Fracture Handbook - Wrist Fractures

CARPAL INJURIES

Introduction:
There is a wide spectrum of carpal injuries, from minor to complex.  Many carpal injuries are benign needing little or no immobilisation.  The scaphoid fractures present some of the greatest dilemmas in management of hand fractures.  The complex carpal injuries generally need an operation, by an experienced hand surgeon, and although emergency provisional reduction is important for any dislocation, the definitive open procedure does not typically need to be performed as an acute emergency.

1. Isolated Carpal Injuries:

a.  Dorsal capsular avulsion
This frequently follows a fall on the outstretched hand, “FOOSH”.  The radiographs show a small avulsion fragment, usually of the triquetrum although it can be very difficult to tell on radiographs.  The treatment is splintage for comfort for 4 – 6 weeks expecting an excellent outcome.  Physio should not routinely be required.

b.  Trapezium
These are rare.  They follow a FOOSH.   Basal thumb metacarpal fractures have the same mechanism of injury, and may occur at the same time. 
i. Undisplaced
They are immobilised in a “scaphoid” cast (below elbow including thumb proximal phalanx) for 4 -5 weeks, then mobilised.
 
ii. Displaced with 2/3 large fragments
Fixation is closed with 2-3 1.1mm K wires or open via a Moberg approach.  If reduction is open use screw fixation (1.5 mm diameter or headless) if possible to avoid wires through the skin. Alternatively, K wires should be buried. and left for at least 6 weeks.

iii. Comminuted
These require traction on the thumb metacarpal for ligamentotaxis as for the comminuted base of thumb metacarpal fractures (see section …), preferably with 2 x 1.6mm K wires from the thumb metacarpal to the index metacarpal. This may need supplementation with closed K wiring or open reduction fixation with wires or preferably screws and possibly bone grafting. (Technical tip: the wire is drilled into the thumb metacarpal, strong traction is applied by an assistant or Chinese finger traps and the wire passed into the index metacarpal through the volar radial cortex and into but NOT THROUGH the far cortex.  This can be felt and confirmed with an Image Intensifier.  If the far cortex is breached there is a high incidence of wire migration and the wire should be repositioned). It is a compromise between early mobilisation and risking loss of position.  The use of the less stiff fixation of 2 x 1.6mm K wires helps this.  Thumb IP joint movement should be maintained whilst the CMC joint is immobilised. Traction can also be applied though an mini external fixator between the thumb and index metacarpals for 5-6 weeks.  This is more rigid but is much bulkier and stiffer which is a disadvantage.  It also makes post-operative radiography of the trapezium more difficult to interpret.

c. Trapezoid
This is a very rare injury.  It typically follows a longitudinal compression force such as a punch.  The trapezoid is usually comminuted.  It is difficult to interpret the radiograph of the carpus.  The most obvious feature is the proximal migration of the IF metacarpal.  Further information is required from CT scan.  Treatment is along the same principles as the trapezium:
i Displaced with 2/3 large fragments:
We have never seen this but in principle if minimally displaced it can be treated non-operatively with POP immobilisation for 4 weeks. If displaced significantly fixation would be closed with K wires or open via a dorsal longitudinal approach.  If reduction is open use screw fixation (1.5 mm diameter or headless). Traction should be tried first (see below) as reduction of the trapezoid may be adequate.  Articular congruity is not so important as there is little movement at the index carpo-metacarpal joint and fusion is a reasonable fallback option if the outcome is poor, but we have never needed to do this even as a late presentation..

ii Comminuted:
These require traction on the index metacarpal alone. Combined traction and ORIF is rare.  The index metacarpal is pulled out to length and held with 2 x 1.1 mm K wires from the Index metacarpal to the Middle metacarpal.  (Technical tip: the wire is drilled across the index metacarpal, traction applied and the wire passed into the radial cortex of the middle metacarpal and into but NOT through the far (ulnar) cortex.  This can be felt and confirmed with an Image Intensifier.  If the far cortex is breached there is a high incidence of wire migration and the wire should be repositioned).  This construct is protected in a POP whilst the wires are in for 5-6 weeks (slightly longer than usual, as stability is more important than mobility).  Finger MCP and IP joint movement should be maintained whilst in POP.


d.  Capitate
Like the triquetrum, this is most commonly fractured as part of a greater arc injury.  Isolated capitate fractures occur typically to the waist of the capitate.  They are easily missed and if mobilised early (< 4-6 weeks) may go to non-union. 

i Undisplaced:
The wrist is immobilised in a neutral wrist POP for 6 weeks and radiographs repeated.  If there is doubt about progression to union, order an urgent CT scan and seek specialist advice.  Fixation may be necessary which can probably still be percutaneous.with a headless compression screw.

