Elbow dislocation

An elbow dislocation is a complete dislocation of the elbow joint between the humerus and the two forearm bones, the radius and ulna , which is usually triggered by an accident with high forces acting on the elbow (traumatic dislocation). Often there are additional injuries, especially to the collateral ligaments or fractures in the adjacent bones, and joint instability often remains. Nerve lesions, especially the ulnar nerve and the median nerve , are also possible.

The incomplete dislocation is called a subluxation . The dislocation of the radial head, especially in small children, is not an elbow dislocation, but is called Chassaignac's palsy .

Elbow dislocation is the second most common dislocation after shoulder dislocation. The incidence is estimated at 6 per 100,000 per year. By falling on the outstretched arm with hyperextension of the elbow, the elbow hook lever out the humerus, which then dislocates forward (or the forearm bones dorsally relative to the humerus, therefore dorsal dislocation as the most common form). Dislocations to the side, ventrally, between the two forearm bones or through the olecranon with an accompanying fracture of the olecranon are rare and account for less than 5% of all elbow dislocations.

therapy

The most important measure is the reduction ( reduction ), which must be carried out immediately, especially in the case of nerve or vascular damage. Due to pain-related muscle tension, direct reduction is often not possible; then it is done under short anesthesia or analgesic sedation . Regional anesthesia should not be used because it is necessary to control any nerve lesions.

In the typical dislocation of the elbow hook (olecranon) to the rear, it can be reduced by pulling on the forearm, with the elbow bent at right angles and pressing dorsally on the distal upper arm. Alternatively, the upper arm can be gripped close to the elbow with both hands from above and behind, and then the elbow hook can be pressed down and forward with both thumbs. If the “closed” reduction does not succeed, it must be “open”, ie surgically with opening of the joint ( arthrotomy ).

After the reduction, it must be checked immediately whether there is any vascular or nerve damage. The stability of the collateral ligaments and any tendency to dislocate should also be checked immediately under anesthesia. After that, an accompanying bone fracture must be excluded in the X-ray image, which cannot always be seen immediately in a first image before reduction. Often, oblique images are also helpful, especially for assessing the radial head and the coronoid process of the ulna.

If there are no accompanying injuries, it is a simple dislocation , which is usually treated with short-term immobilization in a plaster splint. An operation is then usually not necessary. After the initial pain has subsided, increasing physiotherapeutic exercise therapy and increasing mobilization of the elbow are usually carried out from the second or third day. Longer immobilization must be avoided because of the risk of stiffening. Movement devices for continuous passive motion ( CPM = continuous passive motion ) are often used.

Concomitant injuries and complications

• Collateral ligament injury: in principle, capsule-ligament parts are injured with every dislocation, but these usually heal functionally. Surgical treatment does not seem to have any advantages over a non-surgical approach with initial immobilization and early mobilization. Nonetheless, permanent lateral instability can rarely occur, which later has to be surgically stabilized if the pain persists and functional impairment continues. According to O'Driscoll, the increasing severity of the dislocation leads to a circular, increasing tear in the ligament complex, starting from the lateral side and moving towards the medial side. Accordingly, three stages of the O'Driscoll ligament rupture are described:
  • Stage I: tear of the lateral ulnar collateral ligament, possibly resulting in dorsolateral rotational instability and increased external rotation in the humeroulnar joint. This is shown by a dorsal subluxation of the radial head with repeatable clicking of the radial head with forced supination in extension, which can be checked by a "pivot-shift" test according to O'Driscoll. In the X-ray image, the radial head in the lateral view may be displaced / subluxed behind the humeral capitulum when completely supinated.
  • Stage II: rupture of the remaining lateral ligament structures and the anterior and posterior joint capsules
  • Stage III: also tear of the medial ulnar collateral ligament. In particular, the tear in the anterior portion of the ligament can lead to valgus instability, which should be checked in both 30 ° and 90 ° flexion in the elbow joint.
• Broken bones : The fractures of the radial head and the broken off of the coronoid process of the ulna are particularly common . Both serve to stabilize the bones, and a fracture of both bones with additional ulnar ligament avulsion results in severe instability with the risk of renewed dislocation, which is also known as the terrible triad (after Tschnerne). In the case of an isolated fracture of the proc. coronoideus , surgical stabilization is usually not necessary, which is also difficult to carry out in the case of a small fragment or a comminuted fracture. With a simultaneous fracture of the radial head , however, stabilization by means of screw osteosynthesis is usually necessary. Alternatively, the distal biceps tendon can be transferred to the fractured proc. coronoideus (after Reichenheim 1947), which also contributes to a ventral stabilization of the elbow.

Another procedure for avulsion fractures of the coronoid process is fixation with the aid of a transosseous ligament suture in the "lasso technique", in which the ligament suture runs through the tendon attachment and repositions and fixes it together with the small bone fragment to the ulna. This method was proposed by Ring in 2002 and was found to be beneficial in a retrospective comparison in 40 patients. Compared to screw osteosynthesis, healing occurred more frequently, with significantly fewer instability problems and fewer intraoperative complications. Since even small bone fragments can result in considerable instability, the lasso technique was also recommended in these cases.

