# Forearm and carpal bones

FRACTURES OF THE FOREARM

AND CARPAL BONES

Dr. Ritesh Chaudhary

Fellowship in Emergency Medicine

BP Koirala Institute of Health Sciences,

Dharan, Nepal

Radial head fractures

• Occur frequently, usually as a result of a fall onto an

outstretched hand or, less frequently, following a direct

blow to the lateral side of the elbow.

• Usually, there is swelling and tenderness over the radial

head.

3/8/2016 Forearm fracture and carpal bones 2

• Elbow extension and forearm rotation are limited.

• Severely comminuted fractures may have proximal

displacement of the radius, which can be associated with

disruption of the interosseous membrane and subluxation

of the distal radioulnar joint.


Imaging

• Standard anteroposterior (AP) and lateral X-rays of the

elbow are required.

• The presence of an anterior fat pad sign alone on X-ray is

associated with an underlying radial head or neck fracture

in up to 50% of patients.


A subtle radial head fracture with associated positive sail sign


Classification

Mason–Hotchkiss classification of radial

head fractures.

The Mason classification is as

follows:1.Mason type I, displaced <2 mm.

2.Mason type II,displacement >2

mm.

3.Mason type III, comminuted

fractures of the entire radial head.

4.Mason type IV, radial head

fracture with associated elbow

dislocation.


Treatment

• All non-displaced (type I) radial head fractures and those

type II fractures without mechanical block may be

managed with a bandage and sling.

• Mobilization should be started as early as possible.

• If there is severe pain, a posterior splint may be useful but

should not be applied for more than 2 days. Prognosis is

good, but full extension may not be possible for many

months.


• Mechanical block can be difficult to assess acutely due to

pain.

• Intra-articular injection of bupivacaine may assist early

assessment or assessment may be deferred until pain

has settled.

• Surgical options include open reduction and internal

fixation and excision of the radial head with or without

implantation of a prosthesis.


• Displaced or complex radial head fractures (type II or III)

may be treated in the acute setting with a sling or

posterior splint.

• These patients should have early orthopaedic review

(within days).

• Radial neck fractures with up to 20° tilts can be managed

conservatively. More severe tilt can be reduced using

intra-articular local aneasthesia.


• The forearm is pronated until the most prominent part of

the radial head is felt.

• Then traction is applied to the forearm and pressure

applied to the radial head.

• Open reduction is indicated if closed methods fail or

displacement is severe.


Complications

• Complications relate to disturbance of the relationships of

the proximal radio-ulnar and radiocapitellar articular

surfaces causing limitation of movement.


Shaft fractures

• This type of injury requires great force, typically from a

motor-vehicle accident, a fall from a height or a direct

blow.

• These fractures are commonly open and nearly always

displaced.


Examination

• The forearm is swollen and tender and may be angulated

and rotated.

• Look for an open wound, local neurovascular

compromise, compartment syndrome or

musculotendinous injury.


Clinical investigations

Imaging

• AP and lateral X-rays of the forearm, including the wrist

and elbow joints, are needed.

• Displacement and angulation are easily determined, but

torsional deformity may be subtle.


• The ulna and radius are rectangular in cross-section

rather than circular, a change in bone width at the fracture

site indicates rotation.

• The radial and ulnar styloid processes normally point in

opposite directions to the bicipital tuberosity and coronoid

process, respectively.

• A change in this alignment also suggests torsion.


Treatment

• Adult forearm fractures are less stable than those in

children and lack of remodelling limits tolerance to

incomplete reduction.

• Undisplaced fractures may be managed with an above-

elbow cast, but must be reviewed at 1 week for

displacement and angulation.

• Most fractures, however, are displaced and require open

reduction and internal fixation.


Complications

• Early complications include wound infection,

osteomyelitis, neurovascular injury and compartment

syndrome.

• Later, non-union, malunion, reduced forearm rotation and

reflex sympathetic dystrophy are possible complications.


Specific fracture types

Isolated fracture of the ulnar shaft

• Direct blow to the ulna, often when raised in defence;

hence they are also known as ‘nightstick’ fractures.

