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ch-74_wrist

VIEWS: 10 PAGES: 9

									                                                                                                                       CHAPTER 74




                                                                                                                                The wrist




74.1 Introduction                                                   sprained, so that a ’sprain’ is more likely to be a fracture
                                                                    of the scaphoid or of the triquetrum. Fractures of the tri-
One of the ways in which we use our hands is to protect             quetrum are difficult to see in an X–ray, so they are seldom
our bodies from falling. Our outstretched hands are very            diagnosed. Fortunately, they heal spontaneously.
good at doing this, but in doing so our wrists are particu-           Occasionally the wrist can become dislocated on the forearm.
larly likely to get hurt in a variety of ways, which depend         Reduce the dislocation immediately by exerting traction in
on how old we are. This chapter is entirely concerned with          the long axis of the forearm and hand.
these injuries.
                                                                    EXAMINING THE WRIST
0–5 years A young child usually has a greenstick fracture
of the lower third of his radius, and sometimes of his ulna         Observe the patient’s wrist for swelling and deformity, and
also (73.7). If his injury is severe, he may break both his         feel for warmth and tenderness.
forearm bones transversely just above his wrist (73.10).
                                                                    Dorsiflexion Ask him to put the palms of his hands to-
5–10 years In an older child fractures of the lower quarter         gether, as in a position of prayer, and then to raise his el-
of the radius and ulna are more often complete (73.10), and         bows. This will let you compare the dorsiflexion in his wrists.
the fragments may overlap.
                                                                    Palmar flexion Ask him to put the backs of his hands to-
10–15 years A child of this age typically has a fracture            gether and to depress his elbows. This will allow you to
separation of his distal radial epiphysis (73.11).                  compare palmar flexion in his wrists.

Adults An adult is liable to two major groups of fractures          Other movements Ask him to tuck his elbows into his
at the lower ends of his forearm—those caused by hyperex-           sides. How far can he pronate and supinate them and devi-
tension (common) of his wrist, and those caused by hyper-           ate them in a radial or ulnar direction?
flexion (unusual). These are most easily distinguished in a
lateral X–ray.
                                                                                    EXTENSION AND FLEXION
   (1) Hyperextension fractures comprise: (a) The common                                 FRACTURES
hyperextension (Colles) fracture in which the fracture line
                                                                                          FLEXION             EXTENSION
runs across the lower end of the radius parallel to the artic-                                                FRACTURE
                                                                                          FRACTURE
ular surface, with the distal fragment displaced posteriorly.
(b) The much less common posterior marginal fracture in
which the fracture line enters the joint. (c) Sometimes the                                        distal end of
distal fragment of the radius is comminuted.                                                       radius now
   (2) Hyperflexion fractures are rare. A lateral X–ray shows                                       angulated
                                                                                                   posteriorly
the fracture line running obliquely across the distal end of
the radius. In (a) Smith’s fracture, it does not enter the joint,
but in (b) Barton’s fracture, it does.
                                                                       Smith’s fracture                                       comminuted
   There is also a group of minimal fractures, including frac-                                                                Colles fracture
tures of the radial styloid in which manipulation is rarely
needed, and which you can immobilize as for a hyperexten-
sion fracture.
   Falling on an outstretched hand occasionally causes in-          Fig. 74.1: FLEXION AND EXTENSION FRACTURES. In an extension
juries of the carpal bones: (1) The distal row of carpal bones      fracture the normal volar angulation of the distal articular surface of the
can dislocate on the proximal row (intercarpal dislocation,         wrist shown in Fig. 74-3 is reduced or reversed. In this particular flexion
74.5), or (2) the lunate can dislocate. The wrist is seldom         fracture (Smith’s) the fracture line does not enter the wrist joint.



