localized in the periphery, while giant cells are diffusely distributed throughout the loose connective tissue.

Treatment

Good clinical results can be obtained with local excision of a single node. However, if diffuse villonodular syndrome is detected in a young patient, total synovectomy is recommended. If MRI reveals changes that are accessible to arthroscopy, it is advisable to perform arthroscopic resection, since it is relatively less traumatic. However, since the changes usually extend beyond the reach of the arthroscope, open synovectomy may be necessary. Previously, synovectomy was associated with a 40% recurrence rate. Incomplete synovectomy is systematically considered the main cause. The quality of synovectomy for diffuse villonodular synovitis is important in terms of reducing recurrences. With open synovectomies through anterior and posterior approaches to the knee joint, relapses are observed in 8% of cases. If diffuse synovitis is diagnosed in an older patient with degenerative joint disease, arthroplasty may provide excellent results. In a young patient, arthrodesis should be considered a brutal procedure.

Used as an addition to surgical treatment to control the pathological process. In a prospective study, external beam irradiation was combined with partial (anterior) arthroscopic synovectomy. provided successful cure, with the same rate as total synovectomy. For the treatment of diffuse villonodular synovitis during subtotal synovectomy of the knee joint, the authors recommend the use of auxiliary external beam irradiation at an anti-inflammatory dose of 26 Gy. Intra-articular injection of yttrium-90 has been used to treat diffuse villusonodular synovitis. Its effectiveness has not been well studied and it remains an experimental treatment. It may be useful as an adjunct to subtotal resection for extensive lesions where complete removal would result in unacceptable trauma. Before using it, patients should be advised that it may impair tissue healing, increase stiffness, and possibly cause sarcomatous degeneration.

A rare chronic lesion of the joint caused by the proliferation of its synovial membrane with the formation of nodular or villous outgrowths and articular mice. Pigmented villonodular synovitis is characterized by periodic and then constant swelling of the joint and the appearance of pain in it. Diagnostic measures for pigmented villonodular synovitis include blood tests for RF, ANF, CRP, radiography, pneumoarthrography, arthroscopy, diagnostic puncture of the joint and biopsy of the synovium. Treatment of pigmented villonodular synovitis involves removal of the synovium followed by irradiation of the joint.

General information

Pigmented villonodular synovitis was first described in 1941. It is observed mainly in young and middle-aged people. There are known cases of the disease developing against the background of rheumatoid arthritis. Morphologically, pigmented villonodular synovitis is based on the slow growth of the synovial membrane of one, rarely several, large joints. The process can spread to the synovial lining of tendons and mucous bursae.

The formation of nodular and villous outgrowths that occurs during pigmented villonodular synovitis is accompanied by the accumulation of hemorrhagic effusion in the joint cavity and the deposition of hemosiderin on the articular surfaces of the bones entering the joint with the development of reactive synovitis. Outgrowths of the synovial membrane on the pedicle can eventually separate from it, forming bodies that are freely located in the joint cavity, which, when calcified, are transformed into the so-called “articular mice”. A long course of pigmented villonodular synovitis leads to the appearance of degenerative changes in articular cartilage, and sometimes to their erosion.

Causes of pigmented villonodular synovitis

The etiological factors and mechanism of development of pigmented villonodular synovitis are unknown. There is still debate in rheumatology about the genesis of this disease. Previously, it was generally accepted that pigmented villonodular synovitis is a granulomatous inflammatory process in the synovium (synovitis). Modern cytogenetic studies have revealed chromosomal aberrations and signs of atypical proliferation in the growing cells of the synovial membrane of the affected joints, which is a sign of tumor formation. Thus, most authors today tend to consider pigmented villonodular synovitis to be a benign, slowly developing tumor process.

Symptoms of pigmented villonodular synovitis

Pigmented villonodular synovitis is characterized by a gradual onset and slow progression. The disease begins with periodically occurring swelling in the joint, caused by the accumulation of hemorrhagic exudate in its cavity. During stress on the affected joint, pain may occur due to pinching of the outgrowths of the synovial membrane. Over time, swelling in the joint and arthralgia become permanent. Movements in the joint with pigmented villonodular synovitis remain full for a long period, then stiffness gradually appears and increases. In some cases, periodic “blockades” of the joint are observed, indicating the presence of a “joint mouse”.

