Yingze Zhang, Song Liu, and Chenguang Du

A total of 355 patients with 356 radial/ulnar fractures were investigated in the China National Fracture Study (CNFS). The fractures accounted for 20.14% of all patients with fractures and 19.42% of all types of fractures. The population-weighted incidence rate of radial/ulnar fractures was 63 per 100,000 population in 2014. The epidemiologic features of radial/ulnar fractures in the CNFS are as follows:

• More females than males

• More right-side injuries than left-side injuries

• The highest-risk age group is 15–64 years

• Distal fracture of the radius/ulna is the most common forearm fracture

• Injuries occurred most commonly via slips, trips, or falls

Radial/Ulnar Fracture by Sex

A total of 75,850 patients with 76,550 radial/ulnar fractures were treated in 83 hospitals of China over a 2-year period from 2010 to 2011. All cases were reviewed and statistically studied; the fractures accounted for 18.28% of all patients with fractures and 17.73% of all types of fractures, respectively. Among these 75,850 patients, 18,274 were children with 18,334 fractures, and 57,576 were adults with 58,216 fractures. Epidemiologic features of radial/ulnar fractures are as follows:

• More males than females

• More left sides involved than right sides

• The highest-risk age group is 11–15 years; the most affected female age group is 56–60 years, while males between the ages of 11 and 15 years have the highest risk

• Distal fracture of the radius/ulna is the most common forearm fracture

Radial/Ulnar Fractures by Sex

Radial/Ulnar Fractures in Adults by Segment Based on AO Classification

Radial/Ulnar Fractures in Children by Segment

The bony structures of the proximal part of the radius/ulna consist of the olecranon, coronoid process, radial head, radial neck, and part of the metaphysis. The bony surfaces of the humeroradial joint constitute an enarthrosis or ball and socket joint, between the radial head and the capitulum of the humerus, while the proximal radioulnar joint is a trochoid or pivot joint between the radial head and the ring formed by the radial notch of the ulna and the annular ligament. These two joints play an important role in the complex action of turning the forearm over as in pronation or supination. The humeroradial joint is considered similar to a lateral column that provides stability to the elbow joint during its motion in flexion or extension.

The articular surfaces of the elbow joint are connected by a capsule that is attached to the radial neck, 1.5 cm distal to the humeroradial joint. The radial tuberosity, also known as the bicipital tuberosity, is the main insertion of the biceps brachii muscle.

The olecranon and the coronoid process form a large depression called the semilunar notch that serves as an articulation site with the trochlea of the humerus. The humeroulnar joint is a simple hinge joint that allows for flexion and extension. The tendon of the triceps brachii muscle inserts into the posterior portion of the upper surface of the olecranon, while the ulnar nerve winds along the olecranon or epicondylar groove.

A total of 7,202 adult proximal radial/ulnar fractures (segment 21) were treated in 83 hospitals of China over a 2-year period from 2010 to 2011. All cases were reviewed and statistically studied; the fractures accounted for 12.37% of all fractures of the radius/ulna in adult. Their epidemiologic features are as follows:

Fractures of Segment 21 by Sex

Olecranon Fractures

Olecranon multifragmentary fracture can be caused by direct trauma, as in falls on or blows to the point of the elbow. Such types of fractures also occur during a fall on the semiflexed supinated forearm with the hand striking the ground, and the pull of the triceps muscle leading to a transverse or wedge fracture of the olecranon.

Fractures of Radial Head or Neck of the Radius

This type of injury is usually from a fall on an outstretched arm with the force of impact transmitted up the hand through the forearm to the radial head, which is forced to the capitellum and often causes fractures in the anterolateral aspect of the radial head or neck of the radius. Multifragmentary fractures or dislocation may occur by high energy trauma.

Coronoid Fractures

Coronoid fracture, rarely seen in isolation, usually occurs in combination with olecranon fracture; this type of fracture results from an avulsion fracture of the bony structure of the coronoid, by contraction of the joint capsule with the elbow in hyperextension.

The insertion of the triceps muscle on the olecranon is usually compromised when olecranon fractures occur. In most cases, patients cannot fully strengthen their arm due to the pain and are unable to overcome any resistance. The movement of supination aggravates the pain from fractures in the radial head or neck of the radius and limits the range of motion.

Olecranon fractures are unstable fractures, usually requiring surgical intervention. Plate fixation, tension band wiring, and other internal fixators can be utilized in stabilizing the fracture, depending on the fracture type. Stable fractures of the radial head or the neck of radius with no displacement can be managed nonsurgically, but with close monitoring of fracture progression within 4 weeks. Minimal invasive internal fixation is preferable for fractures with dislocation or when nonsurgical treatment fails. Based on fracture type, patient’s age, and general condition, various internal fixators can be selected, including screws, absorbable screws, and Kirschner wires (K-wires). Anatomic reduction to the utmost, rigid fixation, and early mobilization are applied even for complex fractures. Excision of the radial head and replacement with a prosthesis should be considered only as a last resort.