EXAMINER: Please describe the radiographic findings (Figure 17.1a and 17.1b).

CANDIDATE: These are posteroanterior (PA) and lateral radiographs of the wrist that show an extra-articular distal radius fracture. On the PA view, the radial height and inclination are maintained. On the lateral view, there is dorsal comminution with dorsal angulation of the distal radius. The radiographs also showed thumb carpometacarpal arthritis.

EXAMINER: These are the radiographs of an 83-year-old lady. What are the acceptable parameters for conservative management of distal radius fracture post manipulation in A&E?

CANDIDATE: There are several parameters that I would use to judge the adequacy of reduction for distal radius fracture radiologically. I would look at the overall alignment of the distal radius including less than 10° dorsal angulation of the distal radius articular surface; if this was an intra-articular fracture then less than 2 mm gap or step off, radial length within 2 mm of the ulna length, radial inclination of 21°, and no secondary carpal malalignment.

EXAMINER: The on-call registrar has kindly reduced this fracture in A&E under haematoma block. The position in below-elbow plaster post closed reduction at 1 and 2 weeks follow-up in the fracture clinic was acceptable. Please comment on these radiographs taken at 6-week follow-up in the fracture clinic following conservative management of the distal radius fracture (Figure 17.1c and 17.1d).

CANDIDATE: These are posteroanterior (PA) and lateral radiographs of the wrist in a plaster that show extra-articular distal radius fracture. On the PA view, there is loss of radial height and inclination. On the lateral view, there is dorsal angulation of the distal radius with a carpal malalignment.

EXAMINER: What would you do now?

CANDIDATE: I would inform the patient that the fracture has slipped and healed in a less-than-ideal position. I would warn her that there may be some reduction in range of wrist movement and possible activity-related wrist pain. Despite this setback, we would be hopeful she would make a good recovery from her injury. I would arrange urgent physiotherapy in order to maximize her rehabilitation. I would review her progress in clinic in 6 weeks with repeat radiographs.

EXAMINER: The patient asks why the fracture wasn’t fixed surgically.

CANDIDATE: I would explain that the fracture has been in an acceptable position but unfortunately moved, possibly as the swelling in the hand subsided. I would emphasize that conservative management where possible is the best treatment option as it avoids the risks of both anaesthetic- and surgical-related complications. I would mention to the patient the complications that could occur with volar locking plate fixation including infection, painful scar, tendon rupture/irritation, injury to neurovascular structures such as the median nerve and radial artery, screw cut out and hardware failure, carpal tunnel syndrome, secondary fracture displacement and chronic regional pain syndrome (CRPS).

COMMENT: Don’t forget to mention CRPS as a possible complication from any type of hand surgery undertaken.

EXAMINER: That’s assuming you would have treated this fracture with a volar locking plate and not K-wire fixation, but we’ll not go there.

COMMENT: The management of displaced distal radius fractures is controversial. A recent meta-analysis showed no significant difference between patients who underwent internal fixation and conservative management for displaced distal radius fractures (UK DRAFFT). Several other studies have demonstrated no difference in outcome between K-wire fixation and volar locking plate fixation. The aim of the viva was to focus on the management of a complication from trauma, i.e. painful distal radius malunion, and the examiner didn’t wish to take the viva in the direction of discussing the evidence for different treatment options for distal radius fixation.

EXAMINER: The patient comes back in 8 weeks and now complains of difficulty performing her daily tasks due to the wrist deformity. What would you offer her at this stage?

