CHAPTER 73

The forearm

73.1 Introduction

The results of treating fractures of the forearm are often sobad that the literature about them is only exceeded by thaton the hip. Fractures of the forearm are mostly the result of adirect blow. When a patients bones are broken, the musclesattached to the fragments pull them out of place, and maketreatment particularly difficult.

(1) Either forearm bone can fracture alone. (2) Both onescan fracture simultaneously, usually in their middle thirds.When this happens in a child, the fracture is likely to begreenstick. (3) Either bone can fracture, and at the sametime, the upper or the lower joint between them can dis-locate. If the radius fractures, the lower radioulnar jointmay subluxate (Galeazzi fracture). If the proximal third ofthe ulna fractures, the head of the radius may dislocate an-teriorly Monteggia fracture). These dislocations are oftenmissed, so always include a patients wrist and his elbow on aforearm film, particularly if the fragments are overlapped orangulated.

EXAMINING THE FOREARM Palpate the whole of thesubcutaneous border of the patients ulna, and the lower twothirds of his radius.

Squeeze his radius and ulna together in the lower part ofhis forearm. If this hurts him, he probably has a fracture.

Examine the head of his radius (72.1) (Monteggia frac-

0

45

PRONATIONNEUTRALSUPINATION position offunction

this is the mostuseful positionPRONATION AND

SUPINATION

Fig. 73.1: IF PRONATION AND SUPINATION ARE LIKELY TO BELIMITED by the nature of the fracture, the patients hand will be mostuseful to him if his forearm is in a position of midpronation. Kindly con-tributed by John Stewart.

ture) and his inferior radioulnar joint (Galeazzi fracture) tomake sure they are not dislocated.

Examine his elbow and his wrist.XRAYS should include the patients wrist and a lateral

view of his elbow. A line through the long axis of his radiusshould pass through his capitulum in both views, as in Fig.73-4.

XRAY THE PATIENTS WRIST AND HIS ELBOW

Most fractures of the radius and all fractures of both bonesare usually treated by open methods where skills and facili-ties are good. But if you are not a skilled surgeon, and yourfacilities are not perfect, closed methods are more likelyto give your patients adequate function at minimum risk(69.3). Isolated fractures of the ulna are more easily treatedthan those of the radius, because the muscles attached to theulna are much less likely to displace its fragments.

Closed methods of reduction use the long arm cast de-scribed below, modified by varying the position of the pa-tients wrist to suit the needs of particular fractures. If bothhis bones are broken you can gently squeeze the cast fromfront to back to correct the angulation of the fragments to-wards one another. A forearm cast is heavy, so hang it fromhis neck. If you dont, its weight may redisplace the frag-ments, or press on his radial nerve and paralyse it. Mostcasts for forearm fractures, especially those for fractures ofboth bones, must go above the elbow.

CASTS FOR THE ARM

A LONG ARM CAST The first cast on a forearm fractureshould always be a long arm cast. Apply a single layer of cot-ton wool to the patients arm, then put cotton pads over thebony points around his elbow, and in his antecubital fossa.

Apply the cast from just below his shoulder to his MPjoints. Hold his elbow at 90, and his thumb and fingersfree. His thumb must be free enough to touch his little fin-ger. If his thumb is held out in abduction, it will be so stiffwhen you remove the cast as to be temporarily useless.

Carry the cast to the base of his thumb and knuckles andto his distal palmar crease. If you carry it beyond this point,he will not be able to move his fingers.

1

73 The forearm

A LONGARM CAST B

A

C

this thumb must beable to touch hislittle finger

suspending thecast avoidspressure on theradial nerve anddisplacement ofthe fragments

Fig. 73.2: A LONG ARM CAST. Suspending the cast avoids pressure onthe patients radial nerve. Make sure that his thumb is free and able totouch his little finger. Kindly contributed by Peter Bewes.

Adjust the rotation of his forearm as is best for each partic-ular fracture, as described later (73.5). Take a narrow plas-ter bandage, mould a plaster eye over the centre of gravityof the cast, and tie it with a comfortable collar around hisneck.

CAUTION! If the fracture is recent, split the cast (70.4,70.6).

Alternatively: (1) Instead of applying a circular cast, ap-ply anterior and posterior slabs and bandage them in place.Or, (2) apply plaster to the patients forearm first, and whenthis has set, complete the cast above his elbow.

A FOREARM CAST Use this to protect a patients forearmbones from refracture for a few weeks after they have united,until they have consolidated.

73.2 Isolated fractures of the shaft of the ulna

A blow on the back of the patients forearm breaks his ulna.The fracture is complete and transverse, with minimal dis-placement. There may be slight angulation and bowing, butthere is no shift, no overlap, and no rotation. The subcu-taneous border of his ulna is tender and swollen over thefracture. These fractures are common and easily treated, be-cause the intact radius makes a good splint.

FRACTURES OF THE ULNA

Make sure that the head of the patients radius is not dislo-cated by including his elbow in a lateral Xray. If it is, he hasa Monteggia fracture (73.3).

THE UPPER TWO THIRDS Treat him with active move-ments in a sling until he can use his arm without discomfort.

the patients elbowshould have beenincluded in the Xray!

