Postgraduate Orthopaedics Viva GuideFRCS (Tr & Orth) Examination
Trauma

Chapter 13 Upper limb trauma II

📄 pp. 742–774 (PDF)Book: Postgraduate Orthopaedics Viva Guide

source p. 743

Structured oral examination question 1#

source p. 744

Lunate dislocation

EXAMINER
What do these radiographs (Figures 13.1a and 13.1b) show?
CANDIDATE
These are PA and lateral radiographs of a wrist showing a lunate dislocation.
EXAMINER
What signs are there on the radiographs which point to this diagnosis?
CANDIDATE
There is disruption of Gil ulas lines on both views. The lunate can beseen siting palmarly in the carpal tunnel.
EXAMINER
What do you suppose was the mechanism of injury?
CANDIDATE
This is usually caused by high-energy trauma such as a road traffic collision or a fall from a height.
EXAMINER
Why do you infer that?
CANDIDATE
This is a hyperextension injury in ulnar deviation: aMay field stage 4. Lower-energy hyperextension injuries might result in scapholunate ligament injury. In order to dislocate the lunate, this patient must have torn the scapholunate ligament, dislocated the lunocapitate joint, torn the lunotriquetral ligament and the dorsal radiolunate ligament. The only remaining ligamentous attachments are the strong volar radiocarpal ligaments.
EXAMINER
How will you manage this injury?
CANDIDATE
This patient has sustained high-energy trauma, so first I would treat any life-threatening injuries. As regards the wrist, this is an emergency as the median nerve is likely stretched over the dislocated lunate. This needs an emergent reduction in A&E.
EXAMINER
How will you reduce it?
CANDIDATE
Before reduction I would assess and document the neurovascular status of the hand with particular attention to the median nerve. The patient needs to be relaxed and sedated. I would apply traction to the limb to stretch the soft tissues; this is best achieved using gravity and finger traps. I would then hyperextend the wrist and push the lunate back onto the radius with my thumb. Then, leaving my thumb on the lunate to prevent displacement, I would distract and flex the wrist to lift the capitate back onto the lunate. I would then reassess and document the neurovascular status, apply a below-elbow plaster backslab and obtain plain radiographs to confirm reduction.
EXAMINER
What if you can’t reduce it?
CANDIDATE
If I cannot reduce this in A&E then the patient will need to go to theatre for reduction. Ideally this should be done by someone who can proceed to definitive fixation, but reduction should not be delayed for this as it is imperative that the dislocation is reduced to protect the neurovascular structures. I would attempt a closed reduction undergeneral anaesthetic in theatre with an image intensifier, then proceed to open the wrist if I cannot achieve reduction.
EXAMINER
How will you open the wrist?
source p. 745
CANDIDATE
Palmarly first. I would do an extended carpal tunnel release which should relieve pressure on the median nerve and should enable me to reduce the dislocation, which ismy main objective. If I still cannot reduce the dislocation, I will open the dorsum of the wrist. This is done with a midline longitudinal incision centred on Lister’s tubercle. I would incise the third extensor compartment, lift EPL from its bed, then dissect into compartments 2 and 4 to reveal the dorsal carpal ligaments. I would then use a Berger flap to open the wrist joint.
EXAMINER
Can you describe the Berger flap?
CANDIDATE
This is a ligament-preserving technique for opening the dorsum of the wrist. The incision splits the dorsal intercarpal ligament and radiotriquetral ligament inline with the fibres to form a radial-based triangular flap. When elevating the flap, it is important to protect the intrinsic carpal ligaments, particularly the sc apholunate ligament which is most significant dorsally, although in this case I expect it to betorn.
EXAMINER
OK, so let’s assume you are a hand surgeon and are prepared to manage this definitively. How will you proceed?
CANDIDATE
I would first reduce the carpus, by direct means if necessary, and assess the damage. I expect the scapholunate ligament and lunotriquetral ligaments to betorn. I would need to stabilize the carpal bones in their normal orientation using K -wires as joysticks and further K-wires to transfix the carpus. Once the bony anatomy is restored, I would repair the scapholunate ligament, with a bone anchor if necessary, then return to the volar wrist wound where I would pull the contents of the carpal tunnel to the radial side to protect the recurrent motor branch of the median nerve. I would anticipate a rent in the volar capsule in conjunction with avo lar lunotriquetral ligament tear which I would repair directly with sutures. I would apply abacks lab postoperatively and emphasize the importance of elevation as these injuries t end to swell a lot.
EXAMINER
What are the long-term outcomes of this injury?
CANDIDATE
This is a severe injury and the wrist will never be normal. As longas it was treated promptly, I would expect the median nerve to make a full recovery, although this is not guaranteed and depends on the degree of primary injury. Further surgery is required to remove the K-wires at 8 weeks, then intensive physiotherapy will be required to optimize function. The wrist will likely be quite stiff (about 50% normal movement) but should be stable and strong enough to return to most kinds of work. As the joint has been injured, there is a risk of degenerative change in the long term which may require salvage surgery.
source p. 746
Figure
Figurep. 746

