Posterior shoulder dislocation: a rare and difficult injury to detect
Posterior glenohumeral dislocation of the shoulder is difficult to diagnose. It is a rare injury, accounting for less than 3% of all shoulder dislocations. Diagnosis is not straightforward and requires a thorough clinical examination.
The challenge of immediate detection is nevertheless full of implications: late detection of the pathology often leads to a stiff and painful shoulder, and this chronicity results in complex surgery, not always followed by a cure.
What is a posterior shoulder dislocation?
The most common type of posterior shoulder dislocation involves the arm in internal rotation and held in adduction. Its external rotation is limited, as are its elevation capabilities.
The causes of such a dislocation most often stem from direct or indirect, high-energy trauma such as a violent anteroposterior shock or during convulsive crises: epilepsy, alcoholism or even electroshocks.
Dislocations of this type are difficult to detect initially and do not always lead to the correct procedures being applied among all the treatments for shoulder pathologiesThis is why they often recur, because they are not treated in time or are misdiagnosed. The shoulder remains painful with a instability glenohumeral is very disabling, the major risk being avascular necrosis of the humeral head.
Why is glenohumeral dislocation difficult to diagnose?
The patient with a glenohumeral dislocation presents with a stiff and painful shoulder on examination. Initially, no changes in its shape or any particular swelling are visible to the naked eye. Palpation also reveals no changes in appearance.
Upon closer examination, radiology is also not always able to detect it, as the clinical signs of posterior shoulder dislocation are not loud enough on X-rays, hence the importance of the axillary view.
To avoid misjudging the trauma, the practitioner must apply a strict and exhaustive examination, particularly for the radiological examination in order to properly detect the rounding of the humeral head due to internal rotation of the limb and the loss of congruity of the joint.
What are the possible treatments for posterior shoulder dislocation?
Shoulder immobilization and closed reduction under general anesthesia are indicated to reduce pain and improve healing prospects, depending on the patient's age, strength, and physical condition. Surgical techniques that aim to restore anatomy (grafting, osteosynthesis, etc.) have better results than so-called non-anatomical techniques (arthroplasty, rotational osteotomy, subscapularis tendon transfer according to McLaughlin, etc.).
Depending on the protocols, the arm may be immobilized for 45 days before the start of the knee rehabilitation However, more and more surgeons, such as Christophe Charousset, advocate early self-rehabilitation from day 0 to day 21, focusing on learning active shoulder positioning (internal rotation and humeral piston), mobilization in the scapular plane, passively, actively assisted, and then freely, from supine to seated, and finally static and dynamic contractions of all shoulder muscles, especially the subscapularis, within the permitted range of motion. This is followed by active recovery of mobility in all ranges and muscle strengthening, proprioception, and plyometrics. In throwing sports, the Thrower's Ten Program (TTN) rehabilitation protocol can be applied.
Shoulder rehabilitation using the Allyane method
Posterior shoulder dislocations, particularly in young women, often have a significant emotional component, and it is within this context that Allyane offers a comprehensive, innovative, and non-invasive rehabilitation method. The primary goal of neuromotor reprogramming is to rebuild the muscle tone and balance necessary for function and movement, as well as to reduce pain. Rather than focusing solely on pain management, the aim is to restore shoulder mobility using a low-frequency sound generator and motor imagery. The low-frequency sounds induce an alpha state in the brain, a kind of reduced alertness that promotes optimized kinesthetic visualization and bridges the gap between conscious and subconscious awareness. These visualization techniques for our proprioceptive sensations unconsciously modify our muscle tone and normalize our spatial and temporal recruitment during voluntary movements. These modifications take place during a mirror therapy type of work, transferring sensations from the healthy side to the pathological side through a mental imagery protocol guided by the therapist.
The aim is to re-afferent two key muscles that are often centrally inhibited to protect the joint: the serratus anterior and the subscapularis.
The serratus anterior, or serratus anterior, is essential for scapulothoracic stability, a prerequisite for a functional shoulder. It exhibits selective atrophy and impaired recruitment from the first days of immobilization. Re-afferentation using mirror therapy from the unaffected side is vital.
The subscapularis is considered an internal rotator of the humerus, but it is much more. Nicolas Blanchette perfectly highlights the subscapularis's crucial role in shoulder biomechanics. It is far from being a simple internal rotator. This internal rotation function is overshadowed by the pectoralis major and latissimus dorsi, which are much more powerful. The subscapularis depresses the humeral head during shoulder abduction. Thus, along with the other rotator cuff muscles, it counterbalances the superior force exerted by the deltoid. Without this function, the compression of soft tissues by the humeral head in the subacromial space (where a large bursa is located) would be greatly increased.
The subscapularis tendon blends with the anterior ligament capsule of the shoulder, playing a stabilizing and protective role. It stabilizes the humerus anteriorly, preventing the humeral head from sliding excessively forward. It is also the strongest stabilizer of passive external rotation at zero degrees of abduction. Its role is therefore vital in preventing dislocations during forceful movements.
The lower part of the tendon blends with the transverse humeral ligament, which encapsulates the tendon of the long head of the biceps. Together, they form the key mechanism for stabilizing the long head of the biceps during shoulder movements.
According to recent studies, the upper part of the subscapularis tendon also plays a significant role in humerus abduction, a function similar to that of the supraspinatus muscle.
The goal of Allyane neuromotor reprogramming will therefore be:
- to re-afferent these two key muscles for glenohumeral stability,
- to overcome motor inhibitions and improve the muscular function of the shoulder complex through a general relaxation protocol,
- allowing for a rapid return of function and ultimately a significant reduction in pain.
It is probably in complex pathologies such as posterior shoulder dislocation with a strong emotional connotation that the Allyane concept finds its full justification: a non-invasive, rapid and lasting method.
Are you a healthcare professional with questions about the Allyane method? Feel free to contact our team by phone at +33 4 28 29 48 14 or by email at [email address missing]. contact@allyane.com.
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