ISOLATED FRACTUREOF THE SHAFTOF THE ULNA

Fig. 73.3: ISOLATED FRACTURES OF THE SHAFT OF THE ULNA.Make sure that the head of the patients radius is not dislocated by includ-ing his elbow in a lateral Xray. If it is dislocated, he has a Monteggiafracture. Unfortunately, this has not been done here!

THE LOWER THIRD A small plaster slab may ease hisdiscomfort.

Protect both types of fracture in a sling for 5 weeks, thentest for union by squeezing his radius and ulna towards oneanother.

If there is no tenderness, he can use his arm for any-thing he likes, except heavy manual work.

If there is tenderness, the fragments have not yet united,so apply a skin tight cast from his elbow to his wrist, andcontinue active movements. Leave it on for five weeks, bywhich time it should have united.

73.3 Fractures of the proximal third of theulna, with dislocation of the head of theradius (Monteggias fracture)

In places where there is much personal violence, this is acommon and nasty adults fracture; elsewhere it is a rarechildrens fracture. An adult raises his arm to protect hishead from a blow, and receives the full force of the blow onhis forearm, breaking his ulna and dislocating the head ofhis radius. The important part of the injury is the disloca-tion of the head of his radius, not the fracture of his ulna,which is usually broken in its upper third. Rarely, his ulnadoes not break, and dislocation of the head of his radius ishis only injury. When his ulna does break, the fracture maybe greenstick, and its fragments may only bow. Or, it maybreak completely and its fragments overlap, as in Fig. 73-4.

If you suspect that a patient has dislocated the head of hisradius, take an AP and a lateral view, because you may see thedislocation in one view, but not in the other. A line throughthe centre of his radius should pass through his capitulum.If the fragments of his broken ulna overlap, either his radiusmust also be fractured, or its head must be dislocated.

Unless the dislocation of the head of a patients radiusis reduced, he will never be able to bend his elbow again.Closed reduction is usually possible in children, and some-times in adults. Try to reduce this injury early, because thelonger you delay the more difficult it will become.

MONTEGGIAS FRACTURE

The method is the same, whether or not the patient has frac-tured his ulna.

Anaesthetize the patient and find two assistants. Extendhis arm and supinate it. Ask one of your assistants to hold

2

73.4 Fractures of the shaft of the radius with dislocation of the lower radioulnar joint (Galeazzis fracture)

MONTEGGIASFRACTURE

D

C

B

A

1

6

5

23

4

NORMAL linethrough head ofradius passesthrough capitulum

ulna fractured and overlapped

radius dislocated

Fig. 73.4: MONTEGGIAS FRACTURE. A, in a normal arm a linethrough the head of the radius passes through the capitulum. B, in Mon-teggias fracture this line passes through the shaft of the humerus. C, studD, you will need two assistants to help you reduce the head of the radius.After de Palma, with kind permission.

his upper arm (1, in Fig. 73-4) and your other assistant toexert traction on his wrist (2).

While your two assistants are maintaining traction, pressthe distal end of the proximal ulnar fragment posteriorly (3).Then try to press the head of the patients radius posteriorly(4).

Next, while still pressing the head of his radius (5), flex

his supinated forearm (6). The head of his radius shouldreduce with a clunk and his ulna should finally straightencompletely as it does so.

Apply anterior and posterior slabs directly to his skin fromhis axilla to the heads of his metacarpals, with his elbowflexed at about 80 and his forearm supinated. Bandage theslabs in place. They will help to keep the head of his radiusin place.

Start finger and shoulder exercises immediately.CAUTION! The head of the radius is unstable after this

injury and it can redisplace, so Xray him at weekly intervals.Hang the slabs from his neck for 3 weeks, remove them,

change them for a collar and cuff, and add elbow movementsto those he is already doing. Movements will take months toreturndont force them.

IF REDUCTION OF THE RADIAL HEAD FAILS OR THEPATIENT PRESENTS LATE, management depends on hisage.

If he is an adult, refer him for immediate open reduction,as described below. If the head of his radius is not reduced,he will never be able to bend his elbow again.

If he is a child, and the injury is less than 3 months old,refer him. If the injury is more than 3 months old, leavehim. Normal movements will usually return in spite of theunsightly hypermobility of his radial head.

IF REDUCTION OF THE ULNA FAILS so that it remainsseriously angulated, refer him.

DIFFICULTIES WITH A MONTEGGIA FRACTURE

If the HEAD OF THE RADIUS WILL NOT REDUCE, it mayhave gone through a hole in the capsule, and so be irre-ducible by closed methods. Open reduction will be neces-sary, so refer the patient immediately. If the dislocation is anold one, reduction may be impossible by any method. If heis an adult, it may then be necessary to excise the head ofhis radius.

If a Monteggia FRACTURE IS OPEN, do a careful woundtoilet. If there is an haemarthrosis, aspirate the patients el-bow (Fig. 72-4), and reduce the fragments into the best posi-tion you can. Provide skin cover by delayed primary closureor grafting, and then start early active movements.

