Introduction

Anatomy

See Scaphoid
Recall basics of Scaphoid Kinematics which are disrupted in scaphoid fractures as follows:

• After a fracture the proximal pole rotates into extension via triquetral-hamate articulation
• After a fracture the distal pole pulled into flexion by scaphotrapeziotrapezoid articulation
• Reverse manipulations create angulation, which has a deleterious effect carpal kinematics and... fracture healing

Classification

Scaphoid facrures can be classified by pattern / Russe

1. Horizontal Oblique 
2. Transverse 
3. Vertical Oblique

Or by location:

1. Distal articular (2%)
2. Distal pole (8%)
3. Tubercle (8%)
4. Waist (65%)
5. Proximal pole (15%) 

Presentation

The Mechanism of Injury is often a fall on the outstretched hand (F.O.O.S.H.). This causes dorsiflexion and ulnar deviation of the wrist and intercarpal supination

Diagnosis

Physical Examination of a patient with a scaphoid fracture will show typically swelling, a radially deviated posture and so called "Anatomic Snuff Box" tenderness
Tests to perform include
[Scaphoid Compression test]
[Watson test]
[Scaphoid Lift test]

Radiographs 

• PA and Lateral views of the hand/wrist 
• Oblique views: 45 degrees supination and pronation 
• Clinched Fist view 
•  Scaphoid View: ulnar deviation / wrist extension

Plain radiographs may be falsely negative in 35-75% of cases

If you suspect fracture of the scaphoid and the films are negative immobilize the wrist in a cast or splint for 2 weeks and obtain follow-up radiographs.  The surgeon may also consider additional imaging:

Triple Phase Bone Scan

• Should be positive within 24 hr.'s and always positive within 48 hr.'s 
•  Dynamic Flow images are most reliable in acute fractures of the scaphoid 
• useful in shortening the duration of immobilization... without fracture...decreasing complication rate in...fracture" unrecognized by plain films

Problems:time for study to complete, images not as reliable as CT and MRI (ie  False positive rate 25%)

CT Scan

• must be obtained in the scaphoid's plane and with thin cuts 
• Best for surgical planning and accurate assessment of fracture, displacement, angulation 
• Greater sensitivity & specificity than bone scan 
• Less sensitivity but greater specificity than MRI (MRI edema may be over-read as trabecular microfracture)
  

MRI

• Sensitivity: 100%; hence allows early exclusion of occult fracture
• Accurately detects presence of other occult fractures about the wrist 
• Deemed "the gold standard investigation" 
• May be over-read

Treatment

Non-operative management

• Indications: stable fractures with displacement <1mm and normal angulation
• Cast must always include the thumb (thumb motion is transmitted through the scaphoid via ligamentous attachments leading to shear across the fracture site)
• Length of cast (short arm vs long arm) and length of immobilization (8 weeks vs 12 weeks) debatable. Exception: Proximal fractures require ~18 weeks

Non-Operative Healing Rates:
Tuberosity and Distal Third: ~ 100%
Waist: 80-90%
Proximal: 60-70%

Surgical Management:
Indications:
Displaced fractures: >1mm;
Instability;
Fracture angulation (scapholunate angulation <60 degrees)
Proximal pole fractures
Nonunions: no healing after 20 weeks closed treatment
Unrecognized / Untreated Fracture: 4 weeks

Surgical Options:
Closed reduction with percutaneous pinning
Closed reduction with percutaneous compression screw
Open reduction with compression screw

Open Approaches:
Dorsal Approach: (Proximal Pole and Waist)
Volar Approach: (for Distal Pole)

Surgical Technique / Pearls:

• 1.0 mm guide-wire through center of scaphoid
• Guide-wire inserted volar; direct proximally, dorsally and ulnar
• May place anti-rotation wire parallel to guide-wire
• Drive to level of subchondral bone in proximal pole
• Err toward shorter screw size
• After measurement, drive wire into distal radius to prevent displacement
• Importance of central third placement of screw
  43% greater stiffness
  39% greater load at failure
• ORIF Techniques
  Avoid violating the RSCL: preservation maintains the proximal pole within the fossa of distal radius
  If fracture does not reduce with extension and ulnar deviation extend incision to level of RSCL; landmark for realignment is scaphoid articular border with capitate
  Pack corticocancellous bone graft into areas of comminution

Complications

Non-union

Red Flags and Controversies

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