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Dislocations  /  Further Readings and References

Types of shoulder instabilities

There are many elements which need to be considered such as: 

  • in which direction: anterior, posterior or inferior,

  • in one or multiple directions,

  • trauma induced or atraumatic,

  • if there is identifiable structural damage(s) in the shoulder,

  • any generalised joint laxity,

  • any underlying neuromuscular or collagen disorder,

  • abnormal muscle patterning,

  • if the instability is volitional.

 Many classification systems for shoulder instability had been put forward. The Thomas and Matsen system has the virtue of simplicity. [13] They termed the first group TUBS (traumatic, unidirectional, Bankart lesion and surgery). A second group was termed AMBRI (atraumatic, multidirectional, bilateral, rehabilitation and inferior capsular shift). More recently, the Stanmore system described a triangle with three poles of conditions based on presence of trauma, structural changes, and patterning of muscles. This gives a more comprehensive cover of the spectrum of shoulder instabilities. [14]



The TUB and the AMBRI groups described in the above paragraph probably represent opposite ends of the spectrum of various types of shoulder instabilities. Reports of treatment results based on these groups help to give a practical guide.

In the TUB group, historically the re-dislocation rate after non-operative treatment is around 38-44%. [15, 16] Several cohort studies comparing recurrence rates between arthroscopic stabilisation and non operative management [17-20]. All of these studies demonstrated significant reductions in the rate of recurrence with operative stabilisation.

For patients in the AMBRI group, whether they fall into the Stanmore polar group 2 or group 3, a determined attempt at non-operative management is always indicated first. This should be delivered by physiotherapists with specialised experience in this area. Surgery should only be considered if there is a defined structural defect detected on imaging or arthroscopy and only after an initial period of physiotherapy. If there is no structural defect and the main pathology is suspected to be abnormal muscle recruitment (muscle patterning, Stanmore group 3) then surgery is contraindicated.


Treatment debate for first dislocation after reduction

Labrum repair was more effective than non-surgical treatment for first-time dislocation in terms of fewer redislocations. Arthroscopic lavage as an isolated treatment was no more effective at 2 years compared with non-surgical treatment, making arthroscopic lavage a candidate placebo surgical treatment in this context. Previous studies have suggested that delaying surgery and waiting to see whether the patient developed chronic instability after a first time traumatic shoulder dislocation did not lead to a less favourable prognosis of instability, quality of life or glenohumeral joint osteoarthritis. [21, 22]  Compared with routine surgery after a first time traumatic shoulder dislocation, waiting to see if a patient develops chronic instability despite rehabilitation might direct resources more efficiently and may save half of patients from unnecessary surgery.

13. Thomas SC, Matsen FA. An approach to the repair of avulsion of the glenohumeral ligaments in the management of traumatic anterior glenohumeral instability. J Bone Joint Surg Am 1989; 71: 506-13

14. Lewis A, Kitamura T, Bayley JIL. The classification of shoulder instability: new light through old windows! Curr Orthop 2004; 18: 97-108

15. Rowe CD. Prognosis in dislocations of the shoulder. J Bone Joint Surg 1956; 38A: 957-77.

16. Hovelius L. Anterior dislocation of the shoulder in teenagers and young adults: Five year prognosis. J Bone Joint Surg Br 1987; 69A: 393-9

17. Wheeler JH, Ryan JB, Arciero RA, Molinari RN. Arthroscopic versus non-operative treatment of acute shoulder dislocations in young athletes. Arthroscopy 1989; 5: 213-7.

18. Arciero RA, Wheeler JH, Ryan JB, McBride JT. Arthroscopic Bankart repair versus non-operative treatment for acute, initial anterior shoulder dislocations. Am J Sports Med 1994; 22: 589-94.

19. DeBarardino 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 2001; 29: 586-92.

20. Larrain MV, Botto GJ, Montenegro HJ, Mauas DM. Arthroscopic repair of acute traumatic anterior shoulder dislocation in young adults. Arthroscopy 2001; 23: 119-23.

21.  Kavaja L, Pajarinen J, Sinisaari I, et al. Arthrosis of glenohumeral joint after arthroscopic Bankart repair: a long-term follow-up of 13 years. J Shoulder Elbow Surg 2012;21:350–5.