73.4 Fractures of the shaft of the radius withdislocation of the lower radioulnarjoint (Galeazzis fracture)

These are rare, difficult fractures. In children the fracture ofthe radius is greenstick, and the only displacement is an an-terior bow. Adults have a complete fracture of the radius inwhich the distal radial fragment tilts, shifts anteriorly, over-laps, and inclines towards the ulna. At the same time thedistal end of the ulna dislocates from both the radius andthe carpus, and displaces dorsally to make an ugly bulge onthe back of the wrist.Incomplete Galeazzi fractures (children) cause a childs

lower forearm to bow forwards. He is tender over a green-stick fracture of his radius, usually in its distal third. Thedistal end of his ulna is also tender. Closed reduction is usu-ally straightforward.Complete Galeazzi fractures (adults) are often open,

with the skin punctured on the front or back of the patientsforearm, and his radius sticking through it. There is usually

3

73 The forearm

GALEAZZIS FRACTURE

fragments bowanteriorly

fragmentsoverlap

POSTREDUCTIONFILM

if the ulna isdisplaced distal tothe radius, reductionis unadequate

Fig. 73.5: GALEAZZI FRACTURES are rare and difficult. In childrenthe fracture of the radius is greenstick, and the only displacement is ananterior bow. Adults have a complete fracture.

no need to explore the wound because there is no dead tis-sue to remove. Instead, seal the puncture hole with a dress-ing, before you reduce the fracture.

GALEAZZIS FRACTURE

INCOMPLETE GALEAZZI FRACTURES

If the fracture is in the distal third of the radius, evena 45 angulation in a small child does not matter, and sooncorrects itself as he grows. The younger he is, and the closerthe fracture to the epiphysis, the greater the angulation youcan accept.

If the fracture is higher up in the middle third of thechilds radius, moulding is less rapid and less complete,especially if he is older. So anaesthetize him, and bend hisradius back into place. This reduces the fracture and thedislocation of his distal radioulnar joint. If the distal end ofhis ulna happens also to have been fractured, the overlap ofthe radius usually remains.

Apply a long arm cast with his elbow at 90, his arm inmidrotation, and his wrist slightly palmar flexed.

After 6 weeks, replace this cast by a shorter one extendingfrom the upper part of his forearm to above his knuckles.This will hold his radius straight and prevent him dorsiflexinghis wrist. Leave this short cast on for 6 weeks.

COMPLETE GALEAZZI FRACTURES

CLOSED REDUCTION Anaesthetize the patient, using a re-laxant if possible. Then suspend his forearm over the side

AN ISOLATED FRACTUREOF THE RADIUS

Fig. 73.6: ISOLATED FRACTURES OF THE SHAFT OF THE RA-DIUS. Management depends on the degree of augulation. If angulation isminimal, bandage the childs arm. More than a minimal degree of angu-latinn at the centre of the bone is not acceptable. If necessary, break thebone completely and realign the fragments.

of the table from a drip pole as in Fig. 73-10.Reduce the fracture until his forearm looks normal, apply

a long arm cast, and mould it to give it a flat crosssectionas in Fig. 73-9. Complete the cast, and include a ring in it.

Xray him again, and consult Fig. 73-5. If his radial styloidis distal to his ulnar styloid, reduction is adequate. If his ulnarstyloid is distal, reduction is not adequate.

If reduction is adequate, continue treatment as for amidshaft fracture of the radius and ulna (73.6).

If reduction is not adequate, his radius slips anteriorlyinto its displaced position, and his ulna slips distally to thehead of his radius. If possible, refer him within the first weekfor open reduction of his radius. This will correct the positionof his ulna at the same time.

DISASTER WITH A GALEAZZI FRACTURE

If the FRACTURE WAS MISSED, both bones will haveunited solidly, and the lower end of the patients ulna willstick out as a lump on the back of his wrist, which will be stiffand painful. Refer him for the excision of the lower end ofhis ulna.

73.5 Isolated midshaft fractures of the shaftof the radius

The fact that a patients radius rotates makes its fracturesmuch more difficult to treat than those of his ulna. If there isno overlap, no reduction is necessary, and you can treat himwith a plaster forearm splint. But if the fragments overlap,treatment is more difficult, because his intact ulna preventsyou distracting and angulating his broken radius. Closedmethods may work, but if they fail, this fracture needs openreduction and internal fixation. The radius usually breaksthrough its proximal third. If it breaks through the junctionof its middle and distal thirds, closed methods are even lesslikely to succeed.

A fracture allows the proximal fragment of the radius torotate on the distal one. You cannot alter the position of theproximal fragment, so all you can do is to try to find out

4

73.5 Isolated midshaft fractures of the shaft of the radius

ROTATION OFFRAGMENTS OFTHE RADIUS

A

B

pronatorteres

in fractures above theinsertion of pronatorteres, biceps will havesupinated the proximalfragment, so supinatethe distal one also

in fractures below theinsertion of pronatorteres, it will have pulledthe proximal fragmentinto midpronation, sothe distal fragmentmust be in the sameposition

Fig. 73.7: ROTATION OF THE FRAGMENTS OF THE RADIUS. A, infractures above the insertion of pronator teres, biceps will have supinatedthe proximal fragment, so supinate the distal one also. B, in fractures belowthe insertion of pronator teres, this muscle will probably have pulled theproximal fragment into midpronation, so immobilize the distal fragmentin this position also. Kindly contributed by John Stewart.

where it is, and line up the distal fragment with it, beforeyou immobilize them both.

The supinating muscles, biceps, and supinator are at-tached to the proximal end of the radius, and the pronat-ing muscles, pronator teres, and pronator quadratus are at-tached to its distal end. In fractures above the insertion ofpronator teres (halfway down the radius) the supinatorssupinate the proximal fragment. In more distal fractures itsposition is more variable. There are several ways of findingout how far the proximal fragment has rotated.