Figure 13.1a and 13.1b Posteroanterior (PA) and lateral radiographs, lunate dislocation.

source p. 747

References#

Capo JT, Corft SJ, Shamian B, et al. Treatment of dorsal perilunate dislocations and fr acture–dislocations using a standardized protocol. Hand (NY). 2012;7(4):380–387.

Berger RA, Bishop AT, Be tinger PC. New dorsal capsulotomy for the surgical exposure of the wrist. Ann

Plast Surg. 1995;35(1):54–59.

source p. 748

Structured oral examination question 2#

source p. 749

Jersey finger

EXAMINER
This 15-year-old boy noticed that he couldn’t flex the end of his ring finger after a rugby match. What does the radiograph (Figure 13.2) show?
Figure 13.2
Figure 13.2Figure 13.2 Lateral radiograph, ring finger.p. 751
CANDIDATE
This is a lateral radiograph of a finger with a small avulsed fragment of bone siting volar to the proximal phalanx. This is consistent with an avulsion of the FDP from the distal phalanx known as jersey finger.
EXAMINER
What is the typical mechanism of injury?
CANDIDATE
An extension force is applied to the finger while inactive flexion. This is typical of a hand that is grasping a rugby jersey which is jerked from the patient grip.
EXAMINER
What is the anatomy of the flexor mechanism to the ring finger?
CANDIDATE
There are two flexor tendons. The FDP originates from a common muscle belly on the ulna and interosseous membrane and inserts distally into a broad footprint at the base of the distal phalanx. The FDS has its origin from the medial elbow and the radius. Each tendon has its own muscle belly. The tendon splits into two and inserts into the base of the middle phalanx. The FDP passes from deep to superficial through the two slips of FDS at Camper’s chiasm.
EXAMINER
What is the innervation of these muscles?
CANDIDATE
In the ring finger, the FDP is ulnar innervated and the FDS is median innervated. The median nerve supplies all FDS and, via the AIN, the radial two FDPs. The ulnar nerve supplies the ulnar FDPs.
EXAMINER
How would you classify this injury?
CANDIDATE
According toL eddy and Packer this is a grade 2 injury. Grade 1 retracts to the palm, grade 2 to the PIPJ, grade 3 involves a large fragment which sticks at the DIPJ, and grade 4 involves an avulsed fragment of bone which dissociates from the tendon, a so-called ‘double avulsion’.
EXAMINER
In this grade 2 injury, what is preventing further proximal migration of the fragment?
CANDIDATE
The vinculae.
EXAMINER
How will you treat this young man?
CANDIDATE
I would recommend surgery to repair the avulsed tendon and restore active flexion. I would counsel him that there is a prolonged recovery period involving splintage and physiotherapy for around 3 months Alternatively, he may opt for non-operativ e management andre hab the finger with physiotherapy, accepting that active flexion will remain absent at the DIPJ. If he later finds the DIPJ unstable, he could have this fused.
EXAMINER
What other possible sequel is there of treating this non-oper ativ ely?
CANDIDATE
He may develop a lumbrical plus finger.
EXAMINER
What does that mean?
source p. 750
CANDIDATE
