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Shoulder Instability

From WikiSM

Other Names

  • Glenohumeral Instability
  • Anterior Shoulder Instability
  • Multidirectional Instability
  • MDI
  • Unidirectional Shoulder Instability
  • Traumatic Shoulder Instability
  • Atraumatic Shoulder Instability

Background

History

  • MDI first described by Neer and Foster in 1980[1]

Epidemiology

  • General
    • Prevalence of non-pathologic hyperlaxity in the general population is estimated to be between 5 and 15%[2]
  • MDI
    • Incidence, prevalence largely unknown
    • 2008: 7% of shoulder operations in Norway due to MDI[3]
    • Most commonly seen in patients in their 2nd and 3rd decade (need citation)
  • Traumatic instability
    • Traumatic anterior instability accounts for 80-90% of instability experienced by young athletes[4]
    • Incidence reported to be up to 1.7% of general population[5]

Introduction

Passive structures involved in the glenohumeral joint stability[6]
Sheean, Andrew J., Justin W. Arner, and James P. Bradley. "Posterior glenohumeral instability: diagnosis and management." Arthroscopy 36.10 (2020): 2580-2582.</ref>

General

  • There is no clear definition of MDI, glenohumeral instability and shoulder instability is variable in the literature
  • For MDI, sometimes the sensation of instability occuring in more than one direction is sufficient
  • This is not commonly agreed upon by experts
  • Most patients are initially managed non-surgically, with refractory cases having a variety of surgical options

Definition

  • There is no clear definition of MDI, glenohumeral instability and shoulder instability in the literature
  • No pathognomonic finding or widely standardized diagnostic criteria
  • Some literature references the Del Mar and Beighton scoring systems (see below), but these are not universally adopted
  • For MDI, some cite instability in two directions
  • Subsequently diagnosis, research, practice guidelines are lacking

Description

  • In general, shoulder instability is pathological condition characterized by increased length and elasticity of normal glenohumeral joint restraints
  • Indicates deficiency in static or dynamic stabilizers of the glenohumeral joint
  • Subsequently, there is increased translation of the articular surface
  • In MDI, this can be from repetative microtrauma or overall joint hyperlaxity
  • This can also occur due to primary trauma from shoulder dislocation

Hyperlaxity

  • Hyperlaxity by itself is not pathologic
  • May be present in asymptomatic patients or asymptomatic translation of the glenohumeral joint

History of Glenohumeral Dislocation

  • Patients with anterior traumatic shoulder instability without true hyperlaxity
  • Can experience recurrent dislocations and subluxations due to primary injury to the capsulolabral complex, glenoid or humeral head
  • Patients with shoulder instability and hyperlaxity are more likely to experience recurrent subluxations than frank dislocations[7]
    • Due to microtrauma from overuse

Etiology

  • Typical etiology includes repetitive microtrauma imposed on a congenitally lax joint[8]
  • Some degree of imbalance in muscle strength, neuromuscular control and dysfunction scapular biomechanics
  • Most common mechanism for initial anterior dislocation is fall onto outstretched arm with abducted, externally rotated arm

Anatomy of the Glenohumeral Joint

Associated Conditions

Risk Factors

  • Prior Injury (greatest risk)[9]
  • Age of first dislocation
  • Congenital Hyperlaxity/ Ligamentous laxity including
    • Ehler's Danlos Syndrome
    • Marphan Syndrome
    • Osteogenesis Imperfecta
    • Benign Hypermobility Syndrome
  • Age
  • Labral hypoplasia[10]
  • Glenoid size
  • Modifiable
    • Rotator cuff strength
    • Muscular imbalance
    • Activity level
  • Acquired hyperlaxity from Sports
    • Volleyball
    • Swimming
    • Gymnastics

Differential Diagnosis

Differential Diagnosis Shoulder Pain

Clinical Features

History

  • Important to clarify history of dislocations, subluxations or sensation of laxity
  • Any history of developmental delay, seizure disorder, collagen disorder, congenital problems
  • Clarify if the patient can volitionally dislocate their shoulder
  • Symptoms may include vague shoulder pain with sports or demanding activities
  • May endorse recurrent dislocations and/or subluxations
  • In atraumatic cases, pain is usually insidious in onset
  • Patients may endorse declining athletic performance
  • Less commonly parasthesias, weakness
  • Symptoms may occur while sleeping

Physical Exam: Physical Exam Shoulder

  • Important to compare to contralateral arm
  • Examination is best performed through provocative testing

Special Tests

Anterior Instability/ Laxity

Posterior Instability/ Laxity

  • Kim Test: Arm abducted to 90°, apply axial load and elevate arm cranial and anterior
  • Jerk Test: Arm abducted to 90°, internally rotated with axial load and arm is abducted anteriorly in same plane
  • Posterior Apprehension Test: Apply a posterior force through flexed, adducted shoulder
  • Posterior Shoulder Drawer Test: with arm flexed and in partial traction, apply a posterior directed force
  • Fukada Test: apply a posteriorly directed force with the patient seated