(1) You can assume that, (a) in fractures of the proximalthird of the radius (above the insertion of pronator teres), theproximal fragment will be in full supination, and (b) that infractures of the distal two thirds below the insertion of thismuscle, it will have pulled the proximal fragment into midpronation. This is a useful compromise because a forearmfixed in midpronation is only a minor disability, whereasone which becomes fixed in full supination will be a consid-erable handicap.

(2) The most accurate way is to take an AP Xray of theupper end of the patients injured radius, and use the posi-tion of his radial tuberosity as a guide to how far the prox-imal fragment has rotated. Either, (a) use Fig. 73-8 as aguide, or (b) better, if you have plenty of Xray film and can

tuberosityradial

tuberosityradial

CROSS SECTION THROUGH LINE XY biceps

biceps

NEUTRAL FULL PRONATIONFULL SUPINATION

X Y

HOW FAR HAS THE PROXIMALFRAGMENT OF THE RADIUS ROTATED

A B C

Fig. 73.8: HOW FAR HAS THE PROXIMAL FRAGMENT RO-TATED? Take an AP view of the elbow. Look for the position of the radialtuberosity. Match it with positions A, B, or C, and apply the cast with thepatients hand in the position shown. Kindly contributed by John Stewart.

spare it, take several Xrays of his normal radius, in variousdegrees of pronation and supination, and find the positionwhich best matches the fractured one. When you immobi-lize it, do so in this position.

Some surgeons routinely convert isolated greenstick frac-tures of the radius and greenstick fractures of both bonesinto complete ones. If this is done, they are said to be lesslikely to redisplace inside the cast after reduction.

IMMOBILIZE PROXIMAL THIRD FRACTURES INSUPINATION

IMMOBILIZE MIDDLE AND DISTAL THIRD FRACTURES INMIDPRONATION

ISOLATED MIDSHAFT FRACTURES OF THERADIUS

Examine the patients lower radio-ulnar joint carefully tomake sure it is not abnormally prominent and dislocated. Ifit is, he has a Galeazzi fracture.

ADULTS WITH AN ISOLATED MIDSHAFT FRACTUREOF THE RADIUS

If possible, refer the patient for internal fixation, particularlyif: (1) the fracture is at the junction of the middle and distalthirds, or (2) you need to immobilize his forearm in eitherof these extreme positions, because subsequent rotation ismore likely to be limited.

5

73 The forearm

If you cannot refer him, proceed as follows.WITHOUT OVERLAP No reduction is necessary, but the

fragments need a splint to stop them rotating, so apply along arm cast. Use the methods described above to decidethe correct degree of pronation and supination in which toimmobilise his arm. Flatten the cross section of his cast asin Fig. 73-9. Dont pad it, except over the bony points at hiselbow.

Start active finger movements immediately.WITH OVERLAP Make one or even two attempts to re-

duce the fracture by the gentle squeezing grip, shown inFig. 73-9. If you fail, refer him.

CAUTION! Dont grip too hard, or you may impede thecirculation in his arm.

CHILDREN WITH AN ISOLATED MIDSHAFT FRACTUREOF THE RADIUS

Management depends on the degree of angulation.If angulation is minimal, bandage the childs arm.If angulation is more than minimal, anaesthetize him,

suspend his forearm, reduce the fracture, and apply a castas above. To prevent the fracture slipping subsequently,slightly overcorrect the position.

CAUTION! More than a minimal degree of angulation atthe centre of the bone is not acceptable. If necessary, breakthe bone completely and realign the fragments.

Alternatively, apply the cast. While it is still wet andsoft, quickly snap the greenstick fracture through completely.Hold the fragments reduced until the cast is hard.

73.6 Midshaft fractures of the radius andulna

These are common and difficult fractures: (1) The fragmentsare difficult to align, (2) they displace easily, and (3) crossunion may occur, and prevent the patient rotating his fore-arm. If he is under 18, open reduction and internal fixationare unnecessary, but in older patients this is one of the frac-tures which is generally treated by open methodsif skillsand operating conditions are good enough. They seldom are inthe district hospitals for which we write. So refer the patientimmediately if you can; if necessary, internal fixation can bedelayed 10 days. If you wait, make sure you correct overlapby applying traction meanwhile.

If you cannot refer the patient, treat him as we describe.Make quite sure that if rotation will later be limited, his fore-arm will at least be fixed in the most convenient position forhim. This is in 45 of pronation, as in Fig. 73-1. For manypatients a forearm fixed in this position is only a minor dis-ability, because movements of the shoulder can compensateto some extent for pronation and supination of the forearm.Fixation in any other position is a completely unnecessarytragedy. Bowing may be ugly, but it is much less serious.

73.7 Greenstick midshaft fractures of themiddle third of both forearm bones

These cause an obvious bowing of a childs forearm. Cor-rect angulation carefully, because the fracture is in the cen-tre of the bone and remodelling will not correct it later

they should look like thisin a postreduction xray

GENTLY compressingthe cast separates theforearm bones

the bones havedisplaced towardsone another

No !

