by Debra Wood, RN
Shoulder instability occurs when the upper-end of the arm bone, known as the humerus, slides partially or completely out of the shoulder socket.
The disorder is classified by how much the humerus moves and the direction of the movement:
Shoulder instability often results from injury.
Factors that may increase your chance of shoulder instability include:
Symptoms may come on suddenly or develop over time. Shoulder instability may cause:
You will be asked about your symptoms and medical history. A physical exam will be done. Special attention will be given to your shoulders. Your doctor will determine your range of motion and try to move the humeral head within the socket.
Imaging tests evaluate your shoulder and surrounding structures. These may include:
Arthroscopy is done with an instrument with a long tube and miniature camera on the end. Repairs or corrections can be made while the doctor evaluates the shoulder joint.
Therapy will depend on the extent of the injury, the cause, and other factors. Treatment may include:
Guidelines to help protect the shoulder from injury include:
Family Doctor—American Academy of Family Physicians
Ortho Info—American Academy of Orthopaedic Surgeons
Canadian Orthopaedic Association
Canadian Orthopaedic Foundation
Abrams GD, Safran MR. Diagnosis and management of superior labrum anterior posterior lesions in overhead athletes. Br J Sports Med. 2010;44(5):311-318.
Chronic shoulder instability. Ortho Info—American Academy of Orthopaedic Surgeons website. Available at:
...(Click grey area to select URL)
Updated December 2013. Accessed August 24, 2017.
Desmeules F, Barry J, Roy JS, Vendittoli PA, Rouleau DM. Surgical interventions for post-traumatic anterior shoulder instability in adults. Cochrane Database of Systematic Reviews 2014;(5):CD011092.
Dumont GD, Russell RD, et al. Anterior shoulder instability: a review of pathoanatomy, diagnosis, and treatment. Curr Rev Musculoskelet Med. 2011 Aug 2.
Gaskill TR, Taylor DC, et al. J Am Acad Orthop Surg. 2011 Dec 19(12):758-767.
Luime JJ, Verhagen AP, et al. Does this patient have an instability of the shoulder or a labrum lesion? JAMA. 2004;292:1989-1999.
Nassiri N, Eliasberg C, Jones KJ, McAllister DR, Petrigliano FA. Shoulder instability in the overhead athlete: A systematic review comparing arthroscopic and open stabilization procedures. 2015;3(2):suppl2325967115S00154.
Owens BD, Campbell SE, Cameron KL. Risk factors for anterior glenohumeral instability. Am J Sports Med. 2014;42(11):2591-2596.
Provencher MT, Frank RM, et al. The Hill-Sachs lesion: diagnosis, classification, and management. J Am Acad Orthop Surg. 2012 Apr;20(4):242-252.
Recurrent subluxation of shoulder. EBSCO DynaMed Plus website. Available at: http://www.dynamed... . Updated August 21, 2014. Accessed August 24, 2017.
van Tongel A, Karelse A, et al. Posterior shoulder instability: current concepts review. Knee Surg Sports Traumatol Arthrosc. 2011 Sep;19(9):1547-1553.
von der Heyde RL. Occupational therapy interventions for shoulder conditions: a systematic review. Am J Occup Ther. 2011 Jan-Feb;65(1):16-23.
Wilk KE and Macrina LC. Nonoperative and postoperative rehabilitation for glenohumeral instability. Clin Sports Med. 2013; 32:865-914.
Wolf JM, Cameron KL, et al. Impact of joint laxity and hypermobility on the musculoskeletal system. J Am Acad Orthop Surg. 2011 Aug;19(8):463-471.
Last reviewed September 2018 by EBSCO Medical Review Board Warren A. Bodine, DO, CAQSM
Last Updated: 11/21/2013
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