S

Blood Supply -Scaphoid And Its

Clinical Importance

Dr Gajendra Mani ShahMS-OrthoResident

1st year NAMS

Moderator Maj.Dr Bishnu B. Thapa

General features

Forms radial part of the carpus.

Lies obliquely 45 degree to longitudinal axes to 2 rows.

Articulates with 5 bones…..

Since it crosses two rows of carpus, it is more susceptible to fracture.

Obletz & halbestin’s

1. 67% of scaphoid have arterial foramina throughout their length

2. 13%have blood supply predominately in the distal third.

3. 20 %have most foramina in the waist and one foramina near the proximal pole.

Blood Supply

Talesnic & kelly

1. Lateral volar group

2. Dorsal group

3. Distal group

Gelberman & Menon

 Mechanism of Injury

a. Fall onto outstretched hand

b. Forced dorsiflexion (usually beyond 95 degrees extension), radially deviated wrist with intercarpal supination.

c. Palmar flexion in 3 % of cases (Leslie & Dickenson; Clay et al)

 Clinical evaluation (high diagnostic sensitivity, specificity approaches 74-80 %)

a. Wrist pain

b. Swelling and fullness off anatomical snuffbox - indicates effusion

c. Tender palpation of Scaphoid tubercle and anatomical snuffbox

d. Pronation followed by ulnar deviation cause pain

e. Slight reduction in range of motion

f. Reduced grip strength

Anatomical Snuffbox

Scaphoid tubercle palpation tenderness has a sensitivity of 87% and a specificity of 57% as an indicator of a scaphoid fracture

g. Provocative tests

Scaphoid lift test: painful dorsal and volar ballottement.

Watson test: painful dorsal Scaphoid displacement as the wrist is moved from ulnar to radial deviation with compression of the tuberosity.

Scaphoid compression test: longitudinal force along 1 metacarpal elicits pain.

Resisted pronation causes pain.

Scaphoid compression test: The sensitivity 70.5% but the specificity is only 21.8%

Radiographic evaluation (70 % sensitivity)

a. Standard PA

b. Lateral (wrist neutral)

c. 45 degree pronated oblique (STTJ)

d. 45 degree supinated oblique (Radio-scaphoid joint)

e. Scaphoid view (PA with ulnar deviation)

f. Others:

PA with wrist in slight extension (Ziter view)

AP with clenched fist to detect a ligamentous injury

Initial films non-diagnostic in 15-25 % of cases.

Other special investigations

a. Technetium bone scan (92-95 % sensitivity; 60-95 % specificity)

b. MRI (90-100 % sensitivity; 90% specificity - false positives because of bone bruises)

c. CT

i. Less costly and readily available

ii. Clearer visualization of fracture displacement

d. Ultrasound evaluation

Classification

Russe classification -Fracture pattern based

Horizontal oblique (HO) 35 %, Transverse (T) 60 %, Vertical oblique (VO) 5 %

Herbert classification of Scaphoid fractures

Displacement based (stable or unstable)

a. Tuberosity : 17-20 %

b. Distal pole : 10-12 %

c. Waist : 66-70 %

i. Horisontal oblique: 13-14 %

ii. Vertical oblique: 8-9 %

iii. Transverse: 45-48 %

d. Proximal pole 5-7 %

Based on location

Avascular Necrosis

Management

a. Non-operative treatment

i. Indications:

1. Non-displaced distal third fractures

2. Tuberosity fractures

Expected time to union

1. Distal third 6-8 weeks

2. Middle third 8-12 weeks

3. Proximal third 12-24 weeks

Healing rate and prognosis

1. Tuberosity and distal third - 100 %

2. Waist - 80-90 %

3. Proximal pole - 60-70 %

b. Operative treatment

1. Fracture displacement > 1 mm

2. Trans-Scaphoid peri-lunar dislocation

3. Unstable fractures (Herbert classification)

4. Fractures known for AVN

• Proximal pole

• Vertical oblique

• Comminuted

• Diagnosed late (after 4/52)

5. Scapholunate angle > 60 degrees

6. Humpback deformity

7. Non-union

Indications:

References

1. Apley`s System of Orthopaedics and Fractures

2. Miller`s Review of Orthopaedics

3. Campbell`s Operative Orthopaedics

4. Chapman`s Orthopaedic surgery

5. Internet