CANDIDATE: I would like to take a detailed history and examination of the wrist. If the patient had ulnar-sided wrist pain and due to shortening from the distal radius malunion, I would offer her a correction osteotomy of the distal radius using a volar locking plate through an extended flexor carpi radialis (FCR) approach. The fixation is supplemented with an autologous bone graft from the iliac crest. The FCR approach utilizes the interval between the radial artery and the FCR tendon. An incision is made directly along the tendon sheath of the FCR followed by ulnar retraction of the FCR to protect the median nerve. The pronator quadratus muscle is then elevated subperiosteally from the radial volar cortex, and brachioradialis insertion released. I would use an image intensifier throughout the procedure to ensure adequate correction of the deformity. I would immobilize the wrist in a short arm plaster for 2 weeks for wound healing. At 2 weeks I would change it to a future-type wrist splint to allow mobilization of the wrist once the plaster is removed, 4 times a day, and take a check X-ray at 6 weeks to confirm bony union (Figure 17.1e and 17.1f).

COMMENT: Another scenario: a patient with distal radius fracture treated non-operatively came back at 8 weeks with persistent pain, swelling and erythema. Radiographs show the fracture has united in a satisfactory position, but osteopenia is noted in the distal radius.

EXAMINER: How would you approach this patient?

CANDIDATE: I would like to take a thorough history and examination of the wrist. My main concern for this patient is development of chronic regional pain syndrome.

EXAMINER: What is chronic regional pain syndrome?

CANDIDATE: Chronic regional pain syndrome (CRPS) is contingent on the presence of regional pain combined with autonomic dysfunction, atrophy and functional impairment affecting musculoskeletal, neural and vascular structures. CRPS is divided into two types:

EXAMINER: How do you confirm the diagnosis?

CANDIDATE: CRPS is principally a clinical diagnosis based on the patient’s history and physical examination. There are no specific tests to confirm CRPS. The clinical presentations of CRPS can be divided into acute and chronic.

EXAMINER: How are you going to treat the patient?

CANDIDATE: After confirming the diagnosis of CRPS, I would manage this with a thorough explanation of the diagnosis and likely treatment course. I would ensure adequate analgesia, urgent physical and psychotherapy. I will make an urgent referral to the pain team. Other treatments that may be considered include sympathetic nerve block and medical treatment (local anaesthesia, anti-epileptics and anti-depressants).

EXAMINER: What does the photograph (Figure 17.2a) show?

CANDIDATE: This is a clinical photograph of the right hand with the thumb in an abnormally flexed posture at the interphalangeal (IP) joint.

EXAMINER: The patient has recently come out of plaster for a distal radius fracture. What is the likely pathology?

CANDIDATE: This is usually caused by rupture of the extensor pollicis longus (EPL) tendon at the level of the Lister’s tubercle in the third dorsal extensor compartment at around 6–8 weeks. EPL rupture usually occurs after an undisplaced or minimally displaced distal radius fracture. The severity of the fracture is not indicative of the likelihood of EPL rupture. It occurs in about 1% of cases secondary to either attrition or ischaemia. Callus formation around the healed fracture site leaves a roughened surface over which the tendon attrition occurs, leading to rupture.

The other theory is microvascular disturbance secondary to increased pressure present in the non-ruptured tendon sheath with compromised blood supply to the tendon causing degeneration and rupture. It can be thought of as a type of compartment syndrome occurring in the tendon tunnel from fracture bleeding leading to interruption of tendon blood supply, nutrition and eventual rupture. With a more extensive fracture the tendon tunnel is breached and there is no build up of pressure.

EXAMINER: How would you test for EPL rupture?

CANDIDATE: The patient would be unable to extend the IP joint of the thumb.

EXAMINER: I would not rely on testing for thumb IP extension as the EPB tendon inserts into the extensor apparatus of the thumb at varying levels and may be able to extend the IP joint of the thumb. Any other tests you would perform?

CANDIDATE: I would ask the patient to lift their thumb off a table, which is not possible without an intact EPL tendon.

EXAMINER: Can you describe the extensor tendon compartments at the wrist?

CANDIDATE: There are six compartments in which the extensor tendons cross the dorsum of the wrist with contents as below:

First dorsal compartment (site of De Quervain’s tenosynovitis):

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  Extensor pollicis brevis (EPB) – attaches to base of proximal phalanx.