In 80% of cases of pigmented villonodular synovitis, the knee joint is affected. In the remaining 20% ​​of cases, changes are observed in the ankle, hip, and calcaneal-cuboid joints. Damage to the synovium of the mucous bursae manifests itself as bursitis and is most often found in the ankle joint. Involvement of the synovium of the tendon sheath leads to the development of tenosynovitis and is usually observed in the flexor and extensor tendons of the hand.

The general condition of patients with pigmented villonodular synovitis is usually not impaired. Body temperature is normal.

Diagnosis of pigmented villonodular synovitis

To make a diagnosis of pigmented villonodular synovitis, a rheumatologist conducts a comprehensive examination of the patient, assessing laboratory blood parameters, radiological and arthroscopic data, the results of a study of synovial fluid and the tissue structure of a synovial membrane sample.

Pigmented villonodular synovitis is not characterized by inflammatory changes in the clinical blood test, the presence of C-reactive protein, ANF or rheumatoid factor. When performing x-rays of the joint, in some cases osteoporosis of the articular surfaces and some narrowing of the joint space can be observed. Sometimes marginal erosions of the bone articular surfaces and cystic formations of the epiphyses are detected. Pneumoarthrography often reveals filling defects in the synovium of the joint, which are round in shape and multiple in nature. They correspond to the site of formation of giant nodes or villi of the growing synovial membrane.

application of N.p.p. an anti-inflammatory effect is possible regardless of the nature of the inflammation. To many N.p.p. common mechanisms of therapeutic action are characteristic (salicylates and indomethacin reduce capillary permeability; salicylates, indomethacin and pyrazolone derivatives have an inhibitory effect on ATP synthesis: almost all drugs in this group inhibit the production of prostaglandins, etc.).

The combination of anti-inflammatory, analgesic and antipyretic properties of almost all N.p.p. cannot be considered random. It has been established that some inflammatory mediators (bradykinin, prostaglandins) also cause pain and fever. Therefore, by inhibiting these mediators, the anti-inflammatory drugs in question provide an analgesic and antipyretic effect. It is possible that the blockade of peripheral pain receptors by these drugs also plays a role. At the same time, the influence on the nerve centers of thermoregulation and pain perception, contrary to previous views, is not given much importance. However, despite the possible connection of these effects, it must be borne in mind that even if they are actually combined, they can differ sharply in severity. It is important to clinically differentiate the analgesic and anti-inflammatory effects of drugs. In some patients, pain may be the most striking clinical manifestation of the inflammatory process. Therefore, any reduction in pain is sometimes considered as a manifestation of an anti-inflammatory effect, although in principle this approach is incorrect (morphine in such cases also reduces pain without having anti-inflammatory properties).

N.p.p. do not have a proven direct effect on the immune system, however, in some patients they apparently exhibit some “secondary” immunosuppressive effect, since a decrease in capillary permeability in some cases can somewhat impede the contact of immunocompetent cells with the antigen, and antibodies with the substrate; stabilization of lysosomal membranes in macrophages limits the breakdown of poorly soluble antigens necessary for the development of subsequent stages of the immune response. Therefore, with long-term use of N.p.p. in some cases, a therapeutic effect comparable to the prescription of “basic” drugs is achieved.

Among the side effects characteristic of the N.p.p. group. in general (although the degree of their severity varies), the following can be noted: “irritation” of the gastrointestinal tract (including the formation of petechiae, erosions and ulcers), dizziness, headache, allergic skin rashes, increased blood pressure, fluid retention. However, most patients tolerate N.p.p. It turns out to be good and there are no side effects.

TUMORS AND TUMOR-LIKE DISEASES OF JOINTS AND PERIARTICULAR STRUCTURES

Tumors and tumor-like formations of joints are relatively rare in rheumatological practice. An accurate diagnosis is especially important in the case of monoarthritis.