22. Plath JE, Aboalata M, Seppel G, et al. Prevalence of and risk factors for dislocation arthropathy: radiological long-term outcome of arthroscopic bankart repair in 100 shoulders at an average 13-year follow-up. Am J Sports Med 2015;43:1084–90.

Terminology glossary:

  • Bankart lesion
    The labrum is a rim of cartilage that lines the edge of bony glenoid. It deepens the glenoid ‘socket’ to make it more stable. During a shoulder dislocation, fibers in the capsule can pull on the labrum and cause it to tear. A Bankart lesion is the name for such a tear. This is the most common structural lesion found after shoulder dislocations, often at the anterio-inferior position. An un-healed Bankart lesion becomes a weak point and predisposes the shoulder joint for recurrent dislocation.

  • Bony Bankart lesion
    Bony Bankart lesions occur when some of the glenoid bone is broken off with the anterior labrum. This leads to loss of the normal bumper effect of the labrum and also a decrease in the supportive surface area of the bone, making the shoulder joint potentially more unstable than a Bankart tear alone

  • Hill-Sachs lesion
    They are indentation like compression fracture at the posterolateral humeral head, occur during anterior shoulder dislocations, when the back of the humeral head impacts against the lower front edge of the glenoid. A large Hill-sachs lesion reduces the articular surface area of the shoulder joint and renders the joint less stable.

  • ALPSA lesion
    It stands for anterior labral periosteal sleeve avulsion. This is associated with anterior dislocation of the shoulder. The scapular periosteum is unruptured but widely lifted or stripped. The labrum remains attached to the periosteum and can rotate medially to a position along the anterior surface of the scapular neck.

  • HAGL lesion
    It stands for Humeral Avulsion Glenohumeral Ligament. The capsule of the shoulder joint, which contains the Inferior Glenohumeral Ligament is ripped off the humerus with dislocation of the shoulder. This is an injury that is probably associated with a higher risk of recurrent dislocations than a Bankart tear. A HAGL tear can be difficult to diagnose and a high index of suspicion is required.

  • Bankart repair
    It involves re-anchoring and suturing the torn labrum (Bankart lesion) back to the rim of the glenoid to restore security and stability to the shoulder. This procedure is typically performed arthroscopically with suture anchors.

  • Remplissage procedure
    'Remplissage' is French for 'to fill in'. It involves pulling in the posterior capsule to “fill in” the bone cavity of a Hill-Sachs lesion. It is a procedure used to treat a large Hill-Sachs lesion accompanying an anterior stabilisation procedure. 

  • Latarjet procedure
    The Latarjet procedure involves the removal and transfer of a section of the coracoid process and its attached muscles to the front of the glenoid. This placement of the coracoid acts as a bone block which, combined with the transferred muscles acting as a strut, prevents further dislocation of the joint.[3] In simple terms, this procedure involves removing a piece of bone from another part of the shoulder, and attaching it to the front of the shoulder socket. The bone will then act as a barrier which will physically block the shoulder from slipping out of the socket, while the muscles which are transferred with the bone will give additional stability to the joint. This procedure is indicated when there is major of supportive bone surface areas of the shoulder joint in the setting of recurrent shoulder instability. It is also used as a revision procedure for failed stabilisation operations.

  • Inferior capsular shift procedure
    The inferior capsular shift operation is designed to reduce the redundancy of the inferior part of the capsule often used to treat multidirectional instability.


The content of this article is intended to give a personal summary of a shoulder condition. It is intended for the exclusive viewing of qualified Australian medical general practitioners only.


A medical practitioner should only consider adopting or recommending the opinions of the author and proposed approach for the treatment of patients covered in this article, after performing normal clinical practice. This should include a thorough medical history, assessment, and detailed clinical examination supported with relevant scans and other medical tests.


In all cases, it is up to the individual medical practitioner to exercise his/her own discretion to determine the appropriateness of adopting or recommending the opinions and approach of the article for the treatment of patients. 

 The contents of the article cannot and does not purport to provide an exhaustive detailed analysis of this and all shoulder conditions and potential treatments. A further in-depth study from medical textbooks, publications and other medical literature is recommended


for each individual shoulder condition. If you are not a medically qualified person, you should seek the advice of your medical practitioner or other qualified health provider with any questions you may have regarding a medical condition.

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