• Patients present with localized pain and swelling. AP and

lateral X-rays delineate the location of the fracture and

degree of angulation.

• Look for associated dislocation of the radial head if

displacement is present (Monteggia fracture dislocation).


• Fractures displaced less than 50% of the ulna width heal

well with a non-union rate of 0–4%.

• Traditional treatment involves fixing the forearm in mid-

pronation with a plaster cast, extended above elbow if the

middle or proximal thirds of the ulna are fractured.

• The cast is removed once union occurs, usually in about 8

weeks.


• Other proven options include a below-elbow plaster

(BEPOP) for proximal fractures, early mobilization with

bandage after 1–2 weeks in BEPOP or functional bracing

after 3–5 days, which allows movement at wrist and

elbow.

• Fractures with more than 10° of angulation or displaced

more than 50% of the diameter of the ulna require

surgical intervention.


Monteggia fracture dislocation

• This is a rare fracture of the proximal ulna with dislocationof the radial head.

• It occurs either through a fall onto the outstretched handwith hyperpronation or through a force applied to theposterior aspect of the proximal ulna.

• Patients present with pain, swelling and reduced elbowmovement. The forearm may appear shortened and theradial head may be palpable in the antecubital fossa.

• Associated posterior interosseous nerve injury iscommon.


• On X-ray the fracture is obvious, but the dislocation is

commonly missed.

• Check that a line through the radial shaft bisects the

capitellum on both views.

• There are four types of Monteggia fracture depending

upon displacement of the radial head (Bado

classification).


• All Monteggia fractures require open reduction and

internal fixation.

• Common complications include malunion and non-union

of the ulnar fracture and an unstable radial head.


Isolated radial shaft fracture

• Isolated fractures of the proximal two-thirds of the radial

shaft are uncommon and are usually displaced.

• Rare undisplaced fractures can be treated similarly to

isolated ulnar shaft fractures.

• Displaced fractures require open reduction and internal

fixation.


Galeazzi fracture dislocation

• Fractures of the distal third of the radial shaft occur as a

result of a fall onto the outstretched hand or a direct blow.

• There may be an associated subluxation or dislocation of

the distal radioulnar joint (DRUJ), known as the Galeazzi

fracture dislocation.

• Patients have pain and swelling at the radial fracture site.

• Those with a Galeazzi injury will also have pain and

swelling at the DRUJ and a prominent ulnar head.


The Galeazzi fracture dislocation.


X-rays show the radial fracture,

which is tilted ventrolaterally.

Widening of the DRUJ space on

the AP X-ray and dorsal

displacement of the ulnar head

on the lateral X-ray are seen.

An ulnar styloid fracture is seen

in 60% of cases.

• All Galeazzi fracture dislocations require surgical

management.

• Complications include malunion or non-union of the radial

fracture and subsequent instability of the DRUJ.


Fractures of the distal radius and ulna

• Fractures of the distal radius and ulna are common,

particularly in children and elderly women.

• Fractures in the latter group are indications for evaluation

of bone-mineral density.


Clinical features

History and examination

• Fractures usually occur after a fall onto the outstretched hand

resulting in bending, shearing or impaction forces being applied

to the distal metaphysis, or from a direct blow.

• Pain, tenderness and variable degrees of swelling and

deformity.

• Examine for associated injuries to carpal bones, radial and

ulnar shafts, elbow and shoulder joints, for median nerve injury,

vascular compromise and for extensor tendon injury.


Clinical investigations

Imaging

• Anteroposterior and lateral X-rays of the wrist

demonstrate most injuries.

• For patients with significant symptoms or signs and a

normal X-ray, consider an occult undisplaced fracture or

ligamentous injury.


Treatment

• Prompt attention to analgesia, splinting and elevation isessential while awaiting X-rays.

• Reduction is indicated in the following circumstances toimprove long-term function:1.Visible deformity of the wrist

2.Loss of volar tilt of the distal radial articular surface beyond neutral

3.Loss of>5° of the radial inclination of the distal radius (normallyapproximately 20°)

4.Intra-articular step of>2 mm

5.Radial shortening>2–3 mm.