Tumor-like formations of synovial structures, Pigmented villonodular synovitis

a disease of unknown etiology, characterized by diffuse or nodular growth of the synovial membrane with the presence of brown villous outgrowths containing hemosiderin and cholesterol crystals. Microscopically, in places where the villi thicken, multinucleated giant cells are revealed, which are located freely in the stroma or are closely associated with connective tissue. Taking into account the data of histological examination, such a pathological process should be considered not as a tumor, but as an inflammatory granuloma. One of the etiological factors in this case is repeated hemorrhages

V joint. The ability for limited or diffuse damage, its different localization, as well as a complex of changes during morphological examination have become the basis for numerous names for this pathology: benign (giant cell) synovioma, giant cell tumor of the tendon sheath or synovium, xanthoma, xanthogranuloma, hemorrhagic villous synovitis, etc. , which leads to terminological confusion during diagnosis.

P.v.s. observed mainly in young people, more often in men. Usually this affects the knee joint, less often the hip, ankle, elbow, talus, and tarsal joints. Characteristic symptoms are pain and swelling, which may be mild and transient for a long time, but signs of arthritis gradually develop. Lumps are palpable in the joint area. Synovial fluid is usually mixed with blood or dark brown, without clots, and contains polynuclear cells (up to 26%) and red blood cells. X-ray examination of the joint confirms the presence

V synovial bursa of exudate. At a later stage, P.v.s. compaction and multiple cysts are detected in the subchondral parts of the bone. An arthrogram of the knee joint reveals an expansion or stretching of the patellar bursa with a significant number of pockets and a filling defect. The synovial membrane is diffusely brown in color and covered with dense formations in the form of long elongated villi, the fusion of which leads to the formation of “lumps” or nodules of various sizes. The latter are covered with a thin layer of synovial flat cells and contain round or elongated clusters of varying density: hemosiderin granules and cholesterol crystals, both in the form of free clusters and in

in the form of inclusions in the cytoplasm of superficially and deeply located cells. There are areas of fibrosis. When electron microscopic examination is observed, macrophage-like and fibroblast-like cells, formed from normal synovial cells, predominate.

Local nodular synovitis is more common than diffuse synovitis. In these cases, the knee joint is usually affected, symptoms of the disease are often observed for many months or years, but the diagnosis can only be established with a biopsy of the synovium; the picture is similar to that observed with P.v.s.

Pigmented villonodular bursitis - an unusual pathology that can be determined in the area of ​​the patella or ankle joints and is clinically manifested by a slight increase in their size.

Local nodular tenosynovitis

the most common pathology. It usually affects young or middle-aged adults, more often women. In this case, damage to the index or middle fingers is typical. A hard nodular formation appears on the palmar or dorsal surface, sometimes it is localized in the area of ​​the metacarpophalangeal, ankle, wrist joints or toe and consists of single homogeneous, fibrous nodules, but more often the nodule is divided into separate clusters of gray, yellowish or reddish-brown color, rich in fibrous tissue , cholesterol and hemosiderin.

Pigmented villonodular tenosynovitis

observed in the form of local or diffuse damage to the tendon sheaths of the hands and feet. In these cases, the tumor-like formations are sometimes large and cause erosion of nearby bone. The question that is still being debated is whether this formation is a true neoplasm of synovial tissue (benign giant cell synovioma) or a form of chronic inflammation, the etiology of which is still unknown. The appearance of erosions in the nearby bone, relapses after incomplete extirpation and the discovery of areas surrounded by synovial cells indicate the presence of neoplasm. However, the origin of P.v.t. remains unclear. In an experiment on dogs, repeated injections into the joint caused changes reminiscent of this disease in humans.

Treatment. The damaged area is radically removed. In case of relapse, repeated surgical intervention, sometimes radiotherapy (it is also indicated for nodular tenosynovitis in cases of persistent course).

Benign tumors. Synovial chondromatosis

benign neoplasm, more common in men 20-40 years old; The knee joint is usually affected, but the hip, elbow, shoulder and even the temporomandibular joint may be involved. The disease is mainly monoarticular, but there may also be oligoarthritis, for example, when both knee joints are affected. The patient experiences pain, swelling and limitation of movement in the joint, and “snapping” of the joint. S.kh. may be asymptomatic and discovered incidentally.

