Mallet finger and Swann neck deformities Flashcards Preview

Hands FRCS > Mallet finger and Swann neck deformities > Flashcards

Flashcards in Mallet finger and Swann neck deformities Deck (13):
1

What is a mallet finger?

A finger deformity caused by

  • A DISRUPTION of the TERMINAL EXTENSOR TENDON DISTAL TO DIPJ
  • The disruption may be BONY or LIGAMENTOUS

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2

What is the aetiology of mallet finger?

  • Traumatic impaction blow with finger in extended position-> forced flexion at DIPJ
  • Dorsal laceration

3

what is the signs and symtpoms of mallet deformity?

Symptoms

Pain and swelling around DIPJ following impact/injury

Signs

  • DIPJ held in flexion 450
  • Lack of active extension at DIPJ

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4

what investigations are helpful?

Xray

  • exclude a bony component as may just be a ligamentous injury

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5

What is the treatment of Mallet deformity?

Non op

  • For soft tissue/ non displaced bony mallet injury Extension splint DIPJ for 6-8 wks
    • Maintain free rom of pipj avoid hyperextension
    • Volar splint less complications cf dorsal
    • Begin progression flexion exercise at 6 wks

Operative

  • Closed reduction precutaneous pinning vs ORIF-
    • for volar subluxation of distal phalanx
    • or > 50% articular surface involved
    • or >2mm articular gap
    • simple pin fixation/ dorsal blocking wire
  • Surgical reconstruction of terminal tendon
    • for > 12 weeks old chronic injury
    • direct repair/tendon advancement
    • high complication rate- 50%
  • DIPJ Arthrodesis- for stiff/arthritic joint

 

6

When is surgery required? what is your technique?

  • Volar subluxation of distal phalanx
  • realtive Indcations
    • >50% articular surface invovled
    • >2mm articular gap
  • Tx by Simple pin fixation or dorsal blocking wire

7

How would you tx a chronic injury?

  • Surgical reconstruction of terminal tendon injury >12 weeks old from injury
  • Done with direct repair/ tendon advancement
    • high complication rate 50%
  • DIPJ arthrodesis for painful, stiff , arthritic dipj

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8

What are the complications of mallet fingers?

  • Extensor lag - slight residual of <10o may be apparent
  • Swan neck deformities
    • Attenuation of volar plate & Transverse retinaculum at pipj
    • dorsal subluxation of lateral bands
    • -> pipj hyperextension
    • Contracture of traingular ligament maintains deformity

9

What is this?

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A Swan neck deformity

deformity of the phalanx characterise by

  • Hyperextension at PIPJ
  • Flexion at DIPJ
  • NB a swan extends its long neck when gliding and its head is flexed :)

10

How do swan neck deformities occur?

  • 1) Laxity of the VOLAR PLATE -> PIPJ HYPEREXTENSION caused by
    • trauma
    • generalised ligament laxity
    • Rheuamtoid Arthritis

then....

  • 2) imbalance of muscles- pipj extens> flexion due to
    • mallet injury- transfer of dipj exten to pipj
    • FDS rupture- unopposed PIPj extension
    • Intrinsic contracture-tethering of lateral bands by transverse retinacular lig as result of pipj extension
    • MCPJ volar subluxation- RA

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11

What are the symptoms and signs of Swan neck deformity?

Symptoms

Locking of fingers

Signs

Hyperextension at PIPJ and flexion at DIPJ

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12

How can swan neck deformity be tx?

Non op

  • Double ring splint- prevents hyperextension of PIPJ

Operative

  • volar plate advancement and PIP balancing with central slip tenotomy- for progressive deformity
    • volar plate advancement for volar plate laxity
    • Imbalance- FDS tendodesis if fds rupture
    • lateral band tenodesis
    • spiral oblique retinaculum ligament reconstruction
    • Central slip tenotomy- Fowler

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