                                                                                                                                                1
74 The wrist


  CAUTION! Have you examined his elbow? He may also                            (C) Ask him to clench his fist and deviate it radially. Per-
have a fracture of the head of his radius.                                   cuss the head of his middle metacarpal. This is painful when
                                                                             his scaphoid is fractured. There may also be tenderness
                                                                             over the knuckles of his index and middle fingers, but none
SIGNS FOR PARTICULAR FRACTURES OF THE WRIST
                                                                             over those of his ring and little fingers.
Extension fractures (Colles fractures) Look at the back
of the patient’s wrist. Put the tip of one of your index fingers              Carpal dislocation Both carpal dislocations (intercarpal
into the gap between his radial styloid and his wrist. Put the               dislocation and dislocation of the lunate) produce a painful,
tip of your other index finger into the gap between his ulnar                 swollen, Immobile wrist. In addition, if a patient’s lunate is
styloid and his wrist. This will show you the position of the                dislocated, he may have any of these four special signs.
two styloids clearly. The radial styloid is normally distal to the              (1) Is there tenderness and an abnormally deep hollow
ulnar one. It is displaced proximally in an extension fracture.              on the back of his wrist just distal to his radius, in line with
Its replacement is a useful sign of adequate reduction.                      his first finger? Normally, the lunate occupies this hollow. If
   Examine both his wrists as if you were feeling his radial                 the lunate is dislocated this hollow is deep and abnormally
pulses. Has the normal concavity in front of his injured ra-                 tender.
dius been filled out by a tender haematoma?                                      (2) Ask him to clench both his fists. Compare their backs.
   Is there a dinner fork deformity of his wrist? This is only               If his middle metacarpal looks slightly shorter, his lunate may
present if backward displacement is gross, and is also seen                  be dislocated (or his middle metacarpal may be fractured).
in fractures of the lower quarter of the radius and ulna in                     (3) Feel the volar aspect of his wrist, between his thenar
children.                                                                    and hypothenar eminences. If this is tender, and slightly full
                                                                             compared with the opposite side, his lunate may be dislo-
Flexion fractures (Smith’s and Barton’s fractures) Ask                       cated. Percuss the fullness. This may produce paraesthesia
him to hold out his arm. Is his hand displaced anteriorly on                 in distribution of his median nerve.
his forearm, as in Fig. 74-7?                                                   (4) Examine his median nerve (75.3). A dislocated lunate
                                                                             may paralyse it, or produce numbness and tingling.
Fractures of the scaphoid (74.4) Three signs for this                           X–RAYS The routine views are an AP and a lateral. If
fracture are shown in Fig. 74-2.                                             you take a lateral view routinely you will not confuse flexion
   (A) Hold the patient’s hand with your left hand, and put                  and extension fractures. If you suspect a fracture of the sca-
the tip of your finger in the normal depression just distal to                phoid, ask for oblique views. A lateral view is the easiest one
the end of his radius, between the two extensor tendons of                   in which to see displacements of the lunate, and the oblique
his thumb (his ’anatomical snuffbox’). His scaphoid will be                  view gives you another opportunity to see a fracture of the
directly under it. Deviate his hand towards his ulna, and                    scaphoid. These three views can usually be taken on the
press. If he winces, he has probably fractured his scaphoid.                 same film.
The radial nerve passes over the snuffbox, and having this                      CAUTION! If you suspect a scaphoid fracture, but the X–
pressed can also be painful, so compare both sides care-                     ray is negative, repeat it in 7 to 10 days.
fully. Occasionally, there is mild swelling in the anatomical
snuffbox.
   (B) Does moving the patient’s wrist cause him pain only at                 COMPARE HIS INJURED WRIST WITH HIS NORMAL ONE
the extreme of its range?


THREE SIGNS FOR                           A   PRESSURE OVER THE              74.2 Extension (Colles) fractures
                                              ANATOMICAL SNUFFBOX
SCAPHOID FRACTURES
                                                                             These are the most common human fractures. The patient
                                                                             falls on his outstretched hand, he hyperextends his wrist,
    B   PAIN ONLY
        ON EXTREMES
                                                                             he fractures the lower end of his radius, and he sometimes
        OF MOVEMENT                                                          fractures the tip of his ulnar styloid in one of the following
                                              hand in ulna deviation
                                                                             three ways. In all of them he complains of a swollen wrist,
                                                                             and of the signs described in Section 7.1.
                                   C   PAIN ON PERCUSSION THE HEAD
                                                                                (1) In the classical extension fracture he has a single trans-
                                       OF THE MIDDLE METACARPAL
                                                                             verse fracture about 2 cm from the lower end of his radius,
                                               hand in radial                which does not involve the surface of his wrist joint. The
                                               deviation
                                                                             distal fragment is in one piece, shifted dorsally, tilted dor-
                                                                             sally and radially, and impacted on the shaft. In the devel-
                                                                             oping world these fractures are seen in adults of any age,
                                                                             and are not typically injuries of older women as they are
                                                                             elsewhere.
                                                                                (2) In a T–shaped fracture the fracture line extends distally
Fig. 74.2: THREE SIGNS OF A SCAPHOID FRACTURE. A, a patient’s                into the wrist joint, and divides the distal fragment into two.
’anatomical snuffbox’ is the hollow between the tendons on the radial side
of his wrist when his thumb is extended. Pressure here is painful if his        (3) In a comminuted fracture the distal fragment is in
scaphoid is fractured. B, pain only at the extremes of movement is typical   many pieces.
of a scaphoid fracture. C, hit him with a patellar hammer over the head of      X–rays are highly desirable, but not absolutely essential.
his middle metacarpal and see if he feels pain.                              You need them to make sure that the patient has not also got


2
                                                                                                                                74.2 Extension (Colles) fractures