The origin of the lumbricalis on the FDP tendon. The function of the lumbricalis to flex the MCP joint and extend the IP joints. If the origin of the lumbrical migrates proximally such as in FDP avulsion, this applies an extension moment at the IP joints. The patient cannot actively flex the DIP joint due to the avulsion, but also struggles to flex the PIP joint with FDS due to the intrinsic tightness.
EXAMINER
What technique would you use to repair his tendon?
CANDIDATE
After proper consent and a regional or general anaesthetic, I would open the finger with aB runner incision. I would identify the avulsed tendon and deliver it through the pulley system back to the footprint. I expect I may need to vent the pulley system and would probably need to fully release A3 but would take care not to release all of either A2 or A4 as these are the key restraints to prevent bowstringing. I would ensure that the anatomy of the chiasmis correct and that the FDP is appropriately passing between the FDS slips. I would take care to handle the tendon as liti leas possible and would site my core Bunnell suture early and use this to deliver the tendon through the pulley system.
EXAMINER
How would you anchor the tendon to the bone?
CANDIDATE
The bony fragment is too small to fix directly, but I wouldn’t excise it as it may improve the healing potential a t the insertion site. There are various techniques described for anchoring the tendon, but the one I use is to drive two hollow needles though the phalanx from volar to dorsal, distal to the lunula, and pass the sutures through them and tie them over a buft on on the nail plate.
EXAMINER
What is the quadregia effect?
CANDIDATE
The FDP tendons share a common muscle belly. If the FDP to the operated finger is repaired too tight, as the patient attempts to make a fist, the operated finger contacts the palm first. The other fingers are unable to achieve maximal flexion as they are prevented from contracting an y further.
EXAMINER
How would youre hab the patient after his tendon repair?
CANDIDATE
He needs early hand therapy with an early active motion protocol. This is to protect the repair and prevent adhesions forming.
EXAMINER
Do you know of any evidence showing superiority of early active motion over static or passive protocols?
CANDIDATE
There was a systematic review by Staret al. published in the American Journal of Hand Surgery in 2013. They reported a higher risk of finger stiffness in the passive protocols and a higher risk of tendon rupture in early active motion protocols. Despite this, they suggested that modern improvements in surgical technique, materials, and rehabilitation now allow for early active motion rehabilitation that can provide better postoperative motion while maintaining low rupture rates.
source p. 751
Figure
Figurep. 751

Figure 13.2 Lateral radiograph, ring finger.

source p. 752

References#

Khor WS, Langer MF, Wong R, Zhou R, Peck F, Wong JK. Improving outcomes in tendon repair: a critical look at the evidence for flexor tendon repair and rehabilitation. Plast Reconstr Surg. 2016;138(6):1045e–1058e.

Starr HM, Snoddy M, Hammond KE, Seiler JG. Flexor tendon repair rehabilitation protocols: a systematic review. J Hand Surg Am. 2013;38(9):1712–1717.

