What is Anterior Glenohumeral Joint Dislocation (Anterior shoulder dislocation)?
Shoulder instability refers to a range of issues, from discomfort due to instability to fixed dislocations. Depending on the specific nature of the problem, the course, treatment, and outlook may vary. Anterior glenohumeral (GH) dislocation, which is when the joint in the shoulder moves out of place, is usually the first type of shoulder instability that doctors see. It’s worth noting, GH dislocations account for about half of all joint dislocations, and of these, 95% to 97% are anterior dislocations.
The great flexibility of the GH joint does come with a trade-off in stability. A combination of static and dynamic restraints help keep the GH joint stable. Static restraints include factors like the glenoid labrum and ligaments, the natural hollow shape of the glenoid cavity, and the internal pressure within the joint. On the other hand, dynamic restraints are components like the rotator cuff muscles, the muscles around the shoulder blade, and the bicep tendon.
Non-surgical repositioning of dislocated joints should be done promptly. Further tests and long-term care depend on factors like the patient’s age, activity level, and how the injury occurred.
What Causes Anterior Glenohumeral Joint Dislocation (Anterior shoulder dislocation)?
Most cases of sudden forward shoulder dislocations are due to an accident or injury, such as falling on an arm that’s stretched out or overreaching with the arm in a raised and twisted position. If the shoulder keeps getting dislocated, it often means that the parts of the shoulder that keep it stable are damaged.
In younger people, repeated dislocations usually occur due to problems with the labrum or glenoid, which are parts of the shoulder joint. But in people over 40, rotator cuff tears are more likely to cause the shoulder to become unstable and dislocate often.
Risk Factors and Frequency for Anterior Glenohumeral Joint Dislocation (Anterior shoulder dislocation)
It is estimated that traumatic shoulder dislocations, both initial and recurring, occur at a rate of 11.2 per 100,000 people. The highest occurrence of this type of shoulder injury usually happens between the ages of 15 and 30, with nearly double the number of men affected compared to women.
- Traumatic shoulder dislocations happen to about 11.2 out of every 100,000 people.
- These injuries are most common among 15 to 30-year-olds.
- Men are about 2.64 times more likely to experience this type of injury compared to women.
Signs and Symptoms of Anterior Glenohumeral Joint Dislocation (Anterior shoulder dislocation)
It is essential to conduct a thorough patient history and physical examination to identify any hidden injuries, especially before any attempts to adjust a dislocated shoulder or administer sedation. The evaluation of the shoulder should be systematic, as it consists of three key joints: the sternoclavicular (SC) joint, the acromioclavicular (AC) joint, and the glenohumeral (GH) joint.
When looking over and touching the shoulder, the integrity of each joint should be confirmed. If there’s a problem with the GH joint, the humeral head may be noticeable and able to be felt in an incorrect position at the front. Before any adjustment maneuvers, it’s crucial to assess and note down the state of the patient’s nerves and blood vessels.
Particular emphasis should be placed on the axillary nerve due to its location. It tracks along the upper part of the humeral neck and quadrilateral space, then goes on to supply the deltoid muscle. It’s important to confirm the axillary nerve’s health by checking for intact sensation in the upper arm and asking for the deltoid muscle to contract and lift the arm.
Moreover, the health of the axillary artery should be confirmed by checking for good blood flow to the area below the injury and feeling for a strong pulse. You should also look for any swelling or growing bruises in the armpit.
Testing for Anterior Glenohumeral Joint Dislocation (Anterior shoulder dislocation)
If you have injured your shoulder, your doctor will likely start with plain x-ray images from a couple different angles to evaluate how bad the injury is. The first x-ray, the anteroposterior view, shows if the shoulder has shifted up or down. Another x-ray, the orthogonal view, helps your doctor see if the shoulder has moved forward or backward.
