Glenohumeral Instability

Upper Limb

Overview

Glenohumeral instability is a condition characterized by excessive translation of the humeral head within the glenoid fossa, resulting from compromised dynamic or static stabilizers. This can manifest as anterior, posterior, inferior, or multidirectional patterns, with varying degrees of severity from microinstability to frank dislocation. Patients typically present with apprehension, pain, and functional limitations in specific arm positions.

Pathophysiology

The glenohumeral joint relies on a complex balance of static stabilizers (labrum, articular cartilage, joint capsule, and ligaments) and dynamic stabilizers (rotator cuff muscles and scapular stabilizers). Instability develops through traumatic injury (Bankart lesions, HAGL lesions, Hill-Sachs defects), repetitive microtrauma, inherent ligamentous laxity, or neuromuscular dysfunction. Compromised proprioception, altered scapulohumeral rhythm, and weakness in rotator cuff or scapular stabilizers perpetuate the unstable pattern. Chronic instability leads to degenerative changes, further articular surface damage, and secondary impingement.

Typical Presentation

Site

Anterior glenohumeral joint region; pain may radiate to lateral shoulder and upper arm; posterior shoulder pain if posterior instability

Quality

Sharp, catching sensation; sense of shoulder 'slipping' or 'dead arm' phenomenon; aching or dull discomfort with functional activities

Intensity

Variable, typically mild to moderate at rest, severe with provocative positions or functional demands; intensity increases with fatigue

Aggravating

Abduction with external rotation (throwing position, overhead activities); sudden arm movements; certain sleeping positions; fatigue during repetitive activities; specific arm positions (apprehension position); overhead sports

Relieving

Rest and immobilization; internal rotation positioning; anti-inflammatory modalities; controlled movement patterns; scapular stabilization

Associated

Apprehension and fear of movement; loss of proprioception; scapular dyskinesis; reduced rotator cuff strength; clicking or clunking sensations; difficulty with overhead activities; functional weakness; anterior shoulder capsule tightness; posterior capsule tightness (posterior instability)

Orthopaedic Tests

Apprehension Test (Crank Test)

Procedure

Patient supine or seated; shoulder abducted to 90° and externally rotated. Positive response is apprehension that the humeral head will dislocate anteriorly.

Positive Finding

Patient reports apprehension (fear of dislocation) rather than pain alone

Sensitivity / Specificity

72% / 98%

Hegedus et al., 2008, British Journal of Sports Medicine

Interpretation

High specificity for anterior glenohumeral instability; apprehension is more specific than pain. Negative test helps rule out anterior instability.

Relocation Test (Jobe Relocation Test)

Procedure

Performed immediately after positive apprehension test. Examiner applies posterior-directed pressure to the humeral head while shoulder remains in 90° abduction and external rotation.

Positive Finding

Reduction or elimination of apprehension with posterior pressure applied to humeral head

Sensitivity / Specificity

72% / 97%

Hegedus et al., 2008, British Journal of Sports Medicine

Interpretation

Increases confidence in anterior instability diagnosis when apprehension test is positive and relocation abolishes apprehension. Strengthens diagnostic accuracy when used as a cluster with apprehension test.

Anterior Drawer Test (Sulcus Sign Modified for Anterior Translation)

Procedure

Patient seated or supine; examiner grasps humeral head with one hand and translates it anteriorly while the other hand stabilizes the scapula. Movement is assessed qualitatively or with ruler measurement.

Positive Finding

Excessive anterior humeral head translation (>1 cm or grade 2–3 on a scale of 0–3)

Sensitivity / Specificity

50% / 97%

Hegedus et al., 2008, British Journal of Sports Medicine

Interpretation

High specificity suggests anterior instability when positive; low-moderate sensitivity means negative test does not reliably exclude instability. Useful to confirm laxity when apprehension tests are equivocal.

Surprise/Release Test (Jerk Test Variant)

Procedure

Patient supine; examiner reproduces apprehension position (90° abduction, external rotation) then suddenly releases posterior pressure (if applied) or suddenly shifts hand position to assess patient reaction.