A NORMAL                                                                                   if there is any displacement, the distal fragment will be dis-
LEFT WRIST                                                                                 placed backwards in an extension fracture, and forwards in
                                                                                           a flexion one.
                                                                              capitate 3      If a fracture is impacted in a reasonably good position
                                                                                           with only moderate shift, and less than 15◦ of dorsal an-
                                      trapezioid 2                           hamate 4      gulation, don’t try to reduce it. Leaving it alone will let it
                                      trapezium 1                          pisiform 8      heal faster, and will avoid the risk of anaesthesia. It will en-
                                                                                           able active movements to start earlier and thus reduce stiff-
                                                                         triquetral 7
                                           scaphoid 5                                      ness. Reducing a more severely displaced fracture is usu-
                                                              lunate 6
                                                                                           ally easy, but applying a cast in a way that will prevent the
                                                                                           fragments slipping is not so easy, so follow the instructions
                                                                                           carefully. Poor reduction is more often due to putting on
                                                                                           the cast badly, than to manipulating the fracture incorrectly.
                                                                                           Radial instead of ulnar deviation of the distal fragment is
                                                                                           the common mistake. Prevent this by making sure the pa-
                                                                                           tient’s hand is in moderate ulnar deviation when you apply
                                                                                           the cast. Two methods of reduction are described; the dis-
                                                                                           advantage of the first one is that it takes a little longer.
                          2
                      1       3   4
                                       7     8
                          5
                                  6                                                            FULL PRONATION WITH MODERATE FLEXION AND
                                                  23°                                                  MODERATE ULNAR DEVIATION
                                                        11°




                          AP view                                  lateral view            EXTENSION (COLLES) FRACTURES OF THE
                                                                                           WRIST
Fig. 74.3: IN AN X–RAY OF THE NORMAL WRIST: (1) the lunate has
a four–sided appearance, (2) the articular surface of the head of the radius
                                                                                           IF THE DISTAL FRAGMENT IS COMMINUTED OR
is angled forwards about 11◦ and medially about 23◦ . The tip of the radial                T–SHAPED
styloid should be about 2 mm distal to the tip of the ulnar styloid. These
relationships are important in deciding if an extension fracture has been                  If there is less than 15◦ of dorsal tilt and comminution is
adequately reduced or not.                                                                 mild, apply a volar splint for protection and to relieve pain.
                                                                                           Encourage the patient to start active movements of his fin-
                                                                                           gers immediately.
a fractured scaphoid, or some other injury of his carpus. If                                   If displacement or comminution is moderate or se-
you are not sure what fracture he has, rely: (1) on the nature                             vere, management depends on his age. If he is young,
of the injury (flexion or extension) and remember that, (2)
                                                                                           THE POSITION OF IMMOBILISATION FOR
                                                                                           AN EXTENSION FRACTURE       This is the position of the
 A COMMINUTED EXTENSION FRACTURE                                                                                                                 needle for anaesthetising
                                                                                                                                                 the fracture haematoma
                                                                                                              CAUTION! avoid
                                                                                                              full ulnar deviation

                                                                                             MODERATE
                                                                                             ULNAR
                                                                                             DEVIATION




                                                                                                           FULL
                                                                                                           PRONATION




                                                                                                                                     CAUTION! avoid
                                                                                                                                     full flexion




  lateral view, the                                                                            MODERATE
                          AP view before reduction,            AP view after
  distal surface                                                                               FLEXION
                          the normal distal projection         reduction, the
  of the radius           of the radius beyond the             distal projection of
  is angulate             ulna has been lost                   the radius has
  dorsally                                                     been restored               Fig. 74.5: THE WAY TO MAINTAIN REDUCTION IN AN EXTEN-
                                                                                           SION FRACTURE is to apply the cast in full pronation, in moderate flex-
Fig. 74.4: A COMMINUTED EXTENSION FRACTURE with consid-                                    ion and in moderate ulnar deviation. In this position the extensor tendons
erable displacement. If the patient with this X–ray is old, treat him with                 passing over the back of the distal fragment hold it reduced. Extreme flex-
active movements. If he is young, try to reduce it by out of the two methods               ion or extreme ulnar deviation will cause a stiff wrist. The needle shows
described in the text.                                                                     the position for entering the haematoma for local anaesthesia.



                                                                                                                                                                         3
74 The wrist


attempt reduction as described below. If he is oId, apply            fractures, forearm slabs are enough.
a backslab for a few days, and then encourage active move-
ments as soon as pain allows.
   If the distal fragments are in only two pieces and look           SECOND METHOD FOR REDUCING AN EXTENSION
as if they could be fixed internally, refer him if you can,           FRACTURE OF THE WRIST
especially if he is young.                                           The following description assumes that the patient has a
   If active immediate movements are indicated but pain              fracture of his right wrist.
is too great to allow them, apply an anterior plaster slab              Anaesthetize him and lie him down.
or a backslab for about 3 weeks, until the pain has lessened
                                                                        DISIMPACTION Ask an assistant to hold the patient’s arm
enough to allow the patient to begin using his wrist. If pos-
                                                                     just above his elbow.
sible, hold the slab in place with crepe bandages. Remove
                                                                        Hold his fingers in one of your hands and his thumb in the
the slab for periods of exercise and then reapply it. If you
                                                                     other.
have no crepe bandages, use a plaster bandage, and split it
                                                                        Exert traction on his fingers and thumb (1) while your as-
(70.6).
                                                                     sistant pulls his elbow in the opposition direction (2). The

