Article Text

Download PDFPDF
Pisiform dislocation
  1. Faisal Mahmood,
  2. Milind Mehta and
  3. Rahul Kakkar
  1. Furness General Hospital, Barrow-in-Furness, Cumbria, UK
  1. Correspondence to Dr Faisal Mahmood; mahmood.f.94{at}hotmail.co.uk; Mr Rahul Kakkar; rahul.kakkar{at}mbht.nhs.uk

Abstract

A pisiform dislocation is an uncommon injury which can lead to significant morbidity if missed. The literature regarding pisiform dislocation is limited and largely from case reports. In this case, we present a 51-year-old right-hand dominant male who sustained the injury after a fall. He attended the emergency department on the same day and a closed reduction was able to be performed under a haematoma block. On review in follow-up clinic the patient’s symptoms had completely resolved.

  • radiology (diagnostics)
  • trauma
  • orthopaedic and trauma surgery

Statistics from Altmetric.com

Background

The pisiform is a sesamoid bone that develops in the flexor carpi ulnaris tendon.1 When the pisiform is in its correct anatomical position, it is superimposed on the triquetrum on an anterior–posterior film.2 Early diagnosis of a pisiform dislocation is difficult, the injury is rare and sparsely described in the literature; healthcare practitioners are likely to miss the diagnosis.1 2 This poses a specific challenge in terms of management and the long-term outcomes for the patient. This case and further literature review illustrates early diagnosis is associated with a reduced likelihood of an open procedure and lasting morbidity. This favourable outcome was achieved in this case due to a high index of suspicion by the emergency department physician, followed by a prompt referral to the specialist team.

Case presentation

A 51-year-old right-hand dominant male, presented to the Accident and Emergency Department after a fall on an outstretched hand. He complained of right wrist pain and swelling. On examination, he had bruising over the ulnar aspect of the wrist with tenderness on palpation. A marked reduction in grip strength and wrist flexion compared with the left side was noted; there was no neurovascular deficit peripherally. X-ray imaging confirmed a medial dislocation of the pisiform with an associated triquetral fracture (shown in figures 1 and 2). The Emergency Department clinician suspected more than the initial diagnosis of a wrist sprain, and made a prompt referral to the on-call hand and wrist consultant who confirmed the diagnosis.

Figure 1

Anteroposterior view shows the pisiform bone is dislocated medially; this is also associated with a triquetral fracture.

Figure 2

Lateral view of pisiform dislocation.

The patient was seen in the Emergency Department and after consent was gained, a closed reduction was able to be performed under a haematoma block, 4 hours after presentation. Reduction was achieved by placing the wrist in flexion to take tension off the flexor carpi ulnaris, digital pressure was applied to the bone in a lateral direction. The reduction was confirmed radiographically (shown in figure 3). The patient was placed in a cast and followed up in fracture clinic at 2 weeks and then again at 6 weeks post reduction. The patient had full resolution of symptoms and was able to return to work as a manual labourer.

Figure 3

This view was taken post reduction, the pisiform bone is in the correct anatomical position, superimposed onto the triquetral bone.

Outcome and follow-up

The reduction was performed in the Emergency Department; the patient was placed in a cast and was reviewed at 2 weeks post injury in fracture clinic. The bone had not dislocated and clinically the patient was pain free. By 6 weeks post injury, the function of the hand had returned to near baseline and the patient was already back at work as a manual labourer.

Discussion

A literature search was performed, using PubMed, Medline and Embase databases. The following key words and filters were used, Pisiform, luxation, dislocation, last 10 years, humans only. These yielded 14 papers, 7 of these were case reports describing the management of traumatic dislocation of the pisiform bone. The reference lists of each of the papers were also reviewed and further case reports describing pisiform dislocations were also added to this literature review, duplicates were excluded.

Six of the seven reviewed case reports described the mechanism of injury to be a direct blow with the wrist in hyper extension with resultant pain, swelling and reduced wrist flexion.1–7 One paper also described indirect traction on the flexor carpi ulnaris tendon as a mechanism of injury.4 All cases describe a high force injury in a young patient.

The case we present suggests early presentation after injury and accurate radiographic diagnosis allows for immediate closed reduction with good outcomes. This has also been suggested by Saleh et al,5 who report similar findings. A delayed presentation increases the chances an open reduction is required.2 3 7 There is no one standard technique being advocated in the literature regarding open reduction. The following have been described, open reduction and pisiform excision without ligament reconstruction.1 2 4 7

A missed diagnosis is relatively common; three out of the seven papers described a delay in diagnosis of up to 10 days.2 3 7 This could likely be due to the rarity of the injury and difficulty of diagnosis from X-ray findings alone.2 Two of the seven papers used further imaging such as CT scanning to confirm the diagnosis.1 2 Rajeev et al,2 described a pisiform dislocation being misdiagnosed as a wrist sprain due to the subtle X-ray findings. A CT scan was ordered 3 days after the initial injury on review of the patient in follow-up clinic. The CT scan demonstrated the pisiform bone lay beyond the distal triquetrum. The patient was managed via and open reduction in theatre after a failed closed reduction attempt.2

Learning points

  • Identification of the injury early is essential in ensuring the best outcome for patients.

  • Early identification is difficult; many healthcare practitioners would not be aware of the radiographic findings.

  • A high index of suspicion of the injury could be recommended with a young adult presenting with a fall on an outstretched hand with resultant reduction in grip strength and wrist flexion.

  • CT imaging may be useful in reaching a diagnosis.

References

Footnotes

  • Contributors The paper was written and researched by FM, he also performed the literature search. This was reviewed and revised with MM, who developed the initial concept of the paper. RK was the clinician who reduced the dislocation in the emergency department as well as over see this project.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.