Perilunate dislocation

Abstract

This is one of a series of occasional articles highlighting conditions that may be more common than many doctors realise or may be missed at first presentation. The series advisers are Anthony Harnden, university lecturer in general practice, Department of Primary Health Care, University of Oxford, and Richard Lehman, general practitioner, Banbury. To suggest a topic for this series, please email us at easilymissed@bmj.comA 30 year old, right hand dominant mechanic presented to the emergency department with a swollen, painful right wrist after he fell on to an outstretched right hand from a motorcycle travelling at high speed. Radiographs were interpreted as normal and the patient was discharged with a diagnosis of a wrist sprain. The next morning he presented again to the same emergency department with a new symptom: numbness of the right thumb and index, middle, and ring fingers. The radiographs were reviewed and a perilunate dislocation with median nerve compression was diagnosed. That afternoon the patient had median nerve decompression and open reduction and stabilisation of the perilunate dislocation with ligament repair. PRACTICE Key points• Remain vigilant about the possibility of perilunate dislocation in patients who sustain high energy hyperextension wrist injuries with or without carpal bone fractures• Delay in diagnosis can result in injury to the median nerve in the acute setting and post-traumatic arthritis• Confirm the diagnosis with posteroanterior and lateral plain wrist radiography, which would show the "spilled teacup" sign (lunate angulated volarly) and disruption of the smooth borders of the carpal rows (Gilula's lines)• Immediate management involves closed reduction, followed by early surgical repair (stabilisation and fixation)

Ultrasonography Detected Missed Lunate Volar Dislocation Associated With Median Neuropathy: A Case Report

“…Ensuring the continuity of the ‘arcs of Gilula’ on anterior-posterior radiographs and normal collinearity of the distal radius, lunate, capitate, and metacarpal base of the middle finger on lateral radiographs is the most widely-used method for determining abnormalities in a carpal alignment as illustrated in Fig. 2 [ 8 9 10 ]. Although plain radiography has superiority for generally assessing carpal alignment, it cannot assess soft tissue structures, including nerves and tendons.…”

X‐Ray Quiz: A Man with a Painful Wrist after a Fall

“…However, the capitate along with the rest of the carpus will dislocate dorsally to the line of the radius. 6 The lunate or perilunate dislocations are often associated with fractures of the other carpal bones and radial styloid. 7 The sensory deficits in the median nerve distribution may happen.…”

“…However, an open repair and reconstruction of the injured ligament to restore the stability, fixation of displaced or unstable carpal bones, and an emergency carpal tunnel decompression is the definitive management. 4,6 In this patient, an emergent open reduction and internal fixation was done ( Figure 3). After 4 months of follow-up and rehabilitation, he recovered well (Figure 4).…”

Fracture Detectives: A Fracture Review Match Game

“…It is also important to assess neurovascular status on exam since a median nerve injury can occur. 48,49 With regards to imaging, the lateral view will be most indicative of whether a perilunate dislocation is present because it will show dorsal dislocation of the capitate, with the lunate in alignment with the distal radius. The AP view can reveal overlap of the distal and proximal carpal rows, as well as any associated fractures that may be present.…”