What Causes Shoulder Dislocation?
As anyone who has experienced a shoulder dislocation can tell you, it is a very painful experience. A partial or full shoulder dislocation can happen when a shoulder sustains great force. A big impact can overcome the blocking effect of the cartilage rim, ligaments, and muscles surrounding the shoulder, causing a dislocation. Dislocations can happen because of:
- A fall: Such as from a ladder or tripping over furniture.
- A sport injury: From contact sports such as hockey, football, rugby, or lacrosse, or from a fall during skiing or gymnastics.
- Blunt force trauma: A hard blow to your shoulder, such as during a motor vehicle accident.
Overview of the Shoulder
The shoulder is the most mobile joint in the body. It consists of a ball at the top part of the arm bone (humeral head) and a shallow socket (glenoid) that allows full motion—in fact, more motion than any joint in the body!
To stabilize the shoulder, our shoulder socket has more cartilage at the edge as well as a rim of softer fibrocartilage known as the labrum or “lip” of the socket. The labrum helps to deepen the socket as well as acting as a bumper to prevent the ball from slipping out of the joint. The shoulder also contains a number of ligaments which further stabilize the joint and prevent dislocation when the arm is in maximum rotation positions. Four muscles—the rotator cuff muscles—surround the shoulder and work together to keep the shoulder joint stable. In fact, during most of the movements of our shoulder with everyday life, the ligaments are actually loose, and it is the ability of the rotator cuff to hold the ball centered into the socket that provides stability with functional range of motion. When a shoulder dislocates, it overcomes all these natural defenses.
What Happens to the Shoulder when it Dislocates & How to Treat It
A dislocation can cause tearing and stretching of the surrounding ligaments, damage to the cartilage and the bone, as well as injury to the tendons and muscles with more severe dislocations. No wonder it’s so painful!
The shoulder can either dislocate to the front (anterior dislocation) or the back (posterior dislocation). More than 90% of dislocations are out the front (anterior). As the shoulder dislocates, it may tear a segment of the labrum and some of the ligaments surrounding the shoulder. Usually, a small amount of bone and cartilage are also damaged. With certain activities—such as rugby, snowboarding, or motocross—the injury to the bone and cartilage can be severe and require more immediate surgical intervention. Furthermore, patients over the age of 40 have a higher chance of developing a rotator cuff tear during a shoulder dislocation than their younger peers, and again, surgical treatment may be needed early to provide the best outcome.
Depending on the direction of the dislocation, it may prevent the patient from moving their arm. In some cases, the nerves surrounding the shoulder may be stretched and can cause a combination of weakness and/or numbness in the area supplied by the stretched nerve(s). Most of these nerve injuries resolve with time, however, Dr. Romeo checks the nerve function right away and, if necessary, further tests are done to make sure the right treatment plan is followed One special clue is the loss of the ability to rotator the arm outwards from a handshake position. If that is found on the exam after a dislocation, either the rotator cuff is torn or one of the main nerves to the shoulder is damaged.
The initial management of a shoulder dislocation is usually done on the field of athletic play or at the site of injury in recreational sports, followed by an evaluation in an emergency department. After giving pain medications and sometimes a numbing injection to the shoulder, the joint is gently put back (reduced) to its normal position. In rare cases, the reduction may have to be done in the operating room with controlled sedation so that complete relaxation of the muscles is possible. After the reduction of the shoulder, a sling with a wrap around the waist is placed to stabilize the shoulder and prevent it from moving into a position that could allow it to dislocate again. Based on the history what caused the dislocation, the severity of the injury, and the physical examination findings, physical therapy is started one to two weeks after the injury.
Shoulder Dislocation FAQ
Why is shoulder dislocation so painful?
When your shoulder dislocates, it is not simply a matter of the ball-like humeral head popping out of the socket. A dislocation usually happens as a result of a sudden traumatic injury to the shoulder and arm. The movement of the humeral head coming out of its socket joint tears, separates, or stretches the surrounding ligaments, cartilage, and muscles. The intense pain you feel is an indication of how significant the damage can be.
