From Big Medical Encyclopedia

JOINT MOUSE (mus articularis, synonym: artremfit, an intra joint mouse, an intra joint body) — the fibrous, cartilaginous or osteoarticular education moving in a joint cavity.

the Roentgenogram of a knee joint (a side projection) at the deforming gonartroz of the II—III stage (free intra joint bodies are specified by shooters).

The page of m is located in a joint cavity freely (fig.) or is connected with intra joint educations by a mobile leg. The size C. of m — from lentil grain to the sizes of a patella and more. Most often S. of m arises in a knee joint, is more rare — in elbow and as an exception — in humeral, coxofemoral, talocrural and other joints. According to etiol. S.'s factors of m divide into two groups: traumatic, arising at damages of not changed tissues of a joint, and so-called pathological, being a consequence of dystrophic or inflammatory process in a joint. S.'s emergence m is the most typical at the cutting osteochondrosis (see. Keniga disease ).

S.'s structure of m is defined by its origin and duration of stay in a joint. Usually on a structure they are identical to fabrics, from to-rykh separated. Over time they are exposed to changes of dystrophic character, can increase in sizes, break up, resolve, be implanted and get accustomed to a wall of a joint cavity.

Pages of m, according to Smiley (J. S. Smillie, 1980), depending on a structure, divide on:

1) fibrinny, resulting from a hemarthrosis at an injury or hron. a synovitis (e.g., massive fibrinous clots at a pseudorheumatism);

2) the fibrous, resulting hemorrhages in synovial vorsina or at hron. arthritis;

3) fibrocartilage, appearing at injuries of meniscuses or at dystrophic processes in them;

4) cartilaginous (from a joint cartilage), arising owing to injuries of a joint cartilage under the influence of forces, tangents to its surface, or at widespread destructive processes;

5) osteoarticular, being result of intra joint and chressustavny changes, and also diseases of Keniga, an osteochondropathy of a patella, an osteonecrosis, a neurogenic or hydrocortisone arthropathy, sequestration at arthrosis, infectious arthritis, etc.;

6) the other, being result hits in a joint cavity of a foreign body and tumoral processes (high-quality and malignant). In knee joint (see) S. the m can be located in a patellar bag (upper torsion), side departments of a joint cavity, in the field of contact of a patella and a femur, in an intercondyloid pole of a femur, in a joint crack, over and under meniscuses etc.

Clinically The page of m is shown by the repeating short-term blockade of a joint with pains and the subsequent reactive synovitis (see). Constant restriction of movements only large S. cause m in an intercondyloid pole or back department of a knee joint.

S. is frequent the m is probed in a joint cavity and can be fixed by fingers through skin. Crucial importance has rentgenol. research. The artropnevmografiya is necessary for m for X-ray transparent S.' identification (see. Artrografiya ). In recent years the technique of a double contrast study (a contrast agent and oxygen) is considered more informative, edges S. allows not only to reveal and localize m, but also to determine its origin (by change of contours of a joint cartilage). At impossibility to make the diagnosis rentgenol. by methods resort to an arthroscopy of a knee joint (see. Joints ).

Differential diagnosis carry out with injury of meniscuses (see. Meniscuses joint ), infringement hypertrophied vorsin a synovial membrane (see), aged up to 10 years — with anomaly of ossification of a distal epiphysis of a hip, aged up to 15 years — with a juvenile osteochondropathy (see), ossification of a front horn of a meniscus.

Treatment — operational. S.'s removal of m at the deforming arthrosis (see), a chondromatosis is applied as a symptomatic treatment in cases of infringement of S. of the m which is followed by pains and a synovitis. Pages of m probe through skin, fix a needle and then delete through a small section. At S. m of a traumatic origin and because of osteochondropathies good results are yielded by S.'s removal of m along with plastics of big kostnokhryashchevy defects, and as a transplant S. by m or a cartilage from not loaded surface of condyles of a hip can be used. This method is shown for persons of young age for the purpose of the prevention in the subsequent the deforming arthrosis. The following reception is possible: on the operating table at the unbent knee joint radiological define the provision C. of m then, without changing position of a leg, do a section, through to-ry take S. of m. Low-traumatic operation is small S.' removal of m through artroskop.

Forecast S. of m and timeliness of operation depends by nature. During early removal of S. of m of a traumatic origin or because of a disease of Keniga anatomo-funktsio-nalny the result is favorable. During late removal development of the deforming arthrosis is possible, at a chondromatosis — S.'s recurrence of m.

Bibliography: Bashirova F. X. An etiology and a pathogeny of the cutting osteochondrosis, Ortop. and travmat., No. 3, page 68, 1972, bibliogr.; Botulin B. B. To a question of diagnosis and treatment of a disease of Keniga, Uchen. zap. Stavropol medical in-that, t. 13, page 157, 1963; M and r about N about in and 3. Page, A. S's Martens. and Inagamdzha-n about in T. I. Mistakes and complications in diagnosis and treatment of patients with intra joint damages and diseases of a knee joint, Tashkent, 1977, bibliogr.; The multivolume guide to orthopedics and traumatology, under the editorship of N. P. Novachenko, t. 3, page 673, M., 1968; The Multivolume guide to surgery, under the editorship of B. V. Petrovsky, t. 12, page 380, M., 1960; E d-wards D. N of a. Bentley G. Osteochondritis dissecans patellae, J. Bone Jt Surg., v. 59-B, p. 58, 1977; Jackson R. W. a. Dandy D. J. Arthroscopy of the knee, N. Y., 1976; Lehrbuch der Orthopadie, hrsg. v. P. F. Matzen, B., 1967; M u h e i m G. and. In o h n e W. H. Prognosis in spontaneous osteonecrosis of the knee, J. Bone Jt Surg., v. 52-B, p. 605, 1970; S m i 1 1 i e I. S. Diseases of the knee joint, Edinburgh a. o., 1980.

O. A. Ushakova.