IF THE DISTAL FRAGMENT OF THE RADIUS IS IN ONE
PIECE                                                                REDUCING AN EXTENSION FRACTURE
                                                                                                                    you exerting
IF THERE IS MINOR DISPLACEMENT of the distal frag-                                                                  traction
                                                                             assistant exerting
ment, with less than 15◦ of dorsal tilt, don’t reduce it. Apply              counter traction
a slab to the front of the patient’s arm and wrist and start
active movements, as above, as soon as the pain allows.                                        DISIMPACTION                            1
   IF THERE IS MORE SEVERE DISPLACEMENT with
more than 15◦ of dorsal angulation of the distal fragment,
or the patient is in severe pain, or there are signs of pres-                              2                                you can feel
sure on his median nerve, reduce the fracture immediately,                                                                  the fragments
                                                                                                                            disimpacting
as follows.
   ANAESTHESIA (BOTH METHODS) (1) Local anaesthe-                                          your right
sia of the fracture haematoma is very effective if the fracture                            hypothenar
                                                                                                              4
                                                                       REDUCTION           eminence                         5
is recent (A 5.6). its disadvantages are that: (a) it converts
a closed fracture into an open one, with the possible risk
of infection, and (b) it does not relax the muscles. Using                                                              3

careful aseptic precaution, insert the needle on the back of                                                                        Now hyperextend
the patient’s forearm well above his wrist. Aim the needle                                                                          your left wrist as
                                                                                                                                    you press on the
obliquely, as in Fig. 74-5, so that it enters the fracture cavity;                                                                  distal fragment
                                                                                                                                    and force it
aspirate to make sure you are in the haematoma, then inject                                                                         downwards and
                                                                                                        6                           ulnarwards all in
10 ml, not more, of 2% Iignocaine without adrenaline and
                                                                                                                                    one movement
wait 15 minutes. (2) Intravenous forearm block (A 6.19). (3)
Supraclavicular block (A 6.17). (4) Axillary block (A 6.18).
                                                                                                        7

FIRST METHOD FOR REDUCiNG AN EXTENSION
                                                                           corners cut off slab                                 9
FRACTURE OF THE WRIST                                                                                         cotton
                                                                                                              bandage
Lie the patient down. Suspend his arm from a drip stand,                      wet slab bandaged in place
using clove hitches (Fig. 73-10) round his thumb, and index
or middle finger. Put a strap round his upper arm, and apply
5 kg traction to it.
   Wait 10 minutes while the traction corrects the impaction.                                                                   8
At the end of this time the distal fragment will usually be free
                                                                             while the slab is hardening
and you can move it into position with the minimum of effort.                apply the same grip as above
   Apply anterior and posterior plaster slabs. Suspension will
have secured a suitable degree of moderate ulnar deviation,
                                                                                     10
so you have only to make sure that you apply the plaster in
moderate flexion and full pronation.
   Don’t let the anterior slab come further than the patient’s
distal palmar crease. Make sure the tip of his thumb can
touch his index finger.
   If possible, hold the slab in place with a crepe bandage. If
you don’t have a crepe bandage, pad his arm and hold the             Fig. 74.6: REDUCING AN EXTENSION FRACTURE. This is the sec-
                                                                     ond of the two methods described in the text. Disimpact the fracture in
slabs in place with a plaster bandage. Split this while the          steps 1 and 2. Reduce it in steps 3, 4, and 5. The critical movement is 5 in
cast is still damp.                                                  which the distal fragment is moved into a position of moderate flexion and
   If the fracture is unstable, continue the cast up his upper       moderate ulnar deviation, all in one movement. Hold the patient’s fingers
arm with the elbow at 90◦ . For stable or minimally displaced        and thumb as in 8 and 9 while your assistant bandages on the slab.



4
                                                            74.3 Flexion fractures of the wrist (Smith’s and Barton’s fractures)


