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Dislocated shoulder

A dislocated shoulder, also known as shoulder dislocation, occurs when the head of the upper arm bone (humerus) is forced out of the cup-shaped socket of the shoulder blade (glenoid fossa of the scapula), disrupting the glenohumeral joint—the body's most mobile and flexible joint, which makes it particularly susceptible to such injuries.^[1] This injury represents the most common type of major joint dislocation, accounting for approximately 50% of all such cases, with anterior dislocations comprising the vast majority (about 97%) while posterior and inferior types are rarer (2-4% and less than 1%, respectively).^[2] Dislocations can be complete, where the joint surfaces fully separate, or partial (subluxation), where they partially separate, and they often result from high-impact trauma, leading to potential associated damage to surrounding ligaments, nerves, or blood vessels.^[3] The primary causes of shoulder dislocations involve forceful trauma that exceeds the joint's stability, such as falls onto an outstretched arm, direct blows during contact sports like football or rugby, motor vehicle accidents, or even seizures and electrocutions that cause extreme muscle contractions.^[1] ^[3] Risk factors include participation in high-risk activities, previous dislocations (which weaken supporting structures like the rotator cuff or labrum), and inherent joint laxity, with the condition being most prevalent among teenagers and young adults in their 20s, particularly athletes.^[1] In anterior dislocations, the typical mechanism is abduction and external rotation of the arm, while posterior ones often stem from internal rotation forces or anterior chest impacts, and inferior dislocations arise from hyperabduction.^[2] Symptoms of a dislocated shoulder typically manifest immediately and severely, including intense pain that prevents arm movement, visible deformity or bulging at the shoulder, swelling, bruising, numbness or tingling in the arm or hand due to nerve involvement (such as the axillary nerve in up to 40% of cases), and muscle spasms.^[1] ^[3] Diagnosis involves physical examination, medical history, and imaging like X-rays to confirm the dislocation direction and detect fractures, with advanced scans (CT or MRI) used to assess soft tissue damage.^[3] Treatment generally begins with closed reduction—a procedure to manually realign the joint under sedation or anesthesia—followed by immobilization in a sling for 2-6 weeks, pain management with ice and NSAIDs, and physical therapy to restore strength and range of motion.^[3] Surgical intervention, such as arthroscopic repair of torn ligaments or bone reconstruction, may be necessary for recurrent dislocations, severe initial damage, or in young active individuals to prevent chronic instability.^[1] ^[3] Complications can include recurrent dislocations (higher risk in those under 25), nerve or vascular injuries, rotator cuff tears, or long-term arthritis, emphasizing the importance of prompt medical attention and rehabilitation.^[2]

Anatomy and Pathophysiology

Shoulder Joint Structure

The glenohumeral joint, the primary articulation of the shoulder, is a ball-and-socket synovial joint formed by the convex humeral head articulating with the concave glenoid fossa of the scapula.^[4] The humeral head is disproportionately large relative to the glenoid, with a surface area ratio of approximately 4:1, covered by articular cartilage that facilitates smooth movement.^[4] The glenoid fossa is a shallow pear-shaped cavity on the lateral aspect of the scapula, which is deepened by the fibrocartilaginous glenoid labrum—a ring-shaped structure that increases the glenoid's depth by about 50% and expands the articular surface area.^[5] Surrounding the joint is a loose fibrous capsule that attaches from the anatomical neck of the humerus to the glenoid rim and labrum, lined by a synovial membrane that produces lubricating fluid.^[4] Stability of the glenohumeral joint relies on both static and dynamic supporting structures. The rotator cuff, comprising the supraspinatus, infraspinatus, teres minor, and subscapularis muscles, provides dynamic stability by compressing the humeral head firmly against the glenoid fossa during motion.^[4] Key ligaments include the coracohumeral ligament, which reinforces the superior aspect of the capsule and extends from the coracoid process to the humeral tuberosities, limiting excessive external rotation and extension; and the glenohumeral ligaments (superior, middle, and inferior), which form anterior thickenings of the capsule in a Z-shaped configuration to resist anterior and inferior translation.^[5] The scapula contributes to overall stability through its glenoid fossa and associated bony architecture, while the joint's position on the thoracic cage allows for coordinated movement with the acromioclavicular and sternoclavicular joints.^[4] The shoulder's design prioritizes a wide range of motion—enabling up to 180° of flexion, 150° of abduction, and substantial rotation—at the expense of inherent instability, rendering it the most dislocatable joint in the body.^[5] This mobility stems from the shallow glenoid, lax capsule, and minimal bony constraint, balanced by soft tissue restraints.^[4] Biomechanically, joint congruence is maintained primarily by the labrum and negative intra-articular pressure, which creates a vacuum-like seal to center the humeral head within the glenoid, enhancing coaptation during static and dynamic loads.^[5]

