X-ray signs of bone and joint injuries

X-ray examination of the skeleton is performed as prescribed by the attending physician. It is indicated for all injuries of the musculoskeletal system. The basis of the examination is X-ray photography of the bone (joint) in two mutually perpendicular projections. The images should show an image of the entire bone with adjacent joints or a joint with adjacent bone sections. All victims who are conscious and do not have life-threatening signs of damage to internal organs and blood vessels are subject to examination in the X-ray room. Other victims, according to clinical indications, can be examined in a ward or dressing room using a mobile X-ray machine. Refusal to perform X-ray photography in case of damage to bones and joints is a medical error.

It is recommended to take pictures after the traumatologist has administered local anesthesia, which makes the patient's condition easier and fixes the limb during the shooting. In cases where the presence and nature of the injury cannot be accurately determined from the radiographs in two projections, additional pictures are taken: radiographs in oblique projections, targeted pictures, linear tomograms. Sonography, CT and MRI are performed according to special indications.

The main radiological signs of fractures of tubular and flat bones are well known - this is the fracture line (gap) and displacement of fragments.

The fracture line, or crack, is a light strip with uneven and often jagged edges. A classic example of such a line is a crack in one of the bones of the cranial vault. The fracture line is more clearly outlined in the cortical layer of the bone, then crosses it in different directions. If it does not reach the opposite edge of the bone, then we speak of an incomplete fracture. In these cases, there is no noticeable displacement of the fragments. With a complete fracture, displacement of the fragments is observed as a rule. It is caused by both the injury itself and muscle traction.

The nature of the displacement of fragments is determined from images in two mutually perpendicular projections. A distinction is made between displacement by length (longitudinal, which can occur with overlap, wedging or divergence of fragments), by width (lateral), by axis (angular) and by periphery, i.e. with rotation of one of the fragments around its longitudinal axis. The magnitude of longitudinal or lateral displacement is indicated in centimeters, and angular and by periphery - in degrees.

It is necessary to check on the X-rays whether the fracture line passes through the articular surface of the bone, i.e. whether the fracture is intra-articular. In addition, attention should be paid to the condition of the bone tissue around the fracture gap in order to exclude a pathological fracture, i.e. damage that has occurred in an already affected bone (in particular, in the area of tumor development). In childhood, epiphysiolysis is occasionally observed - a traumatic separation of the bone epiphysis from the metaphysis. The fracture line in this case passes along the growth cartilage, but usually bends slightly onto the metaphysis, from which a small bone fragment breaks off. Incomplete and subperiosteal fractures of tubular bones are relatively common in children. In these cases, the fracture line is not always visible and the main symptom is the angular bending of the outer contour of the cortical layer. In order to catch this sign, it is necessary to scrupulously examine the bone contour along its entire length.

Fractures of gunshot origin have a number of features. In the bones of the cranial vault, pelvis and other flat bones, they are predominantly perforated and accompanied by numerous radial cracks. Similar injuries are observed in the metaphyses and epiphyses. In the diaphyses, comminuted fractures with multiple fragments and cracks often occur. Gunshot injuries are often accompanied by the penetration of foreign bodies into bones and soft tissues. Metallic foreign bodies are detected by radiographs, while foreign bodies that do not contrast with X-rays are detected using sonography.

Thus, in the vast majority of cases, conventional X-ray images allow us to establish the nature of bone damage. However, there are situations when there is no displacement of fragments, and the fracture line is not clearly visible or cannot be distinguished from normal anatomical formations, for example, in fractures of individual bones of the vault and base of the skull, facial skull, arches and processes of the vertebrae, damage to large joints. In these cases, it is necessary to additionally use linear or computed tomography. A reliable auxiliary diagnostic method is a radionuclide study - osteoscintigraphy. Scintigrams make it possible to establish a fracture, since the RFP accumulates in greater quantities in the area of damage than in the surrounding bone. In general, a typical scheme for radiological examination of a victim with an acute limb injury is given below. After conservative or surgical reduction of the fracture, control X-ray images are taken in two mutually perpendicular projections. They allow us to evaluate the effectiveness of the reduction and the correct placement of pins and plates in metal osteosynthesis.

In conservative treatment of a fracture using fixing bandages (e.g. plaster), repeat radiographs are taken after each change of bandage. In addition, repeat images are taken if there is a suspicion of a fracture complication.

In case of gunshot injuries, gas infection is a serious complication. Radiographs show an increase in the volume of soft tissues and loss of clarity of outlines of individual muscle groups in the fracture area. A specific sign is the appearance of gas bubbles and stratification of muscle fibers by gas accumulations. Gas absorbs X-ray radiation less than surrounding tissues, therefore it causes clearly visible enlightenment.

Subsequently, radiographs are taken to assess the condition of the bone callus between the fragments of the humeral head.

In the first decade after the injury, the fracture gap is especially clearly visible due to the resorption of damaged bone beams at the ends of the fragments. During this period, the fragments are connected by a connective tissue callus. In the second decade, it turns into an osteoid callus. The latter is similar in structure to bone, but does not contain calcium and is not visible on images. At this time, the radiologist still detects the fracture line and also notes the onset of bone reorganization - osteoporosis. In the third decade, the doctor can palpate a dense callus fixing the fragments, but this callus is still not visible on radiographs. Complete calcification of the callus occurs in 2-5 months, and its functional reorganization continues for a very long time.

During surgical treatment of fractures, the surgeon determines the necessary time for performing control images. It is necessary to check the development of bone callus, the position of metal fixing devices, and to exclude complications (bone necrosis or inflammation, etc.).

Impaired fracture healing includes delayed callus formation, but this should not be confused with nonunion of the fracture and the formation of a pseudoarthrosis. The absence of callus is not evidence of pseudoarthrosis. It is evidenced by the fusion of the medullary canal at the ends of the fragments and the formation of a closing bone plate along their edge.

X-ray diagnostics of dislocations is relatively simple: the images show the absence of the head in the glenoid cavity - a complete discrepancy between the articular ends of the bones. It is especially important to monitor whether the dislocation is accompanied by a breakaway of bone fragments from the articular ends. Bone fragments can prevent normal reduction of the dislocation. In order to recognize a subluxation, it is necessary to carefully examine the relationship of the articular head and the glenoid cavity. Subluxation is indicated by a partial discrepancy between the articular surfaces, as well as a wedge-shaped X-ray joint space.