younger he is the stronger the pull you need. Pull steadily         DIFFICULTIES WITH EXTENSION FRACTURES
for a minute timed by the clock. You will feel the fragments
disimpact, and will sometimes hear them do so.                      If the patient’s fracture has united, but his WRIST IS DE-
   CORRECT THE DEFORMITY Abduct his forearm, stand                  FORMED with an ugly radial deformity, pain, and limited ro-
with your back to him, and pronate his wrist.                       tation, you can refer him for excision of the head of his ulna,
   Put your left thenar eminence (3) over the displaced dis-        together with 2 cm of its adjacent shaft (Darrach’s opera-
tal fragment, with your fingers and thumb round the ulnar            tion). This is a simple procedure with good results, so it is
border of his wrist.                                                better than trying to remanipulate a badly reduced extension
   Put your right hand beneath his distal forearm with your         fracture with radial deviation. The pain over the head of his
right hypothenar eminence just proximal to the fracture line        ulna will eventually improve, but it may last a year.
(4). Curl the fingers of your right hand round his lower fore-          If he IS SUDDENLY UNABLE TO EXTEND HIS THUMB
arm.                                                                some weeks or months after the accident, he has proba-
   Using your right hypothenar eminence as a fulcrum, move          bly ruptured the tendon of his extensor pollicis longus. This
the lower fragment into a position of moderate flexion and           sometimes happens suddenly long after the accident. Refer
moderate ulnar deviation all in one movement (5).                   him to have it repaired.
   If the ulnar styloid is fractured, disregard it.
   IMMOBILIZE THE FRAGMENTS Apply a plaster backslab
(6) with its corners cut (7) to allow movement of the patient’s     74.3 Flexion fractures of the wrist (Smith’s
elbow, fingers, and thumb.                                                and Barton’s fractures)
   While your assistant bandages on the slab, hold the pa-
tient’s fingers in one hand (8) and his thumb in the other (9).      In these two fractures the patient falls on his flexed wrist to
Lean backwards, exert gentle traction, and his wrist will fall      produce the characteristic deformity shown in Fig. 74-7, in
into moderate ulnar deviation.                                      which his hand is displaced anteriorly on his forearm. In a
   While the slab is still soft, move back to the inner side of     lateral X–ray, the fracture line runs obliquely across the dis-
the arm, and apply the same grip as you used to correct the         tal end of his radius, instead of being parallel to its articular
deformity (10), but without applying any pressure. Allow the        surface, as is usual in an extension fracture. Also, the dis-
plaster to set while you maintain this grip.                        tal end of the radius is displaced anteriorly in contrast to the
   CAUTION! (1) Make sure his wrist is fully pronated, mod-         posterior displacement of an extension fracture. In a Smith’s
erately flexed, and moderately ulnar deviated. (2) His MP            fracture the fracture line does not extend into the joint, but
joints must be free. If the slab extends too far distally it will   in a Barton’s fracture it does. In both the fragments are dif-
splint them in extension, and give him a stiff useless hand.        ficult to reduce and hold in place. Although these two frac-
   CHECK X–RAYS The AP view should show that you have               tures should be easy to diagnose, they are so rare that they
corrected the alignment.                                            are often mistaken for extension fractures.
   The lateral view should show that the articular surface of          In Barton’s fracture the fragments can seldom be held in a
the patient’s radius is no longer facing dorsally. It should be     cast, so that open reduction and plating is usually necessary,
facing 5 to 10◦ anteriorly, but a strictly vertical position is     but in Smith’s fractures closed reduction may succeed. The
acceptable. If reduction is unsatisfactory, have one further        fragment is displaced anteriorly, so that the patient’s wrist
attempt at manipulation. if you make further attempts in your       must be held in dorsiflexion, and his hand supinated (the op-
efforts to get a good X–ray, the clinical result will only be       posite to an extension fracture). If you treat either of these
worse.                                                              fractures badly, the loss of wrist movement will be severe.

POSTOPERATIVE CARE FOR AN EXTENSION
FRACTURE (both methods)                                             A FLEXION
                                                                    FRACTURE
Put the patient’s arm in a triangular sling, with his elbow         (Barton’s)
flexed at more than 90◦ . If his fingers become painful, tell
him to return immediately, or to split the bandage with a pair
of scissors. Encourage him to move his fingers, elbow, and
shoulder actively, using the exercises in Fig. 71-7. Early
shoulder movements are especially important because they
will prevent the common complication of a stiff shoulder.
   In a few days, or at the next fracture clinic, complete the
cast around his forearm.
   Where possible, X–ray him again 7 to 10 days later, so
that if redisplacement has occurred, there will still be time to
correct it. This is important in a younger patient, but if an
older patient’s fracture redisplaces, leave it, and encourage
active movements.

A young adult Keep the cast on for 6 weeks.
                                                                    Fig. 74.7: A FLEXION FRACTURE OF THE WRIST. The fracture
An old adult Remove the cast after 3 weeks, and encour-             shown here is Barton’s, in which the fracture line enters the wrist joint.
age him to move his wrist.                                          Kindly contributed by Peter Bewes.



                                                                                                                                            5
74 The wrist


FLEXION FRACTURES OF THE WRIST                                                  74.4 Fractures of the scaphoid