Mechanisms of Dislocation

Shoulder dislocation typically occurs when excessive force overcomes the stabilizing structures of the glenohumeral joint, displacing the humeral head from the glenoid fossa. Primary mechanisms include direct trauma, such as a blow to the shoulder in contact sports or motor vehicle accidents, which applies compressive or shearing forces to the joint.^[2] Indirect forces, like a fall on an outstretched hand with the arm in abduction and external rotation, generate leverage that drives the humeral head anteriorly against the glenoid rim.^[6] Posterior dislocations, less common at 2-4% of cases, often result from seizures or electric shocks, where violent, unbalanced muscle contractions—particularly of the internal rotators—force the humeral head posteriorly.^[2] The role of force vectors is critical in these events, as they determine the direction and extent of joint failure. In anterior dislocations, which comprise up to 97% of cases, abduction and external rotation create a lever arm that presses the humeral head against the anterior glenoid, leading to capsular tearing and detachment of the anteroinferior labrum, commonly known as a Bankart lesion.^[2] This detachment reduces the glenoid's depth and stability, allowing the humeral head to disengage fully.^[7] Posterior force vectors, involving adduction, internal rotation, and forward flexion, similarly exploit the joint's posterior capsule and labrum, causing reverse Bankart lesions through direct impingement.^[6] Dislocations are classified as traumatic or atraumatic based on their onset. Traumatic dislocations arise from acute, high-energy injuries that cause immediate capsular rupture and labral avulsion, often progressing from subluxation—partial displacement—under sudden load to full dislocation.^[7] In contrast, atraumatic dislocations stem from repetitive microtrauma or inherent laxity, leading to gradual capsular elongation and multidirectional instability without a single precipitating event.^[2] Energy transfer in high-impact scenarios, such as sports or falls, amplifies these mechanisms by converting kinetic energy into joint-disrupting forces. For instance, in rugby, the "try-scorer" position—arm abducted and externally rotated during a tackle—transmits impact energy through the arm, escalating subluxation to anterior dislocation via rotational leverage on the humeral head.^[6] Similarly, falls on an outstretched arm in accidents channel axial and rotational forces proximally, overwhelming soft tissue restraints and resulting in combined capsular and labral injuries.^[7]

Epidemiology and Risk Factors

Incidence and Demographics

Shoulder dislocation, particularly anterior types, represents a common musculoskeletal injury with a lifetime prevalence estimated at approximately 2% in the general population.^[8] The annual incidence rate in the United States is reported as 23.9 per 100,000 person-years, with global prevalent cases around 8.23 per 100,000 population, though these figures vary by region and may underestimate true occurrence in underreported areas.^[9]^[10] Higher rates are observed in young adults aged 20-30 years, particularly males engaged in sports, where incidence can reach peaks of up to 169 per 100,000 person-years in high-risk groups.^[11] Demographically, shoulder dislocations disproportionately affect males, accounting for about 72% of cases, with anterior dislocations comprising 70-97% of all instances depending on the cohort studied.^[12]^[2] Among athletes in contact sports such as football and rugby, the incidence is elevated compared to the general population, while in older adults over 60, falls contribute to a notable proportion, though at lower overall rates than in youth.^[13] Racial profiles in reported U.S. cases show a majority among White individuals, but data gaps persist for underrepresented groups.^[13] Temporal trends indicate a stable to slightly decreasing global burden of shoulder dislocations from 1990 to 2021, potentially influenced by improved preventive measures in sports, though increased research attention and diagnostic capabilities in the 2020s have led to more reported cases in high-income regions.^[14]^[15] Geographic disparities are evident, with higher untreated rates and complications in low-resource areas due to limited access to emergency care and imaging.^[16] Regarding recurrence, first-time dislocations in individuals under 20 years carry a high risk, with rates of 50-90% without surgical intervention, compared to lower figures (around 20-40%) in older adults.^[17]^[18]