DISTRACTING THEFOREARM BONES

Fig. 73.9: DISTRACTING THE FOREARM BONES. If you exert gentlepressure on a patients forearm through a soft cast, this will separate hisforearm bones and help to prevent crossunion. Kindly contributed by Peter Bewes.

(69.6). Some surgeons deliberately break greenstick frac-tures through completely with the aim of reducing the riskof displacement recurring.

APPLY THE CAST INMIDPRONATION

GREENSTICK FRACTURES OF BOTH FOREARMBONES

Anaesthesia is kind but not essential. Ketamine is satisfac-tory (A 8.2).

If the fracture is undisplaced, apply a plaster slab.If the fracture is displaced, apply a circular cast from the

childs knuckles to the middle of his upper arm with his fore-arm in midpronation. While the cast is still soft, straightenhis forearm. Correct angulation carefully, especially in thelateral (coronal) plane, which moulds even less readily thanangulation in the anteroposterior (sagittal) plane.

CAUTION! Split the cast. If you dont split it, he would

6

73.8 Complete fractures of the middle third of both forearm bones

be much safer with a plaster backslab. Some surgeons rou-tinely treat displaced greenstick forearm fractures with slabs.

Start active movements of the childs shoulder and fingersas soon as possible.

Xray him during the first 3 weeks, look for angulation,and if necessary, correct it under anaesthesia, as describedbelow for angulation in complete fractures.

After 5 weeks, remove the long arm cast, and test for clin-ical union. If the fracture has united, replace it by a sling,and continue active movement. If it has not united, reapplythe cast.

Alternatively, break his bones through with a sharp bend-ing force, and slightly overcorrect the deformity. Suspend hisforearm as for a complete fracture, apply a long arm cast,and be sure to split it!

73.8 Complete fractures of the middle thirdof both forearm bones

If both a patients forearm bones are broken in the middle,his forearm is free to bend in the middle. You can easilycorrect this angulation; the difficult part is separating thefragments when they have inclined towards one another. Inthe following method the patients arm is suspended ver-tically from a drip stand while a cast is applied. This: (1)prevents the fragments bending under the influence of grav-ity while the cast sets, (2) allows you to apply the cast in asingle stage, and (3) lets you correct the inclination of the ra-dius and ulna towards one another by gently squeezing thecast anteroposteriorly while it sets. This flattens its cross sec-tion, compresses the muscles of the patients forearm, and somakes them push the two bones apart.

This is a potentially dangerous cast, so remember to splitit as described below. If you split it correctly, you will notlose reduction. Never use an ordinary backslab, which isquite ineffective in complete fractures.

The details are critical. If you neglect them, your resultswill be bad. Try to enthuse the patient with the part he canplay in getting his bones to unite by using his fingers earlyand actively. The muscles of his fingers arise from his bro-ken bones, so active finger exercises will cause small move-ments of his muscles inside the cast, and promote union.Tell him to do up his own buttons, to feed himself, and todo anything he can with his hands.

GIVE THE CAST A FLATTENED CROSS SECTION

COMPLETE FRACTURES OF THE MIDDLE THIRDOF THE RADIUS AND ULNA

If you can refer the patient to an expert for open reduction,do so.

CAUTION! If there is: (1) much swelling, or (2) weaknessof finger movements, suspend the patients arm from a dripstand using metacarpal traction (Fig. 70-13), or skin traction(70.10), until these signs have subsided. If he is uncon-scious, apply metacarpal traction until he recovers.

Anaesthetize him. Ketamine is satisfactory (A 8.2). Findan assistant. If a spicule of bone has punctured his skin,wash and dress it before attempting reduction.

Find two assistants.

SETTING A MIDSHAFT FRACTUREOF THE RADIUS AND ULNA

forearm partapplied first

clove withknots

operator kneeling with hishands along the cast

patient anaesthetisedwith ketamine

Fig. 73.10: SETTING A MIDSHAFT FRACTURE OF THE RADIUSAND ULNA. The forearm part of the cast is being applied while a slingand weight are applying traction to the upper arm. Kindly contributed by JohnStewart and Peter Bewes.

If the patient is already in metacarpal traction, leave iton until you have completed the cast.

If he is not in metacarpal traction, use a bandage andclove hitch knots to suspend his thumb and middle fingerfrom a drip stand, so that you can later pass a plaster ban-dage across his palm.

Lie him horizontally close to the edge of the table. Adjustthe height of the drip stand, so that his forearm is vertical,with his elbow flexed at 90 well clear of the table.

If any overlap remains, reduce it by applying a sling anda weight of 5 kg or more to his upper arm. Or, ask your as-sistant to press downwards on his arm, or to hold his elbowand pull it downwards.

Except in very fat, muscular, or swollen arms, you shouldbe able to feel when the fragments are aligned. Tractionusually reduces any overlap, but if it does not, proceed asfollows.

If the patient is an adult, increase the deformity by angu-lating the fragments, getting them to hitch, and then straight-ening them, as in Fig. 73-13.

If he is a child, perfect end to end apposition is not nec-essary, and some overlap is acceptable.

CAUTION! If you fail to correct the angular or rotationaldeformity in an adult or a child, loss of pronation and supine-tion may follow.

APPLY A LONG ARM CAST When the arm looks andfeels good, apply the cast. Apply the forearm part of thecast first, with the sling and weight still attached to the pa-tients upper arm to steady his elbow. First, apply a singlelayer of wool to his arm, then put cotton wool pads over thebony points round his elbow. These will make the cast morecomfortable, and make rehabilitation easier.