If the fracture involves the articular surface (Barton’s frac-                  These can occur at any age, even in children, but they are
ture), refer the patient for internal fixation. If you cannot refer              particularly common in young men. The patient falls on his
him, treat him as for a Smith’s fracture described below.                       hand and forcibly dorsiflexes the joint between the proximal
  SMITH’S FRACTURE Use local anaesthesia as for an ex-                          and distal rows of his carpal bones. The scaphoid, which
tension fracture. Ask an assistant to apply traction in the                     forms part of both rows, breaks across its distal pole, or its
axis of the patient’s forearm.                                                  neck.
                                                                                  Fracture of the distal pole (tuberosity) of the scaphoid is
   While traction is being applied, supinate and dorsiflex his                   a minor injury, because the detached fragment has a good
wrist fully. Apply a plaster slab to the front of his forearm,                  blood supply and unites readily. Treat this fracture by en-
from just above his elbow to the proximal crease of his palm,                   couraging early active movements.
and bind it on with a crepe bandage. Or failing this, pad his                     Fracture of the neck of the scaphoid is a more common
forearm and hold the slab on with a circular plaster bandage,                   and more serious injury, because non–union is frequent. The
split it, as for an extension fracture.                                         patient’s wrist is normal, except for pain at the extremes of
    Take an X-ray to see if the fracture is reduced.                            movement, and local tenderness in the anatomical snuffbox
  If the fracture is reduced, complete the cast on the third                    over his scaphoid. He may complain that his wrist contin-
day; encourage him to use his hand, and keep his shoulder                       ues to hurt after a ’sprain’, but because the pain is so mild, he
moving. Remove the cast after 6 weeks.                                          may continue to use his hand, with the result that this frac-
                                                                                ture is often missed. The signs in Section 74.1 should make
  If the fracture is not reduced, have one more attempt at
                                                                                you suspect the diagnosis, particularly pain on pressing the
reduction. If this fails, refer him for internal fixation immedi-
                                                                                ’anatomical snuffbox’.
ately.
                                                                                  Take an AP, a lateral, and two oblique X–rays at 30◦ and
                                                                                60◦ . The fracture line is a fine crack in the neck of the sca-
                                                                                phoid which you can easily miss. Look for it on a dry film
DIFFICULTIES WITH EXTENSION FRACTURES                                           in a good light with a magnifying glass. If there is clinical
                                                                                evidence of a fractured scaphoid, but the X–ray is negative,
                                                                                apply a scaphoid cast and take another film after removing
If the DISTAL FRAGMENT SLIPS, it will do so anteriorly
                                                                                the cast 7 to 10 days later. The fracture line will then be much
and proximally, but this may not interfere with function. If the
                                                                                more obvious. If clinical signs are strongly suggestive, but
slipping is significant, refer the patient for the application of
                                                                                the X–ray is still negative, assume that the patient has a sca-
a plate.
                                                                                phoid fracture, and treat it.
                                                                                  Neither fragment is significantly displaced, so they need
                                                                                not be reduced, but they do need to be splinted. If they are
    TWO FLEXION FRACTURES                                                       going to unite successfully: (1) splinting must be prolonged
              SMITH’S                             BARTON’S

                                                                                FRACTURES OF THE SCAPHOID




                                                                                                                                    fracture of
                                                                                                                                    the tuberosity


                                                                                                                                 fracture of
                                                                                                                                 the neck




         fracture line does                   fracture line
         not enter joint                      enters joint
                                                                                Fig. 74.9: FRACTURES OF THE SCAPHOID can occur at any age, even
Fig. 74.8: TWO KINDS OF FLEXION FRACTURE. In Smith’s fracture                   in children, but they are particularly common in young men. The patient
the fracture line does not enter the joint, but in Barton’s it does. Barton’s   falls on his hand and forcibly dorsiflexes the joint between the proximal
fracture should be referred for internal fixation. If this is impossible, you    and distal rows of his carpal bones. Fractures of the neck are much more
will have to treat it in the same way as Smith’s.                               important than those of the distal pole.



6
                                                                                                                     74.5 Carpal dislocations


for 10 weeks, (2) the cast must be close fitting (there must be                     APPLYING A SCAPHOID CAST Put a stockinette tube
no movement at the mid–carpal joint), and (3) the cast must                     over the patient’s lower arm and hand. Skilled surgeons
go above the elbow.                                                             usually apply an unpadded circular cast. If you are inex-
   Non–union is the main difficulty with these fractures.                        perienced, apply a thin layer of cotton wool.
This may be due to: (1) a poorly applied cast which allows                         Apply the cast from above the patient’s elbow to just above
movement at the mid–carpal joint, (2) interrupted splinting,                    his knuckles. Bring it just proximal to his distal palmar
(3) splinting for too short a time, or (4) aseptic necrosis of                  crease. Hold his elbow at 90◦ . Dorsiflex his wrist, and bring
the proximal fragment, especially if it is small. All ban-                      his thumb across his palm as if he were holding a glass.
dages and casts for the scaphoid, except the one we have                        The plaster on his thumb should reach just short of its IP
described, are almost certainly useless, so whenever you ap-                    joint. Mould it firmly round his first metacarpal.
ply a scaphoid cast, do so as in Fig. 74-10.                                       As soon as the cast is on, and before it has set, grasp his
                                                                                hand, so as to squeeze the cast from front to back, as in
                                                                                D, Fig. 74-10. Squeezing the cast like this will prevent his
                                                                                hand moving and straining the fracture line. If he can flex or
 IF THE X–RAY OF A SPRAINED WRIST’ IS NEGATIVE, BUT                             extend his wrist even a little, the cast is useless. His wrist
      SYMPTOMS PERSIST, REPEAT IT 10 DAYS LATER                                 will not swell, so don’t split the cast. ncourage him to use
                                                                                all the joints outside the cast. This will soon make it soft, so
                                                                                renew it as necessary.

