Radial head subluxation
| Classification according to ICD-10 | |
|---|---|
| S53.0 | Dislocation of the radial head |
| ICD-10 online (WHO version 2019) | |
A subluxation of the radial head (also Chassaignac paralysis or pronatio dolorosa ; Latin : Subluxatio capituli radii or Subluxatio radii perianularis ; English : Nursemaid's elbow or pulled elbow - German: nanny's elbow or Sunday arm ; French : pronation douloureuse for small children up to) is more than five years frequently occurring Pronationsblockade , often as Teilausrenkung ( subluxation ) of the spokes condyle is called.
It is caused by a strong, unprepared and sudden pull on the fully extended and pronated (inwardly turned) forearm or hand. The most common situation is pulling the screaming, struggling child up off the floor by the hand. But it can also be triggered if the child holds on with one or both hands and is pulled away forcefully, or if it is held with both hands and rotated quickly in a circle. Pediatricians therefore warn against the "angel fly" game, even if subluxation can only occur in the pronation position of the forearm. It has also been described in judo, rarely through direct trauma.
The disease is not to be confused with the congenital radial head dislocation .
Pathomechanism
The exact cause is not known, it is generally assumed that the radial head partially slips forward and distally out of its holding ring ligament ( Annular ligament ), and that it is then trapped between the radial head and the humeral capitulum when the tension is released. The event itself is very painful, afterwards there is usually little or no pain if the arm is not moved or pulled. The child holds the forearm in a gentle posture in an inward rotation (pronation) and slight flexion, so that the arm appears paralyzed ( pseudoparesis ), hence the name Chassaignac paralysis. Occasionally, a click may be heard or felt with the subluxation.
Initial description
It was first described in 1671 by the French surgeon D. Fournier. A symptom of the radial head subluxation ( Chassaignac paralysis ) and the repositioning maneuver ( Chassaignac handle ) are named after the French surgeon Charles Marie Édouard Chassaignac (1805–1879).
frequency
Radial head subluxation is one of the most common injuries in children under 4 years of age. It usually occurs in children between 1 and 4 years of age, in children over 5 years it practically no longer exists. This is explained by the fact that the annular ligament ( lig. Anulareradii ) is stronger and is more firmly anchored distally to the neck of the radius. The ring ligament ensures that the movement in the humerus-radius joint (actually a ball joint) is restricted (by strongly binding the ulna and radius to one another).
diagnosis
The diagnosis is made on the basis of the symptoms described and the course of the injury. The arm is held paralyzed and no longer used for playing. The elbow is usually slightly bent and the forearm is always turned inwards (pronated). In calm and cooperative children, painless flexion and extension of the elbow is possible, but no rotation of the forearm.
If the trauma was not immediately preceded and the presentation was delayed, with symptoms that have existed for several hours or one to two days, or a relieving posture, septic elbow arthritis can very rarely also be present, in which the patient is also relieved with slight flexion and pronation.
roentgen
Whether an X-ray of the elbow joint in two planes is necessary is controversial. On the one hand, an obligatory X-ray check is required in order to rule out accompanying bone fractures of the radial head and distal humerus (no information is available about the actual frequency). On the other hand, other experts consider X-rays to be dispensable and unnecessary if the anamnesis and the findings are clear and typical and there are no longer any complaints after the reduction.
An X-ray of a subluxation of the radial head is normal, there is no visible shift of the radial head to the humeral capitulum , in contrast to a true radial head dislocation. No effusion can be detected echographically.
It is described that the X-ray assistant can already lead to re-adjustment (reduction), since the forearm must be kept fully extended and fully turned out (supination) for an exact frontal (ap) exposure of the elbow.
Sonography
With the help of an ultrasound examination, both the cartilaginous radial head and its position can be shown, and the ring ligament can also be mapped directly with a dynamic examination and good resolution of the ultrasound device.
therapy
There are several reduction techniques, all of which involve forceful supination. In rare cases it can happen that an edge of the ring ligament folds in and thus becomes an "obstacle to reduction". A common reduction technique is the simultaneous extension of the forearm with tension and outward rotation ( supination ). Occasionally, pressure is exerted radiodorsally on the radial head of the forearm with the thumb ( Chassaignac handle ) - although there is no real dislocation and only higher pressure is exerted on the retracted ring ligament instead of the radial head. Another technique is the powerful and brisk supination of the elbow bent at 90 °.
A general anesthetic is not required. The improvement occurs immediately - to the astonishment of the relatives: the arm is moved and used normally again. Subsequent immobilization or further checks are not necessary.
Occasionally, the presentation is delayed, sometimes more than 24 hours later. Then it is often not possible to achieve immediate freedom from symptoms after repositioning, and subluxation can easily occur again, even during sleep. Then an upper arm cast in supination is recommended for a few days to two weeks to protect yourself.
The risk of a renewed subluxation of the radial head is 5%, so parents should be strongly advised not to pull the child up by the hand. Frequently recurring subluxations are also an indication for three to six weeks of immobilization in an upper arm cast - in addition to the serious discussion of the cause of the subluxation with the parents.
Sources and individual references
- ↑ https://www.aponet.de/junge-familie/engelchen-flieg-besser-nicht.html
- ↑ a b c Lutz von Laer: Fractures and dislocations in growing age. 3. Edition. Georg-Thieme-Verlag, Stuttgart 1996, ISBN 3-13-674303-2 .
- ↑ a b c d e J. A. Herring: Tachdjian's Pediatric Orthopedics. 3. Edition. 3 volumes. WB Saunders Company, Philadelphia (USA) 2002, ISBN 0-7216-5685-4 .
