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Blood supply & fractures of scaphoid

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Blood supply & fractures of scaphoid

  1. 1. Blood supply & Fracture of Scaphoid
  2. 2. Blood Supply of Wrist and Carpus Radial Ulnar Anterior interosseous arteries Deep palmar arch
  3. 3. Anastomotic network  three dorsal & three palmar arches connected longitudinally at their  medial and lateral borders by  radial & ulnar arteries  dorsal to palmar interconnections b/w  dorsal and palmar branches of anterior interosseous artery
  4. 4. Intrinsic blood Supply The scaphoid, capitate & 20% of lunate supplied by a single vessel - at risk for osteonecrosis. The trapezium, triquetrum, pisiform & 80% of lunate receive nutrient arteries through two nonarticular surfaces consistent intraosseous anastomoses. ON is rare. The trapezoid and hamate lack an intraosseous anastomosis and after fracture, can have avascular fragments.
  5. 5. Scaphoid Anatomy skaphos (Greek) – boat Cashew shaped within the wrist joint more than 80% of its surface(except tubercle) - covered by articular cartilage
  6. 6. Scaphoid - blood supply two major vascular pedicles1.Volar branch enters the scaphoid tubercle and supplies its distal 20% to 30%2. Dorsal scaphoid branch of the radial artery. Enter through numerous small foramina along the spiral groove and dorsal ridge. (80% of the blood supply).
  7. 7.  No vascular supply (13%) or only a single perforator (20%) proximal to the waist of scaphoid. Unusual retrograde vascular supply - high risk of nonunion and ON after fracture.
  8. 8. Scaphoid Fracture  Most commonly fractured carpal bone  68% of carpal fractures  Fall on outstretched hand – forced dorsiflexion of hand & radial deviation
  9. 9.  When fractured, proximal pole - extend with attached lunate distal pole - remains flexed, creating -hump-back deformity.
  10. 10. Classification Russe -1)Horizontal oblique - compressive forces across fracture site.2)Transverse –combination of compressive & shear forces.3)Vertical oblique – 5% , shear forces across fracture site.
  11. 11. Russe
  12. 12. Herbert classification- stability and delayed & nonunion of fractures. Type A fractures- stableType A1- fracture of tubercleType A2 – incomplete fractures through waist
  13. 13.  Type B –Acute and Unstable fractures Type B1- Distal oblique fractures Type B2- Complete fractures through waistType B3- Proximal pole fracturesType B4- Transscaphoid & Perilunate dislocations of carpusType B5-Comminuted
  14. 14.  Type C fractures – Delayed unions Type D fractures – established Nonunions
  15. 15. Prosser classification Classification of Distal pole fractures Type 1 – Tuberosity fracture. Type 2 - Distal intra-articular fracture. Type 3 – Osteochondral fracture.
  16. 16. Prosser Classification
  17. 17. Diagnosis Wrist pain Tenderness & fullness in anatomic snuffbox. Axial compression of thumb elicits pain Forced ulnar deviation of pronated wrist also elicits pain
  18. 18.  Even if initial radiographs –ve, immobilise in wrist splint/shortarm thumb cast Rpt after 10- 14 days If still –ve and suspecting #,take MRI/ CT Scan Fast,convenient, sensitive and specific.
  19. 19. Associated Injuries Fractures of the distal radius Perilunate dislocation and Transscaphoid perilunate fracture dislocations Joint and ligament damage that inevitably accompanies this injury (x-ray never reveals the true degree of injury)
  20. 20. Management Cast Immobilization Open: Volar Dorsal Percutaneous stabilization Arthroscopy
  21. 21. Cast Immobilization Undisplaced Stable Fractures A1 - 4 weeks A2 - 8 to 12 weeks until radiographic union. decision for conservative Mx - CT scan shows no displacement. patient reviewed 6 weeks after cast removal for clinical and radiological examination and then every 3 months until the outcome is clear. Patients should be seen for a final check up after 1 year.
  22. 22. Cast Immobilization Position of wrist has no affect over healing. No difference b/w longarm & short arm cast. Needs to be continued till fracture has healed. Proximal pole fractures-12 weeks or longer
  23. 23. Surgery - indication Displaced fracture Proximal pole fractures regardless of displacement Associated perilunate injuries Open fractures Polytrauma pts
  24. 24. Percutaneous Fixation Guidewire placed percutaneously along central axis of scaphoid to use cannulated screw system. Main key is to achieve most centrally placed screw while holding fracture in compression
  25. 25.  Risk of open procedures can be Avoided. Healing time found to be same as cast immobilization Bond etal reported average healing time to be 7 weeks in these pts,compared to 12 weeks Rx in cast No functional difference after 2 yrs
  26. 26.  Volar percutaneous approach – distal scaphoid used as entry point. Preferred for distal pole fractures. Use 16 gauge needle to find entry point of guidewire. Proximal cartilaginous surface of scaphoid preserved.
  27. 27.  Dorsal percutaneous approach: Proximal pole is entry point Wrist in flexion & ulnar deviation
  28. 28. Arthroscopic Allows assessment of intraarticular injuries like ligamentous structures Many choices for percutaneous fixation-Herbert screw-Herbert-whipple screw-Acutrak screw
  29. 29. Open-Palmar Classic Russe approach For stable and unstable non union Advantages --Excellent visualization-Less risk of vascular injury
  30. 30.  Disadvantages-potential for scarring-limitation of wrist extension-injury to volar radiocarpal ligament-inability to assess and address dorsal scapholunate ligament.
  31. 31. Open - Dorsal Centered over Lister’s tubercle Transverse incision over prox.scaphoid Do not disturb dorsal ridge Excellent visualization of prox.pole,esp with in maximum flexion Prefered open approac for prox. Pole fracture.
  32. 32. Disadvantages of immobilization Frequent visits to check cast fit. Frequent radiographs to check alignment. Potential skin breakdown Prolonged immobilization till complete healing Stiffness of immobilized joints
  33. 33. Disadvantages of Surgery Potential for infection Wound complications Injury to nerves,ligaments or tendons Injury to vascular supply to scaphoid Hardware failure or need for its removal Associated aneasthesia complications.
  34. 34. Complications Non Union Malunion Osteonecrosis – Preiser’s disease Management – arthroscopic debridement and drilling of the lesion, rest, splintage, and electrical stimulation vascularized bone graft harvesting a pronator quadratus graft.
  35. 35. Pearls Occult scaphoid fractures are easily detected by MRI scans. Percutaneous stabilization of scaphoid fractures significantly reduces the rate of nonunion, as well as reducing the time lost from work and sports. Proximal pole fractures can also be stabilized percutaneously by a dorsal approach.
  36. 36. Pitfalls Scaphoid fractures are easily missed in children. This can result in nonunion and serious problems. Malalignment of scaphoid fractures is often undiagnosed. CT scans are helpful. Conservative treatment often ends in delayed healing. An aggressive operative approach is recommended.

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