eMedicine Specialties > Orthopedic Surgery > Shoulder

Shoulder Dislocations

Author: Scott Welsh, MD, Staff Physician, Department of Orthopedic Surgery, Borgess/Bronson Hospitals, Michigan State University
Coauthor(s): Mark Veenstra, MD, Consulting Staff, K Valley Orthopedics, Southwestern Michigan Sports Medicine Clinic
Contributor Information and Disclosures

Updated: Aug 20, 2008

Introduction

Shoulder dislocations account for almost 50% of all joint dislocations. Most commonly, these dislocations are anterior (90-98%) and occur because of trauma. Most anterior dislocations are subcoracoid in location. Subglenoid, subclavicular, and, very rarely, intrathoracic or retroperitoneal dislocations may occur.

For excellent patient education resources, visit eMedicine's Breaks, Fractures, and Dislocations Center. Also, see eMedicine's patient education article, Shoulder Dislocation.

Related eMedicine topics:
Arthrocentesis, Shoulder
Joint Reduction, Shoulder Dislocation, Anterior
Joint Reduction, Shoulder Dislocation, Inferior
Joint Reduction, Shoulder Dislocation, Posterior
Floating Shoulder

Related Medscape topics:
CME Management of Chronic Shoulder Disorders Reviewed
Resource Center Exercise and Sports Medicine
Resource Center Joint Disorders
Specialty Site Orthopaedics
Surgical versus nonsurgical treatment for acute anterior shoulder dislocation
Conservative management following closed reduction of traumatic anterior dislocation of the shoulder
Clinical Case Challenge - Anterior Shoulder Dislocation

Problem

See Complications for a discussion of associated injuries.

Frequency

Shoulder dislocations account for almost 50% of all joint dislocations.

Etiology

The usual mechanism of injury is extreme abduction, external rotation, extension, and a posterior directed force against the humerus. Forceful abduction or external rotation alone can also lead to dislocation (about 30% of cases), as can a direct blow to the posterior humerus (29%), forced elevation and external rotation (24%), and a fall onto an outstretched hand (17%).1,2,3

Posterior dislocations are less common (2-10%) and are the result of an axial load applied to the adducted and internally rotated arm. Classic posterior dislocations also occur as a result of electrocution or seizures because of the strength imbalance between the internal rotators (subscapularis, latissimus dorsi, pectoralis major muscles), which overpower the external rotators (teres minor and infraspinatus muscles).

Inferior dislocations are rare and result from a hyperabduction force that causes the humeral neck to lever against the acromion. Diagnosing inferior dislocations is critical because of the high incidence of complications. Neurologic injuries (particularly axillary nerve lesions) are associated with inferior dislocations in as many as 60% of cases, vascular injuries occur in about 3.3% of cases, rotator cuff tears in occur in 80-100% of cases, and greater tuberosity fractures and pectoralis major avulsions are also associated with inferior dislocations.

Superior dislocations are extremely rare and result from an extreme force in a cephalic direction to the adducted arm. Acromioclavicular injuries and fractures of the acromion, clavicle, and tuberosities may occur with superior dislocations.

Atraumatic instability is usually multidirectional and commonly occurs in individuals with generalized hyperlaxity due to connective tissue disorders, such as Ehlers-Danlos syndrome and Marfan syndrome. A small or flat glenoid fossa, excessive anteversion or retroversion of the glenoid, weak rotator cuff muscles, neuromuscular disorders, or a redundant capsule may also jeopardize the concavity-compression, adhesion-cohesion, or the glenoid suction-cup phenomena that aid in stability of the shoulder.

Multidirectional instability most commonly occurs in younger populations, usually in patients younger than 30 years, and is often familial and bilateral. The first dislocation often occurs after a minor injury or after a period of disuse. Patients may experience subluxations that progress over time to actual dislocations, which spontaneously reduce. These dislocations may be voluntary or involuntary. Voluntary dislocations have been associated with psychiatric illnesses and may be used in attention seeking behavior. Surgery should be avoided in this population because the instability is likely to recur.

Presentation

Patients with anterior dislocations usually present with the arm in slight abduction and externally rotated. The humeral head can often be palpated in the front of the shoulder. Internal rotation and adduction are limited. Movement is usually very painful as a result of muscle spasms.

Patients with posterior dislocations present with the arm internally rotated and adducted. External rotation is severely limited. A posterior prominence is usually palpable, the anterior shoulder is flattened, and the coracoid process is more prominent. Historically, these dislocations have been missed or misdiagnosed as a frozen shoulder.

Inferior dislocations lead to a condition known as luxatio erecta, which describes a classic presentation of the arm abducted 110-160° with the forearm resting on or behind the patient's head.4

Indications

Surgery may be indicated if patients are unable or unwilling to change their occupation or avoid participating in high-risk sports and if they have recurrent dislocations or subluxations.