source p. 753

Structured oral examination question 3#

source p. 754

Scaphoid fracture

EXAMINER
This gentleman slipped on ice and fell onto his outstretched hand. What do the radiographs show (Figure 13.3)?
Figure 13.3
Figure 13.3Figure 13.3a, 13.3b and 13.3c Right scaphoid series.p. 755
CANDIDATE
These scaphoid views demonstrate a fracture of the proximal pole of the scaphoid.
EXAMINER
What position do you expect the wrist was in when the bone fractured?
CANDIDATE
Extended and radially deviated.
EXAMINER
What would you expect to findon examination?
CANDIDATE
I would expect pain on the radial side of the wrist, with tenderness over the scaphoid tubercle and in the anatomical snutio x. There may also be swelling on the radial side of the wrist.
EXAMINER
So, if he had presented as you describe but with normal scaphoid views, would you assume there was no fracture?
CANDIDATE
I would be suspicious of a scaphoid fracture as they are not always visible on plain radiographs acutely. I would manage him in a below-elbow plaster and see him again in 1–2 weeks for further clinical assessment. If he was still tender, I would repeat the plain films and if no fracture was seen I would arrange an urgent MRI scan.
EXAMINER
You work in a unit where it takes 6 weeks to get an urgent MRI scan. Would a CT scan suffice?
CANDIDATE
A CT scan would detect most scaphoid fractures, but the sensitivity for acute fractures is not as good as MRI. MRI will show bone oedema in the presence of an acute fracture. A CT scan can miss a fracture as the slices could be aligned with the fracture.
EXAMINER
OK, so back to our original scenario with an acute proximal pole fracture. How will you manage him?
CANDIDATE
Fractures of the proximal fitih of the scaphoid have a very high non-union rate approaching 100%. I would advocate surgery to fix the fracture to reduce the risk of non-union and avascular necrosis. I would warn the patient that, even with surgery, there is still a fairly high non-union rate.
EXAMINER
Why is there such a high non-union rate with proximal fractures?
CANDIDATE
The blood supply to the proximal poleis tenuous. It comes via the dorsal carpal branch of the radial artery in a retrograde direction.
EXAMINER
How would you fix the fracture?
CANDIDATE
Following appropriate consent and anaesthesia, I would utilize a dorsal approach to the scaphoid. I recognize that this can be done purely percutaneously, but in my hands, I would use a mini-open approach. I would make a straight incision starting a t Lister’s tubercle and extending distally for about 4 cm. I would incise the third compartment to expose EP Land retract it radially with the ECRB andE CRL tendons. I would then incise the dorsal wrist capsule from the distal edge of the radius up to the dorsal intercarpal ligament. I would maximally flex the wrist over a large bolster to reveal the proximal pole and inspect the fracture to ensure I can identify the centre of the small fracture fragment. I would then place a guidewire through the centre of the fracture fragment and fix it to the main body of the scaphoid with a differential pitch screw to apply compression.
EXAMINER
It’s now 6 months later and the patient is still in some pain and has difficulty using the wrist in his work as a postman. The plain films show no signs of union. What will you do?
CANDIDATE
I’ll order a CT scan to assess for any evidence of union. If there is none I would consider revision surgery with a vascularized bone graft.
EXAMINER
Why is it important to achieve union with a scaphoid fracture?
CANDIDATE
In this case, the patient is still symptomatic and is struggling to work. In any case, if the fracture does not unite there is a high risk of the patient developing symptomatic degenerative changes in the wrist known as scaphoid non-union advanced collapse or SNAC.
EXAMINER
What if the CT showed partial union of the scaphoid?
CANDIDATE
I would allow the patient to mobilize but to avoid contact sports. I would arrange a follow-up CT in 3 months’ timet o confirm union. Singh et al. published a study in 2005 in which a group of patients with partially united scaphoid fractures went on to unite.
Figure
Figurep. 755

Figure 13.3a, 13.3b and 13.3c Right scaphoid series.

source p. 756

References#

Strauch RJ. Scapholunate advanced collapse and scaphoid nonunion advanced collapse arthritis – update on evaluation and treatment. J Hand Surg Am. 2011;36(4):729–735.

Singh HP, Forward D, Davis TR, Dawson JS, Oni JA, Downing ND. Partial union of acute scaphoid fractures.