There’s another type of x-ray called the axillary view, which is taken with your arm raised. This can often be hard to do if you’re in pain or if your shoulder can’t be lifted due to the injury. In these situations, a different type of x-ray called the Velpeau view, can be used. This doesn’t require you to lift your arm, so you can keep it in a sling, leaning back a bit while the x-ray is being taken. If the other views are hard to read, the scapular Y view is used. This view helps the doctor figure out the position of the ball of your upper arm bone in relation to the shoulder blade.
In most cases, if the x-rays are clear, you won’t need additional imaging done immediately after the injury. However, you may have to get more x-rays on an outpatient basis to check for specific types of damage on the upper arm bone or the shoulder blade. If you’re a young patient, you might be evaluated using liquid-filled magnetic resonance imaging to check for damage to the padding of your shoulder joint. If you’re older, you might need magnetic resonance imaging to see if you have a tear in the group of muscles and tendons in your shoulder collectively called the rotator cuff. If your shoulder has been dislocated for a while or multiple times, you might need a computer tomography scan. This scan helps determine the extent of bone loss in your upper arm or shoulder blade, which is crucial for your doctor to plan the best treatment for you.
Treatment Options for Anterior Glenohumeral Joint Dislocation (Anterior shoulder dislocation)
If your shoulder gets dislocated, it’s important to get it put back into place quickly. Waiting longer than 24 hours can cause unstable reductions, muscle spasms, and even problems with nerves and blood vessels. A lot of techniques have been developed over time to help with this process.
In old times, doctors used the Hippocratic method. This involved putting one’s foot under the patient’s armpit for counter-traction and pulling the upper part of the dislocated arm. However, this method isn’t used much now due to risks of damaging arm nerves and blood vessels. The best method to use now depends on the patient and the healthcare provider. Usually, an injection to numb the area or sedation is administered to make the process easier.
The Kocher method is one way to do it. Here, the patient lies on their back while the doctor bends the elbow to a 90-degree angle. Then, the arm is twisted outward until some resistance is felt. The shoulder is then brought toward the body and twisted inward until it’s back in place. This method doesn’t involve tugging but may include a slight pull.
The Milch technique is another approach. Here, the patient lies down while the doctor holds the wrist or elbow and pulls gently. At the same time, they move the arm outward and away from the body.
The Spaso technique is a bit different. With this method, the patient lies down with their shoulder forward at a 90-degree angle. The doctor then tugs vertically and rotates the arm outward.
The Traction and Countertraction technique requires the help of an assistant. The patient lies down with a sheet wrapped around their torso for the assistant to hold. Meanwhile, the doctor pulls the dislocated arm in line with its normal position while the assistant pulls in the opposite direction.
The FARES method is also used. Here, the patient lies down while the doctor pulls the arm, held straight. Then, they make gentle back-and-forth motions, similar to a handshaking motion. This method is reportedly faster and less painful compared to the Hippocratic and Kocher methods.
The Boss-Holzach-Matter Self-Assisted Technique is somewhat unique because the patient plays a crucial role. With this method, the patient sits down with their knee bent to a 90-degree angle. They then wrap their hands around the knee and lean backwards while extending their arms and shrugging their shoulders forward. This method has been found as effective and less painful compared to the Spaso method.
After any of these techniques, it’s important to check the shoulder again, take an X-ray to ensure proper alignment, and wear a sling to prevent further injury.
What else can Anterior Glenohumeral Joint Dislocation (Anterior shoulder dislocation) be?
Before repositioning a dislocated shoulder, doctors need to confirm the dislocation’s direction using x-rays. A posterior (backward) shoulder dislocation is common during seizures or electric shocks, but it’s often missed when the patient first visits the emergency room. In these cases, the affected arm is usually turned inwards with limited outward rotation. Fractures of the “lesser tuberosity” (a part of the shoulder bone) are rare but could indicate a backward shoulder dislocation, so doctors should check for this.
There’s also something called “inferior shoulder dislocations” or “luxatio erecta”, which is the least common type of shoulder dislocation. It typically happens due to severe trauma. Patients with this issue hold their arm in an extended upwards position. Such dislocations frequently involve nerve or vascular injury.
