Fractures of the body of the forearm bones: causes, symptoms, diagnosis, treatment

ICD-10 code

• 552.2. Fracture of the body [diaphysis] of the ulna.
• 552.3. Fracture of the body [diaphysis] of the radius.
• 552.4. Combined fracture of the diaphyses of the ulna and radius.

Anatomy of the forearm

The forearm consists of two bones: the radius and the ulna. Each of them has a body, proximal and distal ends. The proximal ends of the forearm bones participate in the formation of the elbow joint. The body is divided into the upper, middle and lower thirds. The distal end of the ulna ends in the head of the ulna, on which the styloid process is located on the inner side and somewhat posteriorly. The distal end of the radius is expanded and forms an articular surface for articulation with the bones of the wrist. The outer edge of the distal end of the radius protrudes somewhat and is called the styloid process.

The bones of the forearm are covered with muscles, which are divided into three groups: anterior, lateral and posterior.

• The anterior muscle group has four layers.
• The first layer consists of the pronator teres, flexor carpi radialis, palmaris longus, and flexor carpi ulnaris.
• The second layer is represented by the superficial flexor of the fingers.
• The third layer includes the flexor digitorum profundus and the flexor pollicis longus.
• The fourth layer is the pronator quadratus.
• The lateral muscle group consists of the brachioradialis muscle and the extensor carpi longus and brevis.
• The posterior muscle group has two layers.
• The superficial layer consists of the extensor carpi ulnaris, the extensor digitorum communis, and the extensor digiti minimi.
• The deep layer is represented by the supinator, the long muscle that abducts the thumb, the short and long extensors of the thumb, and the extensor of the index finger.

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Classification of forearm fractures

Diaphyseal fractures of the forearm include fractures of both bones or isolated injuries to the ulna and radius. According to the level of integrity violation, fractures of the upper, middle and lower thirds of the forearm bones are distinguished.

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Fractures of both bones of the forearm

ICD-10 code

S52.4 Combined fracture of the diaphysis of the ulna and radius.

Causes and symptoms of a fracture of both bones of the forearm

Displacements can be longitudinal, lateral, angular, and rotational. A lateral displacement occurs due to the mechanism of injury, a lateral displacement occurs due to the traction of the entire muscle sheath of the forearm, and an angular displacement occurs as a result of the mechanism of injury and contraction of the prevailing flexors and radial muscle group, which are stronger than their antagonists. Axis displacements seem to be the most complex. The degree of rotation depends on the fracture level of both bones or the radius and the effect of the antagonist muscle groups on the fragments. If the fracture occurs in the upper third of the forearm, below the attachment of the supinators but above the attachment of the round pronator, the central fragment will be maximally supinated and the peripheral fragment will be maximally pronated. Rotational displacement of fragments exceeds 180°. Another fracture level is when the fracture line passes below the attachment of the round pronator. In this case, the central fragment occupies a position intermediate between supination and pronation, since the force of the muscles rotating the forearm to the palmar and dorsal sides is balanced. The peripheral fragment is pronated under the action of the quadrate pronator.

Treatment of a fracture of both bones of the forearm

Indications for hospitalization

Patients with diaphyseal fractures of the forearm bones are hospitalized.

Conservative treatment of fracture of both bones of the forearm

In the absence of displacement of fragments, treatment consists of anesthesia of the fracture site with a 1% solution of procaine in the amount of 20-30 ml and fixation of the limb with a circular plaster cast from the middle third of the shoulder to the heads of the metacarpal bones. Limb position: for high fractures, the forearm is supinated, for fractures on the border of the middle and lower thirds, the forearm is given an average position between supination and pronation. Flexion in the elbow joint is 90 °, in the wrist - dorsal extension to an angle of 30 °, fingers in the position of grasping a tennis ball. The duration of permanent immobilization is 8-10 weeks, removable - 1-2 weeks.

In case of forearm bone fractures with fragment displacement, closed reposition is performed. It can be either manual or hardware-based. To facilitate the alignment of fragments, Sokolovsky, Ivanov, Kaplan, and N.I. Mileshin devices are used.

Under local anesthesia, after stretching and rotating the fragments (depending on the fracture level), the surgeon manually aligns the ends of the damaged bones. Without loosening the traction, a trough-shaped splint is applied from the middle third of the shoulder to the heads of the metacarpal bones in the position achieved by reposition. A control X-ray is taken. If the reposition is successful, the bandage is converted into a circular one. In case of massive edema, the splint can be left for 10-12 days until it subsides, and then a circular plaster cast can be applied. X-ray control is mandatory! It is always performed after the edema has subsided (regardless of whether the bandage will be replaced or not), so as not to miss secondary displacement of the fragments. The period of permanent immobilization is 10-12 weeks, removable - 24 weeks.

Surgical treatment of a fracture of both bones of the forearm

Surgical treatment involves open reposition of the forearm bones, which is performed using two separate incisions above the fracture site of the radius and ulna. The fragments are exposed and fixed in the chosen manner. Intraosseous fixation is most often performed using Bogdanov pins. One rod is driven into the medullary canal of the central fragment of the ulna until it emerges under the skin in the area of the olecranon. The skin is incised. The fragments are aligned, and the pin is retrogradely driven into the peripheral fragment. On the dorsal surface of the distal end of the radius, after a small additional incision in the skin, a channel is drilled through which the rod is inserted until it emerges from the end of the peripheral fragment. Reposition and osteosynthesis are performed, deepening the pin into the central fragment. For extraosseous fixation, various plates are most often used.

After surgical treatment by any method, external immobilization is necessary. A plaster splint is applied, after 10-12 days it is transformed into a circular plaster bandage. The period of permanent immobilization is 10-12 weeks, removable - 1-2 weeks.

The presented scheme of surgical treatment was considered classical until the last decade. Not very good results of treatment forced traumatologists to study more deeply the biomechanics of implants, the technique of their introduction, the disadvantages of dependence on immobilization and much more. Science has made great strides forward. However, not everyone has moved away from traditional methods of treatment. Some - due to the poor equipment of peripheral medical institutions, others, apparently, are trying to "re-evaluate values".

Thus, Holmenschlager F. et al. (1995) conducted a series of osteosynthesis operations on the forearm bones using bundles of pins, three in each bone (with pins of different lengths), and obtained good results.

However, intramedullary locked osteosynthesis with pins and (especially) extramedullary osteosynthesis with LCP and PC-Fix plates are becoming the method of choice in the treatment of diaphyseal fractures of the forearm. Plates with a locked screw and angular stability are fixed with 6 screws (3 above and 3 below the fracture). Osteosynthesis begins with the radius. At the end of the operation, the fascia is not sutured and is even cut lengthwise to avoid the development of Volkmann's ischemic contracture. Drainage is installed through a counter-opening for 2 days. External immobilization is not required.

In case of multi-fragmentary open fractures of the forearm bones, it is advisable to use pin and rod external fixation devices.

Approximate period of incapacity

After fractures without displacement, work can be resumed 10-12 weeks after the injury. In other cases, work capacity is restored after 12-16 weeks.