  
  
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  Abductor pollicis longus (APL) – attaches to thumb metacarpal.

Second dorsal compartment (intersection syndrome):

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  Extensor carpi radialis brevis (ECRB) – attaches to middle finger metacarpal.

  
  
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  Extensor carpi radialis longus (ECRL) – attaches to the index finger metacarpal.

Third dorsal compartment (passes around Lister’s tubercle):

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  Extensor pollicis longus (EPL) – passes around Lister’s tubercle of radius and inserts on distal phalanx of thumb.

Fourth dorsal compartment (contains PIN on the floor of this compartment):

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  Extensor indicis proprius (EIP) – lies deep to EDC tendon.

  
  
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  Extensor digitorum communis (EDC) – no direct attachment to proximal phalanx, attaches to the extensor expansions.

Fifth dorsal compartment (approach to DRUJ through floor of the fifth compartment):

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  Extensor digiti minimi (EDM) – attaches to extensor expansion of little finger.

Sixth dorsal compartment:

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  Extensor carpi ulnaris (ECU) – attaches to base of little finger metacarpal.

EXAMINER: How do you manage EPL rupture as in this case?

CANDIDATE: I would like to take a full history and perform a clinical examination. I would like to perform a functional assessment of the affected hand to determine the functional loss and deformity from the EPL rupture. If the patient has significant functional loss or deformity from the EPL rupture (reduced span or finds thumb catches when grasping objects), then I would request an ultrasound to confirm the diagnosis and check clinically for an intact EIP. At this stage I would refer the patient to a hand surgeon for surgical reconstruction. The EPL would have retracted and would not be repairable. This would need reconstruction with tendon transfer, normally extensor indicis proprius to restore extension movement of the thumb.

EXAMINER: What is the role of ultrasound scan in EPL rupture?

CANDIDATE: Sonography is to confirm the diagnosis of an EPL tendon rupture.

EXAMINER: You are the hand surgeon, how many incisions would you use? Can you show it on my hand?

CANDIDATE: Three incisions are needed – a 1-cm transverse incision dorsal to the index finger metacarpal head (EIP lies ulnar to the EDC tendon), a 3-cm midline dorsal incision proximal to the wrist to bring the divided EIP tendon proximal to the extensor retinaculum, a zig-zag incision over the thumb metacarpal to identify EPL tendon distal to the rupture. The extensor indicis is sutured to the remnant of the EPL tendon distally using the Pulvertaft weave technique (Figure 17.2b).

EXAMINER: How do you test for extensor indicis preoperatively?

CANDIDATE: Point the index finger with the middle to little fingers fully flexed (this prevents EDC acting).

EXAMINER: What are the basic principles of tendon transfer?

CANDIDATE: Principles when deciding on tendon transfers are:

1. 
   

   1. The donor tendon must match the muscle strength.

   
   
2. 
   

   2. The force of donor tendon should be proportional to muscle cross-sectional area.

   
   
3. 
   

   3. Work capacity = force × amplitude.

   
   
4. 
   

   4. Amplitude should be proportional to length of the muscle.

   
   
5. 
   

   5. Motor strength will decrease one grade after transfer.

   
   
6. 
   

   6. Appropriate tensioning of the donor tendon.

   
   
7. 
   

   7. Appropriate excursion of donor tendon (can adjust with pulley or tenodesis effect).

The other requirements include patient compliance, no joint contractures, no active infection and grade 5/5 power on MRC scale (this will drop one grade after transfer).

COMMENT: The other variant of this question is if an extensor tendon rupture has occurred following volar locking plate fixation. Typically, this would be a comminuted displaced intra-articular fracture treated with volar locking plate. Tendon rupture occurs possibly due to screw or drill penetration of the third extensor compartment. One of the locking screws could be overlong, penetrating the dorsal cortex.

EXAMINER: How will you minimize the risk of extensor tendon rupture following volar locking plate fixation?