Inferior laxity Instability/ Laxity

  • Sulcus Sign: Place axial traction on affected limb with arm resting at side
  • Gagey Test: Hyperabduct arm to barrier or as patient tolerates
A CT scan of the shoulder, showing the mismatch between the size of the glenoid (yellow) and the size of the humeral head (red)[11]
Radiographic findings associated with instability. A, AP shoulder view in internal rotation of a patient with history of dislocation showing a Hill-Sachs defect (arrow); B, West Point view of the same patient as in A demonstrating a Bankart fracture (arrow); C, axillary view with applied stress showing marked posterior humeral head subluxation; D, AP glenohumeral (Grashey) view of another patient shows a glenoid ganglion cyst (arrows) (MRI subsequently revealed a posterior labral tear); E, AP glenohumeral (Grashey) view showing flattened, shallow glenoid with a short neck, compatible with glenoid dysplasia. Note osteoarthritis secondary to chronic instability.[12]

Evaluation

Radiographs

CT

  • Helpful to better evaluate bone abnormalities

MRI

  • Best imaging modality for soft tissue pathology
  • Can add arthrogram to better evaluate labrum and capsule
  • MDI: Hallmark finding is pathologic inferior capsule (IGHL, anterior and posterior bands)
  • May also show Bankart Lesion, Kim Lesion

Classification

Classification of glenohumeral instability[13]

Hospital Del Mar Score

  • Can be used to assess, quantify hyperlaxity[14]
    • Score ranges from 0-10
    • Score of 4/10 (men) or 5/10 (women) or higher suggests generalized joint laxity
  • Criteria
    • Passive hyperextension of the metacarpophalangeal joint of the little finger of 90° or more
    • Passive apposition of the thumb to the flexor aspect of the forearm at less than 21 mm
    • Passive elbow hyperextension of 10° or more
    • Passive shoulder external rotation of 85° or more
    • Passive hip abduction of 85° or more
    • Hyperextension of the first metatarsophalangeal joint beyond 90°
    • Patellar hypermobility, defined as excessive passive displacement medially and laterally as assessed by three or more quadrants of displacement
    • Excessive range of passive ankle dorsiflexion and eversion of the foot with the knee flexed to 90°
    • Passive knee hyperflexion, defined as ‘knee makes contact with the buttock’
    • Appearance of ecchymoses after hardly noticed, minimal trauma (historical datum)

Beighton Criteria

  • Scoring system for hyperlaxity and shoulder instability[15]
    • Score ranges from 0-9
    • Score of 2+ increases likelihood of future instability
    • Ranallette et al: Score of 6 or greater indicative of hyperlaxity[16]
  • Criteria
    • Passive dorsiflexion of the fifth finger beyond 90°
    • Passive thumb opposition to the forearm
    • Active elbow hyperextension beyond 10°
    • Active knee hyperextension beyond 10°
    • Forward flexion of the trunk with knees fully extended so that the palms of the hands rest flat on the floor.

Management

Shoulder Brace

Algorithm for the management of patients with anterior glenohumeral instability.[17]

Nonoperative

  • Indications:
    • First line therapy in most cases
  • Activity modification
  • Physical Therapy
    • Strengthening dynamic stabilizers compensates for lack of stability in passive stabilizers[18]
    • Emphasis on strengthening Rotator Cuff, functional reduction of instability
    • Scapulothoracic training, core stability, proprioceptice exercise programs
  • Can consider Shoulder Brace
    • Preliminary data from Baker et al shows some potential benefit, can be worn during play[19]

Operative

  • Indications
    • Failure of conservative therapy
    • Unidirectional instability
  • Technique
    • MDI: inferior capsular shift, arthroscopic plication, thermal capsulorrphaphy
    • Others: glenoid osteotomy, labral augmentation, capsuloligamentous reconstruction
  • Surgical management should be individualized to address underlying cause of instability
  • In 98% of MDI cases, there are no pathognomonic findings on arthroscopy[20]

Rehab and Return to Play

Rehabilitation

  • Strengthening dynamic stabilizers compensates for lack of stability in passive stabilizers[21]
  • Emphasis on strengthening Rotator Cuff, functional reduction of instability
  • Scapulothoracic training, core stability, proprioceptice exercise programs

Return to Play

  • Systematic review: 60% of athletes returned to sport at the same level, 34% to a lower level and 2% did not return to sport[22]

Prognosis and Complications

Prognosis

  • Age of first dislocation is important prognostic indicator[23]
    • Dislocation under 20 years of age, 90% recurrence rate
    • Dislocation over 40, 10% recurrence rate
  • MDI
    • Conservative management strategies have had inconsistent results, some positive and some negative.

