Introduction
Instabilities occur primarily in the shoulder joint, which can be explained by the anatomy of the shoulder joint. The relatively large head of humerus contrasts with a much smaller glenoid cavity, whose joint surface is only about one third of that of the head of humerus. This anatomical structure of the glenohumeral joint allows a very extensive mobility of the shoulder and arm.
This somewhat unfavorable size ratio of the two joint partners is compensated by various anatomically important structures that ensure that the shoulder joint remains stable and does not dislocate (luxate). For example, the surface of the glenoid cavity is elastically enlarged by the so-called joint lip (labrum glenoidale) and the entire shoulder joint is enclosed by a joint capsule that stabilizes and centers the head of humerus. Optimal freedom of movement in all spatial directions of the shoulder is only possible at the expense of the stability of the joint.
This explains why the shoulder dislocates most often of all joints in the human body. Shoulder joint instability can be congenital or occur after an accident. Shoulder joint instability often results in a sudden rupture of the joint lip or joint capsule as a result of traumatic dislocation of the shoulder joint.
The most common injury associated with shoulder joint instability is the so-called “Bankart lesion”. This is usually caused by a dislocation of the shoulder forward in an accident, whereby the joint lip in the lower part of the anterior glenoid rim tears partially or completely. Due to the Bankart lesion, the joint lip in this area can no longer stabilize the shoulder joint properly and (further) dislocation of the shoulder can easily occur.
The instability of the shoulder joint can manifest itself as severe pain. An instability and associated weakness in the shoulder region and the inability to move the shoulder are also described. Swelling of the shoulder joint may occur, as well as numbness and tingling (paraesthesia) around the shoulder or in the fingers.
Shoulder joint instability most often occurs after an accident, usually during a sporting activity such as soccer or skiing. It is not uncommon for the accident to initially lead to a luxation of the shoulder joint (dislocation of the humeral head), which must be repositioned. The risk for further dislocations that follow later is determined by.
In some cases, shoulder joint instability is not preceded by an accident. In this case, a detailed diagnosis should be made to determine whether surgical intervention is necessary or whether conservative (non-surgical) treatment of the instability can be attempted first.
- The anatomical requirements
- The age of the person concerned and
- The corresponding sports activity
First of all, the patient’s medical history is thoroughly investigated with regard to the complaints caused by shoulder joint instability.
In order to confirm the diagnosis, a clinical examination of the shoulder joint and framing imaging procedures are also necessary. In this way, valuable information about pathological changes in the shoulder joint and the associated soft tissue structures can be gathered. The standard procedure is an x-ray of the shoulder joint, but sometimes magnetic resonance imaging of the shoulder (MRI, magnetic resonance imaging of the shoulder joint) can also be informative.
If an operation is to be performed to treat instability of the shoulder joint, it is usually necessary to perform a few laboratory tests beforehand, rarely an ECG (electrocardiogram) and an X-ray of the chest. The clinical picture of shoulder joint instability can be divided into different categories. First of all, a dislocation can be distinguished from a subluxation, since in the case of a complete dislocation (luxation), no contact between the joint surfaces can be detected.
Furthermore, a distinction is made between traumatic (with accident event) and atraumatic (without accident event) shoulder joint instability, depending on the cause. Most acute dislocations are anterior (anterior) or anterior-inferior (anterior-inferior), only very rarely is the direction of dislocation posterior (dorsal).
- Scope
- Frequency
- Severity and
- Direction
The treatment of shoulder joint instability can essentially be carried out in two different ways: 1. conservative therapy A dislocated shoulder should be repositioned as soon as possible.
Prior to this, an X-ray check should be performed to rule out bony injuries. If necessary, the reduction can be performed under short anaesthesia. If the shoulder has been dislocated before, the dislocation may be performed without anesthesia.
In some cases, conservative (non-surgical) treatment may also be possible, taking into account the individual anatomical causes of shoulder instability. In this case, pain is alleviated with suitable painkillers and after the dislocation, the shoulder is immobilized for a short time (e.g. in a Gilchrist bandage). Subsequently, intensive training of the muscles (especially the back muscles) under physiotherapeutic supervision is recommended.
Surgical therapy Surgical therapy of shoulder instability aims to correct the existing injury in order to restore the normal anatomy as accurately as possible. In most cases, shoulder instability surgery is performed arthroscopically, i.e. as part of a joint endoscopy. This surgical technique is minimally invasive, as only two to three small skin incisions of about one centimeter in length are usually required.
Only in very rare cases may an open surgical procedure be necessary, for example, if bony splinters have been caused by a shoulder joint luxation and are “floating around” freely in the joint space. In an arthroscopic procedure, optics with a camera system and corresponding special instruments are inserted through the small openings in the shoulder joint. In this way, the existing damage to the shoulder joint can be repaired.
In many cases, the torn capsule or the torn joint lip is reattached to the bone with the help of a thread anchor. These sutures are bioresorbable implants, which means that they dissolve after a certain time and do not need to be removed. After this time, the anatomical structure has healed again.
Post-operative treatment Immediately after the operation, the patient is fitted with a shoulder splint (orthosis), which allows only very limited mobility of the shoulder joint. Due to the protection, a stabilization and scarring process can begin, which usually leads to a stable shoulder again. Temporarily, there is a limitation of mobility in the shoulder, especially by avoiding abduction and external rotational movements (this could dislocate the shoulder again).
The prospects of success with surgical treatment of shoulder joint instability are very good; in over 95 percent of cases, stability of the shoulder joint can be achieved again. The prerequisite for this is optimal follow-up treatment in accordance with the recommendations of the treating physician or therapist.