Positive Finding

Patient guards or shows fear response when support is withdrawn; apprehension returns or worsens

Sensitivity / Specificity

Unknown / Unknown

Interpretation

Supplementary test to confirm psychological component and apprehension response to perceived instability. Lacks strong diagnostic validation in literature but clinically useful to differentiate apprehension from pain.

Sulcus Sign (Inferior Instability)

Procedure

Patient seated with arms at side and relaxed. Examiner applies downward traction on the humerus and observes for a sulcus (depression) below the acromion.

Positive Finding

Visible or palpable sulcus depression below the acromion with downward traction; graded 0–3 (grade ≥2 considered positive)

Sensitivity / Specificity

76% / 91%

Hegedus et al., 2008, British Journal of Sports Medicine

Interpretation

Indicates inferior glenohumeral instability or multidirectional instability. Presence suggests capsular laxity and may indicate need for non-operative rehabilitation focusing on rotator cuff and scapular control.

Crank Test (External Rotation at 0° Abduction)

Procedure

Patient prone or supine with shoulder at 0° abduction and elbow flexed 90°. Examiner externally rotates the shoulder, noting range and resistance.

Positive Finding

Excessive external rotation (>75°) compared to contralateral side, or reproduction of apprehension during movement

Sensitivity / Specificity

See current literature / See current literature

Interpretation

Assesses anterior capsular laxity and proprioceptive feedback. Positive test suggests anterior or multidirectional instability, especially when combined with apprehension or relocation tests.

⚠ Red Flags

  • •Acute glenohumeral dislocation requiring emergency reduction
  • •Neurovascular compromise (axillary nerve injury, vascular injury)
  • •Significant bony defects (Hill-Sachs lesion >25%, glenoid bone loss >20%) requiring surgical intervention
  • •Fracture-dislocation or associated fractures
  • •Recurrent dislocation episodes (>2 dislocations, especially in contact athletes)
  • •Failed conservative management with persistent instability despite 3+ months of structured therapy
  • •Signs of associated labral pathology with mechanical locking or catching
  • •Systemically hypermobile Ehlers-Danlos syndrome or Marfan syndrome requiring specialist assessment

⚡ Yellow Flags

  • •High-level athlete with instability affecting career/livelihood
  • •Fear-avoidance beliefs preventing engagement in rehabilitation
  • •Repeated injury pattern suggesting possible inadequate rehabilitation compliance
  • •Psychological distress related to injury and functional limitations
  • •Secondary gains associated with chronic shoulder dysfunction
  • •Perfectionist or high-performance athlete mentality affecting recovery pacing
  • •Limited coping mechanisms for managing shoulder function restrictions
  • •Anxiety regarding re-dislocation during rehabilitation progression

Osteopathic Techniques

Region

Glenohumeral joint and anterior capsule

Technique

Soft Tissue

Rationale

Targeted soft tissue mobilization to anterior shoulder structures, pectoralis minor, and subscapularis releases tension in capsular tissues, improves local circulation, and prepares tissues for mobilization. Reduces protective muscle guarding and facilitates proprioceptive input.

Region

Posterior shoulder capsule and infraspinatus

Technique

MET

Rationale

Muscle energy techniques addressing posterior capsule tightness are essential in anterior instability patterns where posterior capsule contracture contributes to altered scapulohumeral mechanics. Restores balanced capsular tension and reduces compensatory anterior translation.

Region

Glenohumeral joint

Technique

Articulation

Rationale

Gentle passive articulation through pain-free ranges promotes synovial fluid distribution, enhances proprioceptive awareness, and maintains accessory motion patterns without aggressive mobilization that may exacerbate instability. Builds confidence in movement patterns.

Region

Scapulothoracic joint and associated musculature

Technique

Soft Tissue

Rationale

Release of upper trapezius, levator scapulae, and pectoralis minor facilitates normalized scapular positioning. Correcting scapular dyskinesis is fundamental to restoring dynamic stability and reducing compensatory glenohumeral translation.

