Monday, April 15, 2024

Case Report Acute Lunate Dislocation

Acute Lunate Dislocation following an MVC

A 22 12 months outdated male who’s mildly intoxicated presents by way of emergency medical companies following a motorcar crash. He’s primarily involved about his proper hand. After excluding some other critical accidents, you consider his hand. You establish tenderness and swelling alongside the carpal bones alongside the volar and dorsal facet. Radial pulse is 2+. His examination is unbroken within the median, ulnar and radial nerve distribution. Subsequent radiographs establish an remoted volar lunate dislocation.

Illustration of the distinction between a lunate and perilunate dislocation

Watch the video presentation of the case!

Lunate dislocations are a uncommon scientific entity. They’re estimated to account for lower than 3% of all carpal accidents with an incidence of lower than 1 per 100,000 accidents yearly.[1]Kastanis G, Velivasakis G, Pantouvaki A, Spyrantis M. An Uncommon Localization of Lunate in a Transcaphoid Volar Lunate Dislocation: Present Ideas. Case Rep Orthop. 2019;2019:7207856. The traditional damage is fall on an outstretched hand inflicting hyperextension of the wrist, ulnar deviation and intercarpal supination. They’ll additionally occur in motorcar crashes and different excessive pace mechanisms. Sadly, lunate dislocations are often missed because of the subtly of radiographs and as much as 25% of them could also be missed initially.[2]Goodman, Avi D., et al. “Analysis, administration, and outcomes of lunate and perilunate dislocations.” Orthopedics 42.1 (2019): e1-e6. Observe that lunate dislocations shouldn’t be confused with the extra frequent perilunate dislocation during which the lunate stays articulating with the radius however the remaining carpal bones are dislocated dorsally.

The pathophysiology is the next: (a) disruption of the radioscaphocapitate ligament and scapholunate ligament, or generally fracture of the scaphoid, (b) disruption of the lunocapitate articulation and/or fracture via the capitate, (c) damage to the lunotriquetral ligament and/or fracture via the triquetrum and at last, (d) damage to the radiolunate ligament.[3]Aslani H, Bazavar MR, Sadighi A, Tabrizi A, Elmi A. Trans-Scaphoid Perilunate Fracture Dislocation; A Technical Observe. Bull Emerg Trauma. 2016;4:110–112.

Related accidents embody radial styloid, scaphoid, capitate or triquetral fractures. Acute carpal tunnel syndrome or median nerve damage can be generally seen with lunate dislocations.

When acquiring historical past, the affected person will usually describe some type of trauma. They usually endorse ache and swelling over the palmer facet of the wrist. Observe that lunate dislocations usually co-occur with different trauma and the affected person could not endorse any wrist signs if different important pathology is current. On examination, vary of movement is commonly restricted. Sufferers could maintain their fingers in flexion on account of ache with extension. They might have diminished sensation in a median nerve distribution.

PA and lateral view of a lunate dislocation. On the PA view, the lunate is displaced anteriorly (piece of pie signal). On the lateral view, the lunate is anterior to the distal radius (spilled teacup).

Normal radiographs of the wrist are the preliminary imaging modality of selection. Observe that the dislocation is commonly missed. On the PA view, findings can embody disruption of the traditional easy line made by tracing the proximal articular surfaces of the hamate and capitate, elevated radiolunate area and lunate could overlap the capitate (piece of pie look). Lateral radiographs are sometimes extra enlightening. The lunate will be seen displaced and angulated volarly (spilled teacup look) and doesn’t articulate with the capitate or radius. MRI isn’t required to make the analysis however could also be useful to higher consider smooth tissue accidents. CT can be not required to make the analysis however could higher characterize osseous lesions.

Sagittal CT of a lunate dislocation. The lunate is anterior to the radius (inexperienced arrow) and dislocated type the traditional radiocarpal alignment (purple line).

Acute administration of lunate dislocations contains emergent orthopedic or hand surgical procedure session for closed discount. The affected person could require sedation or perhaps a median nerve block to facilitate discount. The method includes finger traps and the elbow flexed at 90 levels for 15 or 20 minutes. Volar reductions require wrist extension, traction and a posterior drive on the lunate earlier than bringing it again right into a impartial place. Following closed discount, the affected person must be positioned in a sugar tong splint.

The overwhelming majority of instances require surgical administration. Nonoperative administration will be thought-about in session with the surgical workforce however is related to poor practical outcomes and a excessive danger of re-dislocation. The most typical surgical method is open discount, ligament restore, fixation and doable carpal tunnel launch and is indicated for all acute accidents. Proximal row carpectomy and wrist arthrodesis have additionally been described and are doubtlessly indicated in additional persistent instances.

Lunate dislocations are related to a poor prognosis. Delayed therapy is related to decreased performance, decreased vary of movement, carpal instability and ache. Even sufferers handled surgically can develop degenerative modifications as early as two months. [4]Inoue G, Shionoya Okay. Late therapy of unreduced perilunate dislocations. J Hand Surg Edinb Scotl. 1999;24(2):221-225. Problems embody acute or persistent median neuropathy or so-called traumatic carpal tunnel syndrome. Sufferers can develop carpal instability which may ultimately progress to scapholunate superior collapse (SNAC). Degenerative arthritis is frequent. Lastly, a transient ischemia of the lunate can happen. In these instances, a radiodense look of the lunate is seen between 1-4 months put up damage however is usually self restricted and will be noticed.

The affected person underwent a profitable closed discount of the lunate following a median nerve block. He tolerated the process properly. He was positioned in a sugar tong splint and had a observe up appointment with orthopedic hand surgical procedure as an outpatient. Sadly, the affected person was subsequently misplaced to observe up.

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