Recurrent Shoulder Dislocation
The shoulder is the most moveable joint in your body. It helps you to lift your arm, to rotate it, and to reach up over your head. It is able to turn in many directions. This greater range of motion, however, can cause instability.
Shoulder instability occurs when the head of the upper arm bone is forced out of the shoulder socket. This can happen as a result of a sudden injury or from overuse.
Once a shoulder has dislocated, it is vulnerable to repeat episodes. When the shoulder is loose and slips out of place repeatedly, it is called chronic shoulder instability.
Normal shoulder anatomy
Your shoulder is made up of three bones: your upper arm bone (humerus), your shoulder blade (scapula), and your collarbone (clavicle).
The head, or ball, of your upper arm bone fits into a shallow socket in your shoulder blade. This socket is called the glenoid. Strong connective tissue, called the shoulder capsule, is the ligament system of the shoulder and keeps the head of the upper arm bone centered in the glenoid socket. This tissue covers the shoulder joint and attaches the upper end of the arm bone to the shoulder blade.
Your shoulder also relies on strong tendons and muscles to keep your shoulder stable.
Shoulder dislocations can be partial, with the ball of the upper arm coming just partially out of the socket. This is called a subluxation. A complete dislocation means the ball comes all the way out of the socket.
Left: Normal shoulder stability. Right: Head of the humerus dislocated to the front of the shoulder.
Once the ligaments, tendons, and muscles around the shoulder become loose or torn, dislocations can occur repeatedly. Chronic shoulder instability is the persistent inability of these tissues to keep the arm centered in the shoulder socket.
There are three common ways that a shoulder can become unstable:
Severe injury, or trauma, is often the cause of an initial shoulder dislocation. When the head of the humerus dislocates, the socket bone (glenoid) and the ligaments in the front of the shoulder are often injured. The labrum — the cartilage rim around the edge of the glenoid — may also tear. This is commonly called a Bankart lesion. A severe first dislocation can lead to continued dislocations, giving out, or a feeling of instability.
Some people with shoulder instability have never had a dislocation. Most of these patients have looser ligaments in their shoulders. This increased looseness is sometimes just their normal anatomy. Sometimes, it is the result of repetitive overhead motion.
Swimming, tennis, and volleyball are among the sports requiring repetitive overhead motion that can stretch out the shoulder ligaments. Many jobs also require repetitive overhead work.
Looser ligaments can make it hard to maintain shoulder stability. Repetitive or stressful activities can challenge a weakened shoulder. This can result in a painful, unstable shoulder.
In a small minority of patients, the shoulder can become unstable without a history of injury or repetitive strain. In such patients, the shoulder may feel loose or dislocate in multiple directions, meaning the ball may dislocate out the front, out the back, or out the bottom of the shoulder. This is called multidirectional instability. These patients have naturally loose ligaments throughout the body and may be “double-jointed.”
Common symptoms of chronic shoulder instability include:
Pain caused by shoulder injury
Repeated shoulder dislocations
Repeated instances of the shoulder giving out
A persistent sensation of the shoulder feeling loose, slipping in and out of the joint, or just “hanging there”
Physical Examination and Patient History
After discussing your symptoms and medical history, your doctor will examine your shoulder. Specific tests help your doctor assess instability in your shoulder. Your doctor may also test for general looseness in your ligaments. For example, you may be asked to try to touch your thumb to the underside of your forearm.
Your doctor may order imaging tests to help confirm your diagnosis and identify any other problems.
X-rays. These pictures will show any injuries to the bones that make up your shoulder joint.
Magnetic resonance imaging (MRI). This provides detailed images of soft tissues. It may help your doctor identify injuries to the ligaments and tendons surrounding your shoulder joint.
CT Scan- This provides details of the bony structure of the shoulder. We are particularly interested in the Socket (Glenoid) shape and bone loss due to injury itself or the effect of rubbing (Erosions) in case of very frequent episode of the dislocation of shoulder. Bone loss on socket (Glenoid) side is important to decide about the possibility of the open bone augmentation procedures. The 3D CT also gives details of the depth of bone depression on the back side of the ball (Humerus Head) of shoulder in the form of Hill Sach’s lesions.
Chronic shoulder instability is often first treated with nonsurgical options. If these options do not relieve the pain and instability, surgery may be needed.
Your doctor will develop a treatment plan to relieve your symptoms. It often takes several months of nonsurgical treatment before you can tell how well it is working. Nonsurgical treatment typically includes:
Activity modification. You must make some changes in your lifestyle and avoid activities that aggravate your symptoms.
Non-steroidal anti-inflammatory medication. Drugs like aspirin and ibuprofen reduce pain and swelling.
Physical therapy. Strengthening shoulder muscles and working on shoulder control can increase stability. Your therapist will design a home exercise program for your shoulder.
Surgery is often necessary to repair torn or stretched ligaments so that they are better able to hold the shoulder joint in place.
Bankart lesions can be surgically repaired. Sutures and anchors are used to reattach the ligament to the bone.
Arthroscopy. Soft tissues in the shoulder can be repaired using tiny instruments and small incisions. This is a same-day or outpatient procedure. Arthroscopy is a minimally invasive surgery. Your surgeon will look inside the shoulder with a tiny camera and perform the surgery with special pencil-thin instruments.
The most common method for surgically stabilizing a shoulder that is prone to anterior dislocations is the Bankart repair. The Bankart repair involves sewing or stapling ligaments, along with the labrum, on the front side of the joint back into their original position.
In a Bankart repair, we first clear away any frayed or torn edges. Holes for the sutures are drilled into the scapula bone. The capsular ligaments and labrum are then attached with sutures to the bone. The ligaments heal, and scar tissue eventually anchors the ends to the bone. With the ligaments back in place, the joint is much more stable.
The advantage of the arthroscopic technique is its minimally invasive nature which minimizes morbidity of surgery and hospital stay. Further it allows excellent visualization of the entire shoulder joint and is very useful in detecting and treating other causes of dislocation like an ALPSA lesion as well as associated pathology like a SLAP lesion.
In cases where there is significant bone loss in the glenoid or a large Hill-Sach’s lesion (engaging Hill-Sach’s), a Bankart repair alone is likely to fail. In such situations a Latarjet procedure (transfer of coracoid process to the glenoid defect) or a bone graft to the Hill-Sach’s lesion needs to be performed. These procedures require an open operation.
The patient may leave the hospital on the same day in case of an arthroscopic repair, and after 2 days after open surgery. The arm is placed in a shoulder immobilizer type of sling which restricts movement of the arm upwards, outwards and outward rotation of the arm. Depending upon the type of surgery performed and the strength of the repair achieved, the arm will be immobilized in the sling for a period of 3- 6 weeks. At around 2-3 weeks after surgery, pendulum exercises (gravity assisted movements of the arm) are initiated. At around 6 weeks after surgery, full range-of-motion exercises as well as shoulder strengthening exercises are started. Overall it will take around 2-3 months after surgery for any patient to return to pre-operation status as far routine day-to-day activities are concerned. It may take around 3-4 months for a recreational athlete to return to sports, and even longer for a professional athlete (depending upon the nature of sport and the level of competition involved).
Be sure to follow your doctor’s treatment plan. Although it is a slow process, your commitment to physical therapy is the most important factor in returning to all the activities you enjoy.