Scaphoid fractures
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Scaphoid fractures

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Scaphoid fractures Scaphoid fractures Presentation Transcript

  • Scaphoid Fractures
  • Scaphoid Fractures• The scaphoid is the most frequently fractured carpal bone, accounting for 71% of all carpal bone fractures.• Scaphoid fractures often occur in young and middle-aged adults, typically those aged 15-60 years.• About 5-12% of scaphoid fractures are associated with other fractures• 70-80% occur at the waist or mid-portion• 10-20% proximal pole
  • Anatomy• The scaphoid lies at the radial border of the proximal carpal row, but its elongated shape and position allow bridging between the 2 carpal rows because it acts as a stabilizing rod.• The scaphoid has 5 articulating surfaces: – with the radius, lunate, capitate, trapezoid, and trapezium.• As a result, nearly the entire surface is covered by hyaline cartilage.
  • Blood Supply• Vessels may enter only at the sites of ligamentous attachment: – the flexor retinaculum at the tubercle, – the volar ligaments along the palmar surface, – and the dorsal radiocarpal and radial collateral ligaments along the dorsal ridge.
  • Blood Supply Classically described as 3 principal arterial groups, but in more recent investigations by Gelberman and Menon described 2: – Entering dorsally – Volar side limited to tubercle
  • Blood Supply The primary blood supply comes from the dorsal branch of the radial artery, which divides into 2-4 branches before entering the waist of the scaphoid along the dorsal ridge. The branches course volar and proximal within the bone, supplying 70-85% of the scaphoid. The volar scaphoid branch also enters the bone as several perforators in the region of the tubercle; these supply the distal 20%-30% of the bone
  • Blood Supply•All studies consistently demonstrated poor supplyto the proximal pole•The proximal pole is an intra-articular structurecompletely covered by hyaline cartilage with asingle ligamentous attachment–Deep radioscapholunate ligament•Is dependent on intraosseous blood supply
  • Blood Supply Obletz and Halbstein in their study of vascular foramina in dried scaphoids found 13% without vascular perforations and 20% with only a single small foramen proximal to the waist Therefore postulated that atleast 30% of mid- third fracture would expect AVN of proximal pole…greater likelihood the more proximal the fracture
  • Pathophysiology The primary mechanism of injury to the scaphoid bone is a fall on an outstretched hand. A scaphoid fracture is part of a spectrum of injuries based on 4 factors: – (1) the direction of 3-dimensional loading, – (2) the magnitude and duration of the force, – (3) the position of the hand and wrist at the time of injury, and – (4) the biomechanical properties of ligaments and bones. These factors affect the end result of the fall: distal radius fracture, ligamentous injury, scaphoid fracture, or a combination of these.
  • Pathophysiology Essentially fractures of scaphoid have been explained as a failure of bone cause by compressive or tension load Compression, as explained by Cobey and White, against concave surface by head of capitate Position of radial and ulnar deviation thought to determine where it breaks Fryman subjected cadaver wrists to loading and observed that: – extension of 35 degrees of less resulted in distal forearm fractures – >90degrees resulted in carpal fractures Combination of radial deviation and wrist extension locks scaphoid within the scaphoid fossa
  • Diagnosis Suggested by: – patient’s age, – mechanism of injury and – signs and symptoms Imaging – Xray – CT Scan – MRI – Bone Scan
  • Radiography The 4 essential views (ie, PA, lateral, supinated and pronated obliques) identify majority of fractures. The scaphoid view is a PA radiograph with the wrist extended 30° and deviated ulnarly 20°. This view helps to stretch out the scaphoid and is also used for assessing the degree of scaphoid fracture angulation. A clenched-fist radiograph has also been useful for visualization of the scaphoid waist.
  • CT Scans CT permits accurate anatomic assessment of the fracture. Bone contusions are not evaluated with CT, but true fractures can be excluded
  • MRI• T1-weighted images obtained in a single plane (coronal) are typically sufficient to determine the presence of a scaphoid fracture.• Gaebler prospectively performed MRI on 32 patients, at average of 2.8 days post injury – 100% sensitivity and specificity• In recent study Dorsay has shown that immediate MRI provides cost benefit when compared to splintage and repeat xray• False positives due MRI’s sensitivity to marrow oedema
  • Nuclear Imaging Radionuclide bone scanning typically is performed 3-7 days after the initial injury if the radiographic findings are normal. Best at 48hours, premature imaging may be obscured by traumatic synovitis Bone scan findings are considered positive for a fracture when intense, focal tracer accumulation is identified. Negative bone scan results virtually exclude scaphoid fracture Teil-van studied cost effectiveness and concluded that initial xray followed by bone scan at 2 weeks if patient is still symptomatic is most effective management option Teil-van also suggested that more sensitive and less expensive than MRI
  • ?