• Greater deformity can be accepted in low-demand, elderlypatients.


• Anaesthetic options for reduction include haematoma

block, Bier’s block and procedural sedation.

• Reduction is traditionally maintained with an encircling

plaster cast moulded to oppose displacement forces and

extending from volar metacarpal crease to proximal

forearm for 6 weeks.

• Weekly X-rays for 2–3 weeks with orthopaedic follow up

are recommended for all displaced fractures, those with

intra-articular extension and potentially unstable fractures.


Indications for operative management

1.Comminuted, displaced, intra-articular fractures

2.Open fractures

3.Associated carpal fractures

4.Associated neurovascular or tendon injury

5.Failed conservative treatment (failed reduction or

unstable after reduction)

6.Bilateral fractures/impaired contralateral extremity.


Complications

• Median nerve injury

• Malunion with chronic wrist pain, arthritis and secondary

radioulnar and radiocarpal instability.

• Long-term complications include osteoarthritis, residual

disability and complex regional pain syndrome (CRPS).

1% to 22%.

• Prophylactic vitamin C may reduce the incidence of

CRPS, the advised dose is 500 mg/day for 50 days


Specific fractures

Colles’ fracture

• Colles’ fracture is a metaphyseal bending fracture.

• The wrist has a classic ‘dinner-fork’ appearance, often

with significant swelling of the soft tissues.


Colles’ fracture. A fracture of the distal

radial metaphysis


• There is often associated damage to the radio-ulnar

fibrocartilage.

• There may be comminution, commonly dorsally, which

can extend into the radiocarpal or radio-ulnar joints.


• The commonly accepted cast immobilization position is

with the wrist joint in 15° palmar flexion, 10–15° ulnar

deviation and slight pronation.

• However, some evidence suggests better outcomes are

achieved with the wrist in dorsiflexion and mid-supination.

• The cast must be carefully moulded over the dorsum of

the distal fragment and the anteromedial forearm.


Smith’s fracture

• This metaphyseal bending fracture of the distal radius

occurs through a direct blow or fall onto the back of the

hand or a fall backward onto the outstretched hand in

supination.

• AP and lateral X-rays of the wrist show a ‘reverse Colles’

fracture’ with a similar AP appearance, but with volar

displacement and tilt on the lateral X-ray view.


Smith’s fracture ( Frontal and lateral )


• Closed reduction to achieve anatomical radial length andvolar tilt should be attempted.

• Traction is first applied to restore length, followed bydorsal pressure over the volar surface of the distal radiusto reverse displacement and angulation.

• A full above-elbow cast is applied with the wrist insupination and dorsiflexion to prevent loss of reduction.

• However, most Smith’s fractures are unstable and requireoperative management. Early orthopaedic follow up ismandatory.


Barton’s fracture

• Barton’s fractures are dorsal or volar intra- articularfractures of the distal radial rim.

• The mechanisms of injury are similar to those seen withColles’ and Smith’s fractures, respectively.

• There is often significant soft-tissue injury and the carpusis usually dislocated or subluxed along with the distalfragment.

• These fractures are complicated by arthritis of theradiocarpal joints and carpal instability.


Barton’s fracture


• Minimally displaced fractures involving less than 50% ofthe joint surface and without carpal displacement may bereduced along the lines of a Colles’ or Smith’s fracture.

• Immobilization should occur with wrist flexed for dorsalBarton’s and extended for volar Barton’s.

• However, most fractures are unstable and potentiallydisabling, requiring early operative management,especially in younger patients.

• Early orthopaedic follow up is mandatory.


Radial styloid (Hutchison’s or chauffeur’s)

fracture

• Oblique intra-articular fracture of the radial styloid.

• Caused by a direct blow or fall onto the hand.

• Displacement is associated with carpal instability and

long-term arthritis.


Radial styloid (Hutchison’s or chauffeur’s) fracture


• Undisplaced fractures can be treated with a cast for 4–6

weeks.

• Displaced fractures should be referred to an orthopaedic

surgeon for anatomical reduction and fixation.


Ulnar styloid fracture

• An isolated fracture can occur through forced radial

deviation, dorsiflexion, rotation or a direct blow.