J Hand Surg Br. 2005;30(5):440–445.

source p. 757

Structured oral examination question 4#

source p. 758

Mallet finger

EXAMINER
This 34-year-old lady presents to you with an injury to the tip of the middle finger sustained when she was struck on the end of the finger by a basketball during a game. What does the photograph (Figure 13.4a) show?
Figure 13.4a
Figure 13.4aFigure 13.4a Clinical picture of mallet finger.p. 759
CANDIDATE
This is a clinical photograph showing the fingers of the left hand viewed from the ulnar side. There is an apparent flexion deformity at the DIPJ of the index finger consistent with a mallet finger.
EXAMINER
What is a mallet finger?
CANDIDATE
This is when the extensor mechanism to the distal phalanx has been disrupted. This can be due to a purely tendinous rupture, or to a bony avulsion from the base of the distal phalanx.
EXAMINER
How would you differentiate the two?
CANDIDATE
Clinically, the purely tendinous rupture tends to be much less painful than the bony avulsion, but I would obtain radiographs to differentiate the two and to characterize any fracture.
EXAMINER
Why do you need to differentiate the two?
CANDIDATE
This would affect my management. The soft -tissue mallet needs to be immobilized for much longer than the bony mallet due to the relatively poor blood supply and healing rate of the tendon. Also, if there is a bony mallet it is important to establish whether there is any subluxation of the joint which would indicate surgery.
EXAMINER
Here is a radiograph of this ladyfinger (Figure 13.4b). What does it show?
Figure 13.4b
Figure 13.4bFigure 13.4b Lateral radiograph of bony mallet finger deformity.p. 759
CANDIDATE
It shows a small bony avulsion from the distal phalanx dorsally, a flexion deformity at the DIPJ and subluxation of the DIP J palmarly.
EXAMINER
How would you manage this injury?
CANDIDATE
Assuming it is closed, isolated and neurovascularly intact, I would fit a splint such as a Stack splint to maintain slight extension at the DIPJ and then repeat the radiographs. If the joint congruity is restored, I would X-ray her weekly for 3 weeks to ensure the reduction was maintained. I would insist that the joint be kept in passive extension at all times. Assuming it doesnt slip, I would leave it in a splint constantly for 4 weeks, then at night and during risky activities for a further 4 weeks.
EXAMINER
What if you couldn’t achieve a satisfactory reduction?
CANDIDATE
I would advocate reducing the joint and maintaining the reduction surgically. I would use the Ishiguro technique of a dorsal blocking wire to prevent proximal migration of the fracture fragment, followed by closed reduction and transfixation of the DIP J with an axial K-wire. I would leave these wires proud for removal in clinic 4 weeks later.
EXAMINER
Do you know any classification systems for this injury?
CANDIDATE
Doyle’s classification Type 1 is a closed tendinous injury with or without a flake of bone. Type 2 is open. Type 3 is open with skin and tendon loss. Type 4 is a mallet fracture such as this one.
source p. 759

Type 4 is subdivided into (A) physeal fractures in children, (B) fractures 20–50% articular surface and

(C) more than 50% joint surface. This would be a C.

EXAMINER
What are the potential complications of this injury?
CANDIDATE
An extensor lag is common but rarely significant enough to cause symptoms. The patient may develop degenerative change and require later fusion. The patient could develop a swanneck deformity which may require correction.
Figure
Figurep. 759

Figure 13.4a Clinical picture of mallet finger.

Figure
Figurep. 759

Figure 13.4b Lateral radiograph of bony mallet finger deformity.

source p. 760

Reference#

Sheth U. Mallet finger. Retrieved from www.orthobullets.com/hand/6014/mallet-finger

Ishiguro T, Itoh Y, Ya beY, Hashizume N. Extension block with Kirschner wire for fracture dislocation of the distal interphalangeal joint. Tech Hand Upper Extrem Surg. 1997;1:95–102.

