What is a collarbone fracture?
The collarbone is the hand-length tubular bone that connects the shoulder blade to the ribcage at the sternum. A clavicle fracture is an injury to this bone caused by a fall or a car accident (by the seatbelt). This usually results in oblique fractures and wedge fractures, which form two main fracture pieces and a so-called bending wedge.
Frequency of clavicle fracture
The collarbone fracture is the most common fracture after the radial fracture (near the wrist). Around 60 out of 100,000 people break their clavicles every year. Children are particularly often affected. Over 85 percent of fractures occur before the tenth birthday. In under-fives, the collarbone breaks more often than any other bone. Sometimes babies even break their collarbone during birth – this happens to around one in 200 newborns. Fortunately, a collarbone fracture is one of the least problematic bone fractures.
Collarbone fracture: causes and risk factors
Most collarbone fractures are sports injuries. The thin tubular bone breaks because you fall on your shoulder or the outstretched arm with which you are trying to break the fall. The following sports are particularly risky for the collarbone:
- Skiing
- Cycling (especially mountain biking)
- Inline skating
- Soccer
Occasionally, a collarbone fracture is caused by direct force, for example when the seatbelt in a car is tightened abruptly in a rear-end collision or by a blow to the front shoulder. As a result of a motorcycle accident, the collarbone sometimes breaks when the lower edge of the motorcycle helmet presses against the bone.
In addition, one in 200 births results in a fracture of the collarbone. Large babies are at risk if their shoulder girdle barely fits through the mother’s pelvis.
Symptoms: Swelling and severe pain
A clavicle fracture usually results in the following symptoms:
- You feel severe pain after a fall or a violent impact on your collarbone. It occurs when pressure is applied to the injured shoulder or you move your arm on the side where the collarbone is broken.
- The area of your collarbone above the fracture swells up considerably and a haematoma develops.
- If you have broken your collarbone, pull your upper arm towards your upper body in a recovery position and tilt your shoulder slightly forwards.
- A visible and also palpable step can occur in the collarbone if the fracture ends of the long bone are displaced. Sometimes the collarbone appears to be shortened by the fracture. This happens because the head turning muscle (sternocleidomastoid muscle) pulls on the bone fragment that is close to the sternum.
- It is very rare for an open collarbone fracture to occur. Symptoms are bleeding and visible bone ends that show through the skin.
- Another typical symptom is a rubbing noise from the broken bone when you move the shoulder joint.
Classification
There are two main classifications that are frequently used:
- Allmann classification (whole clavicle)
- Classification of lateral (outermost third of the clavicle) clavicle fractures according to Jäger and Breitner
Allmann classification
- Type 1: middle third
- Type 2: lateral third
- Type 3: medial third
Classification of lateral clavicle fractures according to Jäger and Breitner
- Type 2a: unstable injury in which ligaments are also affected
- Type 2b: stable / moderate injury in which ligaments are also affected
- Type 3: is a lateral clavicle fracture without ligament involvement
- Type 4: Injuries in children and adolescents in which the clavicle protrudes from the overlying periosteum
In around 80 percent of cases, the collarbone breaks in the middle section, as this is where the diameter of the bone is smallest. A clavicle fracture in the middle of the shaft can cause the fracture ends to shift due to muscle tension of the head turning muscle (sternocleidomastoid muscle).
The collarbone rarely breaks at its outer ends, as the bone is thicker there and numerous ligaments stabilize it.
Collarbone fracture: diagnosis at the USZ
If you have broken your collarbone, your doctor will usually be able to make a diagnosis as soon as he or she notices the typical symptoms:
- You have pulled your upper arm towards your upper body in a resting position and have tilted your shoulder slightly forwards.
- There is swelling and bruising (hematoma) on the collarbone. There may be a visible and palpable step on the broken bone.
- If you move your arm on the side affected by the fracture or exert pressure on the shoulder, you will feel pain on the collarbone.
- Your doctor will hear the rubbing sound of the broken bone when you move your shoulder (known as crepitation).
Your doctor will perform an X-ray examination of the shoulder and collarbone in at least two planes to confirm the suspicion of a collarbone fracture and to localize the fracture more precisely. He or she can diagnose the fracture reliably on the X-ray. The image can also be used to assess the extent, position and type of clavicle fracture.
It sometimes happens that we overlook a clavicle fracture near the sternum on the X-ray due to superimposition effects. In such a case, a computer tomography (CT) scan can support the diagnosis. This imaging procedure can also be used to detect a minor clavicle fracture.
We will also examine whether the collarbone fracture has also injured nerves and vessels that supply the arm on the affected side. If such concomitant injuries exist, they disrupt both the blood circulation and the sensitivity of the arm. They can also hinder the movement of certain muscles. In such cases, it usually makes sense to operate on the clavicle fracture.
Collarbone fracture: prevention, prognosis, complications
As a collarbone fracture is usually the result of an accident, you can only prevent it by avoiding sports that can cause you to fall or by practicing them with the utmost caution.
Prognosis of the clavicle fracture
The prognosis for a collarbone fracture is good, provided you undergo professional therapy and physiotherapeutic follow-up treatment. This usually results in complete healing without movement restrictions. In some cases, the shoulder may be narrowed after conservative treatment (i.e. without surgery). This does not impair the function of the shoulder joint. Overall, you should expect the healing process to take six to eight weeks.
In some cases, you may have to undergo surgery – for example, if the blood vessels or nerves under the collarbone are injured at the same time or the bone fragments are severely displaced. During the operation, the surgeon repositions the fragments and fixes the collarbone with a titanium or metal plate. The healing period after surgery takes about twelve weeks.
Complications of the collarbone fracture
In very rare cases, clavicle fracture surgery can lead to complications: large vessels, nerves or the pleura can be injured. If the fracture does not heal in the bone, a so-called false joint (pseudarthrosis) can form after the operation – but also after conservative treatment. It often makes further surgery necessary.
