Scaphoid Fractures 1

Scaphoid Fractures

Scaphoid fractures

Introduction

• Scaphoid fractures constitute 60-70 % of all carpal bone fractures

• Second only to the distal radius in frequency • Due to the importance of scaphoid in wrist

mechanics and because of the frequency of the

fracture in young adult male, it has an economic as well as physical significance

• Uncommon in children because the physis of distal radius fails first

Anatomy

• Also called Navicular

• An irregular shaped

bone ,more resembling a twisted peanut than the boat for which it is named

• Scaphoid represents floor of the anatomic snuff box

Anatomy

• Articular cartilage covers 80 % of the

scaphoid surface - only narrow area of its neck, & even smaller distal portion, are accessible to blood vessels

• Distally, it articulates with the trapezium and trapezoid in a gliding motion, The articulation with the trapezium forms a base for

independent movement of the thumb

• On the ulnar side, it articulates distally with the capitate, and proximally with the lunate in a rotary motion

• Proximally, its large, biconvex surface allows articulation with the radius

Anatomy

Blood Supply

• Major blood supply comes from the scaphoid branches of the radial artery entering the

dorsal ridge at or just distal to waist area and supplying 70-80 % of the bone including the entire proximal pole - in a retrograde fashion • Second group of vessels, arise from palmar &

superficial palmar branches of radial artery & enter the distal tubercle, it perfuses distal 20-30 % of bone, including tuberosity

Blood Supply

• There are no anastomoses between

the dorsal and palmar vessels

• Vessels enter thru dorsal ridge in 79 %,

distal to waist in 14 %, & proximal to

waist in 7 %

• Fractures across scaphoid may destroy

blood supply to its proximal part

Biomechanics

• Mechanically scaphoid links the proximal

and distal rows

• Scaphoid spans both carpal rows and

therefore has less mobility than other carpal

bones

• Scaphoid carries the compressive loads

from the hand across the wrist to the distal

forearm

Biomechanics

• Scaphoid flexes with wrist flexion &

extends with wrist extension

• It also flexes during radial deviation &

extends during ulnar deviation

• These factors make immobilization of

scaphoid fractures difficult especially

when there is displacement

Biomechanics

• Scaphoid is a principal bony block to dorsiflexion of hand & wrist , and is

susceptible to frx during fall on outstretched hand

• With scaphoid fx, distal scaphoid tends to flex, & proximal scaphoid extends with the proximal carpal row ,, because of this,

angulation occurs at fx site, which gradually

Mechanism of injury

Two different mechanisms

1. Compression injury

2. Hyperextension bending injury

Diagnosis

• A strong index of suspicion is the key to

early

diagnosis

• The diagnosis should be based on :

History

Clinical examination

History

• Occurs after a fall on an outstretched hand,

athletic injury, or MVA

• Usually happens in young adult men

• Pain at the radial side of the wrist

Clinical Examination

• Should demonstrate tenderness in the

anatomic snuff box

• Tenderness to palpation over scaphoid

tuberosity and/or proximal pole just distal

to Lister's tubercle

• Tenderness with axial compression of

thumb toward the snuff box

• Tenderness as patient supinates

forearm against resistance

Clinical Examination

• Radial & ulnar deviation results in pain

on radial side of wrist

• Forced dorsiflexion usually elicits

significant tenderness

• There is usually pain at extremes of

motion

• Limitation of wrist motion

–

but not

dramatically

Radiographic Evaluation

• The best method for determining the

presence of a fracture

• Many different views have been

recommended

• The useful initial views are : PA, lateral,

scaphoid view ( PA with ulnar deviation )

Radiographic Evaluation

• Motion views of the wrist (

flexion-extension-radial & ulnar deviation ) may

demonstrate fracture displacement

• If a diagnosis still can’t be confirmed with

confidence on routine films, further oblique

views can be taken

• If certainty still exists after all these

maneuvers , the patient should be placed in

a cast for 2 to 4 weeks and the clinical &

radiographic evaluation repeated

Radiographic Evaluation

• If the second radiographic examination is

still equivocal , a technetium bone scan,

polytomography, CT or MRI of the wrist is

recommended

• The bone scan is the most sensitive but the

least specific of these modalities, thus if the

bone scan is negative , a scaphoid fx is

Radiographic Evaluation

• If the bone scan is positive, more specific

studies ( e.g. polytomography, CT or MRI )

can be helpful

DDx

• It is the same DDx of radial sided wrist

pain

• Lunate dislocation or fx

• Sapholunate instability

• Radial styloid fx

• Trapezium fx

• Rupture of FCR tendon

Classifications of scaphoid fx

A. Location of the fracture :

5

different fracture sites :