• fractures involving the base of the ulnar styloid disrupt the

major stabilizing ligaments of the distal ulna and the

triangular fibrocartilage complex (TFCC) and may lead to

subsequent distal radioulnar joint (DRUJ) instability.

• Fractures should be treated with a splint or cast with the

wrist in mid-supination and ulnar deviation, patients

should be referred to an orthopaedic surgeon to assess

DRUJ stability


Normal P/A view of wrist joint


1. The carpal bones are arranged in two rows forming three smooth arcs (Gilula lines). 2. The carpal

bones are separated by a uniform 1- to 2-mm space. 3. The scaphoid (S) is elongated. 4. The radius

has an ulnar inclination of 13 to 30 degrees. 5. The radial styloid projects 8 to 18 mm. 6. Half the

lunate articulates with the radius, with equal length over the ulna (neutral ulnar variance). C = capitate;

H = hamate; L = lunate; P = pisiform; Tm = trapezium; Tq = triquetrum; Tz = trapezoid.

Normal Wrist Axis


Normal wrist. Axis of the radius (R), lunate

(L), and capitate (C) are collinear (three C’s

sign).

The capitolunate (CL) angle is <10 to 20

degrees. The scapholunate (SL) angle is

between 30 and 60 degrees. The radial

volar tilt is 10 to 15 degrees

Dorsal intercalated segment instability.

Volar intercalated segment instability.

Scaphoid fracture

• The most common mechanism of injury is a fall on the

outstretched hand with the wrist in radial deviation.

• Wrist pain and local swelling and tenderness over the

scaphoid.

• Imaging with AP, lateral and scaphoid views will detect at

most 70% of all scaphoid fractures.


• Stable fractures are undisplaced with little comminutionand unstable fractures are displaced with considerablecomminution.

• Stable fractures are generally treated with a below-elbowcast for 10–12 weeks.

• Unstable fractures require surgical intervention.

• Complications include non-union and avascular necrosisof the proximal segment.


Imaging

• Early primary CT, magnetic resonance imaging (MRI) orbone scintigraphy.

• All of these imaging modalities have their advantages andshortcomings.

• Bone scintigraphy is recommended as a useful diagnosticmodality to rule out occult scaphoid fractures.

• Bone scintigraphy can rule out scaphoid fracture with asensitivity close to 100% but with the disadvantage of upto 25% false positives.


Dislocations of the wrist

• Dislocations involving the wrist usually result from high-

energy falls on the outstretched hand (such as from a

height) that result in forced hyperextension.

• Clinical features include mechanism of injury, wrist pain,

swelling and tenderness and possibly reduced grip

strength.


Imaging

• Imaging requires PA and lateral X-rays. The normal PA

view should show two rows of carpal bones in a normal

anatomic position with uniform joint spaces of no more

than 1–2 mm.

• No overlap should be seen between the carpal bones or

between the distal ulna and the radius.

• On the lateral film, a longitudinal axis should align the

radius, the lunate, the capitate and the third metacarpal

bone.


Lunate dislocation

• On the usual PA image, the lunate has a triangular shape

rather than its usual trapezoidal shape.

• On the lateral film, the lunate has a ‘C-’ or ‘half-moon’

shape.


Perilunate dislocation

• On the PA film, crowding is evident between the proximal

and distal carpal bones.



Perilunate dislocation.

A. Posteroanterior view shows obliteration of the three smooth arcs as bones overlap one

another (white hash marks).

B. Lateral view shows capitate dorsal to lunate, disrupting the “three C’s” (arrow).

Scapholunate dislocation

• On a PA radiograph, the scapholunate space is greater

than 4 mm (also known as the Terry-Thomas sign).

• The scaphoid rotates, producing the classic signet-ring

sign.

• Associated carpal fractures, especially of the scaphoid,

may be evident.



'Terry Thomas sign' - in

homage to the well

known British actor

Treatment

• All wrist dislocations require orthopaedic consultation and

prompt reduction.


Wrist Radiography


# Forearm and carpal bones

Health & Medicine

Transcript of # Forearm and carpal bones