Use cold water to make the plaster set slowly. First applya cast from the patients knuckles to his lower axilla. Apply itwith his forearm in that position of rotation in which reductionis most easily obtained. Preferably apply it in midpronation,so that if rotation is limited later, it will be in the most useful

7

73 The forearm

range. Bring the cast as far as the IP joint of his thumb, andhis micipalmar crease. This will help to prevent his thumbmoving and dislodging the lower fragment of his radius. Thecast must allow free movements of his fingers, and of thedistal phalanx of his thumb.

As the cast sets, squeeze it lightly between your handsfrom front to back, to flatten it slightly and to separate hisradius and ulna. Some surgeons mould anteroposteriorgrooves in the cast to separate the two bones.

Remove the sling and continue the cast to his axilla. Builda loop into the cast and support it in a sling. Later, supportthe cast with a sling through the loop.

CAUTION! ALWAYS split the cast! Do this while it is stillsoft (70.6). Make a single cut along its ulna side, from thepatients hand to his axilla. If his arm is painful, or he isunable to move his fingers, spread the cast (70.6), and treathim as described below.

Xray him immediately after reduction. If this is unsatis-factory, have one further attempt at reduction. If this fails,refer him for internal fixation.

If reduction is unsatisfactory, and you cannot referhim for internal fixation, accept the overlap and allow hisforearm to heal in midpronation, which is the position offunction. Provided his arm is in this position, he will proba-bly have reasonable function, even if there is overlap.

POSTOPERATIVE CARE Watch the circulation in his fin-gers carefully. The compartment syndrome described belowcan occur.

CAUTION! Can he move his fingers? Is passive extensionpainful?

Start shoulder and finger exercises immediately. Tell himto put his hand as far behind his head as he can. This willexercise his shoulder. Encourage him to use his hands.

Xray him at 2 weeks, and again at 4 weeks, and makesure that the rotation has remained in the position of func-tion. If necessary, correct any angulation.

You can correct mild angulation by wedging (70.7), but achange of cast is safer. If you decide to wedge it, do thiscarefully, because it can precipitate Volkmanns ischaemiccontracture. More severe angulation will need a new cast.After 4 weeks the bones will have united and it will be toolate to do any correction.

If the patient is an adult, the cast must remain intact for6 to 8 weeks. This is a long time, so it must be a good one.Examine for clinical union after 8 weeks. Gently spring hisforearm bones. If these angulate or are tender, reapply thecast. Otherwise, put his arm in a sling, and encourage himto move his elbow and rotate his wrist.

If the cast needs to be changed for any reason, such aslooseness, suspend his arm by his fingers to prevent thefracture angulating while you apply a new one.

If he is a child, keep his long arm cast on for 4 to 6 weeks,and then examine for union. He is very likely to refracture hisarm, so apply a cast for another 6 weeks. This time, applyit to his forearm only. When you remove it, put his arm in asling and encourage active movements.

DIFFICULTIES WITH MIDSHAFT FRACTURES OF THEFOREARM

If PAIN OR LOSS OF FINGER MOVEMENT DEVELOPS,split the cast if you have not already done so, spread it(70.6), and treat him as described in Section 73.7. The soft

tissue swelling may be causing ischaemia which is muchmore serious than loss of position. You can correct this laterby applying another cast.

If his FOREARM BONES WILL NOT UNITE, refer him.Reasons include: (1) sloppy plaster technique resulting infailure to immobilize his bones, (2) the failure to exercisehis fingers, (3) not getting satisfactory reduction, soft tissueinjury, or interposition and infection.

If his FRACTURED ULNA IS OPEN, there will probablybe only a spike of bone projecting through his skin. Cleanit and pull it back, or nibble it away. Toilet the wound, andsuspend his forearm with Kirschner wire traction through hismetacarpals (70.11) or skin traction on his fingers (70.10).Let his forearm hang vertically, so that the weight of his armreduces the fracture. When the wound has begun to heal,treat him as for a closed fracture.

WATCH THE CIRCULATION IN HIS HAND CAREFULLY!HE MUST KEEP MOVING HIS FINGERS!

73.9 The compartment syndrome in theforearm

If a patient with a forearm fracture suffers from the fourPspain, paraesthesiae, pallor (if he is Caucasian), andparalysis, suspect that he has developed the compartmentsyndrome and may be in danger of its sequel, Volkmannsischaemic contracture (70.4). This is more common withfractures of the forearm than it is with supracondylar frac-tures (72.8, 72.9).

The critical test is pain on passive extension of the pa-tients fingers. A normal radial pulse does not rule out ischaemia.If he cannot extend his fingers, there is compression in theanterior compartment of his forearm. If he cannot flex them,there is compression in the posterior compartment (rare). If,when you have removed the cast, the circulation and move-ment of his fingers does not rapidly return, decompress hisforearm as described below. If possible, operate within afew hours of the onset of symptoms, but if he presents late,be prepared to operate even weeks later. If his muscles feeltense, swollen, and almost woody hard, decompression isurgent. Unfortunately, in splitting the cast you will lose re-duction, so as soon as his circulation returns, apply skeletaltraction. Later, reduce the fracture again, and reapply thecast.