Predisposing Conditions

Certain anatomical variations and prior injuries predispose individuals to shoulder dislocation by compromising the glenohumeral joint's stability. A shallow glenoid fossa, which provides limited bony containment for the humeral head, inherently increases the risk of instability and dislocation.^[2] Excessive capsular laxity further weakens the joint's soft tissue restraints, allowing excessive translation of the humeral head.^[19] Previous injuries, such as tears to the glenoid labrum (e.g., Bankart lesions) or rotator cuff, impair the joint's dynamic and static stabilizers, elevating the incidence of both initial and recurrent dislocations.^[2]^[19] Genetic and collagen disorders contribute to ligamentous hyperlaxity, heightening susceptibility to multidirectional shoulder instability. Conditions like Ehlers-Danlos syndrome, characterized by defective collagen synthesis, result in congenitally loose connective tissues that predispose to atraumatic dislocations and subluxations.^[20] This hyperlaxity often manifests as generalized joint laxity, with prevalence rates of 5-15% in the general population and up to 40-70% among those with multidirectional instability.^[20] Lifestyle and activity-related factors, particularly those involving repetitive overhead motions, amplify dislocation risk through cumulative stress on the shoulder. Participation in sports like swimming and volleyball stretches the glenohumeral ligaments over time, leading to chronic instability.^[21] Muscle imbalances, such as weakness in the rotator cuff relative to stronger anterior muscles, and poor posture further exacerbate vulnerability by altering scapular mechanics and joint loading.^[19] Age and sex influence the etiology and prevalence of shoulder dislocations, with distinct patterns for traumatic and atraumatic cases. Traumatic dislocations are more common in males under 40 years, particularly those aged 20-29, due to higher participation in high-impact activities.^[22] In contrast, females exhibit greater risk for atraumatic dislocations stemming from inherent ligamentous flexibility and hyperlaxity.^[23]

Clinical Presentation

Signs and Symptoms

A dislocated shoulder typically presents with intense, sharp pain that begins suddenly at the time of injury and may radiate to the arm or upper chest, often worsening with any attempt at movement.^[1]^[2] The pain is frequently described as severe and debilitating, exacerbated by muscle spasms surrounding the joint.^[3]^[24] Visible signs include a deformed or squared-off appearance of the shoulder, with the humeral head appearing out of its normal position in the glenoid fossa.^[1]^[3] The affected arm is often held in a characteristic position depending on the dislocation type, such as abduction and external rotation for anterior dislocations or adduction and internal rotation for posterior ones.^[2] Patients commonly experience significant functional impairments, including an inability to actively move the arm or shoulder joint, accompanied by weakness in the affected limb.^[24]^[3] Nerve involvement, particularly of the axillary nerve, can lead to numbness, tingling, or weakness extending down the arm, affecting sensation over the deltoid region.^[2]^[1] Associated symptoms often include localized swelling and bruising around the shoulder, as well as involuntary muscle spasms that further intensify discomfort.^[3]^[24] These signs and symptoms can vary slightly by dislocation direction, with anterior types being the most common and typically presenting with the most pronounced deformity.^[2]

Physical Examination

The physical examination of a suspected shoulder dislocation begins with a systematic assessment to confirm the injury, evaluate its extent, and identify associated complications, while correlating with patient-reported symptoms such as severe pain and inability to move the arm.^[2] The examination is typically performed gently to avoid exacerbating pain or causing further damage, often with the patient seated or supine and the affected arm supported.^[3] Inspection reveals characteristic deformities depending on the direction of dislocation, with anterior dislocation—accounting for the majority of cases—showing the arm held in abduction and external rotation, a prominent humeral head anteriorly below the coracoid process, and a visible flattening or hollow in the deltoid region posteriorly, sometimes described as an "empty glenoid" sign in thinner patients.^[2] Swelling, bruising, and asymmetry compared to the contralateral shoulder are common, along with potential skin tenting over the displaced humeral head.^[3] In posterior dislocations, the arm appears internally rotated and adducted, with posterior prominence of the humeral head and anterior flattening.^[2] Inferior dislocations present with the arm fixed overhead, unable to be adducted.^[2] Palpation confirms these findings through careful touch, identifying tenderness over the anterior or posterior glenohumeral joint, the displaced humeral head (anteriorly in anterior dislocations or posteriorly in posterior ones), and possible crepitus if a fracture is present.^[2] The examiner may note an empty glenoid fossa on posterior palpation for anterior dislocations, with the coracoid process more prominent.^[3] Muscle spasms in the shoulder girdle often contribute to guarding and increased tenderness.^[1] Assessment of range of motion demonstrates marked restriction in both active and passive movements, with patients typically unable to actively abduct, flex, or rotate the shoulder due to pain and mechanical blockade.^[2] Limitation in internal rotation and inability to adduct the arm are key findings.^[25] Neurovascular evaluation is critical to rule out complications, starting with inspection of the skin for color changes (e.g., pallor or cyanosis indicating vascular compromise) and palpation of the radial pulse at the wrist, which may be diminished if the axillary artery is stretched or injured.^[3] Sensory testing assesses for numbness or tingling in the arm, particularly lateral shoulder numbness from axillary nerve injury, which occurs in over 40% of anterior dislocations but often resolves after reduction.^[2] Motor strength is checked in the deltoid, biceps, and other shoulder muscles, with weakness potentially signaling brachial plexus involvement; complete assessment includes distal sensation and strength to detect more extensive nerve damage.^[3]