(I have an XR)

ii Displaced:
Radiographs may show a step.  More typically (especially with greater arc injuries) the proximal pole may rotate 180°, giving malalignment that is difficult to interpret radiologically and at operation.  As part of a greater arc injury this is known as the “Scapho-capitate Syndrome”.  Fixation is preferably with a headless compression screw inserted proximal to distal.  (K wires may be used particularly with fixation of other aspects of greater arc injuries).

e. Hamate
There are 2 common types of fracture: Distal articular fractures as part of a little and/or ring finger CMC joint injury; hook of hamate fracture.

i  Distal articular fractures as part of a LF/RF CMC joint injury
 They typically follow a punch injury.  The key is the articular surface.  If this is well reduced it can be immobilised and watched.  These can displace in cast, and so need careful review for 2 weeks.  If displaced they need reduction and fixation.  This is typically done closed with traction on the LF/RF metacarpal and holding the reduction with 2–3 x 1.1 mm K wires into the carpal bones and/or the metacarpals.  If a satisfactory reduction cannot be achieved closed, the fracture can be approached via a dorso-ulnar longitudinal incision, protecting the superficial sensory branches of the ulnar nerve and dissecting down between the extensor tendons.  The fracture should be reduced and held with compression screws. Traction wires should be protected in POP for 5 weeks allowing LF/RF MCP and PIP joint movement. Rigid internal fixation of the hamate should allow early mobilisation.

(I do not recall a recent case – can anyone help)

ii Hook of Hamate fracture
This is an uncommon injury and easily missed.  It usually follows a direct blow such as a fall but can follow hammering.  The presentation is often late. Plain radiographs are often normal.  Carpal tunnel views with the wrist hyper-extended or a supinated oblique fracture may show the fracture but are often difficult to achieve acutely because of discomfort.  The best investigation is a CT scan.  The fracture tends to be about 50% of the hook or all of it extending a little into the body.  The larger fragments can be fixed open with a single screw but excision is much simpler with lower risks and comparable results.  If the patient is reasonably comfortable they may elect to wait to assess the long-term.  Non-union is only a problem if uncomfortable and this is also treated with excision of the fragment.

(I have pictures of a CT somewhere)

f. Triquetrum
i. The commonest injury is an avulsion fracture following a fall (see above (a)). Non-avulsion fractures of the triquetrum are almost always part of a Mayfield greater arc injury (see below) and are treated appropriately with immobilisation if undisplaced, otherwise ORIF (see below).

(need a picture of an undisplaced gter arc injury)

g. Pisiform fracture
i. This is rare.  It is typically stellate (as in the patella), due to a direct blow, usually following a fall.  It is usually treated by splintage and early mobilisation.  We have never seen a case suitable for primary surgery.  At worst, there will be some articular malunion that could be treated late with excision of the pisiform.  The best radiographic views to visualise the fracture are carpal tunnel shoot-through view and supinated oblique view.

(I have no pictures)

h. Lunate
i. Lunate fractures, other than as part of Keinböck’s or part of a greater arc injury (see below), are very rare.   
(show pictures of type 2 and 3 Keinbocks)

 

2. Isolated scaphoid injuries:
This is a complex problem.  Excluding the complex carpal injuries (see below) there are 3 sites: tubercle (distal), waist, proximal pole; and 3 main types: undisplaced, minimally displaced, and clearly displaced.  Starting with the simplest:

a. Tubercle
i. These almost all unite, even if displaced, with minimal if any long-term problems.  They are best treated with splintage (or POP if very sore), early mobilisation and discharge with advice anticipating a good result.  Repeat radiographs are of little value and should only be used beyond 3 months or so in patients still significantly symptomatic.  In theory a painful non-union could present.  We have never seen it.

