Olecranon fractures

Mechanism of injury and classification

Injuries to the proximal forearm bones are frequently accompanied by olecranon fractures. In the vast majority of cases, these are intra-articular injuries, which can be either simple or comminuted.

The fracture line typically has a transverse or oblique-transverse orientation. Most commonly, the bone breaks in the middle of the trochlear notch, slightly less often the base of the process is involved, and fractures of the apex itself are uncommon.

From the perspective of injury mechanism, there are two main pathways:

• Direct blow to the elbow area is the most frequent cause.
• Avulsion mechanism — occurs due to a sharp contraction of the triceps brachii muscle (significantly less common).

The degree of bone fragment displacement is of fundamental importance for the physician. The threshold is a diastasis of 5 mm. If the distance between the fragments exceeds this value, one can reliably speak of a concomitant rupture of the tendon fibers above the fracture zone. This exact factor is decisive in choosing further management tactics.

Clinical examination and inspection

An injury can be suspected already at the visual inspection stage. The patient assumes a forced posture: the injured arm is straightened, hangs powerlessly along the trunk, and the patient supports it against the body with the healthy hand. The posterior surface of the joint appears smoothed out, and pronounced swelling is observed.

Palpation reveals sharp local tenderness. If there is displacement, the physician may palpate a characteristic depression (gap) between the fragments.

Special attention is paid to bony landmarks:

• Normally, the apex of the olecranon and the epicondyles of the humerus form an equilateral Hueter's triangle.
• In a fracture, the apex is displaced proximally (above the line of the humeral epicondyles). The triangle becomes deformed: its base remains the same, while the sides become shorter than the base.
• Important: in comminuted injuries, the fragments may injure the ulnar nerve, therefore a thorough assessment of the patient's neurological status is mandatory.

Joint function assessment and diagnostics

Functional tests play a critical role in establishing the diagnosis. Passive movements in the joint are usually preserved, although they cause pain. Active flexion is also possible. However, active extension is completely impossible if a displaced fracture has occurred (due to the rupture of the triceps tendon).

A special test is used to accurately check the ability of active extension. The patient's shoulder is abducted to the horizontal line, the forearm is flexed at a 90° angle, and slight internal rotation of the shoulder is added. The patient is then asked to actively extend the forearm against gravity. Inability to perform this movement confirms the diagnosis.

The standard radiological examination is radiography in two projections. The lateral projection, performed with the elbow flexed to 90°, is considered the most informative.

At the pre-hospital care stage, it is sufficient to immobilize the limb with a sling or transport splint (from the upper third of the humerus to the phalanges of the hand) and provide analgesia with common analgesics.

Conservative treatment and rehabilitation

Conservative management is indicated exclusively for non-displacement fractures or those with minimal diastasis (up to 2–3 mm).

Main treatment principles:

1. Immobilization: a plaster cast is applied, encompassing the area from the upper third of the humerus down to the metacarpophalangeal joints.
2. Position: the limb is fixed in a neutral position between pronation and supination, with the elbow flexed at an angle of 90–110°.
3. Nuance of fixation: sometimes on the radiograph with a flexed elbow the diastasis exceeds 5 mm, but it completely disappears in the extended position. In such cases, the arm is immobilized with a plaster cast in the extended position.

The duration of permanent immobilization is 3–4 weeks. After this, the cast is converted into a removable splint for 7–10 days, while simultaneously initiating range-of-motion exercises in the joint.

Rehabilitation measures start early: physical therapy (PT) for the fingers is indicated as early as day 2, and PT for the shoulder joint from day 3. Full recovery of the range of motion with adequate therapy usually occurs in 1.5–2 months.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Neurological status assessment in suspected ulnar nerve injury
• Biomechanics and deformation of Hueter's triangle
• Technique for performing the active extension test
• Management tactics for fractures with displacement greater than 5 mm (surgical treatment)

Other topics in the "Specialized Adult Traumatology" section

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