Background and Etiology (cause)
The shoulder complex is built for mobility, however this ability to move comes with the designation of being the most unstable joint in the body. The shoulder is composed of three osseous joints and one articulation, with stability provided by muscles, ligaments, the glenoid labrum and joint capsule.
There are different degrees of instability that occur in the shoulder. When referring to shoulder subluxation we are referring to the glenohumeral joint. The glenohumeral joint is a ball and socket joint between the head of the humerus bone (ball) and the glenoid fossa of the scapula (socket) or shoulder blade. The head of the humerus is large and the glenoid fossa is small, resulting in an unstable but mobile joint.
A subluxation is a partial dislocation of the shoulder, where the humerus does not completely come out of the glenoid fossa. This is most common after trauma to the shoulder or from a fall (often on an outstretched hand.) People with loose or lax ligaments are most susceptible to this type of instability. It can even get to the point where these incidents occur while performing simple activities like putting on a shirt.
- Weakness of the rotator cuff and laxity of the glenohumeral ligaments are the most common cause of shoulder subluxation.
- General ligamentous laxity may predispose an individual to instability.
- Repetitive strain injuries (RSI) at work, or overuse activities are common in people who participate in sport activities and individuals who have jobs that require performing activities of a repetitive nature, like working on an assembly line. These patients may develop instability resulting in a shoulder subluxation.
- Those participating in activities like swimming or activities characterized by overhead motion like tennis, softball, baseball, volleyball, overhead throwing and other repetitive sport activities may aggravate the shoulder resulting in shoulder instability.
- Certain connective tissue disorders that result in ligamentous laxity can result in shoulder instability and eventual shoulder subluxation.
- High risk groups include over head throwing sports, swimming, wrestlers, football and basketball players.
- General tenderness of the shoulder area
- Discomfort with movement, especially with overhead activities
- Pain with overhead activities or sleeping on the effected side
- Feeling that the arm is “dead” after repeated activity
- A feeling that the shoulder will “go out” when reaching up and behind the head. This is called the Apprehension Sign.
Conservative treatment of shoulder subluxation is the first line of action. This includes physical therapy to reduce inflammation and associated pain. In addition, a regiment of exercises to improve rotator cuff strength and shoulder stability should be initiated. In more chronic cases of subluxation or instability involving the glenoid labrum, surgical intervention may be necessary.
Physical Therapy Interventions
Physical Therapists are professionals, educated and trained to administer interventions. As stated in The Guide to Physical Therapist Practice interventions are the skilled and purposeful use of physical therapy methods and techniques to produce changes consistent with the diagnosis, prognosis, and the goals of the patient or client. Common interventions in the treatment of Shoulder Subluxation include:
- Manual Therapeutic Technique (MTT): hands on care, including soft tissue massage, and joint mobilization by a physical therapist to modulate pain and reduce any soft tissue or tendon irritation.
- Therapeutic Exercises (TE) including strengthening exercises to improve strength of the rotator cuff muscles in the shoulder and increase stability.
- Neuromuscular Reeducation (NMR) to restore stability, begin retraining the upper extremity, improve proximal joint stability and improve movement technique and mechanics (for example, throwing or reaching over head) in daily use of the involved upper extremity.
- Modalities that can include the use of ultrasound, electrical stimulation, ice, cold laser and others to decrease pain and inflammation at the shoulder and tendons.
- Home program that includes strengthening, stretching and stabilization exercises as well as instructions to help the person perform daily tasks and advance to the next functional level.
Procedures that your physician may recommend and perform in addition to physical therapy.
- Initial immobilization of the subluxed shoulder
- Avoid over head activities and position of subluxation.
- REST and ICE
- The use of NSAIDS (Non Steroidal Anti-Inflammatory Drugs)
- Steroidal Injections to reduce inflammation
- Pain medication to reduce the discomfort and allow the patient to perform the recommended exercises
- Surgery to correct underlying pathology and avoid repeated subluxations leading to dislocations. This may include labral repairs or procedures to tighten the shoulder capsule or ligaments.
Most people recover full function following a course of conservative care of physical therapy to strengthen and stabilize the shoulder. Those with more involved conditions, like labral tears, chronic dislocations and/or rotator cuff tears will require surgery and intensive physical therapy afterward to restore full function.