The SC and AC (different parts of the shoulder) can be injured at the same time. Injuries to the AC joint may be mistaken for shoulder dislocations; they make up about 9% of shoulder injuries. The Rockwood classification system ranks these injuries based on their severity, using x-ray results. For a more detailed view, doctors can use the “Zanca view” by pointing x-ray beams at a 30-degree angle to the collarbone.
“Proximal humerus fractures” are another common issue and can be present along with shoulder dislocations. These fractures might cause extensive bruising, indicating tissue or bone injury. Sometimes, these fractures can displace the entire “head” or top part of the upper arm bone, and attempts to reposition it without surgery often fail. Therefore, in these cases, emergency orthopedic consultation is recommended as immediate surgical intervention might be needed.
What to expect with Anterior Glenohumeral Joint Dislocation (Anterior shoulder dislocation)
The chance of a shoulder dislocating again and the overall outlook greatly depends on a person’s age and how active they are. Research shows that people, particularly those under 25 years old and who play contact sports, are at a high risk of recurring shoulder dislocations, with rates up to 92%. For those over 30, the recurrence rate is around 72%.
Various factors such as the age when the first injury occurred, follow-up care, and whether a procedure known as a Bankart repair was done, can affect the development of further complications. One of these complications is arthropathy, a type of joint condition. Around 28% to 67% of patients getting a Bankart repair, which could be a result of cartilage damage from repeated dislocations, experience this condition.
Possible Complications When Diagnosed with Anterior Glenohumeral Joint Dislocation (Anterior shoulder dislocation)
Persistent instability is a concern in both surgical and non-surgical treatment methods. However, due to improvements in surgical techniques, procedures to stabilize high-risk patients have been more effective in reducing the chance of the condition recurring.
It is crucial to consider possible surgical complications. For instance, overtightening or prolonged immobilization during capsular and labral repairs can result in stiffness. Bone block procedures might also have complications related to the graft incorporation and the hardware used.
A 2019 review by Williams and colleagues noted specific complication rates for various procedures. For instance, the complication rates for arthroscopic soft tissue repair, arthroscopic soft tissue repair with arthroscopic remplissage, open soft tissue repair, open labral repair with remplissage, open bone block procedures, and arthroscopic bone block procedures were 1.6%, 0.5%, 6.2%, 2.3%, 7.2%, and 13.6% respectively. In particular, there was a ten times higher complication rate with bone block procedures. As one might expect, there were higher complication rates associated with the more technically challenging procedures, which could also indicate a more severe pre-surgery injury.
Recovery from Anterior Glenohumeral Joint Dislocation (Anterior shoulder dislocation)
After surgery, it’s important to balance the need to let the body heal with the goal of avoiding stiffness from lack of movement. Most surgeons suggest immediate immobilization after surgery, which can last from one to six weeks. During this time, it’s important to give your body a chance to repair itself. This could include gentle movement like pendulum rotation, but moving too much can be harmful at first. After this period, patients can start to gradually increase their range of motion under the guidance of a physical therapist. The ultimate goal is to get back to your previous level of activity before the injury. A 2017 study comparing two different types of stabilization procedures found no difference in the rate of patients returning to their previous levels of activity or in how patients felt about their recovery. It’s worth noting that over 65% of athletes were able to return to their previous level of play after surgery.
Preventing Anterior Glenohumeral Joint Dislocation (Anterior shoulder dislocation)
Teaching patients about their conditions is crucial, especially for those who have had one or more dislocations in the past. Repeat dislocations can lead to more damage to the cartilage, loss of bone, and harm to the tissues that help stabilize the joint. It’s important to steer clear of movements that could jeopardize the joint, such as extreme spreading apart and outward twisting. This advice is particularly important for younger patients and athletes, as they have a higher risk of experiencing another dislocation.