Diagnosis

Imaging and Tests

Diagnosis of a dislocated shoulder typically begins with radiographic imaging to confirm the position of the humeral head relative to the glenoid and to identify any associated bony injuries.^[2] Standard X-ray views include the anteroposterior (AP), axillary lateral, and scapular Y projections, which collectively provide a comprehensive assessment of the shoulder joint.^[26] The AP view visualizes the humeral head's overlap with the glenoid, while the axillary view is crucial for detecting anterior or posterior dislocations by showing the humeral head's position inferior to the glenoid; if abduction is limited, a Velpeau view can substitute.^[27] The scapular Y view offers an orthogonal perspective, outlining the humeral head against the scapular body to confirm dislocation without requiring arm abduction.^[26] These views also reveal fractures, such as the Hill-Sachs lesion—a posterolateral humeral head impaction fracture common in anterior dislocations—or greater tuberosity avulsions.^[2] For detailed evaluation of soft tissue injuries, magnetic resonance imaging (MRI) is employed, particularly to assess labral tears (e.g., Bankart lesions) and rotator cuff disruptions that may accompany dislocation.^[26] MRI provides high-contrast images of the glenohumeral ligaments, capsule, and cartilage, with MR arthrography enhancing sensitivity for subtle labral pathologies by distending the joint with contrast.^[28] In cases involving complex bony abnormalities or when surgical planning requires precise quantification of bone loss, computed tomography (CT) is preferred, offering multiplanar reconstructions to measure glenoid defects or engaging Hill-Sachs lesions.^[26] Point-of-care ultrasound serves as a rapid, non-ionizing alternative for dynamic assessment of shoulder dislocation, especially in emergency settings, with high sensitivity (up to 100%) and specificity (up to 100%) for detecting humeral head position and confirming reduction.^[29] Arthrography, though rarely used today due to advances in MRI, can evaluate capsular integrity and leaks in select cases of recurrent instability.^[28] These imaging modalities also aid in excluding differentials such as proximal humerus fractures, isolated rotator cuff tears, or acromioclavicular joint separations, which may mimic dislocation clinically.^[2] Radiographic findings from these tests contribute to classifying the dislocation direction, as detailed separately.^[26]

