2. Scaphoid
• Most common carpal bone fracture (70%), often occurring after a fall onto an
outstretched hand.
• Axial loading of a hyperextended, radially deviated wrist
• 2 :1 male : female
• Third decade of life
• percentage of fractures by scaphoid anatomic location
• waist -65%
• proximal third - 25%
• distal third - 10%
4. Exam
History:
• Young patient, FOOSH, injury to wrist in dorsiflexion
• Wrist pain, but pain can be minimal
Exam:
• Wrist swelling
• Pain worse with circumduction of wrist
• Pain with resisted pronation
1. Dorsally: Anatomic snuffbox tenderness (fx unless proven otherwise)
2. Volarly: Scaphoid tubercle tenderness
3. Compression test (axial compression through thumb metacarpal tenderness)
• 87-100% sensitivity and 74% specificity when all three tests positive within 24
hours of injury
5. Radiograph
• 4 view
– Standard 3 view + Scaphoid view (wrsit extension 30 degrees; ulnar
deviation 20 degrees)
• Adequate initial radiographs detect fractures in 85% to 90% of
the cases
– False negative in up to 16%
• A patient who presents with the appropriate history and has a
positive clinical examination with radiographs that show no
fracture is considered to have a clinical scaphoid fracture
– Splint and repeat radiographs in 14-21 days
• MRI can detect edema within hours
– Can detect coexisting ligamentous injuries
– sensitivity and specificity approach 100% for occult fractures
– No delay
6. Alternative to MRI
Bone Scan
• Occult fractures in acute setting
• specificity of 98%, and sensitivity of 100%
• Need to wait 72 hours and RADIATION
CT with 1mm cut along scaphoid axis
• best modality to evaluate fracture location, angulation,
displacement, fragment size, extent of collapse,
and progression of nonunion or union after surgery
• 62% sensitivity and 87% specific for determining stability
and fracture
• less effective than bone scan and MRI to diagnose occult
fracture
10. Non-operative
• Thumb Spica Casting
• Stable nondisplaced fracture (majority)
• duration of casting depends on location of fracture and risk of nonunion (8-12 wks)
• immobilization maintained until radiographic fracture healing demonstrated, usually no
sooner than 8 weeks
• may be required for up to 12-14 weeks for high-risk fracture patterns/patients
• athletes should not return to play until imaging shows a healed fracture
• Outcomes:
– Nonunion rates increase with delayed immobilization of > 4 weeks after injury
– scaphoid fractures with <1mm displacement have union rate of 90%
11. Percutaneous screw
• unstable fractures as shown by
• proximal pole fractures
• displacement > 1 mm without significant angulation or deformity
• non-displaced waist fractures
• to allow decreased time to union (7 v 12 wk), faster return to work/sport (8 v 15 wk), similar total
costs compared to casting
• outcomes
• union rates of 90-95% with operative treatment of scaphoid fractures
• CT scan is helpful for evaluation of union
• CONSIDER mini-open to avoid extensor tendon injury
12. Anterograde/Dorsal Approach
• Proximal pole fx (small
fragment to large)
• More reliably allows one to
place a screw in the central
axis and thus a longer screw.
• Drawback:
• technically more difficult
• Risk of fracture displacement
of unstable fx with wrist
flexion
• Prominent screw disaster
• Risk of extensor tendon injury
13. Retrograde Volar Approach
• Waist and distal pole fractures
– Fractures with humpback flexion deformities
– Comminuted
– Subacute
• Wrist in extension which helps to reduce the
typical flexion deformity of the scaphoid
• Avoids jeopardizing scaphoid blood supply
• No risk to extensor tendons
• uses the interval between the FCR and the radial
artery
• Screw placement can be limited by trapezium
14. Open reduction internal fixation
• Volar or dorsal approach
• allows direct visualization and reduction at fracture site
• Allow bone graft harvest
• significantly displaced fracture patterns
• 15° scaphoid humpback deformity
• radiolunate angle > 15° (DISI)
• intrascaphoid angle of > 35°
• scaphoid fractures associated with perilunate dislocation
• comminuted fractures
• unstable vertical or oblique fractures
• outcomes
• accuracy of reduction correlated with rate of union
15. Complication
Scaphoid Nonunion/SNAC
• incidence
• 5-10% following immobilization, higher rates for proximal pole fractures
• risk factors
• vertical oblique fracture pattern, displacement >1mm, advancing age, nicotine use
• treatment
• vascularized or nonvascularized bone grafting procedures
Osteonecrosis
• incidence
• 13-50% of all scaphoid fractures
• proximal 5th AVN rate of 100%
• proximal 3rd AVN rate of 33%
Malunion
• Flexion of distal fragment and extension of proximal fragment due to pull of scapholunate
interosseous ligament creating shortened bone with humpback deformity
16. Post op
• Thumb spica splint initially and convert to a spica cast after 2 weeks for 6 weeks
• Weightbearing is avoided for at least 8 weeks based on healing.
• Follow-up wrist X-rays are obtained at 2 weeks, 6 weeks, 3 months, and 6 months
postoperatively
– If there is radiographic healing and no tenderness at the snuffbox 6 weeks postoperatively, can
gradually increase activity
• If there is concern about healing, consider a CT scan at about 10–12 weeks
• 50% trabecular bridge across fracture combined with a centrally placed screw
showed similar load to failure and significantly higher stiffness than the intact
scaphoid -> allow increased activity
Editor's Notes
#3:complex 3-dimensional structure described as resembling a boat, skiff, and twisted peanut
largest bone in proximal carpal row
> 75% of scaphoid bone is covered by articular cartilage
The scaphoid is largely covered by articular cartilage, with limited areas where nutrient vessels may enter the bone. These include a narrow, oblique dorsal ridge where the capsular ligaments attach and a small area palmarly at the scaphoid tubercle. Generally, a single dorsal nutrient vessel penetrates bone at the level of the waist, with an occasional nutrient artery entering more proximally or distally. supplies proximal 80% of scaphoid via retrograde blood flow. minor blood supply from superficial palmar arch (branch of volar radial artery)
enters distal tubercle and supplies distal 20% of scaphoid
Biomechanics
link between proximal and distal carpal row
The scaphoid assists in stabilization of the proximal carpal row through attachments to the radiocarpal and intercarpal ligaments
These attachments ultimately create the characteristic apex dorsal deformity ("humback deformity")
the scaphoid flexes with wrist flexion and radial deviation
#5:Because of the low healing potential of the scaphoid bone, adequate diagnosis and treatment is vital to prevent complications such as non‐union. If a patient is clinically suspected for a scaphoid fracture, their wrist will be immobilised in a cast until definitive diagnosis is obtained. A high sensitivity reduces the risk of missing fractures; a High specificity decreases the number of unnecessary treatments.