Occasionally, a patient with a fractured forearm has signsof the compartment syndrome even before a cast is applied.It can also follow soft tissue injuries of his forearm, espe-cially stab wounds, but sometimes even muscle contusion,as in the case below.

ASLAM (43 years) struck his forearm while waterskiing but didnot fracture it. Eight hours later it became acutely painful and hecould not extend his wrist or fingers. He consulted his neighbour,an orthopaedic surgeon, who decompressed his forearm within thehour, from wrist to elbow, as in Fig. 73-11, leaving his skin and fas-cia open. Dark swollen muscle bulged out of the wound. He wasdischarged the following morning, and his incision was closed 5days later. He recovered completely. LESSONS (1) Remember thecompartment syndrome. A happy outcome followed what mighthave been a major tragedy after a minor injury. (2) Be quick! Imme-diate decompression is imperative.

8

73.10 Fractures of the lower quarter of the radius and ulna (usually young children)

INDURATION OF THEMUSCLES IS PATHOGNOMONIC

THE COMPARTMENT SYNDROME IN THE FOREARM

If a patient in a forearm cast complains of pain, believe him,and if he has a cast on, split it, spread it, and elevate his arm.If this does not rapidly relieve his symptoms, remove it. If thesyndrome is advanced his arm will swell and become red. Ifhis symptoms do not improve rapidly, proceed as follows.

Make an incision from his medial epicondyle to the ulnarend of the flexor crease on his wrist, as in A, Fig. 73-11.Incise the fascia over his flexor carpi ulnaris, and retract thismuscle medially. Retract his superficial flexor muscles later-ally, and incise the fascia over his deep flexors. Decompresseach muscle by making a longitudinal incision through itssheath, carefully avoiding its nerve. The pale compressedmuscle tissue will bulge up gratefully, as you release thepressure in its sheath. If you have acted in time, a con-spicuous hyperaemia will follow. If you are much too late,the deep flexor muscles will be yellow and necrotic.

CAUTION! Dont cut his ulnar nerve or his ulnar artery.The nerve lies close to the artery underneath his flexor carpiulnaris, and between it and his deep flexors.

Put Kirschner wires through his second, third, and fourthmetacarpals (70.12), suspend his arm vertically, and leavethe wound open and unsutured, under a vaseline gauze ora hypochlorite dressing.

Continue to apply traction. This usually reduces the frac-ture.

ulnar nerveand artery

fascial plane

and deep flexorsbetween superficial flexor carpi ulnaris ulnar nerve and

artery

superficial flexorsmedian nerve

flexorsdeep

DECOMPRESSING THE FOREARM

A

B

C

Fig. 73.11: DECOMPRESSION FOR THE COMPARTMENT SYN-DROME showing a cross-section of the forearm with the positions of theulnar nerve and artery. After Matsen with kind permission.

Leave the fascia open. If you can close the skin easily,do so. If you cannot close the skin easily, apply a gauzedressing and attempt secondary closure 5 days later. Applya cast over the graft.

DIFFICULTIES WITH THE COMPARTMENT SYNDROME

If you have NO KIRSCHNER WIRE, decompress the pa-tients forearm, splint it with a plaster backslab, and referhim immediately.

If the SYNDROME IS ADVANCED when you decom-press his forearm, maintain a high alkaline urine output,to assist the excretion of the myoglobin released from thenecrotic muscle, and watch for renal failure (53.3).

If a CONTRACTURE DEVELOPS, apply splints to mini-mize the deformity as much as possible.

DECOMPRESSING THE FOREARM IS AN ACUTEEMERGENCY

73.10 Fractures of the lower quarter of theradius and ulna (usually youngchildren)

In this common injury a young child breaks both his bonestransversely about 4 cm above his wrist. The fracture is usu-ally greenstick, and the lower fragments angulate radiallyand anteriorly. Sometimes his ulna remains intact, and theonly Xray sign is buckling of the cortex of his radius onone side wrinkle fracture). If the fracture is complete, bothlower ragments displace behind the shafts and produce adinner fork deformity. The lower quarter of the forearmbones readily remodel, particularly in very young children,so that unless there is a significant degree of angulation, noreduction is necessary. Opinions vary as to whether youshould reduce overlap or not. If necessary you can leave it.The younger the child, the more the displacement you canaccept. See also Section 69.6 on the bony injuries of youngchildren.

FRACTURES OF THE LOWER QUARTER OF THERADIUS AND ULNA

ACCEPTABLE DISPLACEMENT This includes most green-stick fractures, especially those with any slight buckling ofthe cortex of the bone. (1) Angulation less than 30 in theplane of the wrist. (2) Lateral displacement without shorten-ing. (3) Some surgeons also accept overlap.

Protect the childs arm with a slab and a crepe bandage,put it in a sling, and start active movements immediately.

UNACCEPTABLE DISPLACEMENT (1) More than 30 ofangulation in the plane of the wrist. (2) Rotation. (3) Overlapis sometimes considered unacceptable.

In greenstick fractures anaesthesia is not essential. Incomplete fractures anaesthetize the child, preferably withketamine.

9

73 The forearm

FRACTURE OF THELOWER QUARTEROF THE RADIUS

Lateral view AP view

Fig. 73.12: FRACTURES OF THE LOWER QUARTER OF THE RA-DIUS AND ULNA usually occur in young children. There is posteriorangulation and overlap, but very little angulation in the plane of the wrist.Kindly contributed by John Stewart.