• Reluxation tendency : This is increased especially if there is no bony stabilization, especially if there is a simultaneous fracture of the radial head and fracture of the proc. coronoid . If the ulnar collateral ligament is torn at the same time, there is usually massive instability, which is referred to as a terrible triad . Temporary stabilization can first be achieved with a cross-joint external fixator . Reconstruction is usually difficult because the terrible triad occurs particularly in older women with severely osteoporotic bone.
• Cartilage damage : In addition to osteochondral flakes , i.e. cartilage bone exfoliation, osteochondrosis dissecans and free osteochondral fragments are also possible. Arthroscopy is therefore sometimes recommended after elbow dislocation, but its overall effectiveness is questionable. In the case of persistent painful blockages or synovitis, elbow arthroscopy is usually indicated to remove unwanted free fragments, smooth the cartilage, possibly perform a synovectomy and possibly refix cartilage fragments. Long-term post-traumatic elbow osteoarthritis is possible.
• An open dislocation is an indication for arthroscopy or even arthrotomy in order to flush the joint and remove any foreign bodies. For this purpose, antibiotics must be administered for several days in order to prevent a joint infection ( empyema ) from invading germs.
• Vascular nerve lesions are an absolute emergency indication, arterial injuries in particular must be ruled out or, if confirmed, vascular surgery treated immediately. Either a suture of the affected vessel is possible, or a patch or vascular graft must be used. Complications can include gangrene of the hand or forearm, but also forearm compartment syndrome . Nerve lesions should also be surgically exposed ( neurolysis ) in order to remove any compression of the nerves.
• Joint stiffening is a very common consequence, sometimes only in the final range of motion, so not disturbing in everyday life, but often also functionally restrictive. By arthrolysis the movement deficit can be corrected surgically, but with mixed success. Flexion deficits are often caused by the bone callus after a fracture of the proc. coronoideus , due to osteophytes in the beginning of osteoarthritis, or bony attachments on the front of the humerus and especially in the coronoid fossa. In cases of bony extension deficits, there may be bony reactions of the olecranon fossa or at the tip of the olecranon. To prevent stiffening, early and intensive mobilization of the elbow joint is particularly important in older patients, often using continuous passive movement splints (CPM).
• Periarticular ossifications occur in up to 55% of all elbow dislocations and can also lead to considerable restriction of movement. Surgical treatment is often complex and associated with a high risk of recurrence. Nonsteroidal anti-inflammatory drugs can be used for prophylaxis , as can local radiation.

Long-term results after simple dislocation

If there are no accompanying injuries such as a broken bone or collateral ligament tear, it is referred to as a "simple" dislocation. The treatment usually consists of a “closed” reduction, ie without surgical opening of the joint, and early mobilization from the initial immobilization, e.g. B. in a Gilchristverband . In a few cases, a closed reduction is not possible, so that a surgical procedure must be performed.

The incidence is 2.9 cases per 100,000 population per year. The mechanism is usually a fall, from a great height (13%), from standing height (57%) or during sport (15%). A physical assault (9%) or a traffic accident as a pedestrian (6%) can also be the cause. Women fall from standing height more often, the average age of women is higher than that of men. High-energy trauma is more common at a young age; a minor accident is often sufficient in older years.

A large Scottish survey of 110 cases (54% men, mean age at dislocation 38 years) showed overall good functional results and hardly any instability problems, but pain and stiffness often persisted. A subjective and objective instability existed in 8% and was operated on in 2% later. Subjectively perceived stiffness was found in 56%, but only in 2% an operative intervention was carried out later and persistent pain persisted in 62% with a mean follow-up time of seven years. In particular, a remaining restriction in flexion was associated with a poorer functional result; the result was also poorer in women. A new dislocation did not occur in any case.

Elbow dislocation in children

Dislocations before the age of seven are extremely rare, since the accident mechanism leads to a supracondylar upper arm fracture instead of elbow dislocation .

In the case of congenital elbow dislocation with further joint misalignments, Larsen syndrome must be considered.

From the age of seven, however, the dislocations are identical to those in adults. In addition to the fracture of the coronoid process , there is also a fracture of the ulnar epicondyle more frequently ; the ulnar nerve and also the median nerve can become trapped in the fracture gap . A fracture of the ulnar epicondyle is usually surgically reduced after exposing the nerves and fixed with two K-wires . It is recommended to fix collateral ligament instabilities with surgery. When the elbow joints are closed and repositioned, a cast immobilization in the upper arm cast is usually only carried out for 7–10 days, with subsequent increasing mobilization. Sport is usually pain-free about six weeks after the cast has been removed. However, freedom of movement is only achieved after three to four months - but it is not uncommon for a slight extension deficit that does not interfere with the function.

The growth plates are almost never disturbed, so that there is no incorrect growth, especially since the growth plates near the elbow contribute only slightly to the growth in length of the long arm bones. A tear in the radial collateral ligament occasionally creates a bony fragment that is noticeable on the X-ray but otherwise does not cause any symptoms.

literature

1. ↑ ^{a b} D. Eygendaal: Elbow instability . In: N. Gschwend, PM Rozing (Ed.): Upper arm, elbow and lower arm , Volume 4 of the series Surgical Techniques in Orthopedics and Traumatology. Urban & Fischer Verlag Munich
2. ↑ ^{a b c d e} B. Weigel, M. Nerlich: Praxisbuch Unfallchirurgie , Springer-Verlag Berlin 2005
3. ^ Grant E. Garrigues, Walter H. Wray III, Anneluuk LC Lindenhovius, David C. Ring, David S. Ruch: Fixation of the Coracoid Process in Elbow Fracture-Dislocations . Journal of Bone and Joint Surgery 2011; Volume 93-A, Issue 20 of October 19, 2011, pp. 1873-1881
4. ↑ ^{a b} R. E. Anakwe et al .: Patient-reported outcomes after simple dislocation of the elbow , Journal of Bone and Joint Surgery 2011; 93 (Am): 1220-1226
5. ↑ L. von Laer: fractures and dislocations in growing age . 3. Edition. Thieme-Verlag Stuttgart 1996

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