CANDIDATE: The surgeon should choose the appropriate length of screw to avoid penetration of the far cortex causing tendon irritation and rupture. The use of smooth locking pegs or tines rather than sharp-tipped self-tapping screws can also decrease the risk of tendon rupture. A ‘skyline’ view can be taken to confirm appropriate locking peg length (Figure 17.2c).

EXAMINER: Are there any other causes of EPL rupture?

CANDIDATE: EPL rupture can occur secondary to rheumatoid arthritis, bony spur developing after a scaphoid fracture, misplaced external fixator pin and steroid injection.

EXAMINER: Please describe this X-ray (Figure 17.3a).

CANDIDATE: This is a posteroanterior view of the left hand showing transscaphoid perilunate fracture–dislocation. There are breaks in Gilula’s lines, and fractures of the radial styloid and scaphoid. I would like to confirm my radiological diagnosis with a lateral view of the wrist.

EXAMINER: Here it is (Figure 17.3b).

CANDIDATE: This lateral radiograph shows a perilunate dislocation with dorsal dislocation of the carpus. This is a greater arc injury and stage III on the Mayfield classification. Mayfield classification has divided this injury into four sequential stages.

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  Stage I – scapholunate dissociation.

  
  
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  Stage II – lunocapitate disruption (capitate dislocates).

  
  
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  Stage III – lunotriquetral disruption (‘perilunate’).

  
  
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  Stage IV – lunate dislocation from lunate fossa (usually volar).

This classification describes the stages of disruption of the lunate found when the wrist is hyperextended, pronated and ulnar deviated. Initially, the radioscaphocapitate ligament and the scapholunate interosseous ligament rupture, then the capitolunate joint dislocates as the injury progresses. This is followed by lunotriquetral interosseous ligament rupture and finally the lunate dislocates through the space of Poirier. This is a greater arc injury with bony involvement of the radial styloid and/or scaphoid. Lesser arc injuries refer to purely ligamentous wrist injuries.

EXAMINER: What is the difference between perilunate dislocation and a transscaphoid perilunate dislocation?

CANDIDATE: A perilunate dislocation is where there is dorsal displacement of all carpals except the lunate which stays in place. A transscaphoid perilunate dislocation is the same injury but with an associated scaphoid fracture.

EXAMINER: How would you like to proceed with this patient?

CANDIDATE: Assuming that ATLS has been performed in the initial management and life-threatening injuries have been excluded, I would like to proceed and take a thorough history including hand dominance, occupation and mechanism of injury. I would examine the hand, looking for deformity, swelling, open wound, perfusion status and check for median nerve symptoms. This would need to be reduced as an emergency in theatre with an image intensifier as prolonged dislocation increases swelling to the area and is associated with a higher rate of nerve injuries. Chinese finger traps can be used to help in the reduction by applying longitudinal traction. The sequence of reduction is by extending the wrist, applying direct pressure onto the lunate with the thumb and then palmar flexing the wrist to complete the reduction. I would confirm the reduction with image intensifier and apply a short arm plaster afterwards. I would admit the patient for high elevation with Bradford sling and hourly monitoring for compartment syndrome.

EXAMINER: You have been successful in performing the closed reduction. How would you proceed now?

CANDIDATE: I would request an MRI scan to confirm the extent of injury as part of preoperative planning. The patient would need to have open reduction and internal fixation of the scaphoid and reconstruction of the scapholunate and lunotriquetral ligaments through a volar or dorsal wrist approach. This should preferably be performed by a hand surgeon.

The dorsal approach is favoured by many as it provides access to the midcarpal joints so that intrinsic ligaments can be repaired. The incision is centred over the Lister’s tubercle. A V-shaped flap is created along the edge of the dorsal intercarpal ligament and the dorsal radiocarpal ligament. This can be satisfactorily closed post fixation.

