Basics
Description
- Lunate remains located and in line with the radius but the distal carpal bones are displaced dorsally ( ’ Ό95% of the time) or volarly ( ’ Ό5% of the time)
- Early surgical treatment is recommended.
- This injury has a high incidence of post-traumatic arthritis.
Etiology
- Mechanism of injury is usually wrist hyperextension with ulnar deviation.
- These are high-energy injuries:
- Falls from a height
- Motor vehicle accidents
- Industrial accidents
- Sporting accidents
Scaphoid is frequently fractured with perilunate dislocations.
Diagnosis
Signs and Symptoms
- Severe wrist pain
- Wrist swelling
- Diffuse wrist tenderness
- Paresthesias in the median nerve distribution
History
- History of a high-energy injury
- Any concomitant injuries
- Pain in the wrist
- May complain of paresthesias in the median nerve distribution
Physical Exam
- Wrist swelling
- Possible deformity of the wrist
- Decreased range of motion of the wrist
- Possible decreased sensation in the median nerve distribution
- Special attention should be paid to skin integrity because open fractures are common.
- Neurovascular status should be monitored closely, including 2-point discrimination.
- Check closely for concomitant injuries, specifically of the upper extremity.
Diagnosis is frequently missed on clinical exam.
Essential Workup
Radiographs of the wrist
Diagnosis Tests & Interpretation
Imaging
- Radiographic imaging that includes 3 views of the wrist
- Perilunate dislocation visualized best on the true lateral view:
- Distal carpal row, specifically the capitate, seen dorsally (95% of the time) or volarly (5% of the time) in relation to the lunate
- Lunate is located and in line with the radius
- CT and MRI are not generally needed for diagnosis, but some orthopedists may request them for preoperative planning.
- Wrists are rarely sprained in children.
- Wrist radiographs are difficult to interpret in pediatric patients.
- Comparison view of the other wrist may be helpful.
Differential Diagnosis
- Lunate fracture
- Lunate dislocation:
- Dislocation occurs between lunate and distal radius.
- Scapholunate dissociation and other similar ligamentous disruptions
- Distal radius fracture
Consider nonaccidental trauma.
Treatment
Concern is for concomitant, more serious, injuries.
Pre-Hospital
- Assess for other injuries
- Immobilize
- Pain control
- Elevate
Initial Stabilization/Therapy
- Identify other, more serious, associated injuries.
- Immobilize
- Elevate
- Ice
Ed Treatment/Procedures
- Pain control
- Procedural sedation for closed reduction:
- Etomidate: 0.1 " 0.15 mg/kg IV
- Methohexital: 1 " 1.5 mg/kg IV
- Propofol: 40 mg IV every 10 sec until induction
- Closed reduction of the dislocation should be done emergently:
- Arm is hung in traction for 10 min with 10 " 15 lb of counterweights and the fingers in traps.
- The fingers are then removed from the traps and manual traction is continued.
- One of the physicians thumbs is placed volarly over the lunate and then the injury is recreated with wrist extension.
- Continued traction is applied to the wrist and then slow flexion of the wrist is performed, which usually locates the distal carpal bones.
- Operative fixation to reduce and maintain wrist stability is required.
- Immobilize wrist using a sugar-tong splint in neutral position. Obtain postreduction radiograph.
Although perilunate dislocation is unusual in pediatric patients, children with wrist pain should be splinted and referred to a pediatric hand surgeon.
Medication
- Diazepam: 2 " 5 mg IV q2 " 4h (peds: Max. dose is 0.25 mg/kg q4h) PRN anxiety
- Fentanyl: 0.05 " 0.2 mg IV q1h PRN pain
- Hydromorphone: 0.5 " 1 mg IV q4 " 6h (peds: 0.015 mg/kg/dose q4 " 6h) PRN pain
- Lorazepam: 0.5 " 1 mg IV q1 " 6h (peds: 0.044 mg/kg q4 " 6h) PRN anxiety
- Morphine sulfate: 0.1 mg/kg IV q1h PRN pain
Follow-Up
Disposition
Admission Criteria
- Open dislocation, presence of multiple trauma, or other, more serious, injuries
- Inability to reduce dislocation or maintain reduction
- Neurovascular compromise
Discharge Criteria
- Closed injuries
- Adequate reduction
- No neurovascular involvement
- Orthopedic follow-up within 2 " 3 days
Issues for Referral
All patients with perilunate dislocations should be referred to a hand surgeon for surgical stabilization and ligament repair.
Follow-Up Recommendations
- All patients with a perilunate dislocation must follow-up with a hand surgeon for surgical stabilization and ligament repair.
- Follow-up should be within 2 " 3 days.
Pearls and Pitfalls
- Up to 25% of these injuries are missed on initial presentation.
- In a patient with wrist pain, swelling, and limited range of motion, it is important to obtain adequate x-rays of the wrist and make sure that the lunate and capitate are located in their fossa on the lateral wrist x-ray.
- Late presentation of these injuries leads to a very poor outcome and often requires a salvage operation.
- Complications include median nerve injury, tendon problems, complex regional pain syndrome, wrist instability, and post-traumatic arthritis.
- Even with appropriate treatment, there is a high incidence of post-traumatic arthritis and loss of grip strength.
Additional Reading
- Budoff JE. Treatment of acute lunate and perilunate dislocations. J Hand Surg Am. 2008;33A:1424 " 1432.
- Forli A, Courvoisier A, Wimsey S, et al. Perilunate dislocations and transscaphoid perilunate fracture-dislocations: A retrospective study with minimum ten-year follow-up. J Hand Surg Am. 2010;35:62 " 68.
- Kardashian G, Christoforou DC, Lee SK. Perilunate dislocations. Bull NYU Hosp Jt Dis. 2011;69(1):87 " 96.
- Melsom DS, Leslie IJ. Carpal dislocations. Curr Orthoped. 2007;21:288 " 297.
- Stanbury SJ, Elfar JC. Perilunate dislocation and perilunate fracture-dislocation. J Am Acad Orthop Surg. 2011;19(9):554 " 562.
See Also (Topic, Algorithm, Electronic Media Element)
- Carpal Fractures
- Lunate Dislocation
- Scaphoid Fracture
Codes
ICD9
- 814.01 Closed fracture of navicular [scaphoid] bone of wrist
- 833.09 Closed dislocation of wrist, other
ICD10
- S62.009A Unsp fracture of navicular bone of unsp wrist, init
- S63.095A Other dislocation of left wrist and hand, initial encounter
- S63.096A Other dislocation of unspecified wrist and hand, initial encounter
- S63.094A Other dislocation of right wrist and hand, initial encounter
SNOMED
- 263026000 Dislocation of perilunate joint (disorder)
- 281513007 Transscaphoid-perilunate fracture dislocation (disorder)
- 209270002 Closed fracture dislocation perilunate (dorsal) (disorder)
- 281518003 Volar transscaphoid-lunate fracture dislocation (disorder)
- 209269003 Closed fracture dislocation lunate (volar) (disorder)