Classification by Direction

Shoulder dislocations are classified primarily by the direction of humeral head displacement relative to the glenoid fossa, which influences associated injuries, mechanisms, and management approaches.^[2] Anterior dislocations represent the vast majority, comprising up to 97% of all cases, where the humeral head displaces anteriorly and often inferiorly out of the glenoid.^[2] This type typically results from a traumatic mechanism involving forced abduction and external rotation of the arm, such as during a fall on an outstretched hand or a direct blow.^[30] Associated lesions are common, including Bankart lesions (avulsion of the anteroinferior labrum) in approximately 73% of cases and Hill-Sachs lesions (posterolateral humeral head impaction fractures) in 40% to 90% of cases.^[30]^[31] Posterior dislocations are less frequent, accounting for 2% to 4% of shoulder dislocations, with the humeral head displacing posteriorly behind the glenoid.^[2] They often arise from axial loading on an adducted and internally rotated arm, direct anterior trauma, or convulsive events like seizures or electric shocks.^[32] Characteristic radiographic findings include the lightbulb sign, where the internally rotated humeral head appears rounded and symmetric on anteroposterior views.^[32] Inferior dislocations, also known as luxatio erecta, are rare, representing less than 1% of all shoulder dislocations, with the humeral head positioned below the glenoid fossa and the arm locked in full abduction overhead.^[2] The primary mechanism involves hyperabduction of the arm, often from high-energy trauma such as a fall from height while grasping an overhead object.^[33] These injuries carry a high risk of complications, including neurovascular compromise (affecting up to 60% of cases, particularly the axillary nerve) and associated fractures (in about 80%).^[33] Multidirectional instability (MDI) differs from unidirectional traumatic dislocations, involving bidirectional or multidirectional laxity without a single defining traumatic event, often stemming from generalized ligamentous hyperlaxity or repetitive microtrauma.^[34] It is characterized by instability in at least two planes (anterior, posterior, or inferior) due to imbalances in static (e.g., glenohumeral ligaments) and dynamic stabilizers (e.g., rotator cuff), with genetic factors like Ehlers-Danlos syndrome contributing in some cases.^[34] While prevalence is not precisely quantified due to diagnostic challenges, MDI typically presents insidiously in young adults, particularly in the second or third decade, and may lead to subluxations rather than frank dislocations.^[34]

Treatment

Closed Reduction Techniques

Closed reduction involves the manual realignment of the humeral head into the glenoid fossa without surgical intervention, serving as the primary treatment for most shoulder dislocations to restore joint stability and alleviate pain.^[35] This approach is effective in approximately 80-90% of cases, particularly for anterior dislocations, which comprise over 95% of shoulder dislocations, provided there are no contraindications such as associated fractures or neurovascular compromise.^[35] Success depends on adequate analgesia or sedation to relax the surrounding musculature, with techniques adapted to the direction of dislocation.^[36] Prior to reduction, radiographic imaging, including anteroposterior and axillary views, is essential to confirm the dislocation and rule out fractures, which may necessitate surgical management.^[35] Analgesia options include intra-articular lidocaine (10-20 mL of 1% solution) or procedural sedation with agents like propofol or ketamine to minimize patient discomfort and facilitate muscle relaxation.^[37] Following successful reduction, post-procedure X-rays verify proper alignment, and the shoulder is immediately immobilized in a sling or swathe for 1-3 weeks to promote soft tissue healing.^[35] Contraindications include suspected humeral neck or greater tuberosity fractures, as forceful manipulation could exacerbate injury, and signs of vascular or neurologic compromise, which require urgent surgical evaluation.^[36] For anterior dislocations, several techniques leverage traction, leverage, or rotation to disengage the humeral head from its anterior position. The traction-countertraction method, also known as the Hippocratic technique, positions the patient supine with the arm abducted 45° and elbow flexed; an assistant applies countertraction via a sheet wrapped around the torso, while the clinician provides longitudinal traction on the arm, often with the foot in the axilla for leverage.^[36] This method requires sedation and multiple personnel due to the force involved. The Stimson technique, suitable for sedated or relaxed patients, involves placing the patient prone with the affected arm hanging freely off the bed edge, a 5-10 lb weight attached to the wrist, allowing gravity-assisted reduction over 15-20 minutes.^[35] External rotation methods, such as the Kocher or Hennepin variants, start with the patient supine, arm adducted and elbow flexed 90°; gradual external rotation to 70-110° over 5-10 minutes disimpacts the humeral head, with caution advised to avoid proximal humerus fractures from excessive torque.^[37] The Milch technique abducts the arm overhead to 120°, applies axial traction with external rotation, and uses thumb pressure on the humeral head to lever it into the glenoid, achieving success rates of 70-90% and often requiring less sedation.^[35] Posterior dislocations, which are less common (2-4% of cases), are reduced using axial traction combined with direct posterior pressure on the humeral head. In the supine position, the clinician applies gentle longitudinal traction to the adducted and internally rotated arm while an assistant pushes the humeral head anteriorly; external rotation is avoided until the head clears the glenoid rim to prevent iatrogenic fracture.^[35] Techniques like DePalma's involve adducting the arm, applying caudal traction, and laterally pushing the upper arm to rotate the scapula.^[36] Inferior dislocations, or luxatio erecta, demand prompt reduction to avert neurovascular damage; axial traction is applied with the arm elevated overhead, gradually increasing abduction while adding cephalad pressure to the humeral shaft until the head relocates inferiorly into the glenoid.^[35] A two-step maneuver may first convert the position to an anterior subcoracoid type by flexing the arm 15-20° and externally rotating, followed by standard anterior reduction techniques.^[36] Adaptations for dislocation direction, as classified by anterior, posterior, or inferior displacement, guide technique selection to optimize outcomes while minimizing complications like recurrent instability.^[35]