The volar approach is via an extended carpal tunnel approach. The benefit of this approach is that it allows fixation of the volar capsule and decompression of the carpal tunnel. However, it does not allow the same exposure as found in the dorsal approach. A combined approach can also be undertaken. K-wire fixation is still routinely used. Scaphoid fractures are generally fixed with a headless compression screw. Stabilization of the lunate and reconstruction of the scapholunate ligament are frequently performed using suture anchors (Figure 17.3c).

EXAMINER: What is the expected outcome following this injury?

CANDIDATE: Patients should be counselled following this injury that there is a high risk of long-term problems of pain, stiffness and post-traumatic arthritis (36%). Carpal instability is also linked with this injury. Scapholunate instability and chronic perilunate dislocation can be treated with proximal row carpectomy or total wrist arthrodesis. Both of these result in reduced range of movement in the wrist, which can be unsatisfactory for the active patient.

EXAMINER: What is the normal scapholunate angle?

CANDIDATE: The average scapholunate angle is 45° (abnormal if < 30° or > 60°).

EXAMINER: What is the ‘spilled tea-cup sign’ (Figure 17.3d)?

CANDIDATE: The spilled tea-cup sign describes abnormal volar displacement and tilt of a dislocated lunate on a lateral radiograph of the wrist. The convexity of the lunate is no longer congruent with the lunate fossa of the distal radius, while the concavity is no longer in articulation with the capitate head on a lateral wrist radiograph. It is an important sign to help differentiate lunate dislocation from perilunate dislocation. In perilunate dislocation, the lunate remains in articulation with the distal radius and therefore does not appear to ‘spill’ forward.

EXAMINER: You saw a 44-year-old patient in the fracture clinic with the above radiographs 2 days following an injury. Please comment on these radiographs (Figure 17.4a and 17.4b) and how you would manage this patient.

CANDIDATE: The radiographs taken show a scaphoid waist fracture. I would take a thorough history and examination of the hand and wrist. I would like to know the handedness, occupation, hobbies and previous similar injury in the history. I would like to examine the wrist for swelling and tenderness over the anatomical snuffbox and see further lateral and oblique views. If these confirmed the fracture was undisplaced, I would manage this non-operatively in a short arm cast without thumb immobilization for 6 weeks initially. A randomized prospective study published by Dias et al. has shown no evidence to support thumb immobilization in the treatment of scaphoid fracture [1]: 292 patients with scaphoid fracture were randomized to receive either Colles cast (forearm gauntlet) or scaphoid cast incorporating the thumb as far as its interphalangeal joint in the study. The incidence of non-union at 6 months follow-up is independent of type of cast used. The healing rate for conservative treatment is 80–90% for undisplaced waist of scaphoid fracture.

EXAMINER: What is the blood supply to the scaphoid?

CANDIDATE: The major blood supply of the scaphoid bone is distally based derived from branches of the radial artery entering the dorsal ridge. Between 70% and 80% of the intraosseous vascularity and the blood supply to the entire proximal pole enters this way with no blood vessels penetrating the cortex of the proximal pole separately, explaining the higher rate of avascular necrosis with proximal pole fractures [2,3].

EXAMINER: What are the indications for internal fixation of the scaphoid?

CANDIDATE: The indications for internal fixation of scaphoid fracture include displacement of more than 1 mm, intrascaphoid angle > 20° (humpback deformity), delayed union, proximal pole fracture or scaphoid fracture associated with perilunate dislocation.

The indications for internal fixation of the scaphoid remain debatable. A systematic review and meta-analysis performed in 2010 concluded that there is currently insufficient evidence to make definitive conclusions on the indications for, or effectiveness of, operative versus non-operative management of acute scaphoid fractures [4]. Some evidence does suggest acute fixation of minimally displaced or undisplaced fractures in high-level athletes and manual workers to have a better functional outcome in the short term [5,6].

EXAMINER: These are the patient scaphoid radiographs at 4 months follow-up in the fracture clinic (Figure 17.4c and 17.4d). He remains symptomatic. What would you do?