The diagnosis is established by x-ray: small round formations are detected in the joint cavity. An x-ray is not very informative in cases where the cartilage is not yet calcified. An accurate diagnosis is made with arthrography.

Treatment. Synovectomy is indicated (to reduce pain and restore joint function). The operation must be performed radically to avoid recurrence of chondromatosis. Osteochondroma is observed in children at the site of tendon attachment in large joints. The tumor is accompanied by pain in the joint and is painful on palpation. X-ray reveals protrusion of trabecular bone in the metaphysis. Removal of the tumor is indicated.

Chondroma

most often appears at the age of 10-50 years, the phalanges of the fingers and toes are affected. It is detected mainly by x-ray (a small, well-circumscribed tumor is detected). Removal and curettage of the tumor is indicated.

Osteoid osteoma

observed in children and young people. When the tumor is located near a joint, arthritis occurs. Localized O.o. in the femur, tibia or vertebrae. Characterized by sharp pain in the corresponding joints, especially at night. X-ray examination reveals widespread osteoporosis, local sclerosis or rarefaction fields with focal compactions. To establish a diagnosis, images in oblique projections, tomography and scanning are sometimes necessary. The tumor must be removed.

Hemangioma

located in the synovium and tendon sheaths, usually in the knee joint.

Characterized by attacks of acute swelling of the joint, often associated with minimal trauma, pain and discomfort due to jamming and blocking of the joint. With palpation, it is sometimes possible to detect compaction of the soft tissues of the joint and hypertrophy of the epiphysis. When a joint is punctured, either blood or a dark yellow fluid with a high bilirubin content is obtained.

The diagnosis can often be confirmed only by arthroscopy and angiography.

Benign giant cell tumor

arising in the epiphysis of the femur, tibia, radius. Characterized by sharp pain, which intensifies with movement and thickening of the end of the bone. X-ray reveals a large “X-ray negative” zone, round, with multiple partitions. There is no periosteal reaction.

Benign tumors that can simulate arthritis also include simple solitary cysts, local eosinophilic granuloma, lipoma, and fibroma. The last two are of interest to the rheumatologist.

Lipoma

usually localized in subsynovial fat and on the patellar ligament. It can be found in the tendon sheath of the hands, wrists, feet and ankles. The extensor tendons are often affected symmetrically. It is believed that this tumor often arises in response to chronic irritation, is often associated with degenerative joint diseases and should not be classified as a neoplasm.

True fibrous tumor

It is rare and usually develops in older people due to villonodular synovitis. No surgical treatment is required.

Malignant tumors. Synovial sarcoma (synovioma)

develops in young people, is localized in the synovial membrane of the joints, usually of the lower extremities. Characterized by increasing pain, swelling and tenderness around the joint. X-ray reveals a shadow with calcifications and cystic changes in the bone. Treatment: radical removal, irradiation.

Chondrosarcoma

affects the cartilage of the knee, shoulder joint, and pelvis. It is usually localized near the muscle attachments. The pain in the joint is very pronounced and worsens at night; dense swelling around the joint and sometimes flexion contractures are detected. X-ray shows a dome-shaped shadow with calcifications. Treatment is radical surgery.

Metastatic tumors in the joints

are rare, but can be found in small peripheral bones (patella, phalanges, in which metastasis is usually localized near the joint). The most common source of metastasis is lung carcinoma. Total destruction of the patella may occur with the development of severe pain in the joint, effusion and hemorrhage into the joint. Malignant cells are usually found in the synovial fluid.

Tumors of non-synovial structures of tendons, fascia and aponeuroses. Histiocytoma

a benign tumor in the form of one or, less commonly, multiple nodules of various sizes located in the skin or in fascial structures, mainly of the lower extremities. The growth of nodules occurs slowly and sometimes stops. The diversity of the microscopic structure of the tumor, associated with the cellular polymorphism of its sources, and the frequent accumulation of lipids and hemosiderin in the tumor elements have led to an abundance of synonyms for this disease: angiofibroma, angiofibroxanthoma, sideroxanthoma.

