Perilunate Injuries

David Sauder, M.D., FRCSC
Assistant Professor, University of Saskatchewan
Saskatoon, SK

Introduction
Perilunate injuries are uncommon, severe disruptions of carpal anatomy. Their defining feature is dislocation of the capitate head from the concavity of the distal lunate. There are two common patterns: 1) the perilunate dislocation and 2) the transscaphoid perilunate dislocation1. The perilunate injury is a high energy disruption of carpal anatomy and it is crucial that a search for associated injuries be undertaken.

 

Pattern of Injury
This injury occurs when a patient lands heavily on the thenar eminence causing wrist hyperextension, ulnar deviation and carpal supination. Mayfield was able to establish four stages of progressive injury2. First, the scapholunate ligament is torn. Second, the lunocapitate dislocates. Third, the lunotriquetral ligament is torn. Fourth, the dorsal radiocarpal ligament is torn and the lunate dislocates volarly. If the injury is purely ligamentous, it is called a lesser arc injury. If the force goes through the bone rather than the ligament, a fracture occurs (most commonly scaphoid) and a great arc injury occurs.

Initial Management
Median nerve status should be documented at all stages of treatment as it is commonly injured. Closed reduction in the emergency room is recommended3. Ten pounds of traction is applied for ten minutes followed by gentle dorsiflexion and gentle volar flexion to allow the capitate to slip back into the sulcus of the lunate. Counter pressure must be maintained on the volar lunate. A palpable clunk is often felt. The only absolute indications for median nerve decompression are a progressive median nerve deficit and an acute carpal tunnel syndrome.

 

sauder_images
Figure 1. This is a clinical case of periluate dislocation in a 56 year-old male. The injury films show the capitate dislocated dorsal to the lunate. The intraoperative films show the carpus reduced, the proximal row is pinned and the scapholunate ligament is reattached to the scaphoid with a suture anchor. Despite stiffness, weakness, and a WCB claim, this patient returned to his previous occupation.

Definitive Management
Surgical reduction and fixation is recommended for all acute perilunate injuries unless the patient is not a surgical candidate4. If a closed reduction is achieved, open treatment can wait for up to ten days from the time of injury. A period of waiting and elevation can lessen the swelling seen at surgery and postoperatively. A dorsal midline incision allows for access to all the injured areas and is often all that is required. Entering through the third or fourth compartment reveals the dorsal capsule. A ligament sparing capsulotomy preserves the dorsal ligaments5. A volar approach can be added if a carpal tunnel release is needed and affords access to the rent in the volar capsule for suturing.

 

The head of the capitate should be assessed as damage is very common and helps the surgeon predict the likelihood of postoperative midcarpal arthrosis. The next step is to pass K-wires using an inside-out technique. This allows for precise placement of wires in the triquetrum and scaphoid and ensures that they will end up in the lunate in the proper position6. The wrist needs to be dislocated to accomplish this technique. The carpus is then reduced by traction and shoehorning the capitate back on to the lunate. If the scaphoid is fractured, it can be reduced and fixed with proximal to distal headless screw. Reduction is often more difficult in this situation than with an isolated scaphoid fracture and great care must be taken. K-wires used as joysticks can be very helpful.

If the scapholunate ligament is torn, the scapholunate joint needs to be reduced and pinned. Reduction can be performed by extending the scaphoid and flexing the lunate until the ligament lies in an anatomic position. A pointed reduction forceps placed on the two bones to reduce the gap is also very helpful. The previously placed K-wires can now be driven into the lunate. The lunotriquetral joint can be reduced in a similar fashion although there is often less rotation of the bones to contend with. The scapholunate ligament is then reattached to the bone from where it was avulsed (most often the scaphoid) with a small suture anchor. Images are obtained to ensure adequate reduction. If K-wires are left out of the skin, they can be bent over and stabilized with felt. A splint is applied.

Postoperative Management
At least one night in hospital is recommended to watch for acute carpal tunnel syndrome and to control pain. Elevation is extremely important as swelling can be significant. The splint is changed to a cast at two weeks. Pins are removed at ten weeks. Physiotherapy starts gradually with range of motion and slowly transitions to strengthening with a full recovery period of four to six months. This injury is a severe disruption of carpal anatomy and moderate outcomes are expected. Often motion and strength are not fully regained yet most people will return to their previous occupation. Midcarpal arthrosis is very common within a few years of injury but may not be symptomatic7,8.

 

References

 

  1. Herzberg G., Comtet J.J., Linscheid R.L., et al. Perilunate dislocations and fracture-dislocations: a multicenter study. J Hand Surg Am. 1993;18:768-779.
  2. Mayfield J.K. Patterns of injury to carpal ligaments: a spectrum. Clin Orthop 1984;187:36-42
  3. Watson-Jones R. Fractures and joint injuries. 3rd edition. Edinburgh (Scotland): E & S Livingstone; 1943. p. 568-77.
  4. Aspergis E., Maris J., Theodoratos G., et al. Perilunate dislocations and fracture-dislocations: closed and early open reduction compared in 28 cases. Acta Orthop Scand 1997;68(Suppl 275):55-9.D
  5. Berger R.A., Bishop A.T., Bettinger P.C. New dorsal capsulotomy for the surgical exposure of the wrist. Ann Plast Surg 1995;35(1):54-9.D
  6. Sauder D.J., Athwal G.S., Faber K.J., Roth J.H. Periluate Injuries. Orthop Clin N Am 2007;38:279-288.
  7. Herzberg G, Forissier D. Acute dorsal trans-scaphoid perilunate fracture-dislocations: medium-term results. J Hand Surg [Br] 2002;27:498-502.
  8. Hildebrand K.A., Ross D.C., Patterson S.D., et al. Dorsal perilunate dislocations and fracture-dislocations:questionnaire, clinical, and radiographic evaluation. J Hand Surg [Am] 2000;25:1069-79.

Submit Community Content

If you have orthopedic information that you would like to share with the Orthogate Community, please register/login and submit your news, event, job, article, case or workshop from the Submit Content menu under the My Account area. Learn more!