FRACTURE OF THE NECK OF THE SCAPHOID                                            THE POSTOPERATIVE CARE OF A SCAPHOID
In 15% of cases the patient has some other injury, so exam-                     FRACTURE
ine his wrist carefully. Anaesthesia is unnecessary.                            At 6 weeks, renew the cast, but this time bring it below the
                                                                                patient’s elbow. At 10 weeks, remove the cast and take an-
                                                                                other X–ray.
A SCAPHOID CAST                                                                    If his fracture has united, allow him to use his wrist pro-
                                                                                gressively.
                                         A                                         If his fracture has not united, proceed as follows.
                                                                                   (1) If wrist movements are very important to him, refer
                                                                                him. If you cannot refer him, apply another cast for 3 more
                                                                                weeks. Twelve weeks in a cast is the maximum time. If you
                   cast should go                                               leave it on longer than this, his wrist will become excessively
                   above the elbow
                                                                                stiff and osteoporotic.
                                                                                   (2) If wrist movements are less important to him, remove
                   B                 C                     D                    the cast, and allow a false joint to form. Often, there are no
                                             his thumb                          symptoms, even if the fragments fail to unite.
                                             must be
                                             able to
                                                                                   (3) If, later, he continues to have unacceptable disability,
                                             touch                              refer him for bone grafting, or removal of the avascular frag-
                                             his
                                             index                              ment.

                                                                                DIFFICULTIES WITH A FRACTURED SCAPHOID

                                                                                If the fracture has NOT UNITED and the PROXIMAL
                                                                                FRAGMENT LOOKS VERY DENSE on the X–ray, it has
                                                                                probably undergone avascular necrosis. It can be excised,
                                                         grip the cast firmly   but the operation is difficult. If you cannot refer him, encour-
                                                         while it sets          age him to disregard his disability and use his hand as much
                                                                                as he can.
                                                                                   If you have NO PLASTER, aim for a pseudarthrosis and
                                             Can he do this when you
                                             have finished the cast?            start active movements immediately.

                               E                                        F
                                                                                REGARD A SPRAINED WRIST IS A FRACTURED SCAPHOID
                                                                                            UNTIL PROVED OTHERWISE




                                                                                74.5 Carpal dislocations

Fig. 74.10: A SCAPHOID CAST. Note that it goes above the patient’s              In these rare injuries, the patient falls on his hand and dor-
elbow, that it ends just proximal to his distal palmar crease and the inter-    siflexes his wrist violently, so that the second row of carpal
phalangeal joint of his thumb, and that his thumb is able to touch his index    bones dislocates on the first row. His lunate remains in its
finger. Adapted from Perkins with kind permission.                               normal place in the proximal row, and in its normal place in


                                                                                                                                              7
74 The wrist


TWO CARPAL DISLOCATIONS                                                          between the lunate and the scaphoid, as shown in B, Fig.
                                                                                 74-12.
     NORMAL                 INTERCARPAL                    DISLOCATION OF           The methods for reducing both these injuries are similar.
                            DISLOCATION                    THE LUNATE
                                                                                 The first step is to exert strong traction on the patient’s hand.
                                                                                 In an intercarpal dislocation, press over the back of his wrist
                                                                                 and then flex it. In a dislocation of his lunate, press over the
                                                                                 front of his wrist and then extend it.

                                                                                 INTERCARPAL DISLOCATION
                                                                                 Anaesthetize the patient. Bend his elbow to 90◦ , and se-
                                                                                 cure his upper arm to the table with a bandage, as in C, Fig.
                                                                                 74-12. Supinate his forearm, and ask an assistant to pull
                                                                                 strongly on his fingers for 10 minutes.
                                                                                    While your assistant is maintaining very strong traction,
                                                                                 place both your thumbs against the back of the patient’s
    the carpus is in          the carpus has shifted        the carpus and the   wrist. Push forwards, and at the same time slowly flex his
    the same plane as         poseriorly, and the lunate    radius are in the
    the radius                is only slightly displaced    same plane again,
                                                                                 wrist (not illustrated).
       POSTERIOR                                            the lunate lies         Take an X–ray to make sure you have not dislocated his
       ANTERIOR                                             anteriorly


Fig. 74.11: TWO CARPAL DISLOCATIONS. A, a normal wrist. B,                       DISLOCATION
the carpus has been pushed backwards leaving the Innate in its normal
position in relation to the radius (intercarpal dislocation). C, the carpus      OF THE                                 A
has sprung forwards and displaced the radius anteriorly.                         LUNATE
                                                                                                                             B
relation to the radius. Sometimes the injury stays like this so
that he has an intercarpal dislocation. But, if the distal row of
carpal bones now springs forwards again, it may push his
lunate forwards, out of its position in the proximal row, and                         traction
away from its normal relation with the radius. He now has                                  1
an anterior dislocation of his lunate. Rarely, the lunate dislo-
cates posteriorly.
   These dislocations are important, because you can usually
reduce them. If you don’t, severe disability follows, and the                                                               abnormally wide space
greater the delay, the worse it becomes. Exactly the same                                      C                            between the scaphoid
                                                                                                                            and the lunate
kind of injury fractures the scaphoid, so in injuries of the
lunate, always look for a fractured scaphoid. Distinguishing
between these two lunate injuries clinically can be difficult.                                                                              D
The lateral X–ray is the critical one.



