Nursemaid Elbow

Nursemaid elbow, or “pulled elbow” of childhood occurs when an axial traction force is applied to an abducted arm with the elbow in extension and pronation, resulting in a tear of the incompletely developed annular ligament in children.

Nursemaid elbow typically occurs in children less than 5 years old, with a range from as young as 3 months to 73 months. The peak age for occurrence is approximately 26 months.

Nursemaid elbow is a common pediatric injury, representing approximately 20 percent of upper extremity injuries.

See Also: Nursemaid Elbow Reduction

Nursemaid Elbow Mechanism of Injury

Traditionally, a subluxation of the radial head (the entity’s other name) was thought to result directly, but cadaver studies performed by Hutchinson and Salter describe a more complex process. As the radius subluxes inferiorly and anteriorly due to the applied traction, a tear of the most distal insertion of the annular ligament on the radial neck occurs.

This results in a subluxation of the partially torn annular ligament superiorly, exposing the anterior portion of the radial head. The torn segment of the annular ligament becomes interposed in the joint space between the radial head and capitellum.

Pronation is a prerequisite along with elbow extension for this injury to be produced; it will not occur in supination.

The classic situations in which this mechanism results in the nursemaid injury occur when a child is being pulled by the wrist by a parent and the child either resists or falls, or by picking up or swinging a child by the arms.

On presentation, the classic mechanism of a pulling injury has been reported to be present in 51 to 93 percent of cases. More typically, a non-classic mechanism is elicited in one-third of cases. Other reported mechanisms offered by parents have included falls or unknown mechanism.

In children less than six months old, a common alternative mechanism is rolling over or being assisted in rolling over. A possible contributing factor involved in some of the non-classic mechanisms reported may be due to reluctance on the part of parents to accurately describe what occurred due to issues of responsibility for contributing to the injury.

See Also: Elbow Anatomy

Clinical Evaluation

Parents usually report that at the time of the injury, the child suddenly started crying for a variable period of time followed by a refusal to move the injured extremity. However, parents are frequently unable to localize the level of the injury on the affected arm.

In the study by Quan that looked at presenting chief complaints of patients ultimately found to have a nursemaid elbow injury, elbow injury was only recorded 10 percent of the time.

Other chief complaints included:

1. arm injury (61%),
2. shoulder injury (10%),
3. sprain (11%),
4. wrist injury (4%).

There is a slight predilection for involvement of the left arm (61% reported by Schunk, 58% by McDonald and 57% by Teach) which is postulated to result from the fact that most parents are right handed and would therefore be expected to favor grasping the child’s left hand with their right hand.

Physical Examination

At the time of examination, the pediatric patient is usually not experiencing active pain but is observed not to move the affected arm and cannot be coaxed to use it with offers of a toy or food.

The elbow should look uninjured (no gross deformities) but still (no spontaneous movements).

The classic attitude of the injured extremity (referred to as the nursemaid’s position), is one of adduction, with flexion at the elbow and partial pronation.

What will be absent on inspection is any degree of supination which is a clue to the diagnosis. There should also be no observed swelling and no ecchymosis.

On palpation, tenderness may be elicited over the radial head but none should be found over the distal humerus, olecranon or proximal ulna.

Limited passive range of motion for flexion and extension may be tolerated by the patient but typically supination will be resisted and will frequently elicit crying.

Assessment of the neurovascular status should be performed including:

1. Documentation of normal motor function for the anterior interosseus nerve (“OK” sign with thumb and index finger),
2. Posterior interosseus nerve (“Hitchhikers” sign with thumb extension),
3. Ulnar nerve (“Crossed finger” sign, ability of middle finger to cross dorsally over index finger),
4. Sensory function of the radial nerve (first dorsal webspace), median nerve (volar pad of index finger), and ulnar nerve (volar pad of small finger).

Documentation of the presence of radial and ulnar pulses and adequacy of capillary refill should be recorded.