source p. 761

Structured oral examination question 5#

source p. 762

Animal bite

EXAMINER
A lady presents to you with a cat bite on the index finger that was sustained when she was breaking up a fight between two cats. There are puncture wounds over the palmar and dorsal surface of the index finger, which is swollen and red (Figure 13.5). What key findings are you looking for on examination?
Figure 13.5
Figure 13.5Figure 13.5 Cat bite.p. 763
CANDIDATE
I would look for signs of injury to the neurovascular and tendinous structures of the finger and for signs of flexor sheath infection.
EXAMINER
How would you diagnose flexor sheath infection clinically?
CANDIDATE
I would look for Kanavel’s signs. These are: a flexed atitude to the finger, pain on passive extension, tenderness along the flexor sheath and sausage-shaped swelling.
EXAMINER
What is the classic organism that causes infection with c at bites?
CANDIDATE
Pasteurella multocida is classically associated with cat bites.
EXAMINER
Let’s say you find convincing signs of flexor sheath infection. How would you manage this?
CANDIDATE
This is a surgical emergency. The patient needs to go to theatre as soon as possible, ideally within 6 hours, for a washout of the flexor sheath. I would immediately elevate the limb in a Bradford sling. As longas theatre is not delayed and the patient not septic, I would hold off antibiotics un til I have a sample of pus for microbiological assessment.
EXAMINER
Talk me through your surgical technique.
CANDIDATE
After appropriate consent and regional or general anaesthesia, I would elevate the limb in theatre and inflate an arm tourniquet. I would not exsanguinate the limb forfear of driving infection proximally. I would open the region of the A1 pulley with an oblique incision in the palm, retract the neurovascular structures, open the flexor sheath proximally and take a sample of pus or fluid from the sheath. I would then make a transverse incision in the DIP joint skin crease palmarly, open the distal end of the flexor sheath and irrigate the sheath from proximal to distal via a cannula in the proximal window. I would leave the proximal wound open for drainage. I would keep the patient on IV antibiotics and elevation and take them back to theatre for a second look and closure at 24– 48 hours.
EXAMINER
Which antibiotic would you start empirically?
CANDIDATE
In my hospital, I would use co-amoxiclav for animal bites as per the local antibiotic guidelines. I would then await the sensitivities from microbiology and adjust my therapy accordingly.
EXAMINER
What are the consequences of missing a flexor sheath infection?
CANDIDATE
Locally, adhesions form between the tendon and the flexor sheath resulting in a very stiff finger. The infection can spread into the palm and up the limb and the patient can become septic. The tendon or a pulley can rupture.
source p. 763
EXAMINER
A slightly different scenario now. Let’s say there are no Kanavel signs. How would you manage this cat bite now?
CANDIDATE
This still needs to be treated aggressively as there is a high risk of infection developing and there is potential contamination of the flexor sheath which may give rise to infection here. I would admit the patient for elevation and plant o open and washout the wounds. If there were signs of flexor sheath contamination intra operatively I would wash this out too. If the patient can go to theatre within 6 hours and is not septic, I would hold off antibiotics un til samples can betaken. If not, I would commence empirical co-amoxiclav IV.
Figure
Figurep. 763

Figure 13.5 Cat bite.

source p. 764

References#

National Institute for Health and Care Excellence. Clinical Knowledge Summary Scenario: Managing a cat or dogbite. 2015. Retrieved from htip s://cks.nice.org.uk/bites-human-and-animal#!scenario:2.