Region

Thoracic spine and ribcage

Technique

HVLA

Rationale

Thoracic mobility restrictions limit scapular positioning and contribute to altered scapulohumeral rhythm. High-velocity low-amplitude thrust to mid-thoracic segments restores extension and rotation, optimizing scapular mechanics and proximal stability.

Region

Cervical spine and cervicothoracic junction

Technique

Articulation

Rationale

Cervical and cervicothoracic restrictions limit shoulder girdle positioning and proprioceptive input from cervical mechanoreceptors. Gentle articulation restores cervical-scapular coordination and upper quarter neurodynamics essential for shoulder stability.

Add-On Approaches

Chinese Medicine

TCM approach emphasizes Qi stagnation and Blood deficiency in the Channels of the shoulder (particularly Large Intestine and Triple Burner meridians). Acupuncture points LI15 (Jianyu), TE14 (Jianliao), and SI9 (Jianzhen) address local pain and circulation. Moxibustion and herbal therapy (e.g., Du Huo Ji Sheng Tang) support tissue healing and reduce inflammation. Cupping over posterior shoulder releases myofascial tension.

Chiropractic

Chiropractic management includes glenohumeral manipulation for accessory motion restoration, scapulothoracic adjustments to correct dyskinesis, and cervical spine manipulation to optimize shoulder girdle position. Soft tissue techniques targeting rotator cuff and scapular stabilizers complement manipulative therapy. Proprioceptive training and postural correction are integral.

Physiotherapy

Progressive resistance training targeting rotator cuff (external and internal rotators), scapular stabilizers (lower trapezius, serratus anterior), and kinetic chain (core and lower body). Proprioceptive neuromuscular facilitation (PNF) patterns enhance dynamic stability. Closed-chain exercises (push-ups, wall slides) and sport-specific functional training restore confidence and performance. Postural re-education and ergonomic modification prevent recurrence.

Remedial Massage

Deep tissue massage of rotator cuff muscles, scapular stabilizers, and thoracic muscles reduces protective guarding and myofascial restrictions. Trigger point therapy to subscapularis, infraspinatus, and pectoralis minor addresses referred pain patterns. Soft tissue mobilization combined with passive range of motion facilitates tissue extensibility and proprioceptive awareness during healing phases.

Rehabilitation Exercises

Pendulum Circles

Range of MotionBeginner

Cross-Body Shoulder Stretch (Horizontal Adduction)

StretchingBeginner

Sleeper Stretch (Posterior Capsule)

StretchingBeginner

Scapular Retraction with Prone Walkout

PosturalIntermediate

Isometric External Rotation (Neutral Position)

StrengtheningBeginner

Prone Shoulder External Rotation with Band

StrengtheningIntermediate

Prone Horizontal Abduction at 90 Degrees

StrengtheningIntermediate

Lower Trapezius Activation (90/90 Position)

StrengtheningIntermediate

Quadruped Shoulder Taps

BalanceIntermediate

Prone Push-up with Scapular Emphasis

StrengtheningAdvanced

PNF D2 Flexion Pattern (Standing with Resistance Band)

BalanceAdvanced

Submaximal Rowing Machine (Controlled Ergometer)

CardiovascularIntermediate

Referral Criteria

  • •Acute dislocation or recurrent dislocations (>2 episodes) requiring orthopedic evaluation for imaging and surgical consideration
  • •Failure to progress after 8-12 weeks of structured conservative management
  • •Severe pain with significant functional limitations unresponsive to manual therapy and exercise
  • •Clinical suspicion of labral pathology (SLAP lesion, Bankart lesion) with positive imaging findings
  • •Significant bony defects or fracture-dislocation requiring surgical stabilization
  • •High-demand athletes seeking return to contact or overhead sports requiring specialist clearance
  • •Neurovascular compromise or axillary nerve injury
  • •Systemic connective tissue disorders (Ehlers-Danlos, Marfan syndrome) requiring multidisciplinary team approach
  • •Persistent instability despite optimal rehabilitation suggesting possible undiagnosed pathology
  • •Mental health concerns or significant psychological distress interfering with rehabilitation engagement