Shoulder instability is the term that is used to denote the incapability to keep the humeral head in the glenoid fossa. The ligamentous and muscle structures around the glenohumeral joint will make a balanced net joint reaction force under non-pathological conditions. If the reliability of any of these structures is disturbed, it can lead to traumatic or atraumatic instability. Shoulder Instability can occur posteriorly, anteriorly, or in multiple directions, irrespective of the mechanism of the wound.
When designing a non-operative rehabilitation program for patients with shoulder instability, it is vital to consider some of the key factors that include:
- Level of instability and the outcome of their functions
- Onset of pathology
- Frequency of displacement
- Concomitant pathologies
- Direction of instability (anterior, posterior, or multidirectional)
- End range neuromuscular control
While considering these six factors, each patient will have a dissimilar structure of the non-operative rehabilitation program.
Some of the common classifications of the non-operative rehabilitation program for shoulder Instability include:
Traumatic shoulder instability is a general condition that happens in young patients. It is linked with high repetition rates. The anterior dislocation because of trauma is the most common type, related to over 90% of the cases. However, it will differ in length for each person according to the six key factors and the arm supremacy, preferred goals, and activities.
The rehabilitation program for Traumatic shoulder Instability consists of four different phases with different goals. They are:
- The acute motion phase: This phase involves the decrease of pain, muscular spasms, and inflammation. However, patients should meet certain criteria before they enter the subsequent phases. These criteria include:
- Full functional Range of motion
- Minimum soreness and reduced inflammation
- Enough static stability
- Satisfactory neuromuscular control
- Intermediate phase: The major goal of this phase is to improve the kinesthesia, proprioception, and dynamic stabilization.
- Advances strengthening phase: The objective of the rehabilitation phase is to perk up the neuromuscular strength, control, power, and staying power.
- Return to activity phase: By entering this phase, patients will be capable of increasing their activity level gradually to get themselves ready for the functional return to their usual activities.
Atraumatic refers to non-traumatic shoulder instability. It is a sub-categorization of glenohumeral joint instability, in which the pain is not considered the main aetiology.
This type of shoulder instability is of two types that include congenital instability and chronic recurrent instability.
Congenital instability happens because of the laxity of structures in the shoulder that present ever since birth. On the other hand, chronic recurrent instability may be seen after operation for shoulder dislocation because of glenoid rim lesions.
Eventually, microtrauma can lead to shoulder instability, as well.