CLOSED REDUCTION OF FRACTURES OF THE LOWERQUARTER OF THE RADIUS AND ULNA

If the lower fragment of the radius is angulated, straighten it.Disregard the ulna.

If you decide to reduce the overlap, increase the an-gulation as far as possible, press on the base of the distalfragments when they are fully angulated, get the ends tohitch, and then straighten and distract them as in Fig. 73-13. Apply a long arm cast in full pronation.

Consolidation takes 6 weeks. Keep the cast on for the full6 weeks. The child may fall again and refracture his arm, soapply a forearm cast for another six weeks, and split it!

IF CLOSED REDUCTION FAILS Attempts to correct over-

BEFOREREDUCTION

GETTING THEBONE ENDSTO HITCH

AFTER REDUCTION

increase angulation

REDUCING OVERLAP

A

C

B

D

Fig. 73.13: REDUCING OVERLAP. Start by increasing the angulation,then get the ends of the bones to hitch (get their ends into contact). Finally,straighten them. Kindly contributed by Peter Bewes.

lap may fail because the pronator quadratus muscle comesbetween the bone ends. Management now depends onwhether the childs epiphyseal growth lines have closed ornot.

If the epiphyseal growth line at the lower end of thechilds radius is open, it is not important if the fragmentsare end on or not, provided you get his radius reason-ably straight. They will remodel themselves completely in2 years, so some overlap is permissable. If you fail aftertwo attempts, stop. Apply a long arm cast (73.1), and startexercises immediately.

If the epiphyseal growth line is closed, make a secondattempt at closed reduction. If this fails, refer him.

Or, you can attempt open reduction if you are experi-enced. Do this as early as you can, but before 10 days.

OPEN REDUCTION Incise the back of the childs forearmlongitudinally over the fracture, separate the muscles, openthe periosteum longitudinally, and lever the displaced frag-ments into place with any convenient instrument, such asMacDonalds dissector. Close the wound in layers, and ap-ply a backslab held in place with a crepe bandage. Take outthe stitches a week later, and apply a long arm cast as foran extension fracture of the wrist (74.2), but extending abovehis elbow with his wrist in a neutral position.

Leave the long arm cast on for 6 weeks, and then apply aforearm cast for 4 more weeks.

73.11 Fracture separation of the distal radialepiphysis (10 to 15 years)

This is the most common epiphyseal injury. The fracturepasses partly through the metaphysis of the childs radius,and partly through his epiphyseal line (Salter Harris TypeII, Section 69.6). Its lower end usually displaces and tilts ra-dially and posteriorly. There may also be a fracture of thestyloid process of his ulna, or a separation of its epiphysis.

DISPLACEMENT OF THE DISTALRADIAL EPIPHYSIS

AP view lateral viewtrinangularligament

Fig. 73.14: FRACTURE SEPARATION OF THE DISTAL RADIALEPIPHYSIS is the most common epiphyseal injury. A more typical ap-pearance is that in N, and O, Fig. 69-7, which shows the fracture linepassing partly through the metaphysis of the childs radius, and partlythrough his epiphyseal line (Salter Harris Type II).

10

73.11 Fracture separation of the distal radial epiphysis (10 to 15 years)

Fortunately, if you reduce the epiphysis, subsequent disabil-ity is rare.

CHIBWE (7 years) had a minor fracture separation of his distalradial epiphysis. When he was first seen there was no displacementor swelling. A circular cast was applied and he was sent home.Next day he returned complaining of pain and stiff fingers. He wasgiven aspirin and again sent home. Three days later he returnedwith a gangrenous hand and his forearm muscles sloughing underthe cast. His forearm was amputated. LESSONS (1) Always splitall circular casts on fresh fractures. (2) Where possible use slabs. (3)Take painful casts seriously. (4) Think Volkmanns!

FRACTURE SEPARATION OF THE RADIAL EPIPHYSISGive the child ketamine or a general anaesthetic.

If his radial epiphysis is displaced dorsally, press it firmlyforwards into place. There is no need to exert traction, be-cause his epiphysis is not impacted. It will hinge forwards onhis intact dorsal periosteum, which will prevent over correc-tion. Apply a well moulded cast extending above his elbowwith his forearm pronated and his wrist ulnar deviated andslightly flexed. As always, split it (see the sad story above!).Leave it in place for 3 weeks.

His epiphysis may redisplace, so Xray his wrist at shortintervals. If it displaces, refer him for internal fixation.

The prognosis is good, even if there is slight residual an-gulation after reduction.

11

The forearmIntroductionIsolated fractures of the shaft of the ulnaFractures of the proximal third of the ulna, with dislocation of the head of the radius (Monteggia's fracture)Fractures of the shaft of the radius with dislocation of the lower radio--ulnar joint (Galeazzi's fracture)Isolated midshaft fractures of the shaft of the radiusMidshaft fractures of the radius and ulnaGreenstick midshaft fractures of the middle third of both forearm bonesComplete fractures of the middle third of both forearm bonesThe compartment syndrome in the forearmFractures of the lower quarter of the radius and ulna (usually young children)Fracture separation of the distal radial epiphysis (10 to 15 years)