source p. 765

Structured oral examination question 6#

source p. 766

Boxer’s fracture

EXAMINER
This gentleman punched a wall during a night out. He presents to you the next day with a painful, swollen hand. What do these radiographs (Figures 13.6a–c) show?
CANDIDATE
These are AP, lateral and oblique radiographs of the left hand showing a fracture at the neck of the litile finger metacarpal. This is angulated palmarly. This is commonly known as a boxer’s fracture as it is typically sustained from a punch.
EXAMINER
What do you need to assess clinically?
CANDIDATE
I need to see if there is any wound associated with the injury. If there is any full-thickness break in the skin, there is a high likelihood of the MCP joint being open. There is a risk of contamination from whatever the patient struck, which may have been another person rather than a wall. This is known as a ‘fight bite’. I would also need to assess rotation as this will not remodel and can result in functional difficulties if it mal unites.
EXAMINER
What if you are not sure that there is a full-thickness wound to the skin?
CANDIDATE
I would rub the skin with a saline-soaked swab to hopefully reveal whether this was just an abrasion. If I was still unsure I would treat this as an open joint injury or open fracture. I would admit the patient for elevation, IV antibiotics and surgical washout and debridement.
EXAMINER
How will you ensure intra operatively that the joint is not open?
CANDIDATE
I would first confirm whether the skin was indeed broken by attempting topass a narrow blunt instrument through it, such as one limb of a non-toothed forceps. Assuming the skin is broken, I would then open the skin sufficiently to inspect the extensor tendon and dorsal capsule. This would need to be approximately 2–3 cm. As the finger was flexed when the injury was sustained, it is important to assess the tendon intra operatively with the finger flexed. If this is not done, any rent in the tendon may migrate proximal to the incision and be missed.
EXAMINER
Let’s say this is a closed injury and there is no rotational malalignment How will you manage it?
CANDIDATE
I would strongly recommend conservative management to the patient This would involve mobilization of the finger with the aid of a Bedford splint or neighbour strapping. I would explain that these injuries almost always will malunite, resulting in a pain- freehand with normal function. I would explain that any extensor lag will improve with time as the muscle shortens. I would explain that, when the patient makes a fist, the liti le metacarpal head will always appear depressed, but this will not be painful or affect function.
EXAMINER
What if the fracture were more proximal, let’s say in the shaft of the metacarpal?
CANDIDATE
Malunion here isless well tolerated than in the neck. I would advise the patient that this ought to be reduced and held somehow to improve long-term function and cosmesis. This can be achieved by manipulation and plastering, but with a significant risk of displacement. Personally, I would stabilize the fracture with an intramedullary wiring technique according to Foucher.
Figure
Figurep. 767

Figure 13.6a, 13.6b and 13.6c Anteroposterior (AP), oblique and lateral radiographs, left hand.

source p. 768

Reference#

Foucher G. ‘Bouquet’ osteosynthesis in metacarpal neck fractures: a series of 66 patients. J Hand Surg Am.

1995;20(3 Pt 2):S86–90.

