From Big Medical Encyclopedia

BONE CALLOSITY — the regenerative fabric education providing a spayaniye of bone fragments at disturbance of an integrity of a bone in cases of cracks, changes, regional or perforated defects. Formation of a callosity is defined by features of blood supply of the bones having periosteal and intradermal vascular networks.

A source of an osteogenesis are the undifferentiated connective tissue cells which are located in a marrowy cavity, in interframe spaces of spongy substance and in vascular channels of cortical substance, and also located around a bone (a cambial layer of a periosteum).

Features of structure To. m depend on a number of conditions: from what bone is injured — flat or tubular, there was a change of its diaphysis or the epiphyseal end; whether full it is a change or a crack, regional or perforated defect; from degree of safety of the periosteal and intra bone vascular networks feeding a bone; from extent of comparison of fragments, existence or lack of their mutual mobility.

Healing change (see) — not only local process. It is followed by the general reaction of an organism that is expressed in changes of mineral metabolism, especially salts of calcium. As calcification To. the m cannot occur only at the expense of local resources (the salts of calcium arriving from fragments), in sites of a skeleton, remote from a change, there is a demineralization, edges clearly is visible radiological already in 2 — 3 weeks after an injury of a bone.

By full comparison of fragments the osteogenesis passing in a marrowy cavity of fragments consists in formation endosteal To. m. The osteogenesis on a periosteal surface leads to formation of a periosteal callosity. The epiphyseal departments of tubular bones consisting of spongy bone substance and very narrow cortical substance grow together generally at the expense of an endosteal callosity, the periosteal callosity is expressed poorly here, and under the capsule of a joint where there is no periosteum, it is absent completely.

Fig. 1. The diagrammatic representation of formation of a bone callosity on longitudinal section of a tubular bone at primary union: 1 — cortical plates of a diaphysis; 2 — the marrowy channel; 3 — an endosteal callosity; 4 — a periosteal callosity; 5 — an intermediary callosity.
Fig. 2. Microdrug of a bone callosity. A zone of an union in 14 days after an osteosynthesis: primitive bone beams (1) of the forming intermediary callosity which is accustoming to drinking fragments (2) of cortical substance of a diaphysis; x 75.

In spongy bones an endosteal and small part periosteal To. m, in the form of «bridge» passing from one fragment to another, promote recovery of an integrity of a bone. At changes of the diaphysis having thick (to 8 mm) cortical substance, after formation of a periosteal and endosteal callosity is necessary still spayany fragments of a diaphysis on the end surface of fragments representing the plane of a break of a cortical plate. It occurs due to formation of the intermediary bone callosity filling a mezhotlomkovy crack that marks a final bone union of fragments of a diaphysis (fig. 1,2). Vessels together with an osteogen burgeon in a crack of a change from a periosteum and an endosteum. At elimination of a mezhotlomkovy crack (e.g., at a compression of fragments devices) vessels can sprout by the ends of densely close fragments only from osteons. Therefore in the absence of a crack between fragments development To. the m takes more time, than at the remained small crack in the field of a change.

After comparison and fixing of fragments of the spongy bone rich with vessels having wide interframe spaces there are favorable conditions (existence of vessels and an endosteum) for formation To. m. Total absence of a crack between fragments, contrary to a compact bone, does not slow down, and accelerates healing.

Mobility of the compared fragments or their obezdvizhennost, having significant effect on a condition of blood circulation in them, considerably defines the nature of reparative processes and morphology of a callosity. In stability conditions of bone fragments and insignificant posttraumatic damages of bone vascular networks the bone union with endosteal and very small periosteal callosity forms at once. Terms of formation of a bone union take 2 — 4 weeks that depends on the size of the growing together bone. Such type of healing is called primary union.

At stability of fragments, but considerable damages of bone vascular networks or elimination of a crack between fragments of a compact bone the union of fragments of a bone also happens primary, but on terms of education To. it is estimated in m not for weeks, but months, can sometimes be late for long months. Such type of healing is called the detained primary union, at Krom the bone union quite often happens incomplete that can lead to a repeated change.

When sufficient stability of fragments of a bone and safety of bone vascular networks of t is reached and the mezhotlomkovy crack is filled with an osteogen, a constant slow (no more than 0,5 — 1 mm a day) distraction by special devices (see. Distraktsionno-kompressionnye devices ) causes in this fabric filling gradually increasing diastases, formation of a rostkovy plate and on its basis processes of an osteogenesis as growth, with gradual maturing of bone structures are continuously carried out that leads to lengthening of a bone. The termination of distraction is followed by fusion of a rostkovy plate and an union of bone fragments as primary. At more intensive rate of stretching (more than 1 mm a day) in mezhotlomkovy fabric there are processes of a desmogenez (development of connecting fabric), but not bone formation.