This is not an injury you can nurse at home. In most cases, you will want to go to an emergency room, where medical professionals will attempt to put the humeral head back in place, and fortunately, they are successful most of the time. However, if they are unable to do that, you may need to be sedated either in the emergency department or the operating room so that you and your muscles completely relax, allowing the movement of the humeral head back into the socket.
How is shoulder dislocation or instability diagnosed?
In cases of a history of dislocation or instability, experienced Chicago orthopaedic surgeon Dr. Anthony Romeo:
- Examines the shoulder to check for sensitivity
- Measures range-of-motion
- Makes sure that the main muscles of the shoulder are working
- Gently assesses the looseness of the shoulder
X-rays are important in ruling out other conditions, such as a shoulder fracture, and they usually confirm the direction of the dislocation An MRI or CT scan is valuable to check the integrity of bones, ligaments, muscles and cartilage, and survey the extent of damage. Patients referred to Dr. Romeo often have already had an MRI. However, Dr Romeo may still order a 3-D CT scan to clearly identify the amount of bone that has been damaged. Remarkably, the difference between a high level of success with arthroscopic stabilization surgery may be just a few millimeters of bone loss, which is best seen on a 3-D CT scan. This can be performed easily on most modern-day CT scanners.
Is surgery necessary?
Maybe. Depending on the damage done in a shoulder dislocation, it is very likely to happen again, increasing the likelihood of surgery being required. Due to the typical sports played, men under the age of 30 have a very high chance of having recurrent shoulder dislocations, and therefore may elect to have the shoulder surgically stabilized even after one dislocation to allow them to go back to their sports and to avoid early arthritis. The more times the shoulder slips out of place, the more damage that is done to the shoulder joint. While physical therapy may help some patients, a good percentage of patients go on to dislocate their shoulder again. In fact, if you follow patients who presented to the emergency department with a dislocation, more than 50% will have another dislocation some time in their life, and more than 75% of men under 30 years of age who return to sport will have additional dislocations. If shoulder pain and instability continue to happen, it becomes difficult to achieve the level of performance that was possible before the injury without surgical repair.
Experienced Chicago orthopaedic surgeon Dr. Anthony Romeo has been on the forefront of arthroscopic Bankart Repair, a procedure in which the torn tissue is sewn back to the socket rim.
The key factor in determining whether the arthroscopic repair is going to be successful or not is related to how much bone has been damaged. With one dislocation, this is usually less than 10% of the socket rim. However, if the shoulder keeps coming out of place, the bone loss increases, sometime to more than 20%, which affects the results of the repair. In this situation, procedures to restore the bone loss have been developed to improve the results. When the bone loss is less than 10%, successful surgery can be accomplished arthroscopically by repairing the torn labrum and capsule back to the rim of the socket.
The arthroscopic procedure involves the use of a tiny camera inserted through a small incision, allowing the surgeon to determine the condition of the joint and assess the extent of tears. Special instruments, sutures, and tiny anchors placed into the bone are used to connect the torn labrum and capsule back to the socket after the injured area has been prepared for a successful healing process. The operation in performed as an outpatient in an ambulatory surgery center.
Before you leave the facility, Dr. Romeo and his team will inform you of the findings at the time of the surgery, what was done, and reassure you of the postoperative plan that was discussed before your procedure, including your physical therapy instructions and your next appointment.
Want to see how it’s done? In this video, watch Dr. Romeo perform an Arthroscopic Bankart Repair procedure.
When more bone is missing from the rim of the socket (which is evaluated with a 3D CT scan before surgery) the arthroscopic repair procedures cannot provide enough strength to insure a stable shoulder. This is especially true if you want to return back to contact or collision sports, or other challenging activities related to the responsibilities of first responders, military personnel, or occupations that put the arm in a risky position. For these patients, a procedure to restore the missing bone, and secure the capsule, ligaments, and labrum is a better option.
