What are Dislocations of the Hand?
Dislocations of the bones of the hand occur in the wrist joint. The skeleton of the hand consists of a large number of small bones of the wrist and joints and half-joints between them. The wrist joint is the joint between the ulnar and radial bones on the upper side and the eight bones of the hand on the lower side. Eight small short bones, connecting together in two rows, form a wrist. Their upper row is formed by scaphoid, lunate, trihedral and pea-shaped. Dislocations of the scaphoid and lunate bone meet. The remaining bones of the wrist are extremely dislocated.
Causes of Hand Dislocations
Dislocations of the hand occur, as a rule, when falling with an emphasis on the hand, as well as with a direct impact in the area of the corresponding joint.
Symptoms of Dislocation of the Hand
True dislocations of the hand. Such dislocations are characterized by a complete displacement of the articular surfaces of the proximal row of the wrist bones together with the hand relative to the articular surface of the radius. Distinguish between rear dislocation and extremely rare – palmar dislocation of the hand. Such damage can be accompanied by a fracture or separation of the styloid processes and the edge of the radius, as well as severe bruises. In clinical practice, true dislocations of the hand are rare. Perilunar lesions predominate, which account for up to 90% of all dislocations in the area of the wrist joint.
Perilunar dislocation of the hand. Dislocation occurs with the extensor mechanism of injury in the wrist joint. The lunate bone in this case remains in place and is in contact with the radius, and the remaining bones along with the capitate are displaced to the back and proximal. In some cases, such damage can be accompanied by a fracture of the styloid processes of the radius and ulna.
Perilad-lunar dislocation of the hand. Such damage is characterized by the fact that the scaphoid and lunate bones remain in place and articulate with the radius, and the remaining bones of the hand are displaced to the back and proximal.
Perithehedral-lunar dislocation of the hand. Damage is characterized by a dislocation of the hand, in which the lunate and trihedral bones remain in place, and the remaining bones of the hand move in the back and proximal. This type of injury is very rare.
Amyloid-perilunar dislocation of the hand. Such a dislocation refers to a fracture. In this type of damage, a scaphoid fracture occurs, as a rule, in the middle third, and perilunar dislocation of the hand. The lunate bone and the proximal scaphoid fragment associated with it, with the help of the semi-moon scaphoid ligament, remain in place and are in contact with the urethra. The distal fragment of the scaphoid along with the bones of the hand is shifted to the back side.
Transradicular-transresolunar dislocation of the hand. It is also a fracture. A fracture of the scaphoid and lunate bones is characteristic, in which their proximal fragments come into contact with the radius. The remaining bones of the hand with distal fragments of the lunate and scaphoid bones are shifted to the back side and proximal.
The clinical picture of dislocations of the hand and fractures of the wrist is similar to that of fractures of the radius in a typical place. With a true dislocation of the hand, a symptom of springy fixation of the hand is detected, in all other cases there is a significant restriction of active and passive movements in the wrist joint and soreness.
Diagnosis of Hand Dislocations
Palpation on the rear of the hand is determined by the bulge. All types of back dislocations are characterized by flexion of the fingers. It is possible to compress the median nerve in the area of the carpal tunnel. The final diagnosis is established on the basis of compulsory x-ray examination in the direct and lateral projections, and if necessary, x-ray in a 3-D projection.
Hand Dislocation Treatment
In fresh cases, the elimination of all types of hand displacement is performed under conduction anesthesia or anesthesia (local anesthesia is possible). The hand and the assistant carry out the direction of the hand, the angle of flexion in the elbow joint is 90 °. The assistant holds the limb by the shoulder, and the surgeon produces traction along the axis of the forearm, stretching the wrist joint, while one hand of the surgeon produces traction for the first finger of the hand, and the second for the other four.
After stretching the wrist joint and with continued distraction using the thumbs of the hands of the hands, the surgeon presses on the protruding part of the hand in the wrist joint until the back dislocation is removed.
Having eliminated the back dislocation, the hand is fixed in the flexion position at an angle of 40 ° from the neutral position with the back plaster cast from the metacarpophalangeal to the elbow joint and a control x-ray is made. After 2 weeks, the hand is removed from the position of bending and again fixed for 2 weeks for all types of dislocations of the hand. After reposition of the supracoid-perilunnar dislocation of the hand, the treatment is carried out, as in a scaphoid fracture.
With instability of the wrist joint, which is determined by the relapse of the dislocation immediately after repositioning and by the control x-ray, the joint can be fixed with Kirschner spokes. The spokes are carried in an oblique direction through the distal end of the radius from its outer surface, through the wrist joint and the middle third of the V metacarpal.
Reduction of dislocations can be done with the help of distraction devices in the following cases: if it is impossible to close the dislocation of the dislocations and fractures of the hand, in the absence of symptoms of compression of the anatomical formations in the wrist channel, as well as with late access to medical care (after 1-3 weeks). The operative reduction of dislocations is especially indicated with compression of the median nerve in the wrist channel. Prolonged compression of the nerve can lead to its degeneration. Access to the carpal joint is carried out through the back arched incision. Finger extensor tendons and hands do not cross. If necessary, additionally cut the capsule of the wrist joint. With distraction along the axis of the forearm, interponing tissues are eliminated and dislocation is corrected. In case of instability of the wrist joint, transarticular fixation with Kirschner spokes is performed, then the wound is sutured in layers. The period of fixation of the wrist joint is 4-6 weeks, and in case of an extracostal-perilunar dislocation – up to 3-4 months.
With chronic dislocations and fractured dislocations of the hand (after 3 weeks or more), two-stage surgical treatment is indicated. At stage I, a distraction apparatus is applied. Spokes for 2 rings or half rings are passed through the radial bone, and one through the bases of the II-V metacarpal bones. After stretching the wrist joint for 7-10 days, an open reduction of the dislocation is performed, and the apparatus is removed. The wrist joint is transarticularly fixed with needles. In the case of an extracostal-perilunar dislocation of the hand, after reposition of the dislocation, fragments of the scaphoid bone are repaired and fixed with their needles. The postoperative period is, as with conservative treatment. In advanced dislocations with the development of deforming arthrosis, surgical treatment is indicated aimed at arthrodesis of the joint. After the termination of immobilization conduct a course of rehabilitation treatment.
With a true dislocation of the hand, wrist arthrodesis is performed according to Brockman with resection of the articular surface of the radius, head of the ulna and economical resection of the articular surfaces of the scaphoid, lunate and, if necessary, three faceted bones. The hand is set in the extension position at an angle of 20-30 ° to the axis of the forearm. The wrist joint is fixed with Kirschner spokes.
The reduction of a long-standing super-conoid-perilunar or fiperilad-lunar dislocation of the hand with the development of deforming arthrosis consists in performing primary limited osteoplastic arthrodesis of the wrist joint according to Ashkenazi using cylindrical grafts from the iliac wing crest.