Executive Editor: Chris Colton

Authors: Matej Kastelec, Renato Fricker, Fiesky Nuñez, Terry Axelrod

Carpus - Perilunate fractures

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Glossary

1 Introduction top

Carpus – Perilunate fractures – Open reduction internal fixation enlarge

Perilunar fracture dislocations present an extensive spectrum of injury. Fractures of carpal bones around the lunate may occur, instead of pure ligamentous ruptures, when the disrupting force propagates around the midcarpal joint: 95% of all perilunar fractures are trans-scaphoid.
Recognition and repair of all bony and soft-tissue components are essential in order to restore carpal stability, and to prevent posttraumatic degenerative joint disease (DJD).


Carpus – Perilunate fractures – Open reduction internal fixation enlarge

There are many combinations of injury patterns.
Concurrent bony and soft-tissue lesions of the carpus are not mutually exclusive (e.g. concomittant scaphoid fracture and scapholunate rupture).
The radiograph shows a transscaphoid perilunar fracture dislocation, associated with a fracture of the ulnar styloid.


Carpus – Perilunate fractures – Open reduction internal fixation enlarge

The proximal pole of the scaphoid was displaced deeply into the second extensor compartment.

2 Reduction top

Carpus – Perilunate fractures – Open reduction internal fixation enlarge

Small fragments

Osteochondral fragments are either fixed, or removed, depending on their size.
Small fragments must be removed, as in this case of an osteochondral fragment from the head of the capitate.


Carpus – Perilunate fractures – Open reduction internal fixation enlarge

Reduction of the scaphoid

The transscaphoid perilunar fracture dislocation is the most common of all perilunar displacements.


Carpus – Perilunate fractures – Open reduction internal fixation enlarge

Reduction of the the displaced scaphoid is the first step prior to screw fixation, using a double-pitch headless screw. Preserve the vascular supply that enters through the dorsoradial ridge.

3 Screw Fixation top

Carpus – Perilunate fractures – Open reduction internal fixation enlarge

Guide wire insertion

The orientation of the shaft of the first metacarpal should act as an alignment guide for K-wire insertion.


Carpus – Perilunate fractures – Open reduction internal fixation enlarge

The entry point is at the proximal pole, directly adjacent to the scapholunate ligament insertion.
Image intensification is used to confirm accurate wire placement along the scaphoid axis, and as perpendicular as possible to the fracture plane.
Do not penetrate the scaphotrapezial joint with the guide wire.


Carpus – Perilunate fractures – Open reduction internal fixation enlarge

Measuring the length

Two methods can be employed for measuring the required screw length:

  1. Insert a measuring device over the guide wire, through the dedicated drill guide which must be firmly positioned on the proximal pole for a reliable measurement.
  2. If no drill guide was used, take another guide wire of the same length and place its tip onto the insertion point. The length that protrudes beyond the end of the first guide wire indicates the length of the drill hole for the screw.

In most cases, a 16-20 mm screw is the appropriate size.


Carpus – Perilunate fractures – Open reduction internal fixation enlarge

Drilling and tapping

Using a power drill will exert less force on the fragments than manual drilling, and reduces the risk of displacement. A small power drill with slow rotation is preferred.
Use Ringer lactate to cool the drill bit, in order to minimize thermal damage.
Then tap the drill hole manually if no self-tapping screws are used.


Carpus – Perilunate fractures – Open reduction internal fixation enlarge

Screw insertion

The proximal end of the screw should be advanced until it is buried under the subchondral bone.

Caution
The distal thread must not lie within the fracture plane as this would prevent compression and risk fracture separation.

4 Comminution top

Carpus – Perilunate fractures – Open reduction internal fixation enlarge

Comminuted scaphoid

From the plain radiographs, it is not always possible to recognize the presence of comminution. Post-reduction CT scans are always advisable.


Carpus – Perilunate fractures – Open reduction internal fixation enlarge

In cases of extensive comminution, or scaphoid bone defects, fixation with a headless screw alone is unlikely to give enough stability.


Carpus – Perilunate fractures – Open reduction internal fixation enlarge

In cases of comminution, a combination of two screws, or a screw and a K-wire, may be necessary to achieve the required stability.
Before the final fixation, reduce all displaced fragments.


Carpus – Perilunate fractures – Open reduction internal fixation enlarge

Final fixation

The goal of final scaphoid fixation is to achieve sufficient stability. Insert the screws and/or K-wires in such a way that this goal is achieved. Use bone graft from the distal radius for scaphoid bone defects, in order to assist fracture healing.


Carpus – Perilunate fractures – Open reduction internal fixation enlarge

The accompanying illustrations show a comminuted scaphoid fracture fixed with  two headless screws. The second screw was needed to improve stability of the construct.

5 Lunotriquetral ligament repair top

Carpus – Perilunate fractures – Open reduction internal fixation enlarge

In transscaphoid perilunar injuries, the lunotriquetral ligament can be torn from the lunate (in most cases), from the triquetrum, in its mid-substance, or as a bony avulsion from either bone. There must be sufficient ligament remnant for repair with bone anchors. Otherwise, it is repaired by direct suture.


Carpus – Perilunate fractures – Open reduction internal fixation enlarge

A suture anchor is inserted into the debrided area of the avulsion.


Carpus – Perilunate fractures – Open reduction internal fixation enlarge

The LT joint is reduced, and two 1.4 mm K-wires are inserted percutaneously from the ulnar side of the triquetrum across the LT joint into the lunate. Confirm the position of the wires using image intensification.
The suture of the ligament can now be completed.

6 Palmar approach top

Carpus – Perilunate fractures – Open reduction internal fixation enlarge

A palmar approach will reveal the characteristic disruptions of the extrinsic palmar ligaments, which occur through the space of Poirier.  A rent in the palmar capsule, between proximal and distal ligament arches, exposes the midcarpal joint.


Carpus – Perilunate fractures – Open reduction internal fixation enlarge

The midcarpal joint is irrigated. Loose bodies or subchondral flakes are removed, and the rent is repaired anatomically using interrupted resorbable sutures.

7 Larger osteochondral articular defects top

Carpus – Perilunate fractures – Open reduction internal fixation enlarge

In cases of larger osteochondral defects (as in this illustration of a defect of the articular surface of the head of the capitate), aftertreatment with an external fixator is advisable.


Carpus – Perilunate fractures – Open reduction internal fixation enlarge

Gentle distraction during healing offloads the damaged joint and facilitates the formation of fibrocartilage.

8 Palmar approach top

Perilunate – Lunotriquertal dissociation – ORIF – Open reduction internal fixation enlarge

A palmar approach will reveal the characteristic disruptions of the extrinsic palmar ligaments, which occur through the space of Poirier.  A rent in the palmar capsule, between proximal and distal ligament arches, exposes the midcarpal joint.


Perilunate – Lunotriquertal dissociation – ORIF – Open reduction internal fixation enlarge

The midcarpal joint is irrigated. Loose bodies, or subchondral flakes, are removed,...


Perilunate – Lunotriquertal dissociation – ORIF – Open reduction internal fixation enlarge

... and the rent is repaired anatomically using interrupted resorbable sutures.

v1.0 2008-11-08