What are Dislocations and Subluxations of the Radial Head?
Isolated dislocations and subluxations of the radial head are rare. Most often, the head of the radius is shifted anteriorly, less often – outward and posteriorly. Dislocation of the radial head anteriorly may be accompanied by a fracture of the ulna in the upper third, damage to the deep branch of the radial nerve. Dislocation occurs when falling on an unbent and supinated arm, when a hand hits the rotating mechanisms of machines.
Symptoms of Dislocation and Subluxation of the Radial Head
With a dislocation of the head, lateral flexion in the elbow joint is slightly limited. With other dislocations, bending is difficult and limited. Dislocation of the head outside is determined by palpation. Radiography clarifies the diagnosis.
Diagnosis of Dislocation and Subluxation of the Radial Head
Diagnosis is based on the clinical picture.
Treatment of Dislocation and Subluxation of the Radial Head
Eliminate dislocation under anesthesia. The assistant fixes the shoulder in the supine position, the surgeon extends the forearm pronounced and bent in the elbow joint, fixes the elbow joint with the other hand and presses the thumb on the head of the radius at the time of supination of the forearm. After control x-ray, the limb should be immobilized with the posterior plaster cast in the position of extreme supination of the forearm for a period of 3 weeks. In the case of an unstable position of the head after repositioning it must be fixed transarticularly with knitting needles. With an irreparable dislocation of the radial head, an open reduction or resection of the head is performed, the results of which are much better if it is performed in the early stages after an injury.
The pronational subluxation of the radial head is a common lesion in children aged 1 to 4 years. Usually, such a subluxation occurs when a child is sharply pulled by the hand and forearm. Predisposing factors for this dislocation are the relative weakness of the annular ligament and the underdevelopment of the radial neck. In addition, the articular bag between the radial head and humerus in young children is wider, the synovial membrane forms a fold that is restrained between the articular surfaces. The diagnosis is based on a typical medical history and clinical presentation. Usually the forearm is penetrated, bent at the elbow joint, pressed to the body. Movement of the forearm causes sharp pain. Children often indicate pain in the lower third of the forearm and wrist joint. X-ray examination, as a rule, does not reveal a defect.
Repositioning the head is easy, usually without pain relief. The surgeon draws the patient’s hand in the position in which the arm is located, achieving full extension in the elbow joint, then performs rotational movements – supination and pronation of the forearm. With the other hand, the surgeon puts pressure on the head of the radius and slowly bends the supinated forearm in the elbow joint. When the head is adjusted, a click is felt. After 2-3 minutes, the child calms down and independently makes movements in the elbow joint. The limb is immobilized for 2-3 days with a scarf. For relapses of subluxation after reduction, apply a plaster cast for 10-15 days.