Chiu-chiu, a three-year-old boy, went to a playground with his parents on a Sunday. When he was amusedly playing on a slide, he broke into tears all of a sudden, crying, “I got hurt in my arm! Don’t touch me!” Surprised by this unexpected reaction, the parents tried to figure out what had happened and started to check on the arm with their bare eyes. But, as they could see, everything was normal. There was no swelling or bruise on the arm of the little boy, who, however, just kept crying regardlessly and disallowed his parents to hold his hand. This made the parents very anxious, and they could only decide on sending Chiu-chiu for checking in a nearby hospital by taxi.

After checking, a doctor on duty identified that Chiu-chiu suffered from pulled elbow, which is caused by subluxation (but not dislocation) as a result of twist. It is also known as nursemaid’s elbow as the injury is quite common to children looked after by childminders.

A human arm consists of two parts, namely forearm and upper arm. There is only one bone in upper arm, while forearm comprises two pieces of bone (namely radius and ulna). The three bones are jointed at elbow and are bound by an annular ligament so that the stability of an arm’s inwards and outwards rotational movements can be maintained.

When forearm rotates outwards, radius and ulna are parallel, and annular ligament tightens at the same time; when it rotates inwards or moves to a neutral position, radius and ulna cross each other with a lax annular ligament. It is the stretch and relaxation of annular ligament to allow the free movement of elbow and arm.

Nonetheless, the ligaments of children are relatively weak and of more flexibility. In addition to the fact that their connective tissues are still undergrown, their radii are likely to slip forwards slightly when their elbows are in a vertical position and their forearms are being vigorously pulled simultaneously (for instance, parents lift or drag their children by holding at their forearms). Consequently, their annular ligaments, which act like rubber bands to bind radii in normal elbows, will dislocate and get trapped. It is painful as the ligaments are being squeezed.

Girls are more easily to suffer from pulled elbow

It is observed that the most common sufferers of pulled elbow are children of two to three years old, of whom girls are of the majority. Yet the reason of this is still unknown. In most of the cases, doctors could slip the radii back into place with bare hands. Treatment process may cause pain though, an affected forearm can move at ease again just a few minutes after the treatment.

In the emergency room, the doctor used his hand to support the painful elbow of Chiu-chiu, while turning his arm outwards and bending his elbow gently at the same time. Suddenly, a “pop” sound from the elbow was heard, and then the little boy started to laugh and said loudly, “The pain is gone! The pain is gone!” The parents also thought it was amazing that the little boy could smile his tears away for a treatment of only a few seconds’ time.

Stronger ligaments make subluxation unlikely

Sequela is absent from the majority of pulled elbow cases, and the injury will not cause negative effect to children’s skeleton development. When children turn seven to eight, their ligaments will become tougher, and that makes subluxation unlikely. To avoid subluxation, adults should not pull children at their forearms. Parents should also remind the elderly and domestic helpers responsible for taking care of the kids that they should lift them by holding at their upper arms or shoulders instead.

However, in order to rule out other possibilities, such as fracture, being the cause of pain, the injured, in principle, are required to be X-rayed before or after restoration in accordance with their respective conditions. That being said, the majority of pulled elbow cases could be duly diagnosed by clinical checking and observation of symptoms, as well as tracing the clinical histories of the injured. After a successful restoration, additional treatment and putting the arm in a sling are usually unnecessary.

In fact, it is quite often that a “pop” sound can be heard from children’s elbows due to collision of their connective tissues. If the kids keep moving freely without uncomfortableness, such collision is of no harm in general. As bones and connective tissues grow, the situation can be improved. On the other hand, if the children show discomfort and their abilities to move are undermined, their parents should turn to a doctor for a detailed checkup.