source p. 769

Structured oral examination question 7#

source p. 770

Fight bite

EXAMINER
Please describe this clinic photograph (Figures 13.7a and 13.7b).
CANDIDATE
This is a clinical photograph showing a wound on the dorsum of the left hand between the ring and middle metacarpal heads. It appears slightly erythematous, but there is no gross swelling or pus exuding.
EXAMINER
What do you suppose is the mechanism of injury?
CANDIDATE
This type of injury is commonly sustained by punching someone or something. I would be concerned that the patient has punched someone in the mouth and has sustained a fight bite injury.
EXAMINER
Why is a fight bite injury a significant problem?
CANDIDATE
The metacarpophalangeal joint is very superficial and located very near to the wound. It is likely that the wound may communicate with the MCP joint, predisposing the patient to septic arthritis. This could make the patient quite ill, but could also result insignificant damage to the joint, with long-term stiffness and dysfunction.
EXAMINER
How does infection cause joint damage?
CANDIDATE
Metalloproteases are released by inflammatory cells which destroy the articular cartilage.
EXAMINER
How will you determine whether the wound has breached the dermis?
CANDIDATE
It is often very difficult to assess this, especially if the presentation is delayed. I would attempt to clean the skin with a saline-soaked swab to see if this was just an abrasion or a full- thickness wound. I would have a very low threshold for treating this as a full-thickness wound as I find it quite difficult to be sure that the dermis has not been breached.
EXAMINER
So how would you treat this patient?
CANDIDATE
This is a significant injury. I would admit the patient for IV antibiotics and high elevation in a Bradford sling. My local hospital protocol for animal and human bites is to use co-amoxiclav 1.2 g IV tds. I would arrange plain X-rays to check for signs of fracture or foreign body. I would plan for surgery as soon as reasonably possible. I would not normally take such a case to theatre in the night, but would operate same day if possible, or next morning if not.
EXAMINER
What operation would you do?
CANDIDATE
Under GA or regional block, I would excise the wound edges and extend the wound as far as necessary to access the extensor mechanism and MCPJ. If there is any pus I will send a swab for microbiology. I will carefully assess the integrity of the extensor mechanism and joint. It is important to note that the rent in the extensor hood will migrate proximally when the fingers are extended, so one must be mindful of this as it may disguise a deeper injury. When the finger is passively flexed into a fist, the zone of trauma becomes clearer. It is important to assess the joint capsule to determine whether this has been breached. Often it is and the joint will need washing out. I would assess the status of the articular cartilage and comment upon any defect. I would washout the wound thoroughly with saline and loosely tack the skin only to prevent drying out of the tendon. I would plan to return to theatre for a second look and formal closure in layers at 48 hours, assuming the wound was clean at that stage, otherwise a third operation may be needed.
EXAMINER
And what would be your postoperative instructions?
CANDIDATE
After the first surgery I would continue IV antibiotics and elevation . Whether to mobilize at this point is controversial, but I would splint the hand in the Edinburgh position for comfort. After the definitive closure I would allow the patient home on oral antibiotics and elevation . Unless I had to repair a divided tendon, I would mobilize the fingers with the help of physi oto avoid stiffness. I would see the patient again in clinic a few days later to check that the infection was subsiding and further surgery was not indicated.
EXAMINER
What is the characteristic organism that causes infection with human bites?
CANDIDATE
Eikenella corrodens is the classic organism with human bites, but the most common infective agents are Streptococcus viridans and Staphylococcus aureus. These are generally sensitive to co- amoxiclav, but I will be guided by local antibiotic guidelines and by sensitivities on tissue and pus samples.
EXAMINER
OK, let’s assume that you treat a particularly bad case which presented late, and although you were able to save the finger, the joint was destroyed and you see the patient 5 years later with a very stiff, painful, arthritic middle MCP joint. What can you offer him?
CANDIDATE
In manyways I would treat him much like any other osteoarthritis of the MCP J. I would explain that there are a number of treatment options and recommend conservative treatment in the first instance. This would be painkillers, splintage and lifestyle modifications. If I were to consider invasive treatment I would want to be sure the infection had fully resolved. I would check inflammatory markers and for features in the history suggestive of infection. If conservative measures failed and I was happy there was no residual infection, I would offer X-ray or ultrasound- guided steroid injection. If this was ineffective I would consider surgery in the form of fusion or replacement. For most young adult patients, I would recommend fusion, but only if conservative measures fail.
EXAMINER
Why would you recommend fusion over replacement?
CANDIDATE
Fusion is a reliable way of relieving pain, but at the cost of stiffness. In a young adult I feel that silastic replacement is unlikely to tolerate heavy use or provide longevity. Anatomic MCPJ replacements are available and are a motion-pr eserving option, but come with risks of infection, wear and loosening. Medium-term results are encouraging. Professor Dias has presented his 5-year results in 13 joints. He had one revision for infection and three joints with evidence of loosening. The range of motion and patient reported outcome scores were good. If apa tien t was very keen to preserve motion, I would refer them on to a hand surgeon experienced in this technique for discussion about suitability.
Figure
Figurep. 772

Figure 13.7a and 13.7b Clinical picture of a 21-year-old male presenting to accident and emergency department with a painful left hand following an injury.

source p. 773

Reference#

Singh H, Dias J. Surface replacement arthroplasty of the proximal interphalangeal and metacarpophalangeal joints: the current state. Indian J Plast Surg. 2011;44(2):317–326.

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