Surgical Options

Surgical intervention for shoulder dislocation is typically reserved for cases of recurrent instability, significant damage to the labrum or bone structures such as glenoid defects, or when closed reduction fails due to interposed soft tissues.^[38] In recurrent anterior instability, surgery aims to restore joint stability by addressing underlying pathologies like labral tears or bone loss, particularly in young, active patients where nonoperative management has failed.^[39] Common procedures include the arthroscopic Bankart repair, which involves reattaching the detached anteroinferior labrum to the glenoid rim using suture anchors to recreate the glenolabral bumper and stabilize the joint.^[38] This technique is indicated primarily for isolated soft-tissue injuries without substantial glenoid bone loss (less than 20-25%).^[38] The Latarjet procedure, involving transfer of the coracoid process with its attached conjoint tendon to the anterior glenoid, is preferred for cases with significant bony defects or after failed Bankart repairs, providing both a bone block and sling effect from the transferred tendon.^[39] It can be performed openly or arthroscopically, with the latter offering potentially less invasive access but requiring advanced technical expertise.^[39] For multidirectional instability or capsular laxity, capsulorrhaphy tightens the redundant joint capsule through plication or shifting, often combined with labral repair, to reduce volume and enhance stability.^[38] Arthroscopic approaches, such as in Bankart repair or arthroscopic Latarjet, are minimally invasive, allowing for better visualization of intra-articular pathology and generally leading to improved postoperative range of motion with fewer complications like infection.^[38] However, open techniques may offer superior stability in complex cases; for instance, meta-analyses show the Latarjet procedure achieves lower recurrence rates of 1.6-6% compared to 11-22% for arthroscopic Bankart repair, particularly in high-risk patients with bone loss.^[39] Risks of Latarjet include coracoid nonunion (up to 10%) and potential for osteoarthritis, while Bankart repair carries a higher redislocation risk in contact athletes.^[39] Postoperative care emphasizes immobilization in a sling for 4-6 weeks to protect the repair, followed by early passive mobilization to prevent stiffness and adhesions, with progression to active exercises under supervised rehabilitation.^[38] This phased approach balances stability restoration with functional recovery, typically allowing return to light activities by 3 months.^[39]

Post-Treatment Rehabilitation

Following successful closed reduction or surgical intervention for a dislocated shoulder, rehabilitation is essential to restore range of motion (ROM), strength, and stability while reducing the risk of recurrent instability. This process is typically guided by a physical therapist and progresses through distinct phases based on patient tolerance and healing milestones, with immobilization initially protecting the joint capsule.^[3]^[40] Phase 1 (0-4 weeks): During this initial period, the shoulder is immobilized in a sling for 1-3 weeks to promote soft tissue healing and prevent further displacement, with the duration adjusted based on age and injury severity—shorter for older patients to avoid stiffness. Passive ROM exercises, such as pendulum swings or therapist-assisted movements, are introduced early (often after 1 week) to maintain joint mobility and prevent adhesive capsulitis (frozen shoulder), targeting gentle flexion and external rotation without active muscle contraction. Submaximal isometric exercises for the rotator cuff and scapular stabilizers may also begin to retard atrophy, performed under supervision to ensure no pain or apprehension.^[41]^[19]^[40] Phase 2 (4-12 weeks): As immobilization ends, the focus shifts to active-assisted ROM exercises, progressing from wand-assisted flexion and abduction to self-assisted pulley systems, aiming for full passive ROM by week 6-8. Isometric strengthening of the rotator cuff muscles (e.g., external rotation holds at 90° abduction) is incorporated to rebuild endurance, alongside scapular stabilization drills like wall slides, all advanced gradually to avoid provoking instability. Pain levels dictate progression, with non-surgical cases often advancing faster than post-surgical ones, where surgical influences on the capsule may extend this phase by 1-2 weeks.^[41]^[19]^[40] Phase 3 (12+ weeks): Once full active ROM is achieved without pain or guarding, the program emphasizes advanced strengthening with resistance bands or light weights for the rotator cuff and deltoids, integrated with sport-specific training such as throwing progressions for athletes. Proprioception drills, including closed-chain exercises on unstable surfaces (e.g., balance board perturbations), enhance neuromuscular control and joint position sense to support return to daily or athletic activities, typically by 3-6 months.^[19]^[40]^[3] Throughout rehabilitation, progression is pain-guided, with physical therapists monitoring for signs of instability and customizing protocols to prevent re-injury—such as emphasizing external rotation limits in non-surgical cases versus cautious loading post-surgery. Regular assessments ensure symmetrical strength (at least 90% of the uninjured side) and functional stability before discharge.^[41]^[40]^[19]

