2. Scaphoid Fractures

3. 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 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

4. 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.

6. 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.

7. 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

8. 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

11. Blood Supply
All studies consistently demonstrated poor supply to the proximal pole
The proximal pole is an intra-articular structure completely covered by hyaline cartilage with a single ligamentous attachment
Deep radioscapholunate ligament
Is dependent on intraosseous blood supply                                                        

12. 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

14. 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.

15. 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

16. Diagnosis Suggested by: Imaging patient’s age, mechanism of injury and
signs and symptoms
Imaging
Xray
CT Scan
MRI
Bone Scan

17. 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.

20. CT Scans CT permits accurate anatomic assessment of the fracture.
Bone contusions are not evaluated with CT, but true fractures can be excluded

22. 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

25. 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

26. ?

27. 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.

28. 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

29. Herbert’s Classification
Type C (delayed union)
Type D (established non-union)
D1: fibrous union
D2: pseudarthrosis

31. 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)

33. Classification according to location
A: tubercle
B: distal pole
C: waist
D:proximal pole

35. 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

36. 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

39. Management Distal Pole Are infrequent
Usually extra-articular with good blood supply
Best treated with short arm thumb spica for 3-6 weeks

41. 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

42. 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

43. 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)

48. 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

49. 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

51. 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 patient's 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

52. 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%.

53. 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

55. Salvage procedures Radial styloidectomy Distal scaphoid resection
Proximal row carpectomy
Partial arthrodesis