  • Classification Determining optimal treatment depends on accurate diagnosis and fracture classification Herbert devised an alpha-numeric system that combined fracture anatomy, stability and chronicity of injury.
  • Herbert’s Classification  Type A (stable acute fractures) – A1: fracture of tubercle – A2: incomplete fracture  Type B (unstable acute fractures) – B1: distal oblique – B2: complete fracture through waist – B3: proximal pole fracture – B4: trans-scaphoid perilunate fracture dislocation of carpus
  • Herbert’s Classification Type C (delayed union) Type D (established non-union) – D1: fibrous union – D2: pseudarthrosis
  • Russe Classification Russe classified scaphoid fractures into 3 type according to the relationship of the fracture line to the long axis of the scaphoid – Horizontal – Oblique – Vertical (unstable)
  • Classification according to location A: tubercle B: distal pole C: waist D:proximal pole
  • Management Proximal pole – Depends on size and vascularity of fracture – Growing sentiment that most should be treated operatively because of high propensity for non-union and increased duration of immobilisation required for non-operative management – If large enough to accommodate a screw than every attempt should be made
  • Management DeMaagd and Engber showed 11 of 12 patients with proximal pole fractures healed with Herbert screw Retting and Raskin had 100% union in 17 cases with Herbert screw If fragment too small then K-wires can be used
  • Management Distal Pole – Are infrequent – Usually extra-articular with good blood supply – Best treated with short arm thumb spica for 3-6 weeks
  • Management of waist fractures Most common type of fracture High rate of delayed and non-union – With delays in treatment adversely affect results Operative vs non-operative – Controversial
  • Management of waist fractures Most stable fractures can be treated with below elbow thumb spica Unstable fractures best treated with compression screw fixation – >1mm displacement – Fragment angulation – Abnormal carpal alignment With advent of percutaneous techniques of cannulated screws under flouroscopic control trend towards operative management
  • What about the undisplaced waist fractures??? Netherlands study: – Average time away from work 4.5 months Saeden in prospective randomised study with 12 year follow-up compared early operative vs cast immobilisation – Return to work quicker in operative – No significant long term difference in functional outcome between 2 groups Bond has shown return to work 7 weeks earlier and time of union 5 weeks quicker – Other papers disagree Some surgeons published union rates of 100% with surgery(Green’s volume 1 page 721)
  • Complication$$• Malunion – Malunion may lead to limited motion about the wrist, decreased grip strength, and pain. – The most frequent pattern of malunion is persistent angular deformity, or the humpback deformity. – Malunion usually can be treated with osteotomy and bone grafting to correct angular deformity and length. • Literature confusing with no comparative studies to document improvement in hand function
  • Complication$$• Delayed union and non-union – Delayed union is incomplete union after 4 months of cast immobilization. – Non-union is an unhealed fracture with smooth fibrocartilage covering the fracture site. – About 10-15% of all scaphoid fractures do not unite. – Some degree of delayed union or non-union occurs in nearly all proximal pole fractures and in 30% of scaphoid waist fractures
  • Complication$$ Delayed union is anticipated if fracture treatment is delayed for several weeks. The risk of non-union increases after a delay of 4 weeks. These delays may be related to the patients failure to seek treatment for a presumed sprain, but they more frequently are related to improper or incomplete immobilization or a failure to diagnose and treat the acute fracture
  • Delayed union treatment If the delayed union is stable and less than 6 months old relative to the time of injury, prolonged cast immobilization with or without electrical stimulation may be used. Treatment of choice for a symptomatic non-union is placement of a bone graft and fixation. – Russe corticocancellous iliac graft – Fisk-Fernandez volar wedge graft – Pronator pedicle graft • Braun ‘83 reported 100% union in 8 pts • Kawai, Kuhlmann, Papp reported 100% 37 pts – Pechlaner reporrted 25 free vascularised iliac grafts with 100% Success rates for the treatment of non-union are as high as 82%.
  • AVN• Osteonecrosis occurs in 15-30% of all scaphoid fractures, and most of these involve the proximal pole.• Its incidence increases as the fracture line becomes more proximal; this decreases the probability that the blood supply to the proximal pole is preserved
  • Salvage procedures Radial styloidectomy Distal scaphoid resection Proximal row carpectomy Partial arthrodesis