Concomitant Distal Radius Fracture, Scaphoid Fracture, and Pisiform Dislocation with Ulnar Nerve Neuropraxia: A Case Report with Biomechanical Analysis.

Introduction

Distal radius fractures commonly result from falls onto an outstretched hand, making them a frequent presentation in orthopedic practice. However, pisiform dislocation associated with a distal radius fracture is uncommon, due to the pisiform's protected anatomical position and the distinct biomechanical forces typically required for its displacement. When this combined injury pattern is further complicated by ulnar nerve neuropraxia, it becomes rare and may be easily overlooked. The clinical subtlety of pisiform dislocation can lead to diagnostic delay, potentially resulting in inappropriate management if not recognised early.

Case repoprt

We report a rare clinical scenario involving a right-hand dominant woman in her early 50s who sustained a distal radius fracture along with a scaphoid fracture and pisiform dislocation complicated by ulnar nerve neuropraxia following a high-velocity motorcycle-related trauma. At presentation, the patient exhibited severe wrist pain, swelling, and notable sensory impairment within the ulnar nerve distribution. Initial standard radiographs identified distal radius and scaphoid fractures. Following closed reduction of the radius fracture, a pisiform dislocation was revealed radiographically and confirmed through computed tomography (CT) imaging. Sagittal CT sections demonstrated volar migration of the pisiform relative to the triquetrum, with significant widening of the pisotriquetral joint space and complete loss of articular congruity, confirming a volar pisotriquetral dislocation. Closed reduction was successfully performed with the wrist placed in palmar flexion, significantly alleviating ulnar nerve symptoms immediately. A short-arm plaster cast immobilization was utilised, extending to the thumb to stabilize the scaphoid fracture simultaneously. The cast was maintained for six weeks, resulting in complete fracture healing and maintenance of pisiform alignment, as confirmed by follow-up imaging. At 9 months post-injury, structured physiotherapy facilitated a full return to routine activities with excellent wrist and finger mobility and resolution of all neurological deficits.

Conclusion

Pisiform dislocation associated with distal radius fracture represents a rare and complex injury combination, further complicated by ulnar nerve involvement. Clinicians must maintain a high degree of suspicion and adopt advanced imaging modalities early to avoid missing such diagnoses. Prompt closed reduction and conservative management can yield favorable outcomes, highlighting the importance of early recognition and appropriate intervention in such uncommon scenarios.