Proximal third ( proximal pole ) .. 25%

Middle third ( waist )… most common 65%

Distal third …..10%

Tuberosity

Classifications of scaphoid fx

B. Direction of the fracture

:

Horizontal Oblique , Transverse , and

Vertical Oblique

Classifications of scaphoid fx

C. Time since injury

:

• Acute fracture - less than 3 weeks

old

• Delayed union - 4 to 6 months old

• Nonunion - more than 6

Classifications of scaphoid fx

D. Amount of fracture displacement

( stability )

:

• Undisplaced ---- stable

• The unstable

fracture (displaced)

is defined as :

Prognosis

• Negative prognostic factors are : late diagnosis

proximal location displacement

angulation

obliquity of the fracture line smoking

Treatment

Is determined by:

Location

Degree of displacement

Fresh vs old fracture

Treatment

• Undisplaced ( stable) fracture

Nonoperative (

cast immobilization

have been three main areas of disagreement in non-operative treatment of acute non

displaced fractures of scaphoid :

1- the position of the wrist in the cast

2- the need to include joints other than the wrist in the cast

Treatment

Many types of cast immobilization have been described in the literature

No evidence exists to prove greater efficacy for one casting position over another. Although

above elbow casts may have a slightly shorter time to union, the final rate of union is the same for below or above elbow casts. The key factor in treatment of scaphoid fractures is the duration of immobilization rather than the specific position

• The current

recommendation is to use a short arm thumb spica with the thumb

interphalangeal joint free. The wrist is placed in

radial deviation • Long arm cast is

recommended for

nondisplaced proximal pole fx

• Consider changing the cast every 10-14

days for the first 6 weeks so that it

remains firm around forearm muscles

and the wrist

• Time to healing by location :

– Distal third fx heals in 6-8 weeks

– Middle third fx 8-12 weeks

– Proximal third fx 12-24 weeks

• Removal of the cast should not occur until union has been documented on CT or tomography

• Prognosis is excellent in undisplaced, stable fractures if diagnosed and immobilized early (95 % with x-ray evidence of beginning

• Initial delay in treatment does not preclude casting • If treatment is instituted within four weeks no

effect on healing time or rate of union has been shown

• Delay beyond six months invariably requires operative treatment

• The difficulty lies in fractures between six weeks and six months. If no evidence of bony resorption exists, casting may result in union. If bony

resorption or displacement greater than 1 mm

exists, operative reduction and bone grafting will be needed

Treatment

• Cast immobilization and electrical

stimulation

:

(esp.when there is nonunion ), though there is a lack of reliable double-blind study which compares between series of patients treated with immobilization alone and those treated with immobilization and ES,

• If the patient will not tolerate prolonged cast

immobilization (e.g. professional athletes

and manual laborers ) early internal fixation

should be performed

• Internal fixation for fresh nondisplaced

proximal pole fractures has been

Treatment

• Displaced fractures

– Primary internal fixation is treatment of choice for unstable scaphoid frxs

– Fractures treated by primary internal

fixation, average time for return to work is 3.7 weeks with union rate 97 %

• Indications of Surgery in

Scaphoid fractures

Delayed union or nonunion when bone grafting is insufficient to provide adequate internal fixation

S.Fx associated with a perilunate fx or dislocation Ligamentous injury

Non displaced fx of proximal pole

Non displaced fx if the pt will not tolerate

prolonged cast immobilization (e.g. professional athletes and manual laborers )

• The choice of the surgical procedure will

vary with the surgeon’s preference and

experience, the type of the fracture, the

patient’s age, and the presence of

periscaphoid arthrosis

• The most important aspect of the treatment

is meticulous technique and not the device

or equipment selected

• Reduction of the fracture should be

anatomic

• ORIF of scaphoid fractures can be done by

many ways :

K-wires ( easy insertion )

Herbert screws ( headless,

multipitched,difficult insertion )

AO screws

Herbert-whipple screw

Ender’s plate

• The surgical approaches :

– Volar approach -- is most of the time the preferred approach to limit the injury to the blood supply of the scaphoid

– Dorsal approach – will be used to address the fractures of the proximal approach

Volar approach: between FCR

and the radial artery

Treatment of middle third fxs

They are the commonest (65%)