Epithelioid sarcoma

manifests itself in the form of dense, painless nodules up to several centimeters in diameter, prone to ulceration. The tumor tends to spread along the fascia and tendons. Mainly localized on the extremities (palmar surface of the fingers, extensor surface of the forearm, anterior surface of the legs). The name “epithelioid” is given because of the external similarity of tumor elements with squamous epithelial cells. Treatment is surgical.

The joint disease villonodular synovitis is difficult to diagnose and difficult to treat. Women and men of any age category are susceptible to this disease, but its peak occurrence occurs during reproductive age. The course of synovitis is unpleasant: frequent relapses, spread of the lesion beyond the joint capsule, destruction of bone tissue. If the diagnosis is incorrect or treatment is not timely, the disease can result in limb amputation.

What are the causes of joint damage?

The etiology of the disease is not fully understood; scientists continue to search for pathological factors. Common causes of synovitis include the following:

1. Slowly developing benign changes.
2. Increased activity of the autoimmune system directed against collagen structures.
3. Previous lesions of the organ of an inflammatory nature.
4. Allergic reaction.
5. Traumatic injury to the knee joint.

Cytogenetic studies confirm the tumorigenesis of the disease, proving the presence of chromosomal aberrations in proliferating multinucleated cells. Rheumatologists consider synovitis as granulomatous inflammation. A failure of the defense system activates pathological autoimmune and allergic reactions. The collagen fibers of the joint are damaged by their own antibodies.

Synovitis occurs as a consequence of arthritis or arthrosis, accompanied by the appearance of typical hair growths. The torn piece is dangerous; it gives rise to a new growth called an articular mouse. It is characterized by oncological growth. Patients feel subcutaneous movements of small nodules. The rarest cause of synovitis is trauma complicated by bursitis. Pigmented villonodular synovitis is characterized by the appearance of villous and nodular formations, damage to the synovium and tendon bursae.

Types of disease, classification features

Pigmented synovitis has 3 forms: diffuse, extra- and intra-articular. For diagnosis, the area of ​​the lesion, the type of spread and growth are important. Considering these factors, rheumatologists offer the following classification:

• by localization - knee, elbow, hip joint;
• according to the type of growth and prevalence of the process - local or diffuse;
• according to the location of the lesion - intra- or extra-articular.

How not to miss manifestations of synovitis?

Where is the lesion located?

The disease develops gradually and slowly, but progresses steadily. Symptoms depend on the location and extent of pathological damage. The disease primarily affects the joints of the legs in the following order with decreasing frequency:

1. knee in 80% of cases;
2. hip;
3. ankle and calcaneocuboid joint of the foot.

Symptoms you need to know

The affected joint swells due to the accumulation of hemorrhagic effusion. With exertion, pain occurs due to pinching of the villous outgrowths. The further course is accompanied by more pronounced swelling and arthralgia, which become permanent. Movements that do not change for a long time become limited, the joint becomes inactive. The appearance of blockades is characteristic, proving the presence. Differential diagnosis is required with hemophilic and amyloid arthropathy, chondromatosis. The main manifestations that distinguish the disease from other types:

• signs of allergy in the affected area;
• acute sharp pain when bending the joint;
• pronounced swelling around the perimeter of the pathology;
• moving neoplasms under the skin of the joint.

A typical symptom is mobile, round, elastic balls under the skin, which can be malignant. If they are detected, an urgent consultation with a rheumatologist is necessary.

Difficulties in diagnosing villonodular synovitis

Laboratory tests and instrumental examinations are carried out comprehensively. One of the main methods is synovial membrane biopsy. For diagnosis, a wide range of mandatory studies are prescribed:

• CBC - detects increased ESR.
• Blood biochemistry confirms autoimmune pathology, contains increased levels of RF, ANF, and CRP.
• for the analysis of synovial fluid - blood is detected, color change to xanthochromic.
• Ultrasound of the joint - shows villi and round formations, a thickened wall, a change in shape.
• Biopsy - finds hemosiderosis, multinuclear proliferation.
• X-ray - reveals the absence of signs of osteoporosis.
• Arthropneumography - reveals numerous defects of the articular cavity due to villi and nodes.
• MRI - detects an artifact of magnetic susceptibility, confirming the presence of synovitis.
• Arthroscopy - diagnoses brown nodes of various shapes and sizes, changes in the color of cartilage, as a result of hemosiderotic effects.