Relevant Anatomy

See Surgical therapy.

Contraindications

Surgery should be avoided in patients with voluntary shoulder dislocations associated with psychiatric illnesses because the instability is likely to recur.

More on Shoulder Dislocations

Overview: Shoulder Dislocations
Workup: Shoulder Dislocations
Treatment: Shoulder Dislocations
Follow-up: Shoulder Dislocations
References
Further Reading

References

  1. Pettrone FA. Athletic Injuries of the Shoulder. New York:. McGraw-Hill;1995.

  2. Rockwood CA, Matsen FA, Wirth MA, et al. The Shoulder. 2nd ed. Philadelphia:. WB Saunders Co;1998.

  3. Rowe CR. The Shoulder. New York:. Churchill Livingstone;1988.

  4. Fung DA, Menkowitz M, Chern K. Asymmetric bilateral shoulder dislocation involving a luxatio erecta dislocation. Am J Orthop. May 2008;37(5):E97-8. [Medline].

  5. Saupe N, White LM, Bleakney R, Schweitzer ME, Recht MP, Jost B, et al. Acute traumatic posterior shoulder dislocation: MR findings. Radiology. Jul 2008;248(1):185-93. [Medline].

  6. Sanders TG, Morrison WB, Miller MD. Imaging techniques for the evaluation of glenohumeral instability. Am J Sports Med. May-Jun 2000;28(3):414-34. [Medline].

  7. Itoi E, Sashi R, Minagawa H, et al. Position of immobilization after dislocation of the glenohumeral joint. A study with use of magnetic resonance imaging. J Bone Joint Surg Am. May 2001;83-A(5):661-7. [Medline].

  8. Wen DY. Current concepts in the treatment of anterior shoulder dislocations. Am J Emerg Med. Jul 1999;17(4):401-7. [Medline].

  9. Kirkley A, Griffin S, Richards C, et al. Prospective randomized clinical trial comparing the effectiveness of immediate arthroscopic stabilization versus immobilization and rehabilitation in first traumatic anterior dislocations of the shoulder. Arthroscopy. Jul-Aug 1999;15(5):507-14. [Medline].

  10. Yuen MC, Yap PG, Chan YT, Tung WK. An easy method to reduce anterior shoulder dislocation: the Spaso technique. Emerg Med J. Sep 2001;18(5):370-2. [Medline].

  11. Kosnik J, Shamsa F, Raphael E, et al. Anesthetic methods for reduction of acute shoulder dislocations: a prospective randomized study comparing intraarticular lidocaine with intravenous analgesia and sedation. Am J Emerg Med. Oct 1999;17(6):566-70. [Medline].

  12. Moharari RS, Khademhosseini P, Espandar R, Soleymani HA, Talebian MT, Khashayar P, et al. Intra-articular lidocaine versus intravenous meperidine/diazepam in anterior shoulder dislocation: a randomised clinical trial. Emerg Med J. May 2008;25(5):262-4. [Medline].

  13. Yuen CK, To DB. Is operative repair better than conservative treatment after primary anterior shoulder dislocation?. Arthroscopy. Aug 2008;24(8):971; author reply 971. [Medline].

  14. Itoi E, Hatakeyama Y, Urayama M, et al. Position of immobilization after dislocation of the shoulder. A cadaveric study. J Bone Joint Surg Am. Mar 1999;81(3):385-90. [Medline].

  15. Hovelius L, Olofsson A, Sandström B, Augustini BG, Krantz L, Fredin H, et al. Nonoperative treatment of primary anterior shoulder dislocation in patients forty years of age and younger. a prospective twenty-five-year follow-up. J Bone Joint Surg Am. May 2008;90(5):945-52. [Medline].

  16. Maeda A, Yoneda M, Horibe S, et al. Longer immobilization extends the "symptom-free" period following primary shoulder dislocation in young rugby players. J Orthop Sci. 2002;7(1):43-7. [Medline].

  17. Hovelius L, Augustini BG, Fredin H, et al. Primary anterior dislocation of the shoulder in young patients. A ten- year prospective study. J Bone Joint Surg Am. Nov 1996;78(11):1677-84. [Medline].

  18. Kralinger FS, Golser K, Wischatta R, et al. Predicting recurrence after primary anterior shoulder dislocation. Am J Sports Med. Jan-Feb 2002;30(1):116-20. [Medline].

  19. DeBerardino TM, Arciero RA, Taylor DC, Uhorchak JM. Prospective evaluation of arthroscopic stabilization of acute, initial anterior shoulder dislocations in young athletes. Two- to five-year follow-up. Am J Sports Med. Sep-Oct 2001;29(5):586-92. [Medline].