Radiology

Standard radiographs of the elbow (AP, lateral and oblique) are typically negative for abnormal findings.Classically, this has been explained by the fact that although the radial head subluxes inferiorly and anteriorly due to the distracting force that occurs during the injury, the radial head then spontaneously reduces and therefore, no radiographic abnormality should be expected.

It is for these reasons that radiographic imaging is felt not to be indicated when the suspicion is high for a pulled elbow injury.

However, two reports describe abnormalities involving the radiocapitellar line (normally a line drawn through the center of the proximal humerus should always bisect the middle-third of the humeral capitellum on any view) on X-rays obtained in patients ultimately determined to have nursemaid’s elbow injuries. Both the studies described displacement of the radiocapitellar line off the capitellum.

Approach to the Child with a Suspected Nursemaid Elbow

Scenario 1:

The history is consistent with a nursemaid elbow mechanism of injury. The arm is in the nursemaid’s position.

At most, only mild tenderness is localized over the radial head without elbow swelling or ecchymosis.

Recommendation: Elbow radiographs are not indicated and it is acceptable to proceed directly to reduction. The hyperpronation technique is the recommended first technique to employ.

Scenario 2:

History is unclear (either not witnessed by caregiver or nonstandard mechanism). The arm is in the nursemaid’s position.

Tenderness is limited to the radial head (no distal humeral, olecranon, proximal ulna tenderness), no elbow swelling or ecchymosis.

Controversial: Some authors recommend radiographs first, to rule out possibility of supracondylar fracture with the attendant risk of fracture displacement resulting from attempted nursemaid reduction maneuver. Other authors noting the high incidence of atypical histories state, it is acceptable to proceed without X-rays first as long as no “atypical” physical findings are present (point tenderness was included as an atypical feature).

Recommendation: In the setting of witnessed or suspected fall onto the elbow or outstretched hand, it is prudent to obtain radiographs first to rule out fracture. Otherwise, it is acceptable to proceed directly with a reduction attempt without first obtaining elbow radiographs, adhering to the caveat that at most minimal tenderness limited to the radial head may be present, but the presence of tenderness at other locations, elbow swelling, or ecchymosis should prompt radiographic evaluation before attempted reduction.

Scenario 3:

History is unclear or non-standard mechanism. Any of the following findings are present: swelling, ecchymosis, or tenderness over distal humerus, humeral condyles, olecranon, proximal ulna.

Recommendation requires radiographic imaging first to rule out an osseous injury, in particular a supracondylar fracture.

Nursemaid Elbow Reduction

The standard reduction technique is Supination-flexion involves supination at the wrist followed by flexion at the elbow.

An alternative technique is the pronation or hyperpronation technique (with or without flexion).

See Also: Nursemaid Elbow Reduction

References

1. Teach S. Prospective study of recurrent radial head subluxation. Arch Pediatr Adolescent Medicine. 1996;150:164-6.
2. Hutchinson J. On certain obscure sprains of the elbow occurring in young children. Annals of Surgery.1885;2:91-8.
3. Hutchinson J. Partial dislocation of the head of the radius peculiar to children. British Medical Journal. 1886;1:9-10.
4. Irie T, Sono T, Hayama Y, Matsumoto T, Matsushita M. Investigation on 2331 cases of pulled elbow over the last 10 years. Pediatr Rep. 2014 May 6;6(2):5090. doi: 10.4081/pr.2014.5090. PMID: 24987508; PMCID: PMC4076648.
5. Quan L. The epidemiology and treatment of radial head subluxation. American Journal of Diseases of Children. 1985;139:1194-7.
6. McDonald J, Whitelaw C, Goldsmith LJ. Radial head subluxation: comparing two methods of reduction. Acad Emerg Med. 1999 Jul;6(7):715-8. doi: 10.1111/j.1553-2712.1999.tb00440.x. PMID: 10433531.
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