The Latarjet procedure involves taking a small piece of the scapula bone (coracoid), which is not part of socket, and fixing it to the front edge of the socket to restore the missing bone from this area. The bone is fixed with two screws, and sometimes a tiny metal plate so that it heals to the front of the socket. Attached to this piece of bone are two small tendons that reinforce the stability of the shoulder. Finally, the labrum and capsule in this area is repaired with sutures.
This “triple” effect of restoring the bone loss, adding the tendon sling, and repairing the capsule and labrum is highly effective at stabilizing the shoulder, and allowing the patient to return to all activities with a very low risk of having any instability problems again. This operation is also a great choice when a patient has had a failed arthroscopic Bankart repair and is much more successfully at resolving the problem instead of repeating another arthroscopic repair.
Want to know more? In this video, watch Dr. Romeo gives a short presentation on the Latarjet procedure. (Contains brief surgical videos.)
In this video, Dr. Romeo demonstrates the details of the Latarjet procedure using a cadaver shoulder and the Arthrex Glenoid Bone Reconstruction set. Dr. Romeo also uses these instruments and devices when performing the Distal Tibia Allograft procedure, discussed below.
Distal Tibia Allograft Procedure
In some patients with recurrent instability of the shoulder and loss of bone from the socket, the use of a cadaver bone and cartilage (a Distal Tibia Allograft) may be the best choice for the patient. This procedure works well when the bone loss is more than the size of the coracoid process bone used in the Latarjet procedure and when patients have had a Latarjet or coracoid transfer procedure that has not successfully resolved the patient’s symptoms. Theoretically this graft restores not only the bone loss, but also the loss of cartilage (the shiny white covering of the joint), which may help to prevent arthritis and provide a more normal shape to the socket.
Because this graft can restore bone and cartilage, it can also be used as a first line of treatment when trying to preserve the surface of the joint and restore the cartilage, even if the bone loss is not the major problem.
The surgical procedure follows the same incision at the Latarjet procedure, however, the piece of the scapula used in the Latarjet (coracoid process) is not moved. A split is made in the muscle and tendon that covers the front of the shoulder to get access to the joint, however, the tendon attachment remains in its normal position. After preparing the area of the injury to ensure a successful healing process, the graft is cut from the donor bone. Normally, the size of the graft is approximately 8 millimeters of articular surface, 2 centimeters of length, and 1.5 centimeters of depth. The graft is fixed to the socket in the same way that the coracoid bone is fixed during the Latarjet procedure: with two screws and, occasionally, a tiny metal (titanium) plate. The procedure is performed as a same day surgery in an ambulatory surgery center.
After the procedure, Dr. Romeo and his team will inform you of the findings at the time of the surgery, what was done, and reassure you of the postoperative plan that was discussed before your procedure, including your physical therapy instructions and your next appointment.
Although this procedure, as well as the Latarjet procedure, are more invasive than the arthroscopic Bankart repair, patients are remarkably similar after the surgery in terms of their pain relief from medications, ability to move their elbow, wrist and hand without difficulty, and resuming many of their normal daily activities independently within a few days of the procedure. Full recovery is also similar, including return to full activities without restrictions before 6 months after surgery.
Want to know more? In this video, Dr. Romeo presents on treatment of complex shoulder instability problems using a Distal Tibia Allograft, including the management of patients who have had a Latarjet procedure that did not get the desired results:
In this video, Dr. Romeo give a presentation on revision shoulder instability surgery.
Here’s a great guide that explains the special instruments and tools designed for the Distal Tibia Allograft procedure:
Working with Dr. Matt Provencher from Vail, Colorado, Dr. Romeo has been a pioneer in the use of the Distal Tibia Allograft for treating shoulder instability. Here are a few of his publications:
- Anatomic osteochondral glenoid reconstruction for recurrent glenohumeral instability with glenoid deficiency using a distal tibia allograft.