  20. Patel RV, Leith J. Primary arthroscopic stabilization for a first-time anterior dislocation of the shoulder. J Bone Joint Surg Am. Aug 2008;90(8):1786; author reply 1786-7. [Medline].

  21. Robinson CM, Jenkins PJ. Primary Arthroscopic Stabilization for a First-Time Anterior Dislocation of the Shoulder. J Bone Joint Surg Am. Aug 2008;90-A(8):1786-1787. [Medline].

  22. Larrain MV, Botto GJ, Montenegro HJ, et al. Arthroscopic repair of acute traumatic anterior shoulder dislocation in young athletes. Arthroscopy. Apr 2001;17(4):373-7. [Medline].

  23. Arciero RA, Taylor DC, Snyder RJ, Uhorchak JM. Arthroscopic bioabsorbable tack stabilization of initial anterior shoulder dislocations: a preliminary report. Arthroscopy. Aug 1995;11(4):410-7. [Medline].

  24. Hintermann B, Gachter A. Arthroscopic findings after shoulder dislocation. Am J Sports Med. Sep-Oct 1995;23(5):545-51. [Medline].

  25. Karlsson J, Magnusson L, Ejerhed L, et al. Comparison of open and arthroscopic stabilization for recurrent shoulder dislocation in patients with a Bankart lesion. Am J Sports Med. Sep-Oct 2001;29(5):538-42. [Medline].

  26. Beeson MS. Complications of shoulder dislocation. Am J Emerg Med. May 1999;17(3):288-95. [Medline].

  27. Guanche CA, Quick DC, Sodergren KM, et al. Arthroscopic versus open reconstruction of the shoulder in patients with isolated Bankart lesions. Am J Sports Med. Mar-Apr 1996;24(2):144-8. [Medline].

Further Reading

Shoulder trauma.
American College of Radiology - Medical Specialty Society.  1995 (revised 2005).  6 pages.  NGC:004632

Clinical practice guidelines for shoulder subluxation.
Ottawa Panel - Independent Expert Panel.  2006.  4 pages.  NGC:005313

Keywords

shoulder dislocations, shoulder instability, shoulder dislocation, anterior shoulder dislocation, posterior shoulder dislocation, inferior shoulder dislocation,  subglenoid shoulder dislocation, subclavicular shoulder dislocation, intrathoracic shoulder dislocation, retroperitoneal shoulder dislocation, luxatio erecta, multidirectional shoulder instability, traumatic shoulder dislocation, atraumatic shoulder dislocation, atraumatic shoulder

Contributor Information and Disclosures

Author

Scott Welsh, MD, Staff Physician, Department of Orthopedic Surgery, Borgess/Bronson Hospitals, Michigan State University
Scott Welsh, MD is a member of the following medical societies: Michigan State Medical Society
Disclosure: Nothing to disclose.

Coauthor(s)

Mark Veenstra, MD, Consulting Staff, K Valley Orthopedics, Southwestern Michigan Sports Medicine Clinic
Disclosure: Nothing to disclose.

Medical Editor

Cato T Laurencin, MD, PhD, University Professor, Lillian T Pratt Distinguished Professor and Chairman, Department of Orthopaedic Surgery, The University of Virginia
Cato T Laurencin, MD, PhD is a member of the following medical societies: American Academy of Orthopaedic Surgeons
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

Pekka A Mooar, MD, Associate Professor, Department of Orthopedic Surgery, Temple University School of Medicine
Pekka A Mooar, MD is a member of the following medical societies: American Academy of Orthopaedic Surgeons
Disclosure: Nothing to disclose.

CME Editor

Dinesh Patel, MD, FACS, Associate Clinical Professor of Orthopedic Surgery, Harvard Medical School; Chief of Arthroscopic Surgery, Department of Orthopedic Surgery, Massachusetts General Hospital
Dinesh Patel, MD, FACS is a member of the following medical societies: American Academy of Orthopaedic Surgeons, American Association of Physicians of Indian Origin, American College of International Physicians, and American College of Surgeons
Disclosure: Nothing to disclose.

Chief Editor

Mary Ann E Keenan, MD, Professor, Vice Chair for Graduate Medical Education, Department of Orthopedic Surgery, University of Pennsylvania School of Medicine; Chief of Neuro-Orthopedics Program, Department of Orthopedic Surgery, Hospital of the University of Pennsylvania
Mary Ann E Keenan, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Orthopaedic Surgeons, American Orthopaedic Association, American Orthopaedic Foot and Ankle Society, American Society for Surgery of the Hand, and Orthopaedic Rehabilitation Association
Disclosure: Nothing to disclose.

 
 
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