Prognosis and Complications

Recovery Expectations

Following closed reduction, patients typically experience significant pain relief within hours to days, aided by immobilization, analgesics, and anti-inflammatory medications.^[42] Most individuals can resume daily activities with 80-90% functionality within 4-6 weeks, provided there is no associated fracture or soft tissue injury requiring extended immobilization.^[43]^[3] For first-time dislocations treated non-operatively, full recovery—defined as pain-free range of motion and near-normal strength—generally occurs in 3-6 months with consistent rehabilitation.^[44] Surgical intervention, such as arthroscopic Bankart repair, extends this timeline to 4-6 months before unrestricted activity but achieves success rates exceeding 90% in preventing recurrence.^[45] Early rehabilitation following either approach reduces recurrence risk to under 20% in patients over 40 years, compared to 70-100% in those under 20 without intervention.^[46] Recovery outcomes are influenced by age, with younger patients (<25 years) showing faster restoration of strength and function but higher instability risk, while older adults (>50 years) experience lower recurrence (14-22%) due to reduced activity demands.^[46] Adherence to rehabilitation protocols and the extent of initial damage, such as labral tears, are critical; non-compliance can prolong recovery by 1-2 months.^[42] In athletes, return-to-sport rates reach 70-85% at pre-injury levels after non-operative management.^[47]

Potential Long-Term Issues

A dislocated shoulder can lead to recurrent instability if not surgically addressed, with the risk ranging from 40% to 90% in nonoperative cases, particularly among younger patients under 30 years old where rates can exceed 70%.^[46] This recurrent instability often results in chronic shoulder pain, functional limitations, and apprehension during overhead activities or contact sports, as repeated dislocations progressively damage the glenohumeral ligaments and labrum.^[48] Associated injuries frequently accompany shoulder dislocations, including rotator cuff tears, which occur in 30% to 50% of cases among individuals over 40 years of age due to the degenerative changes in tendon quality with aging.^[49] Nerve damage, particularly axillary neuropathy, affects up to 40% of patients, manifesting as deltoid weakness, sensory loss over the shoulder, and potential long-term muscle atrophy if recovery is incomplete.^[2] Vascular complications, such as axillary artery injury, are rarer, occurring in less than 1% of dislocations, but can lead to ischemia, thrombosis, or pseudoaneurysm formation requiring urgent intervention.^[50] Degenerative changes, including post-traumatic osteoarthritis, arise from cartilage damage during the initial or recurrent dislocations, with the risk elevated 10- to 20-fold compared to uninjured shoulders, especially in untreated cases or those with multiple episodes.^[51] This arthritis typically develops over years, causing progressive joint stiffness, pain, and reduced range of motion due to humeral head flattening and glenoid erosion.^[52] Psychological impacts, such as kinesiophobia—the fear of movement due to reinjury apprehension—can persist after dislocation, correlating with worse pain, diminished function, and lower quality of life, often hindering return to daily activities or sports.^[53] These effects may be mitigated through targeted rehabilitation focusing on gradual exposure and confidence-building exercises.^[54]