- Glenoid Reconstruction With Distal Tibia Allograft for Recurrent Anterior Shoulder Instability.
- Distal Tibia Allograft Glenoid Reconstruction in Recurrent Anterior Shoulder Instability: Clinical and Radiographic Outcomes.
- Outcomes of Latarjet Versus Distal Tibia Allograft for Anterior Shoulder Instability Repair: A Matched Cohort Analysis
For most patients after shoulder instability surgery, four weeks of resting and protecting the surgical repair and reconstruction of the shoulder is an effective balance between letting the tissue heal and avoiding too much stiffness of the shoulder. You should be able to begin movement and limited use of your hand, wrist, and elbow the day after surgery. It is important to wear the sling even during sleep to prevent accidental injury and disruption of the repair. In rare cases, such as overhead throwing athletes, early movement may begin within a few days of surgery.
Dr. Romeo will give you specific instructions for post-op pain management. Fortunately, for most patients who are not taking any pain medications before surgery, they are usually able to discontinue pain medications after surgery within 3-5 days, even if the procedure includes bone. Also, within the first 5-7 days, the surgical arm can be used to feed yourself, bath, and assist with getting dressed, if the arm remains by your side.
After four weeks, the sling can be removed and protected motion, as well as light stretching will be introduced. In patients who have very loose joints and elastic tissue, the sling protection may be extended to 6 weeks after surgery. At this point, you will begin physical therapy, which is key to a successful outcome At six weeks, a light strengthening program will be implemented, beginning with isometric exercise, then Theraband exercises, followed by light weight training.
A full recovery is expected between four to six months, however in some severe cases or when returning to high level sports or physical work, a full recovery of strength and functional performance may not occur for nine months to a year. Remarkably, return to collision or contact sports is occasionally faster (as short as four months) after the Latarjet procedure when compared to the arthroscopic Bankart repair, which often takes 6 months.
The way the ligaments, cartilage and muscles heal is important. If they heal while in a stretched or loose position, this increases the chances of future shoulder dislocation or instability. That is why following your doctor’s recommendations on rest and activity is essential. Regaining motion is an important priority for the success of the procedure. However, the pace of this process needs to carefully coordinated with Dr. Romeo and the physiotherapist based on the preoperative injury and the findings at the time of the surgical procedure. Dr. Romeo uses a coordinated, integrated physical therapy plan after surgery to give you the best chance of returning to your full potential.
The good news is that when you have the surgical procedure that is ideal for stabilizing your shoulder, whether it is the arthroscopic Bankart, Latarjet, or distal tibia allograft, and then follow through with a carefully planned and integrated rehabilitation program, the risk of dislocating your shoulder again is less than 5%. If there is a future dislocation, it is almost always a result of another serious injury that would have caused a full dislocation in a normal shoulder. While the risk is not “0%”, it is tremendously less than the risk if no surgery was performed and the treatment includes only rest, physical therapy, and avoidance of activities. And, following these surgical procedures, a high percentage of athletes and workers with physically demanding work will be able to return to the same level of performance as they were able to accomplish before the injury.
For more information about treatment options for shoulder dislocation or instability, please request an appointment with experienced Chicago orthopaedic surgeon Dr. Anthony Romeo. Call or email our office today to schedule your visit.
Shoulder Surgery Videos & Animations
Anatomy of the Shoulder as it relates to Surgery
Bankart Repair Animation
Additional Shoulder Dislocation Links
Want to know more? Here a few of Dr. Romeo’s recent medical journal articles about shoulder dislocation and instability:
Anthony Romeo, MD
Dr. Anthony Romeo is one of the nation’s leading orthopaedic surgeons specializing in the management and surgical treatment of shoulder and elbow conditions. His state-of-the-art practice employs minimally-invasive arthroscopic techniques to accelerate the recovery process for a range of challenging conditions.