The shoulder joint is the most flexible joint in the body, and it is also one of the joints most prone to dislocation (instability). Shoulder dislocation accounts for 45% of all joint dislocations in the body, 85% of which are anterior dislocations.
According to the length of time after dislocation occurs, it can be divided into
1.Acute dislocation (dislocation within 24 hours): it is the easiest and most effective to reset at this time, so it is necessary to seek the doctor’s help in time to reset correctly.
2. Chronic recurrent dislocation (dislocation occurs several times or more): In this period, the reset is usually more difficult and requires reset under anesthesia or even incisional reset. The risk is also relatively higher at this time.
3.Random dislocation: The patient can dislocate or semi-dislocate the shoulder joint repeatedly under his own control, such as some special patients, or acrobats or contortionists. For this type of patient, the doctor can give rehab instructions for the scapular muscles, but if it is not effective, the doctor can basically “do what you need to do” or move a bench and watch the show, because this type of patient usually has poor surgical results.
Subluxation (instability) can be divided according to the onset factors.
1. Traumatic instability: Patients mostly have a history of traumatic dislocation, such as traffic accidents, falls and injuries, sports activities, etc.
2. Non-traumatic instability: Patients in this category have multi-directional instability of the shoulder joint, or bilateral shoulder joint onset at the same time, and are often accompanied by generalized joint laxity.
3.Neuromuscular instability: such as sequelae of encephalitis, cerebral palsy, birth palsy, brachial plexus injury, stroke (stroke), epileptic seizure, etc.
4.Unexplained instability: without clear trauma or disease factors, but unstable.
According to the direction of dislocation, it can be classified as
1.Anterior dislocation: the most common, about 85%.
2.Posterior dislocation: about 2%, the single leakage rate is very high, and the literature reports a leakage rate of more than 60%.
3.Below dislocation (straight lifting humeral dislocation): Because the symptoms are very typical, it is rarely missed.
4.Superior dislocation.
5.Bilateral dislocation: rare, mostly serious accidental injuries.
After dislocation occurs, the combined injuries that often result are.
1.Ligament and joint capsule injury: The glenohumeral ligament and joint capsule around the shoulder joint can be avulsed from the glenoid lip attachment, sometimes with avulsed bone mass, such as Bankart injury, Bony-Bankart injury, anti-Bankart injury, Hill-Sachs injury, anti-Hill-Sachs injury.
2.Fracture: Articular pelvis fracture, humeral head fracture, humeral tuberosity fracture, humeral stem fracture, rostral process fracture.
3, Rotator cuff tears: in patients over 40 years old, the incidence is greater than 30%, and in patients over 60 years old, the incidence is greater than 80%.
4. Vascular nerve injury: It may occur both when dislocation occurs and when the dislocation is reset. Injuries to the axillary artery, axillary vein and its branches, axillary nerve and suprascapular nerve are more common.
It is important to note that the recurrence rate of dislocation is often closely related to the patient’s age. The literature reports that patients whose initial dislocation occurs under the age of 20 years have a 90% chance of re-dislocation, while patients whose initial dislocation occurs over the age of 40 years have a dramatic decrease in the chance of re-dislocation to 10%-15%. It is especially noteworthy that re-dislocation occurs in the first 2 years after the first traumatic dislocation, and the easier the first dislocation, the easier the recurrence.
After understanding the pathogenesis of shoulder dislocation, do you understand that if a dislocation occurs for the first time, it is important to seek the most professional help in a timely manner and pay attention to protection and exercise within 2 years to prevent recurrent dislocations, so that your shoulder joint can be restored to an unbreakable “shoulder” again?