Recomendados
Más contenido relacionado
La actualidad más candente
La actualidad más candente (20)
Destacado
Destacado (20)
Similar a Wrist biomechanics
Similar a Wrist biomechanics (20)
Último
Último (20)
Wrist biomechanics
- 1. MUN Wrist Biomechanics and Carpal Instability
- 2. MUN Wrist Biomechanics • Anatomy • Kinematics • Force transmission
- 3. MUN Anatomy • 8 bones • Complex interlocking shapes • Intrinsic and extrinsic ligaments
- 4. MUN
- 6. MUN Wrist ligaments • Volar stronger than dorsal • Double V shape with weak area ; space of Poirier • Important interosseous ligaments are SLIL and LTIL • Dorsal ligaments tend to converge on triquetrum
- 7. MUN Kinematics • Three axes of motion – FEM 90 – 70 degrees – Flex/ext split between radiocarpal & midcarpal – RUD 20 – 50 degrees – PSM 90 – 90 degrees
- 9. MUN Kinematics • Rows • Columns (Navarro) • Oval ring • Longitudinal columns (Weber) • “Link Joint”
- 10. MUN Link Joint
- 11. MUN Kinematics • Rows – Proximal and Distal with scaphoid as a bridge – Motion within and between rows • Columns – Central(flex/ext) lunate,capitate,hamate – Lateral (mobile) scaphoid,trapezoid,trapezium – Medial (rotation) triquetrum
- 12. MUN
- 13. MUN Kinematics • Center of rotation : head of capitate
- 14. MUN Kinematics • Radial deviation : scaphoid flexes proximal pole goes dorsal “pulling” lunate into palmar flexion • Ulnar deviation : scaphoid extends proximal pole goes volar pulling lunate into dorsiflexion
- 15. MUN Kinematics • Triquetrohamate helicoid joint • Ulnar deviation : “low” position distal and dorsiflexed pulling lunate into dorsiflexion • Radial deviation : “high”position proximal and palmar flexed pulling lunate into palmar flexion
- 16. MUN Force Transmission • Principal force transmission is through capitate lunate and proximal pole of scaphoid • 75% radius 25% ulna
- 17. MUN Classification of Carpal Instability • CID (dissociative) – DISI – VISI • CIND (non-dissociative) – Radiocarpal,Midcarpal,Ulnar transloc’n • CIC (complex) – Perilunate Dislocation
- 18. MUN Progressive periLunate Instability • Stage I – scapholunate instability • Stage II – capitate dislocation • Stage III – triquetral dislocation • Stage IV – lunate dislocation • Spectrum of injury
- 19. MUN PLI
- 20. MUN Mechanism of injury • Impact on thenar side of wrist causes hyperextension , ulnar deviation and intercarpal supination • Progressive damage around lunate • Bony or ligamentous
- 21. MUN Normal wrist
- 24. MUN Gilula lines
- 26. MUN Carpal Height • L2/L1 = 0.54 • New ratio L2/capitate = 1.57
- 27. MUN Scapholunate Instability • Most common form • Rarely diagnosed acutely • Local tenderness • Scaphoid shift(Watson) • Associated with other injuries eg distal radius
- 28. MUN Scapholunate Instability: Classification • Type 1 – dynamic – Neg Xray;+ve Watson:+ve cine • Type 2 – static – +ve plain films • Type 3 – degenerative • Type 4 – secondary – Kienbock’s ; SNAC
- 29. MUN Scapholunate Instability: Radiographs • Scapholunate gap >2mm • Foreshortened scaphoid • Cortical ring sign • Taliesnik,s “V” sign • Lack of parallelism?
- 31. MUN DISI
- 33. MUN
- 34. MUN
- 35. MUN Scapholunate Instability: Treatment • Acute (0-3 wks) : open repair vs arthroscopically-assisted PCP x 8wks • Chronic (>4 wks) : repair + reconstruction – STT – Blatt – SLC
- 39. MUN STT Fusion
- 41. MUN Scapholunate Instability: Arthrosis • SLAC • PRC • Arthrodesis • RSL
- 42. MUN Triquetrolunate instabliity • Limited understanding of ulnar side • TL or TH ?? • Ulnar pain post injury • Click • +ve ballottement test • Beware ulnar impaction syndrome • Conservative Rx; rarely need limited fusion
- 43. MUN VISI
- 44. MUN Perilunate Dislocation • Perilunate & Lunate are same basic injury • Still missed in ER • Rx of choice : open reduction & repair of ligaments/bones • Dorsal and volar approach • Late: fusion or PRC
- 45. MUN Lesser and Greater arcs
- 48. MUN Ulnar Translocation • Rare • Difficult to treat • Non-traumatic causes : RA,Madelung’s
- 50. MUN
- 51. MUN Carpal Instability: Unresolved Issues • Role of arthroscopy • Method of reconstruction SLIL eg bone- tendon-bone • Ulnar side pathomechanics • Role of MRI
- 52. MUN Grade III
- 53. MUN Grade IV