Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

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Elbow Injuries in Children

Elbow injuries in children

Unique bony problems of the elbow are seen in children and adolescents. The pathology of these problems corresponds to each stage in the development of the elbow—that is, prior to the appearance of all the secondary centers of ossification in children; prior to fusion of the ossification centers in adolescents; and prior to the completion of bony growth in young adults. The majority of injuries are due to overuse resulting from an increase in frequency, rapidity, and duration of throwing.

Medial injuries

The medial side of the elbow is subjected to distraction forces which may cause injury to the medial epicondyle and the medial soft tissues, including the capsular structures and the ulnar nerve. In children, ossification of the medial epicondyle may be disturbed by enlargement of the epicondyle or by osteochondrotic (bone-cartilage) changes. In adolescents, avulsion fractures of the medial epicondyle may occur. The epicondyle may occasionally displace in the joint causing mechanical derangement. After fusion of the medial epicondyle, muscular injuries are more frequent and may cause the development of osteophytes (bone spurs).

Lateral injuries

On the lateral side of the elbow, bony disturbance from repetitive compression and shearing forces may occur during childhood at both the head of the radius and the capitellum. Injury to the lateral aspect may affect the entire epiphysis with enlargements and fragmentation throughout. During adolescence, the periphery of the ossification center is affected more with avulsion fractures damaging the articular cartilage and forming loose bodies. The capitellum and sometimes the head of the radius are affected by lesions.

Posterior injuries

In children, stress fractures and nonunion of the olecranon epiphysis (growth zone) may occur, as well as ectopic bone formation around the olecranon tip and loose body formation at a later date.

The various throwing injuries can be related to the various stages of the throwing mechanism. An understanding of this mechanism, as well as of the stages of the skeletal maturation in the youthful athlete, is important in diagnosing and treating throwing injuries.

Clinical examination

Examination starts with inspection followed by palpation, evaluation of motion, strength testing, and instability testing.

Any gross swelling or muscle hypotrophy should be noted. Holding the forearm and hand supinated and the elbow extended, the angle formed by the humerus and forearm is determined (the carrying angle). The average is 10° for men and 13° for women. An inflamed olecranon bursa with swelling on the posterior aspect is a sign of olecranon bursitis.

The bony landmark needs to be palpated. Any tenderness is noticed as this usually indicates the area of injury.

Motion is important in assessment of elbow function. The motion occurs around two axes: flexion and extension and forearm rotation with pronation and supination. Flexion and extension ranges from 0° to 140° ± 10°. Pronation is often 70° and supination is 85–90°.

Flexion and extension strength testing is performed against resistance with the forearm in neutral rotation and the elbow at 90° of flexion. Elbow extension strength is normally 70% of flexion strength and is best measured with the elbow at 90° of flexion with the forearm in neutral rotation. Pronation and supination strength are also best studied with the elbow at 90° of flexion. Supination strength is normally about 15% greater than pronation strength.
The collateral ligament instability is evaluated with the elbow flexed and in 30° extension. Varus stress is applied with the humerus in full internal rotation and the lower arm pressed inwards. Valgus instability is
best measured with the arm in full external rotation and the lower arm pressed outwards.

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