1. Current Concepts in
Shoulder Instability
Mr Mike Walton BMedSci BMBS MSc FRCS(T&O) MFSEM(UK)
Consultant Shoulder Surgeon

2. Natural Selection
• The ability to throw / hunt
revolutionised our survival
Armed And Deadly: Shoulder,Weapons Key
To Hunt by Christopher Joyce Charles Darwin

3. Quadrapeds
• Straight Line of
Pull
• Shoulder flexor &
elbow extensor
• Powerful stride

4. Bipedal Apes
• Dorsally placed
scapula
• Internal rotation
of GHJ

5. Apes
• Dorsally placed
scapula
• Internal rotation of
GHJ

6. Humans
• Lengthened clavicle
• Scapula moves
further to dorsum
• GHJ Externally
rotates

7. Humans
• Clavicle Lengthens
• Scapula moves
further to dorsum
• GHJ Externally
rotates
• We can Throw

8. Not Evolved Enough!!!

9. Instability
• GlenoHumeral joint is
Inherently Unstable
• The most commonly
dislocated joint in body
• Usually Anterior
• Combined ER and
ABduction

10. Instability

11. Instability

12. Instability

13. Instability
• Dynamic
• Concavity
Compression
• Force Couples
• Neural Control

14. Instability
Lewis A, Kitmura T & Bayley JIL.The classification of
shoulder instability: new light through old windows!
Current Orthopaedics, 2004; 18(2):97-108.

15. Instability
Lewis A, Kitmura T & Bayley JIL.The classification of
shoulder instability: new light through old windows!
Current Orthopaedics, 2004; 18(2):97-108.

16. Traumatic Structural

17. Traumatic Structural

18. Traumatic Structural

19. Traumatic Structural

20. Traumatic Structural

21. Traumatic Structural
HAGL

22. Assessment
• Mechanism of injury
• Apprehension Tests
• Xrays
• MR Arthrogram
• Gadolinium joint
injection

23. Modified O’Briens Test
• Forward Elevation to 90
• Adduction / Internal Rotation
• Pain - SLAP
• WEAKNESS - Post Instability

24. Modified O’Briens Test
• Posterior Translation
occurs in simulated
Active Compression Test
J Shoulder Elbow Surg. 2013 Mar;22(3):365-74. doi: 10.1016/j.jse.2012.02.003. Epub 2012 May 19.
Glenohumeral contact pressure in a simulated active compression test using cadaveric shoulders.
Lin T1, Javidan P, McGarry MH, Gonzalez-Lomas G, Limpisvasti O, Lee TQ.

25. Assessment
• Mechanism of injury
• Apprehension Tests
• Xrays
• MR Arthrogram
• Gadolinium joint
injection

26. Investigations
• MR Arthrogram
• Accurate for isolated anterior and posterior
lesions (78.5%, 69%)
• Accuracy ONLY 37% in combined lesions

27. Bone Loss
• Predictors of failure
• Age
• Glenoid Bone Loss
• Engaging Hill-Sachs
Ahmed I, Ashton F, Robinson CM. Arthroscopic Bankart repair and capsular shift for
recurrent anterior shoulder instability: functional outcomes and identification of risk
factors for recurrence. J Bone Joint Surg Am. 2012 Jul 18;94(14):1308-15

28. Atraumatic Instability
Lewis A, Kitmura T & Bayley JIL.The classification of
shoulder instability: new light through old windows!
Current Orthopaedics, 2004; 18(2):97-108.