          LOOK CAREFULLY AT THE LATERAL X–RAY
                                                                                                                             press
                                                                                                                               2
                                                                                                 counter traction

74.6 Intercarpal dislocation (perilunate
                                                                                            3                       E
     dislocation)
                                                                                          dorsiflex
This makes the patient’s wrist swell. Neither he nor you
can move his wrist, and its antero–posterior diameter is in-
creased. His styloid processes are in their normal places. His
radial pulse and the concavity of the lower end of his radius
are normal, and you cannot localize tenderness anywhere.
   The X–rays are difficult to interpret. Take a lateral view
and compare it with one of his normal wrist. In an inter-
carpal dislocation the lunate is more or less in its normal
place in relation to the radius, and is facing in its proper di-
rection, but its distal cup–shaped articular surface is not in
contact with the dome–shaped surface of the capitate. In-                        Fig. 74.12: REDUCING A DISLOCATION OF THE LUNATE. You
stead, the patient’s hand and his carpus lie in a plane pos-                     may find it easier to pull with the patient’s arm horizontal and provide
terior to his radius. This dislocation is less easy to see in an                 counter–traction by fixing his upper arm to the head of the table. After de
AP view. A useful sign is an increase in the normal space                        Palma with kind permission.



8
                                                                                                      74.7 Dislocation of the lunate


lunate by mistake. Look carefully to make sure that he has          DISLOCATION OF THE LUNATE
not also fractured his scaphoid. If reduction fails, refer him.
                                                                    Try to reduce a patient’s lunate as soon as you can, before
  POSTOPERATIVE CARE If he has not fractured his sca-
                                                                    his median nerve is permanently injured. Every few hours
phoid, apply a splint for 2 weeks to allow some healing, then
                                                                    make a difference. After 2 weeks, closed methods usually
encourage active movements immediately.
                                                                    fail.
  If he has fractured his scaphoid, apply a scaphoid cast,
                                                                        CLOSED REDUCTION Give the patient a general anaes-
and split it. In a few days, when swelling has subsided, re-
                                                                    thetic that will relax the muscles of his arm completely. Bend
place it with an unsplit cast.
                                                                    his elbow to 90◦ and fix his upper arm with a bandage to the
                                                                    table as in Fig. 74-12.
DISASTER WITH AN INTERCARPAL DISLOCATION                                Supinate his forearm, and ask an assistant to pull strongly
                                                                    on the patient’s fingers for 10 minutes (1).
If the DIAGNOSIS WAS MISSED, this may be because no-
                                                                        After 10 minutes of traction and while it is still being main-
body listened to what the patient said. If he says "There is
                                                                    tained, place both your thumbs against the front of the pa-
something wrong with my hand"; believe him, even though
                                                                    tient’s wrist over his lunate, and press hard posteriorly (2)
his X–ray seems normal. If the dislocation was overlooked
                                                                    while dorsiflexing his wrist (3). Then flex his wrist while keep-
at the time of the injury, refer him for open reduction. If this
                                                                    ing up traction and pressure (not illustrated). If this fails, refer
is not possible, his wrist movements will remain limited and
                                                                    him for open reduction. If this is impossible, encourage early
painful.
                                                                    active movements. If he is lucky, he may have comparatively
                                                                    little disability.
74.7 Dislocation of the lunate                                          POSTOPERATIVE CARE If his scaphoid has been frac-
                                                                    tured, apply a scaphoid cast. If it has not been fractured, en-
This is the second stage of an intercarpal dislocation. The         courage active movements from the start, and splint it only
displaced distal row of carpal bones springs back and ro-           for the relief of pain. Irritation to his median nerve will im-
tates the lunate forwards. As it does so, the posterior radio–      prove quickly after you have replaced his lunate.
lunate ligament ruptures, but the anterior one remains in-              Alternatively, hang 5 kg of traction round the patient’s up-
tact. The displaced lunate presses on the patient’s median          per arm, as for the first method for an extension fracture
nerve, and if it is not replaced, he may lose the function in it    (74.2) of his wrist. Then try to manipulate his wrist.
permanently.
   The patient falls and injures his wrist, after which it is
swollen and painful, and he can can only move it a little.
                                                                    IN AN X–RAY OF THE WRIST LOOK FIRST AT THE LUNATE
His fingers remain partly flexed, and will not straighten. He
may have any of the four signs in Section 74.1.
   In a lateral X–ray, the proximal dome-shaped surface of
the patient’s lunate faces posteriorly, and is no longer in con-
tact with his radius. Its distal cup–shaped surface faces ante-
riorly, and is no longer in contact with his capitate. His capi-
tate and the carpus are in the same plane as his radius. Signs
in the AP view are characteristic, but are often missed. The
normal lunate appears to have four sides in an AP view, but
when it is dislocated, it seems only to have three. So look for a
triangular lunate. Look also for a widened space between the
scaphoid and the lunate. Normally they touch. Dislocations
of the lunate are so easily missed that the lunate is the first
bone to look at in any X–ray of the wrist.




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