A supracondylar humerus fracture is a fracture of the distal humerus just above the elbow joint. The fracture is usually transverse or oblique and above the medial and lateral condyles and epicondyles. This fracture pattern is relatively rare in adults, but is the most common type of elbow fracture in children. In children, many of these fractures are non-displaced and can be treated with casting. Some are angulated or displaced and are best treated with surgery. In children, most of these fractures can be treated effectively with expectation for full recovery. Some of these injuries can be complicated by poor healing or by associated blood vessel or nerve injuries with serious complications.
Signs and symptoms
Supracondylar humerus fractures typically result from a fall on to an outstretched arm, usually leading to a forced hyperextension of the elbow. Typically, this is an isolated injury to the elbow (no injuries elsewhere). Children with this injury present with pain and swelling about the elbow. Motion at the elbow and at the wrist make the pain worse. With mild or moderate fracture displacement, there may be deformity at the elbow.
The fracture is caused by a fall on an outstretched hand (FOOSH) in 70% of cases. As the hand hits the ground, the elbow is hyperextended, resulting in a fracture of the distal humerus above the condyles. With hyperextension, the olecranon process of the ulna is forced against the weaker, immature metaphyseal bone of the distal humerus, producing the typical extension-type supracondylar fracture”. A flexion type fracture can result from a direct blow to the posterior aspect of the elbow when the elbow is in a flexed position. This causes the distal condylar fragment to displace in an anterior direction.
Diagnosis | Imaging
Diagnosis is confirmed by x-ray imaging. Displaced fractures are readily apparent. A non-displaced fracture can be difficult to identify and a fracture line may not be visible on the X-rays. However, the presence of a joint effusion is highly suggestive of a non-displaced fracture. Bleeding from the fracture expands the joint capsule and is visualized on the lateral view as a darker area anteriorly and posteriorly, and is known as the sail sign. Depending on the child's age, parts of the bone will still be developing and if not yet calcified, will not show up on the X-rays. At times, X-rays of the opposite elbow may be obtained for comparison. There are landmarks on the X-rays that can be used to assess displacement, including the "anterior humeral line", which is a line drawn down along the front of the humerus on the lateral view and it should pass through the middle third of the capitulum of the humerus.
Diagnosis | Imaging | Baumann's angle
"Baumann's angle", also known as the humeral-capitellar angle, is measured on an AP radiograph of the elbow between the long axis of the humerus and the growth plate of the lateral condyle.
Reported normal values for Baumann's angle range between 9 and 26° An angle of more than 10° is generally regarded as acceptable. When reducing paediatric supracondylar humerus fractures, a deviation of more than 5° from the contralateral side should not be accepted.
Alteration of Baumann angle: Baumann's angle is created by drawing a line parallel to the longitudinal axis of the humeral shaft and a line along the lateral condylar physis as viewed on the AP image normal is 70-75 degrees, but best judge is a comparison of the contralateral side deviation of more than 5 degrees indicates coronal plane deformity and should not be accepted.
Diagnosis | Classification
There are two primary types of supracondylar humerus fractures, referred to as extension and flexion types. These terms relate to the fracture displacement and the injury mechanism.
Diagnosis | Classification | Extension type
This is the most common type, accounting for 95% of all supracondylar fractures. Hyperextension occurs during a fall onto an outstretched hand (FOOSH) injury. The distal fragment is angulated posteriorly and may be displaced posteriorly as well. Extension type supracondylar humerus fractures are further classified according to the Gartland classification system, based upon the degree of angulation and displacement of the distal fragment.
- Gartland Type 1 fractures are non-displaced fractures
- Gartland Type 2 fractures are angulated fractures, usually "hinged" on the posterior cortex or the periosteum on the posterior bone surface.
- Gartland Type 3 fractures are angulated and displaced with angulation and complete separation between the fragments.
Diagnosis | Classification | Flexion type
This is the less common type, accounting for roughly 5% of supracondylar fractures. Flexion type injury is a result of direct trauma or a direct fall onto a flexed elbow. The distal fragment is angulated anteriorly and maybe displaced anteriorly as well.
Treatment | Neurovascular complications
The Pink and Pulseless hand in supracondylar fracture has been assigned the following causes:
1. tear or entrapment of the brachial artery
2. spasm of the artery and
3. compression of the artery relieved by manipulation of the fracture
4. compression of median nerve.
Thus there is loss of circulation of forearm, causing lack of reperfusion of tissues resulting in tissue death causing compartment syndrome.
Therefore, the complications of elbow dislocations include the following:
- Posttraumatic periarticular calcification, which occurs in 3-5% of elbow injuries
- Myositis ossificans or calcific tendinitis
- Neurovascular injuries (8-21% of cases) — palsy to the anterior interosseus nerve at time of index injury is most common, followed by brachial artery injuries (5-13%). Injury to the ulnar nerve is reported with percutaneous pinning through the medial epicondyle.
- Osteochondral defects, intra-articular loose bodies, and avascular necrosis of the capitulum
Supracondylar humerus fractures account for 55%-75% of all elbow fractures. They most commonly occur in children between ages 5–8, because remodeling of bone in this age group causes a decreased supracondylar anteroposterior diameter.