Fig. 3. Gistotopogramma of a diaphysis in 2 months after a change. Secondary bone union: 1 — the voluminous periosteal osteoarticular callosity which is accustoming to drinking fragments of a diaphysis (2); 3 — a small endosteal callosity; 4 — a mezhotlomkovy crack.
Fig. 2. Microdrug of a bone callosity. A zone of an union in 14 days after an osteosynthesis: primitive bone beams (1) of the forming intermediary callosity which is accustoming to drinking fragments (2) of cortical substance of a diaphysis; x 75.
Fig. 5. Macrodrug of a diaphysis of a femur: incorrectly accrete change in 1 year after an injury.

If fragments of a bone at a diaphyseal change kept mobility, diastases between them no more than 2 — 3 mm (e.g., at treatment by a plaster bandage or skeletal traction). that not earlier than 2 months after a change forms a periosteal osteoarticular callosity (owing to continuous destruction by mobile fragments of the vessels burgeoning in a crack between them). In such conditions the avascular cartilaginous tissue eating in the diffusion way is formed. On its basis during the subsequent time there is an enchondral osteogenesis and gradual formation To. m. At sufficient development the periosteal callosity immobilizes fragments and is preliminary — provisional. Such nature of recovery of an integrity of a diaphysis is called a secondary union (fig. 3, 4). The big periosteal callosity at a secondary bone union sometimes is called excess (callus luxurians). At primary union of a diaphysis formation To. the m comes within the first month. Time of a secondary union is usually estimated for months. In the absence of comparison of fragments of a diaphysis and their big mobility there can be a parostalny callosity forming in the muscles surrounding a bone that quite often leads to the wrong accretion of a change (fig. 5). At a diastase more than 4 — 5 mm the compared, but not quite immobilized fragments of a diaphysis, as a rule, do not grow together.

Cracks of bones, as a rule, begin to live as primary bone union. At complete fractures such union is almost possible only when fragments are driven or they are kept by the special fixers which are not destroying vascular network of a bone.

Perforated defects of bones more than 4 — 5 mm are not filled with a bone regenerate as for adjournment of a neogenic bone tissue the dense basis is necessary. Considerable distance between edges of a bone wound and damage of a periosteum over defect interfere with formation full To. m. Therefore at regional defects of a diaphysis in the conditions of good safety of vascular parostalny network defect is filled with an osteoarticular regenerate with gradual substitution by a bone tissue.

In the course of an union of fragments of a bone there is not only spayany their callosity, but also a reorganization To. m. There comes its gradual reduction, edges is that fabric of a callosity gradually acquires osteonny structure, typical for a bone. In the absence of the conditions necessary for an osteogenesis and formation To. m, arise nearthroses (see), the rassasyvaniye of the ends of fragments can be observed.

Radiodiagnosis of a bone callosity. At rentgenol, a research at adults To. the m comes to light in 3 — 4 weeks after a change when in a X-ray transparent callosity the small centers of calcification begin to form. On roentgenograms they have an appearance of gentle oblakovidny shadows around bone fragments (a periosteal callosity) and about inner surfaces of fragments in a zone of a change (an endosteal callosity). Then sites of calcification increase in sizes, become more dense and homogeneous, merge among themselves and, densely covering fragments, turn into a uniform bone conglomerate. This stage of bone consolidation proceeds 3 — 5 months. In the same time, as a rule, on the roentgenogram there is invisible a line of a change, and on its place the strip of an osteosclerosis appears. In the next 1 — 2 years at recovery of function of a bone there is a further reorganization To. m, involution of its excesses and recovery of normal structure of a bone.

Rentgenol, signs of healing of changes come to light after clinical since fixing of fragments comes in early terms of formation of a callosity. At multisplintered changes signs To. m appear on roentgenograms, as a rule, earlier, than at cross or slanting changes with the insignificant shift of fragments. At children To. the m develops quicker, and at senile age healing of changes happens more slowly. At advanced and senile age the periosteal callosity quite often develops quicker; it considerably big, than at middle-aged persons. However feature of such callosity, as well as all bones at advanced age, is her osteoporosis, i.e. at rather bystry rentgenol, healing of a change slower is observed a wedge, healing.

Bibliography: Vinogradova T. P. and Lavrishchev G. I. Regeneration and change of bones, M., 1974, bibliogr.; Kaplan A. V. The closed injuries of bones and joints, M., 1967, bibliogr.; Marx V. O. Healing of the closed fracture of a bone, Minsk, 1962, bibliogr.; The multivolume guide to pathological anatomy, under the editorship of A. I. Strukov, t. 5, page 203, M., 1959, t. 6, page 13, M., 1962; P e y N e r S. A. Radiodiagnosis of diseases of bones and joints, book 1, page 62, M., 1964; Chernavsky V. A. Diagnosis and treatment of changes and dislocations, Tashkent, 1977, bibliogr; M with To i foto i of V. of The biology of fracture healing in long bones, J. Bone jt Surg., v60-B, p. 150, 1978.

G. I. Lavrishcheva; Yu. G. Elashov (rents.).,