Another name for this disease of the knee joint is pigment villous synovitis. It consists of a proliferative-dysplastic lesion of the synovium with the formation of a mass of villous and nodular growths of a red-brown color.

It can affect any joint, but is most often localized in the knee (80%). Then, as the percentage of damage decreases, the hip, ankle joints, hand joints, elbow, shoulder joints, mucous bursae, and tendon sheaths follow.

Pigmented villous nodular synovitis (PVUS) is a rare pathology (accounts for about 1% of joint diseases), occurs more often in women. It is most often diagnosed in people aged 16 to 30 years.

The basis of the disease is a violation of lipid metabolism, later inflammation joins with the formation of synovitis. This type of synovitis differs markedly from typical synovitis due to significant effusion, preservation of the full range of movements and a slight pain reaction during them.

Patient complaints

Swelling appears in the area of ​​the affected joint, mild discomfort when walking and moving, half of the patients experience slight and intermittent pain.

Often the patient notes the appearance of pseudoblockades of the joint associated with pinching of nodules and villi. A feature of such blockades can be considered spontaneous elimination without any intervention.

As a result of the slow progression of the pathological process, patients retain normal gait and full or almost full range of motion in the joint.

Clinical examination

On examination, slight muscle atrophy, smoothness of the contours and swelling of the joint are noted, and a slight increase in local temperature is possible (for example, above the superior inversion of the knee joint).

Diagnostics

To diagnose pigmented villous nodular synovitis, examination of joint effusion is of paramount importance. In most cases it has a brick or brown-red color, less often yellow. Cytological examination reveals a mass of xanthoma cells, fibroblasts, histiocytes, lymphocytes, and synovial cells.

Standard radiography makes it possible to detect an increase in the volume of soft tissue in the affected area, diffuse or, less commonly, compaction in the form of nodes. Compacted fabrics have a clear outer contour. On radiographs, shadows from compaction of soft tissues appear, and later areas of destruction in the bone are revealed. These areas may look like small cyst-like clearings, like marginal lesions, and sometimes resemble osteoblastoclastoma.

Arthropneumography and angiography are more informative methods for PVUS than radiography. Arthropneumography performed in three projections reveals an increase in the size of the torsions, thickening of the walls of the capsule, waviness of its internal contour and the presence of seals in the joint cavity in the form of threads and nodes of different sizes. In some areas, oxygen in the joint cavity can be traced in the form of clusters of cleared areas of a round shape measuring 0.1-0.2 cm. On angiograms performed in two projections, an increase in vascularization is noted due to the expansion of the lumen of all arterial vessels and the identification of vessels of the 4th-5th order . MRI examination allows us to accurately predict the presence of this pathology.

A common finding during diagnostic arthroscopy or arthrotomy may be chondromas of various sizes, which are formed from separated and calcified villi.

Differential diagnosis

A rare tumor form of the disease is expressed in the appearance of a dense, tuberous tumor with foci of calcification on radiographs. In such cases, it is necessary to differentiate with synovial sarcoma and hemangioma.

Besides, PVUS differentiated from diseases such as arthrosis deformans, tuberculous arthritis, meniscus damage.

Treatment of pigmented villous nodular synovitis

The basis of treatment is synocapsulectomy, which can be performed either open or arthroscopically with mandatory histological examination of the removed tissue. In case of relapse of the disease or in its tumor-like form, total synocapsulectomy is indicated in combination with radiation therapy at the second stage (3-4 weeks).

Rehabilitation

After surgery, it is necessary to avoid putting weight on the leg for about 6 weeks, but all movements in the joint are allowed, aimed at preventing joint stiffness. After radical synovcapsulectomy, the rehabilitation process requires maximum effort on the part of both the patient and the therapeutic exercise instructor.