If fresh stable: short-arm thumb spica cast

If fresh undisplaced but potentially unstable

(e.g. vertical oblique) and stable fx older

than 3 wks : long-arm thumb spica cast

Proximal Pole Fractures

• challenging

• Often difficult to heal

• Prolonged immobilization- snug , well

molded long arm cast- (sometimes exceeds

9 mos) has been necessary with

conventional casting

• Early incorporation of PES has been

recommended

Proximal Pole Fractures

• There is increasing favor to proceed to ORIF

• A dorsal approach allow s direct visualization of the fracture

• If it is a fresh fx, can be fixed by 2-3 k-wires

• The k-wires are extracted in a retrograde fashion in 6-8 weeks

• Alternatively ,one may use a Herbert screw which may be inserted retrograde while the fragment is stabilized in a k-wire

Proximal Pole Fractures

• Determination of bony union is not easy

• Tomography or CT is needed

• Multiple follow up films should be obtained

for several months after the assumed

Distal Pole Fractures

• These are often avulsion injuries of the

tuberosity and can be expected to heal

promptly with cast treatment

• Fresh and undisplaced should heal in 4-8

wks in a cast

After treatment care

• After achieving a rigid fixation , there is a

big controversy about the need for

immobilization

• Some authors recommend a long arm cast

after k-wire or compression screw fixation

for 2-3 weeks

• New literature is in favor of early

mobilization

Complications of Scaphoid Fx

• Delayed union or Nonunion

• Malunion (Humpback deformity)

• SLAC wrist

Nonunion

• The incidence of scaphoid nonunion for undisplaced fx is 5-10%

• The incidence increases up to 90% in displaced proximal pole fxs • Risk factors : – Proximal pole fx – Displacement – Late diagnosis – Inadequate immobilization

Nonunion

• Failure to heal after 6 months establishes the Dx of nonunion

• Recent studies indicated that virtually that all unstable nonunions lead to carpal collapse and

posttraumatic arthritis,, for this reason treatment is recommended for all scaphoid nonunions even if asymptomatic

• Thin cut CT scan show more details than conventional tomograms

• Sagittal views are helpful in determining the

Treatment of Nonunion

A) Bone grafting :

• 2 types of bone grafting are indicated for tx of nonunion:

• Russe bone graft (inlay):

stable nonunions .the initial procedure used a single corticocancellous strut across the

fracture line;a later modification involved two corticocancellous struts inserted into the

scaphoid excavation with their cancellous sides facing each other,the remainder of the cavity is filled with cancellous chips. Usually

Con’t Russe bone graft

• The time to union with this procedure is relatively long ,generally requiring cast immobilization for 6-4 months

• Healing rates of 85-90 % have been reported

• Satisfactory relief of symptoms has been reported ; 78 % of painful wrist became free of symptoms and 88 % of patients were satisfied with the results

Con’t

Bone Grafting

• Fernandez bone graft (interpositional

graft

humpback deformity require interpositional grafting. Fernandez has described the use of a

trapezoidal iliac graft to correct the angulation and carpal collapse pattern.Fixation is achieved with screws or k-wires

• In both types of bone grafting ,a volar approach is used, and care must be taken to preserve the

Treatment of Nonunion

• B) Electrical stimulation:

– Pulsed Electromagnetic Field ( PEMF ) stimulation has been investigated as a noninvasive treatment for scaphoid

nonunion.Although controversial, there appears to be some benefit (shorter healing time)when electric stimulation is combined with bone

Treatment of Nonunion

• C) Proximal pole excision:

when a small proximal fragment is not amenable to bone grafting ,proximal pole excision and fascial hemiarthroplasty are recommended

Treatment of Nonunion

• D) Salvage procedures :

Are indicated when nonunion has lead to carpal collapse and secondary degenerative changes

Proximal row carpectomy,intercarpal arthrodesis, or radiocarpal arthrodesis is recommended in patients with chronic wrist pain and stiffness

Radial styloidectomy and scaphoid interposition

arthroplasty may be combined with other procedures or performed independently in the younger patient with less severe symptoms

Malunion

• Malunion of the scaphoid may occur when a displaced or angulated fracture is allowed to heal without anatomic reduction

• In most of cases , there is a dorsal angulation resulting in a fixed humpback deformity

• DISI pattern ensues ,resulting in pain ,loss of motion, and decreased grip strength

• Treatment in a young patient includes osteotomy,volar wedge bone graft,and internal fixation

• Once degenerative arthritis has begun ,treatment is limited to a salvage procedure such as proximal row

SLAC

• scapholunate advanced collapse

(SLAC) refers to a specific pattern of

osteoarthritis and subluxation which

results from untreated chronic

scapholunate dissociation or from

chronic scaphoid nonunion

Case # 1

•

J.D. 24 y.o male . Fell on his out stretched

hand while snowboarding on March 7/2000

•

C/0 pain Lt wrist , no other injuries.

•

O/E : Lt wrist tenderness, neurovascular

intact

•

X-rays :

May1/2000

May1/2000

May 29/2000

11 wks