Prevention

Injury Avoidance Strategies

Preventing shoulder dislocations involves adopting behavioral and environmental strategies tailored to high-risk scenarios, particularly in sports and daily activities. In contact sports such as football, employing proper tackling techniques—such as keeping the head up and initiating contact with the inside shoulder—can significantly reduce the risk of shoulder injuries by minimizing direct impact on the joint.^[55] For older adults, fall prevention measures like maintaining a clutter-free home environment and using assistive devices such as canes or walkers help mitigate the likelihood of falls that could lead to dislocations, especially in those with predisposing factors like hyperlaxity.^[24] Utilizing appropriate protective gear is essential for individuals engaging in high-impact activities or those with a history of shoulder instability. In contact sports, shoulder pads provide cushioning to absorb forces that might otherwise displace the humeral head, thereby lowering dislocation incidence.^[24] For athletes or patients with recurrent instability, specialized braces like the S2 Shoulder Stabilizer limit excessive range of motion in abduction and external rotation, enhancing joint stability and facilitating a quicker return to play without surgical intervention.^[56] Ergonomic adjustments in occupational and recreational settings further contribute to risk reduction by addressing repetitive strain. Workers involved in tasks requiring frequent overhead reaching, such as painting or assembly line operations, should alternate arm usage and incorporate scheduled breaks to avoid cumulative stress on the glenohumeral joint that could precipitate instability.^[57] Prior to any physical exertion, implementing a brief warm-up routine—focusing on gentle arm circles and dynamic movements—prepares the shoulder musculature and improves joint lubrication, decreasing vulnerability to acute dislocations.^[42] Educating individuals on acute responses to early warning signs empowers timely intervention to avert full dislocations. Recognizing shoulder subluxation, characterized by a sensation of the joint "giving way" or partial slippage during overhead or reaching motions, allows for immediate cessation of activity and application of supportive measures like a sling, preventing progression to complete displacement.^[57] Prompt medical evaluation upon experiencing such symptoms is crucial, as untreated subluxations can exacerbate underlying instability.^[58]

Strengthening and Stability Exercises

Strengthening and stability exercises play a crucial role in enhancing shoulder resilience by targeting the rotator cuff muscles, scapular stabilizers, and proprioceptive mechanisms, thereby reducing the risk of anterior dislocations in at-risk populations.^[59] These exercises focus on building dynamic control and joint awareness, particularly beneficial for individuals with shoulder laxity.^[60] Rotator cuff strengthening exercises emphasize the supraspinatus, infraspinatus, teres minor, and subscapularis muscles to maintain humeral head centering in the glenoid fossa. External rotation with resistance bands involves standing with the elbow bent at 90 degrees and tucked to the side, then rotating the forearm outward against the band's tension while keeping the elbow fixed; perform 3 sets of 8-12 repetitions.^[59] Internal rotation follows a similar setup but rotates the forearm inward across the body; the same repetition scheme applies.^[59] Side-lying external rotation requires lying on the unaffected side with a light weight (1-2 pounds) in the hand, elbow bent at 90 degrees resting on the side, and lifting the forearm upward; aim for 2-3 sets of 10 repetitions, progressing by increasing weight as strength improves.^[59] Scapular stabilization exercises promote coordinated movement between the scapula and humerus to enhance overall glenohumeral stability. Wall slides entail standing facing a wall with forearms and hands against it, elbows bent, then sliding the arms upward into a "V" position while squeezing the shoulder blades together, maintaining contact with the wall; complete 2-3 sets of 10-15 repetitions.^[61] Rows using a resistance band involve securing the band at waist height, pulling the elbows back while squeezing the scapulae, as if pinching a pencil between them; perform 3 sets of 8-12 repetitions.^[59] Planks, held in a forearm position with the body in a straight line, engage the scapular stabilizers through isometric contraction; maintain for 20-30 seconds per set, progressing to variations like shoulder taps for added challenge.^[62] Proprioception training refines joint position sense and reactive control, essential for athletes in dynamic sports. Balance board exercises, such as standing on an unstable board with arms at the sides and maintaining equilibrium while performing gentle shoulder circles, improve sensory feedback; conduct 2-3 sets of 30-60 seconds.^[63] Perturbation drills simulate sudden forces, like a partner applying gentle pushes to the arm in various positions while the individual resists to stabilize the shoulder; these are advanced and typically done under supervision for 10-15 trials per session.^[64] Progression typically involves 2-3 sets of 10-15 repetitions per exercise, performed 3 times per week, with gradual increases in resistance or hold times once form is mastered and no pain occurs.^[59] Integration into routines is recommended for at-risk groups, such as overhead athletes or those with prior instability, starting with lower intensities and advancing over 4-6 weeks to maintenance levels.^[60]

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