Complications

  • Athletes with pathologic hyperlaxity or hypermobility are at risk of injury to other joints[24]
    • Including knee, ankle injuries
  • Surgical

See Also

Internal

External

References

  1. ↑ Alpert, Joshua M., et al. "Arthroscopic treatment of multidirectional shoulder instability with minimum 270 labral repair: Minimum 2-year follow-up." Arthroscopy: The Journal of Arthroscopic & Related Surgery 24.6 (2008): 704-711.
  2. ↑ Remvig L, Jensen DV, Ward RC. Epidemiology of general joint hypermobility and basis for the proposed criteria for benign joint hypermobility syndrome: review of the literature. J Rheumatol. 2007;34:804–809.
  3. ↑ Blomquist, Jesper, et al. "Shoulder instability surgery in Norway: the first report from a multicenter register, with 1-year follow-up." Acta orthopaedica 83.2 (2012): 165-170.
  4. ↑ Owens, BD, Duffey, ML, Nelson, BJ, DeBerardino, TM, Taylor, DC, Mountcastle, SB. The incidence and characteristics of shoulder instability at the United States Military Academy. Am J Sports Med. 2007;35(7):1168-1173.
  5. ↑ Simonet WT, Melton LJ, Cofield RH, Ilstrup DM. Incidence of anterior shoulder dislocation in Olmsted County, Minnesota. Clin Orthop Relat Res. 1984;186:186–91.
  6. ↑ Mancuso, Matteo. Evaluation and robotic simulation of the glenohumeral joint. No. 10009. EPFL, 2020.
  7. ↑ An YH, Friedman RJ. Multidirectional instability of the glenohumeral joint. Orthop Clin North Am. 2000;31:275–285.
  8. ↑ Warby, Sarah A., et al. "The effect of exercise-based management for multidirectional instability of the glenohumeral joint: a systematic review." Journal of shoulder and elbow surgery 23.1 (2014): 128-142.
  9. ↑ Cameron, KL, Mountcastle, SB, Nelson, BJ. History of shoulder instability and subsequent injury during four years of follow-up: a survival analysis. J Bone Joint Surg Am. 2013;95(5):439-445
  10. ↑ Doukas, William C., and Kevin P. Speer. "Anatomy, pathophysiology, and biomechanics of shoulder instability." Orthopedic Clinics 32.3 (2001): 381-391.
  11. ↑ IOmage courtesy of orthopaedia.com
  12. ↑ Sanders, Timothy G., William B. Morrison, and Mark D. Miller. "Imaging techniques for the evaluation of glenohumeral instability." The American journal of sports medicine 28.3 (2000): 414-434.
  13. ↑ Jana, Manisha, and Shivanand Gamanagatti. "Magnetic resonance imaging in glenohumeral instability." World journal of radiology 3.9 (2011): 224.
  14. ↑ Bulbena A, Duró JC, Porta M, et al. Clinical assessment of hypermobility of joints: assembling criteria. J Rheumatol. 1992;19:115–122
  15. ↑ Beighton P, Horan F. Orthopaedic aspects of the Ehlers-Danlos syndrome. J Bone Joint Surg Br. 1969;51:444–453.
  16. ↑ Ranalletta M, Bongiovanni S, Suarez F, et al. Do patients with traumatic recurrent anterior shoulder instability have generalized joint laxity? Clin Orthop Relat Res. 2012;470:957–960
  17. ↑ Moya, Daniel, et al. "Current concepts in anterior glenohumeral instability: diagnosis and treatment." SICOT-J 7 (2021): 48.
  18. ↑ Beasley L, Faryniarz DA, Hannafin JA. Multidirectional instability of the shoulder in the female athlete. Clin Sports Med 2000;19:331–49
  19. ↑ Baker, Hayden P., et al. "Protective sport bracing for athletes with mid-season shoulder instability." Sports Health 15.1 (2023): 105-110.
  20. ↑ Choi, C. H., and D. J. Ogilvie-Harris. "Inferior capsular shift operation for multidirectional instability of the shoulder in players of contact sports." British journal of Sports medicine 36.4 (2002): 290-294.
  21. ↑ Beasley L, Faryniarz DA, Hannafin JA. Multidirectional instability of the shoulder in the female athlete. Clin Sports Med 2000;19:331–49
  22. ↑ Longo, Umile Giuseppe, et al. "Multidirectional instability of the shoulder: a systematic review." Arthroscopy: The Journal of Arthroscopic & Related Surgery 31.12 (2015): 2431-2443.
  23. ↑ c LH, Cavallaro WU. Primary anterior dislocation of the shoulder. Am J Surg. 1950;80(6):615–21. passim.
  24. ↑ Decoster LC, Bernier JN, Lindsay RH, et al. Generalized joint hypermobility and its relationship to injury patterns among NCAA lacrosse players. J Athl Train. 1999;34:99–105
  25. ↑ Boileau P, Richou J, Lisai A, et al. The role of arthroscopy in revision of failed open anterior stabilization of the shoulder. Arthroscopy. 2009;25:1075–1084.
Created by:
John Kiel on 17 June 2019 19:16:59
Authors:
Last edited:
8 July 2025 23:53:04
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