Luxatio Erecta (Inferior Glenohumeral Joint Dislocation)
Inferior glenohumeral joint dislocation also known as luxatio erecta is a very rare and complex type of shoulder dislocation that accounts only for 0.5% of all glenohumeral dislocations.
While anterior dislocations have a high incidence rate, inferior shoulder dislocations have an occurrence of 1 in 200 of all dislocations.
“Luxatio erecta” which means erect dislocation in Latin is derived from the typical way in which the arm is abducted and held above.
Although it is very uncommon, it is more frequent in men than in women. The patients suffering from inferior shoulder dislocation are young and it is likely that a significant number of them may suffer from recurrent shoulder dislocation in the future.
What is Inferior Glenohumeral Joint Dislocation?
The glenohumeral joint, a ball-and-socket joint, is the most flexible part of the body providing maximum range of motion. The glenoid fossa, 1/3rd the size of the humeral head, is extremely shallow, allowing for extreme mobility of the humeral head. The rotator cuff with labrum and tendons attached to it add stability to the joint.
Inferior dislocations occur when the humeral neck is hyper abducted against the acromion causing it to force the humeral head out of the socket, tearing the inferior capsule.
Causes of Inferior Glenohumeral Joint Dislocation
Luxatio erecta is mainly caused by a traumatic injury to the shoulder with 80% of patients sustaining greater tuberosity fracture or rotator cuff tear injury and up to 60% of patients having neurologic compromise.
A fall from height, motor vehicle collision is a very likely cause. Low-impact falls although rare have also been reported to cause inferior dislocation.
Symptoms of Inferior Glenohumeral Joint Dislocation
Patients suffering from inferior glenohumeral joint dislocation show symptoms of:
- Not being able to move shoulder in any direction
- Severe pain and swelling in the inferior region of the shoulder
- Neurological injury up to 60%
- Vascular damage up to 40%
- Inflammation in the inferior region and around it
- Deformity in the shoulder- a squared like appearance in the shoulder
Diagnosis of Inferior Glenohumeral Joint Dislocation
Performing a diagnosis of inferior dislocation begins with a good detailed medical history of the patient followed by a physical examination.
The doctor will ask the patient about the injury in great depth to ascertain the other injuries that may have occurred to the soft tissues surrounding the shoulder. If the injury was due to high force trauma, the doctor will look into other traumatic injuries too. If the injury is caused due to a simple fall while the arm was abducted it is highly likely to cause injury to the inferior capsule of the joint.
The patient may also suffer damages to the rotator cuff muscles, bone vascular, and surrounding nervous structures.
An inspection will reveal that the arm is fully abducted above the head with the elbow flexed at 90 degrees. The patient will not be able to lower the arm without any significant pain.
Physical examination is followed by carrying out X-rays and MRI scans. The x-rays will show the overlapping of the structures. MRI scans can further help in revealing rotator cuff, glenoid bone bruises.
If the doctor suspects neurovascular damage, angiography or Doppler studies should be done.
Diagnosis of inferior glenohumeral joint dislocation is simple as the problem itself is very uncommon.
Treatment for Inferior Glenohumeral Joint Dislocation
The majority of the cases of luxatio erecta are successfully managed with closed reduction and post-reduction immobilization. Two methods of reduction have been suggested.
- Traction-Countertraction Method:
In this method, the doctor will wrap a sheet around the patient’s upper torso and have an assistant pull on it in such a way that force is applied in the opposite direction of the traction followed by gentle abduction after the humeral head has been disengaged. The degree of shoulder abduction is gradually decreased.
- Two-Step Maneuver Method:
In this method, inferior dislocation is converted into anterior dislocation before being reduced. One hand is placed on the dislocated humerus and the other hand on the medial condyle. The humerus is then adducted with any of the common anterior reduction techniques to reduce the head of the humerus into the glenoid fossa. The two-step maneuver method is advantageous because it requires minimal force.
In both methods when the humeral head returns to its normal anatomic position, a “clunk” is heard.
After coming back into its anatomical position, the arm should be placed in a shoulder immobilizer to avoid recurring dislocation as the soft tissues and muscle stabilizers are injured and will be lax.
In rare cases, if the reduction is not achieved through nonsurgical methods the doctor will opt for surgery. Indications of surgery are irreducible dislocation by closed techniques, open dislocation, and vascular injury.