CANDIDATE: The scaphoid radiographs shown non-union of the waist of scaphoid fracture with sclerosis at the fracture site. If the patient remains symptomatic, I would offer the patient surgical fixation of this non-union. I would like to request a computed tomography (CT scan) to confirm the diagnosis of non-union, which forms part of preoperative planning. I would offer the patient bone grafting and surgical fixation with a headless compression screw through either a volar approach if the CT scan confirms a humpback deformity, or the dorsal approach if there was no carpal malalignment. The ideal position for a headless compression screw should be down the central axis of the scaphoid for maximal compression and fixation.

The volar approach to the scaphoid utilizes the FCR as an anatomical landmark with incision extended 2 cm proximal to the scaphoid tubercle with the distal incision directed towards the base of the thumb. The FCR sheath is then opened as distally as possible and retracted ulnarly to protect the radial artery and retracted radially to expose the capsule. Capsulotomy is then performed through a longitudinal incision from the volar lip of the radius to the proximal tubercle of the trapezium to expose the scaphoid. The capsule and intracapsular ligaments are carefully divided and reflected off the scaphoid. The capsule needs to be preserved as it contains the radioscaphocapitate ligament, which needs to be repaired if possible at the end of the procedure. The bone graft can be harvested either from the distal radius or iliac crest.

The dorsal approach is the preferred technique for proximal pole scaphoid fractures. The dorsal approach to the scaphoid utilizes Lister’s tubercle as an anatomical landmark with an incision over it and extended distally as desired. The structure at risk is the superficial radial nerve branch. The extensor retinaculum is identified and incised, taking care to protect the EPL. The EPL is then retracted radially to expose the capsule. Capsulotomy is then performed to expose the scaphoid.

EXAMINER: The patient has heard about percutaneous fixation techniques. What will you say to the patient?

CANDIDATE: Percutaneous fixation techniques are suitable for minimally displaced or undisplaced scaphoid fractures that allow earlier mobilization without adverse effects on healing. Haddad reported the results of 15 patients with minimally displaced or non-displaced scaphoid fractures treated percutaneously using a volar approach, traction and a cannulated screw [7]. The early rigid fixation of scaphoid fractures allows early mobilization, patients were allowed movement soon after operation. Union was achieved in all at a mean of 57 days. The range of movement after union was equal to that of the contralateral limb and grip strength was 98% of the contralateral side at 3 months. Patients were able to return to sedentary work within 4 days and manual work within 5 weeks. Results of the study showed percutaneous scaphoid fixation permitted a rapid functional recovery.

EXAMINER: What are the complications of percutaneous fixation techniques?

CANDIDATE: The complications of percutaneous fixation techniques can be divided according to the approach being used, either the volar or dorsal approach. The complications through the volar approach include damage to the FCR, radial artery and suboptimal position of screw placement (the trapezium tends to block the path of the guide wire). The complications of the dorsal approach include damage to the PIN, EPL and EDC. Possible complications for both approaches include guide wire breakage, prominence of the screw (through the subchondral bone), bleeding, infection and chronic regional pain syndrome.

EXAMINER: If the fracture fails to unite after a period of conservative management and goes into non-union, what are the other surgical options?

CANDIDATE: The surgical options for non-union depend on the blood supply to the proximal pole and the presence or absence of osteoarthritis. Magnetic resonance imaging (MRI) of the scaphoid may help in preoperative planning to determine the vascularity and avascular necrosis (AVN) of the scaphoid. Open reduction internal fixation with a headless compression screw using a corticocancellous bone graft can be used in the absence of AVN and higher success rates are seen in more distal fractures [8]. Where AVN is present, a vascularized bone graft can be considered. There are various options available for re-vascularizing the proximal pole, including a vascularized pedicled bone graft or potentially a vascularized periosteal patch onlay graft, although this technique has demonstrated disappointing union rates [9].