Shoulder Instability and Dislocations
Instability of the shoulder joint is a condition in which the ball slides out of the joint outside of its normal physiologic movement. This may occur partially (subluxation) or completely (dislocation). The joint is supported by many factors including the ligaments of the joint capsule, the labrum (a rim of cartilage around the cup), the muscles around the shoulder (rotator cuff) and other factors. Instability is more common in younger athletic patients but can occur at any age.
When the shoulder suffers trauma in the form of a torsional movement, a direct blow or a fall, instability of the shoulder can result. Subluxation of the shoulder can be difficult to diagnose and requires specific training in the diagnosis and treatment of such injuries. Delays in diagnosis can be very frustrating to the injured person. People with subluxation often complain of a sensation of discomfort when the shoulder is sliding out of the joint with increasing symptoms as it progresses out of the joint. This may be accompanied by mechanical symptoms such as a pop.
When the shoulder fully dislocates it often requires sedation to place the ball back in the socket. In addition various structures in the shoulder can be damaged during the dislocation including the bones (fractures), cartilage, ligaments, labrum, tendons and nerves. Any of these tissues can be injured in isolation or in combination. There are two typical fractures that occur when the shoulder dislocates. When a piece of the glenoid (cup) fractures it is referred to as a Bankart fracture and when it occurs on the humeral head (ball) it is called a Hill-Sachs lesion. An MRI is usually required to fully diagnose the extent of tissue injury.
The risks associated with an acute dislocation typically depends on the age of the injured person. People in their mid-thirties and younger typically are at significant risk of re-dislocation and those in college and younger will have repeat dislocations close to 100% of the time. When the shoulder dislocates in people over the age of forty, the recurrence of dislocations is less than 10%. However, this age group is at significantly higher risk of rotator cuff tendon injury.
A second group of patients can have symptoms of instability without an acute trauma. This is common in athletes who have a repetitive and cumulative stretching of the ligaments and capsule from repeated arm movements such as swimming, throwing or pushing. Often these shoulders can be successfully treated with a focused therapeutic physical therapy regimen. When the rotator cuff and other shoulder stabilizing muscles are strengthened they can compensate for the “looseness” of the stretched out capsule. Occasionally, symptoms persist and an arthroscopic surgery is necessary.
Depending on the persons age, functional demands of the shoulder and tissues that have been damaged in the shoulder non-operative care may be appropriate. This would include a period of rest with avoidance of specific activities and a possible regimented therapeutic physical therapy regimen. Over the counter medications for inflammation and pain can aid the recovery of the shoulder functions.
When surgery is indicated for instability there are multiple treatments available as options for repair. The majority of these procedures are able to be performed arthroscopically, which is Dr. Lenarz’s preferred option. These surgeries include:
Bankart (labral) Repair with capsular tightening (capsulorrhaphy)
Bony Bankart Repair
Rotator cuff repair
Occasionally open surgical techniques are required for treatment of instability. This is usually necessary when there is significant bony damage. This usually occurs when there are repetitive dislocations wearing increasing amounts of the bone from the glenoid (cup) and humeral head (ball). These surgeries include:
Latarjet Coracoid Transfer
Resurfacing of the humeral head (Ball)