(picture of displaced tubercle fracture needed)

b. Waist

i. Undisplaced
Even undisplaced scaphoid waist fractures have a 10 -15 % chance of non-union.  There is an increasing vogue for primary acute scaphoid fixation with a percutaneous cannulated screw.  In the majority of cases this is not necessary but can be for social reasons or in the presence of other injuries.  We favour immobilisation in a scaphoid POP (acknowledging the work of Dias et al in Leicester favouring a simple wrist POP).  There is no point taking radiographs at 2 weeks when the diagnosis is clear.  The POP should be taken off at 6 weeks and the patient assessed clinically and with plain radiographs.  The default position should be return to POP for 4 – 6 weeks unless there is both minimal tenderness over the scaphoid and suggestion of progression to union on the radiographs.  If so, then a splint is worn intermittently for 2-4 weeks and only then if comfortable should they start weightbearing and contact sports.  This is a cautious approach but minimises non-unions.  The rest are reviewed out of POP at 10 – 12 weeks from injury as is convenient.  If there is significant continuing tenderness or unsatisfactory radiographs then request an urgent CT scan in the long axis of the scaphoid.  Percutaneous fixation, with percutaneous bone graft, is still an option at this stage. 
We use the Acutrak screw through a distal retrograde approach.  We immobilise them for 10 – 14 days in POP for comfort and then provided check radiographs are satisfactory mobilise with a splint and protective weightbearing for 4 weeks.  If at 6 weeks the patient is comfortable and the check radiographs are satisfactory the patient can mobilise freely.
Further work from Dias has suggested that fractures can appear united at 3 months but be ununited at 1 year.  They recommend a long-term follow-up at one year.  Our experience is that when we are sure the fracture has united we have never had a non-union at one year, but do see non-unions in other patients who have been discharged early.  If we are unsure we either progress to further investigations or fixation (see above).
 (GG has pictures of scaphoid waist undisplaced and acute fixation)

ii.  Minimally displaced:
Recent work suggests these are usually more displaced on CT scans than shown by plain radiographs.  We recommend a very urgent CT scan.  The fracture can then be classified as: “barely displaced and not comminuted” and treated as for undisplaced fractures although with a lower threshold for percutaneous fixation (some surgeons would fix all these acutely); or as displaced/comminuted fractures when we recommend Percutaneous screw fixation (see below).

(we need to look out for an appropriate set of XR’s and CT)

iii.  Displaced:
Displaced waist fractures treated conservatively have a non-union rate of 50%.  Almost all of these fractures should be fixed.  Again, we fix these percutaneously (see above).  It is usually not possible to reduce these perfectly closed.  We believe the benefits of a perfect reduction are outweighed by the risks of open surgery and the inevitable increase in scarring and stiffness and so accept some minor displacement rather than opening the fracture.  We have never seen marked scaphoid displacement except as part of a complex wrist injury (see SS  …).

c. Proximal pole injuries.
These can be very difficult to treat.  They are the most likely of the scaphoid fractures to look normal on initial radiographs.  The poor blood supply to the proximal pole fragment results in a very high rate of non-union.  Even if definitely undisplaced, there is a very good case for acute percutaneous fixation. 

i. If undisplaced, we organise a very urgent CT scan.  If still undisplaced we would discuss with the patient and recommend fixation.  If we treat this non-operatively, we would expect the patient to be in POP for 10 – 12 weeks or needing delayed percutaneous fixation.

(GG to find CS scaphoid XRs)

ii. Minimally/obviously displaced
We recommend acute percutaneous scaphoid fixation with a headless compression bone screw via a dorsal antegrade approach..


3.  Greater/Lesser Arc Injuries
These are major carpal injuries, following a high energy impact on the wrist such as a fall from a height or whilst running.  The injury is often missed as the PA radiograph is difficult to interpret and the lateral radiograph is somehow ignored.  The injury is usually obvious on the acute radiographs or in combination with post reduction radiographs.  Rarely is a CT scan required.
a. Acute treatment:
These are usually closed injuries.  If open, they should be taken to theatre for cleaning and debridement within 6 hours of injury, although the definite treatment can wait 7 -10 days.  If closed, they should be reduced, especially if there is any median neuropathy, which is very common.  This can usually be done in A&E.  Post reduction radiographs should be taken, ideally before the backslab is applied, as much better views are obtained.  The wrist can then be immobilised, finger movement encouraged, and the hand properly elevated whilst awaiting definitive treatment,.  If any symptoms of median neuropathy do not settle quickly (i.e. within 12 hours) then the median nerve requires very urgent decompression.  Definitive treatment can be undertaken then if a suitably experienced surgeon is unavailable for definitive fixation of the fracture..

