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.
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Mechanism
The fracture is caused by a fall on an outstretched hand 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.
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Signs and symptoms
History: The injury typically results 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).
Presenting complaints: The child presents 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.
Diagnosis
Examination:
- There is pain and swelling about the elbow. Bleeding at the fracture results in a large effusion in the elbow joint.
- Depending on the fracture displacement, there may be deformity. With severe displacement, there may be an anterior dimple from the proximal bone end trapped within the biceps muscle.
- The skin is usually intact. If there is a laceration that communicates with the fracture site, it is an open fracture, which increases infection risk. For fractures with significant displacement, the bone end can be trapped within the biceps muscle with resulting tension producing an indentation to the skin, which is called a "pucker sign".
- The vascular status must be assessed, including the warmth and perfusion of the hand, the time for capillary refill, and the presence of a palpable radial pulse.
- The neurologic status must be assessed including the sensory and motor function of the radial, ulnar, and median nerves. In displaced fracture, a neurologic deficit is found in 13% of patients. The mostly commonly injured nerve is the median nerve (specifically, the anterior interosseous portion of the median nerve). Injuries to the ulnar and radial nerves are less common.
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.
- The anterior humeral line is a line drawn down along the front of the humerus on the lateral view and it should pass through the middle of the capitellum.
- The central axis line of the radius should point to the capitellum and AP and lateral views.
- The ulnohumeral arc is a curved line drawn on the lateral view, that follows the superior surface of the ulna, curving up at the coranoid, and extending up along the anterior aspect of the humerus.
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.
Extension type:
This is the most common type, accounting for 95% of all supracondylar fractures. 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.
Flexion type:
This is the less common type, accounting for roughly 5% of supracondylar fractures. The distal fragment is angulated anteriorly and maybe displaced anteriorly as well.
Treatment
Initial treatment is based on the fracture type and displacement:
- Non-displaced fracture are treated with a long arm cast for 4-6 weeks. Initial treatment may be with a posterior splint for the first few days until the risk for progressive swelling decreases. The splint is then replaced with a long arm cast. Repeat X-rays are often done to make sure that the fracture remains non-displaced.
- Displaced fractures are generally treated with surgery. "Most orthopedic surgeons (96%) agreed that the treatment of choice for displaced supracondylar fractures of the humerus in children is closed reduction and percutaneous pinning" Among adult patients, most of displaced distal humeral fractures are managed with open reduction and internal fixation.
Additional initial treatment if needed:
- Most supracondylar humerus fractures are are closed (skin intact) injuries. If there is a laceration associated with the fracture, the laceration and the fracture site are carefully examined to remove visible debris and cleaned with fluid with a procedure referred to as "irrigation and debridement".
- If there are changes to the vascular status, treatment starts with addressing the fracture. Repositioning the fracture may lead to improved blood flow. If the blood flow remains compromised, it may be necessary to open the fracture and assess the blood vessels. It may be possible to relieve pressure on the artery to improve blood flow. If the is damage to the artery and vascular surgery may be needed to repair or bypass the injured area.
- If there is evidence of a nerve injury, recovery usually occurs with time. It often takes several months for full recovery. If there is not evidence of recovery with a 2-3 months, nerve testing may be needed to clarify the injury and to look for subtle signs of recovery. If recovery is not apparent by 6 months, surgery to address the nerve injury may be needed.
Subsequent treatment:
- Following initial treatment with casting or surgery, follow up is needed to confirm treatment is progressing. Typically, a followup X-ray is done after 1 week to confirm that the fracture is still in a good position. The initial cast or splint may be removed or reinforced with an overwrap of fiberglass casting material.
- After 3-4 weeks, the cast is removed. If there are percutaneous pins, the adjacent skin is cleansed and the pins are grasped and removed with gentle twisting. This is mildly uncomfortable for the child for few minutes, but reasonably well tolerated. The arm is often stiff and weak after cast removal. Removing the cast early at this point helps to minimize stiffness.
- Use of a sling may be recommended for 1-2 weeks following removal of the cast. Good skin care and gentle stretching is recommended to address dry skin and help to recover motion. Physical therapy is usually not needed. Return to activities is allowed after 6-8 weeks.
Neurovascular complications
The Pink and Pulseless hand in supracondylar fracture has been assigned the following causes:
- tear or entrapment of the brachial artery
- spasm of the artery and
- compression of the artery relieved by manipulation of the fracture
- 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. (See Volkmann's contracture)
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
- Instability
Other injuries
- Most commonly brachial artery injury, and if left untreated could lead to Volkmann's contracture (permanent flexion contracture of the hand at the wrist, resulting in a claw-like deformity of the hand and fingers).
- Cubitus varus: Also known as gunstock deformity. This is more of a cosmetic problem, and does not affect the range of motion of the elbow joint.
- Malunion: The condyles of the distal humerus do not correctly join together.
Source of the article : Wikipedia
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