Anterior shoulder dislocation occurs when the humerus (upper arm bone) displaces forward out of the glenoid (shallow socket of the shoulder blade). This injury happens due to trauma, such as a fall onto an outstretched arm or a direct blow to the shoulder, especially when the arm is abducted and externally rotated. It is the most frequent type of shoulder dislocation, accounting for approximately 95% of all dislocations. Prompt medical attention is necessary to restore alignment and address the pain, lack of motion, and visible deformity.
Immediate Medical Care
Upon presentation, a medical professional will first assess the affected shoulder for tenderness, swelling, and any deformity, and also check for signs of nerve or blood vessel injury. To confirm the dislocation and rule out fractures, imaging like X-rays is obtained. Point-of-care ultrasound (POCUS) can also be used for rapid diagnosis, offering high sensitivity and specificity.
Once the diagnosis is confirmed, the primary goal is to perform a “closed reduction,” which involves gentle maneuvers to guide the humeral head back into its socket. This procedure can be painful, so pain relief and muscle relaxation are provided to make the reduction process smoother. Options for pain management include intravenous medications like midazolam-fentanyl or propofol for conscious or deep sedation, or an intra-articular injection of a local anesthetic such as lidocaine into the joint space. Intra-articular lidocaine injections may lead to shorter emergency department stays and fewer side effects compared to intravenous sedation.
Post-Reduction Management
After a successful reduction, immobilizing the shoulder is a common next step to protect the healing tissues and minimize pain. A sling is used, with duration varying, often from 1 to 3 weeks. While older studies suggested no benefit from prolonged immobilization, more recent evidence supports immobilization in external rotation for anterior dislocations to potentially reduce recurrence rates. Gentle exercises for the fingers, wrist, and elbow are encouraged during this immobilization period to prevent stiffness in these adjacent joints.
Physical therapy plays a significant role in regaining full function of the shoulder. The rehabilitation program is phased, initially focusing on reducing pain and inflammation. Early exercises may include pain-free passive range of motion, progressing to active-assisted range of motion, and then active range of motion, especially in internal and external rotation within the scapular plane. Strengthening exercises for the rotator cuff muscles, which are the primary stabilizers of the shoulder, are introduced.
These exercises aim to restore muscle balance, improve dynamic stability, and enhance proprioception, which is the body’s sense of its position in space. Examples include submaximal isometrics initially, progressing to isotonic strengthening of the rotator cuff, deltoid, biceps, and triceps, and scapular stabilizers. The progression of exercises is tailored to the individual’s pain levels and range of motion, with the goal of preparing the shoulder for a return to daily activities and, for athletes, sport-specific movements.
Surgical Options
While many anterior shoulder dislocations are managed without surgery, certain situations may warrant surgical intervention. Surgery is often considered for individuals experiencing recurrent dislocations, particularly young patients or those involved in high-risk contact sports, as this can prevent further damage. Significant bone loss, such as an osseous Bankart lesion (a fracture of the glenoid rim) or a large Hill-Sachs defect (an indentation fracture on the humeral head), are also indications for surgery.
Other associated injuries that may necessitate surgical repair include large rotator cuff tears or nerve damage. The general goal of surgical intervention is to stabilize the shoulder joint by repairing torn ligaments or the joint capsule, or by addressing bone defects. For instance, an arthroscopic capsulolabral repair might be performed to fix torn tissues, or procedures like the Latarjet procedure may be used for significant glenoid bone loss. Following surgery, a structured rehabilitation program is necessary, often involving immobilization for several weeks before progressing to strengthening and range of motion exercises.
Long-Term Recovery and Recurrence Prevention
The long-term outlook after an anterior shoulder dislocation varies depending on factors such as age, activity level, and the presence of associated injuries. A significant concern following a primary dislocation, especially in younger individuals, is the high risk of re-dislocation. Recurrent episodes of instability can lead to increased damage to soft tissues and bone, potentially complicating future management. Some individuals may also experience chronic instability or persistent stiffness in the shoulder joint.
To help prevent recurrence, a continued focus on strength and stability exercises is recommended, even after formal physical therapy concludes. Individuals should also be advised to avoid specific high-risk movements or positions that mimic the mechanism of their initial injury, such as extreme abduction and external rotation. Gradually returning to activities and modifying participation in certain sports can also contribute to long-term joint health and reduce the likelihood of future dislocations.