b. Definitive treatment:
This is a difficult specialist operation.  Closed reduction alone may not be adequate.  Many surgeons favour open reduction and stabilisation of bone and ligament injuries. We have done this many times but increasingly favour percutaneous techniques although would not hesitate to open the wrist if we could not gain an adequate reduction.
Trans-scaphoid perilunate dislocation:
This is the “best” injury to have as the scaphoid shoid unite restoring the radial column and the triquetro-lunate ligament complex often settles reasonably. We perform a retrograde Percutaneous fixation of the scaphoid with a headless compression screw (we favour a mini Accutrak 2 screw. This seems adequate and if ther are problems could be exchanged for a standard screw). Again we aim for an anatomical reduction but this is difficult to achieve and we would accept a “good reduction” i.e. a step up to 1 mm. On the ulnar side we hold the triquetro-lunate ligamentwith 2 or 3 x 1.1 mm K wires but this does not provide compression so we now favour a compression screw across the middle of the joint inserted percutaneously from the ulnar side. A headless screw can be buried but is harder to remove (at 8 – 10 weeks). A headed screw is bulkier, but may be easier to remove and may provide better compression. We aim to close the joint to a normal joint space and hold this for 8 – 10 weeks. We immobilise the wrist in a POP for 8 weeks and then mobilise the wrist gently with a splint for support depending upon the radiographic findings. We would remove the ulnar screw under local anaesthetic as a daycase in the next 2 weeks. This is best planned well in advance.
If we needed to open the wrist this may be both volar and dorsal but this is now infrequent:
i. Volar
Longitudinal incision zig-zagging across the wrist, decompressing the median nerve, aiding reduction of the carpus and allowing repair of the volar tear in the capsule with a 2/0 absorbable suture.

ii. Dorsal
Longitudinal incision.  The extensor retinaculum is raised from the 5th to the 2nd or 3rd compartment.  The anterior and posterior interosseous nerve terminal branches are resected to reduce long term wrist pain.  The wrist is opened through the Mayo approach along the lines of the ligaments.  It needs to go well out to the ulnar side to ensure adequate access to the dorsal part of the triquetro-lunate ligament.  The carpus is reduced.  If the scaphoid is fractured it is fixed with a antegrade headless compression screw (eg. Acutrak).  (Technical tip: whilst drilling and inserting the screw the fragments may rotate.  This can be prevented by holding the reduction with 2 x 1.1mm K wires).  The S-L ligament is the hardest to repair satisfactorily.  Bone anchors can be used but the suture tends not to crimp the ligament down tightly.  Drill hole through the scaphoid or lunate are better but more fiddly.  The T-L ligament is well reinforced by the extrinsic ligament complex and seems to repair well with simple sutures or use of bone anchors/drill holes.  The repairs need protection with K wires.  There is rarely a need to cross the radiocarpal joint.  Rather 2 x 1.1mm wires can be passed from the triquetrum to the lunate and 2 x 1.1mm wires from the scaphoid to the lunate.  This is confirmed on II.  Ideally the wires should not cross as this may distract the relevant joint.  The wires should NOT breach the far side of the lunate to prevent migration.  The wires should always be buried, as they need to stay in for a minimum of 8 and preferably 12 weeks, particularly for the S-L ligament repair.  We protect them in a POP for 8 weeks and then allow some gentle wrist movement out of a splint to start to free up the radiocarpal joint. 

(many pictures needed here of greater arc injuries etc – see carpal photos file)
 

Perilunate dislocation (lesser arc injury):
This is a worse injury as the scapho-lunate ligament rarely if ever heals “normally” or close to normal. As for the triquetro-lunate ligament (see above) we have held these with K wires but would now plan a temporary compression screw fixation from the radial side as for the triquetro-lunate ligament.
If we repair the scapholunate ligament we would expect to supplement the ligament repair with some form of extra support such as a limited capsulodesis such has been our disappointment in treating these injuries. A closed Percutaneous technique has the advantage of leaving relatively scar free soft tissues suitable for a later ligament reconstruction such as a Brunelli 4 repair it the scapho-lunate repair fails.

Scaphocapitate syndrome:
This is the worst injury as the capitate fracture may not heal and then the mid-carpal joint is significantly compromised. This always requires open reduction and internal fixation primarily to address the capitate fracture which has usually displaced (typically rotated) and needs careful reduction and hoding with a compression headless screw (or 2-3 1.1mm K wires if very thin). The other carpal injuries are repaired open as above.

 
 

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