Anatomy of the Shoulder
The shoulder complex comprises the humerus, clavicle, and scapular, which form four different joints, including the glenohumeral joint, sternoclavicular joint, acromioclavicular joint, and the “floating” scapulothoracic joint.
The glenohumeral joint is the mobile joint in the human body as it is a “ball and socket” joint. It has three degrees of freedom, which include flexion/extension, internal rotation/external rotation, and abduction/adduction. The “ball” is the head of the humerus while the “socket” is the glenoid cavity of the scapula, which connect together to form this joint. In order to maintain stability, the glenohumeral joint relies on the teamwork of the dynamic stabilizers (surrounding shoulder musculature) and the static stabilizers (ligaments, joint capsule and the labrum).
The dynamic stabilizers include the rotator cuff muscles, scapular muscles, deltoids, biceps, pectoralis major, and latissimus dorsi. These muscles work together synergistically to allow the glenohumeral joint to have a wide range of mobility while also providing enough stabilization to keep the ball within the socket.
The static stabilizers comprise of the glenoid labrum, joint capsule, glenohumeral ligaments, coracohumeral ligament, and coracoacromial ligament. The glenoid labrum is made of fibrocartilage that deepens the glenoid cavity in order for the head of the humerus to fit into it better. The joint capsule provides a negative intra-articular pressure to keep the joint together and functions as a stabilize, along with the shoulder ligaments, at the extreme ranges of motion. The glenohumeral ligaments include three main ligaments that are called the superior, middle, and inferior ligaments. The other two ligaments the provide stability are called the coracohumeral ligament and coracoacromial ligament.
Due to the amount of mobility of the glenohumeral joint, it sacrifices stability and therefore is the most commonly dislocated joint. The most common type of glenohumeral joint dislocation is anterior dislocation, which encompasses 97% of all shoulder dislocations. An anterior shoulder dislocation is usually caused when the arm is positioned at excessive ranges of external rotation and abduction.
Causes and Symptoms of Anterior Shoulder Dislocation
Anterior shoulder dislocations are commonly seen in contact sports such as football and hockey and in sports where there is potential for falls such as gymnastics, volleyball, and skiing. Other common causes include motor vehicle accidents or falls while performing daily tasks or job duties, especially when falling with an outstretched arm.
Common symptoms of an anterior shoulder dislocation include visibly deformed or out of place shoulder, swelling or bruising, intense pain in the upper arm and shoulder, especially when trying to move the shoulder, and inability to move the shoulder joint. You can also possibly experience numbness or tingling to your neck or down your arm as well as weakness.
Physical Therapy Examination
During a physical therapy examination, the physical therapist will take your history including past medical history, how you injured your shoulder, and what activities you would like to get back to in order to tailor the treatment to your specific goals. The physical therapist will also likely utilize special tests to confirm or exclude the diagnosis of an anterior shoulder dislocation, especially if you are coming to physical therapy via direct access.
These special tests include:
Physical Therapy Treatment
Most folks, who dislocate their shoulder for the first time, usually opt for conservative approaches such as physical therapy. Surgery may be necessary, however, depending on the severity of the injury, age, and if you are considered a high-risk individual, such as a person who plays contact sports. The rehabilitation of a traumatic anterior shoulder dislocation can be broken up into three phases. These phases are from a 2017 systematic review called “Current Concepts in Rehabilitation for Traumatic Anterior Instability” by Ma et al.
Phase I – Acute Phase After Injury
The goals of this phase include (Ma et al., 2017):
In this phase, physical therapy treatment includes:
Phase II – Intermediate Phase After Injury
In order to enter this phase, the person should also have reduced pain, good shoulder static stability, and adequate neuromuscular control. The main goal of this phase is for the person to get full active and passive shoulder range of motion, with the exception of external rotation at 90 degrees of abduction to avoid overstressing the anterior capsule and ligaments in the shoulder.
In this phase, physical therapy treatment includes:
Phase III – Advanced Strengthening and Return to Sport After Injury
The criteria to enter this phase include “(1) minimal to no pain in the injured shoulder; (2) full shoulder motion and capsular mobility; and (3) good strength (4/5 on manual test), endurance, and dynamic stability of the scapulothoracic and upper extremity.” (Ma et al., 2017)
In this phase, there is a progression of isotonic exercises, especially in the position of 90 degrees of abduction, which is required for specific sports. Patients in this phase can perform exercises such as bench press, seated row, and lat pull downs in protected ranges. Low resistance, high repetition exercises are included to address fatigue, loss of neuromuscular control, and joint instability. In addition, plyometric exercises can be prescribed to improve neuromuscular control for sports and examples of these type of exercises include two-handed throwing drills and one-handed throwing drills against a trampoline.
For return to sport Ma et al. came up with the following criteria: