Mallet deformity



Background

  • X-ray to look for avulsion fracture (better chance of healing).
  • With a large fragment check that the DIP joint is not subluxed.
  • A small percentage of patients develop hyperextension of the PIPJ (old volar plate injury or lax ligaments). This hyper extension must be corrected (splint PIPj in neutral also) if present. (Please see swan neck deformity below)

Management

  • For the majority, general management includes : Apply a mallet splint full-time for 6 weeks, then at night for 2 weeks. GP follow up.
  • If there is still a lag as patient begins to mobilise at 6 weeks, place back into splint for a further two weeks.
  • If splint is removed the finger must be kept straight.
  • Explain the prognosis - (½ left with deformity even if in splint) but that the function of the hand / finger will not be effected.
  • Warn the patient that it may not heal.
  • Patients with exceptional hand requirements should be referred to the fracture clinic.
  • It is important that the mallet splint allows for full flexion at the PIP joint and patients are encouraged to mobilize at the PIPJ level.
  • If the joint is subluxed please refer to the on-call orthopaedic or discuss with the plastics team Referral form
Mallet Diagram
"Dropped" finger tip or mallet injury
Swan neck deformity
Beware dominant "middle slip"


Content by Dr Íomhar O' Sullivan 20/05/2005. Reviewed by Dr ÍOS 06/11/2005, 31/01/2007, Last review Dr ÍOS 28/12/18.