Executive Editor: Chris Colton

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

Perilunate - Scapholunate dissociations

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Glossary

1 Introduction top

Carpal bones - Perilunate - Scapholunate dissociation - Ligament repair enlarge

Rupture of the scapholunate ligament is the first event in any sequence of perilunar ligament ruptures. It is the most common pattern of wrist instability.


Carpal bones - Perilunate - Scapholunate dissociation - Ligament repair enlarge

Its characteristics are the dissociation of the scaphoid and the lunate, with flexion of the scaphoid, and extension of the lunate.
The reconstruction of rotational stability between the scaphoid and the lunate is the key to restoring normal wrist kinematics.

2 Reduction top

Carpal bones - Perilunate - Scapholunate dissociation - Ligament repair enlarge

Two joystick K-wires are inserted into the scaphoid and the lunate.


Carpal bones - Perilunate - Scapholunate dissociation - Ligament repair enlarge

They are used to reduce the scapholunate joint.


Carpal bones - Perilunate - Scapholunate dissociation - Ligament repair enlarge

Assessment of dorsal and proximal ligament parts

In most of the cases, the SL ligament is avulsed from the scaphoid, and still in contact with the lunate.
The avulsion site is debrided for better contact and healing.

3 Suture anchors top

Carpal bones - Perilunate - Scapholunate dissociation - Ligament repair enlarge

A suture anchor is inserted into the debrided area of the avulsion.
The suture anchor must be placed in position slightly oblique to resist rotational forces between both bones (the scaphoid should be pulled from flexion, or the lunate from extension).
The anchor is placed distally in the scaphoid, or proximally in the lunate.
Often, one anchor will be sufficient, but occasionally two anchors will be needed.


Carpal bones - Perilunate - Scapholunate dissociation - Ligament repair enlarge

The suture is inserted into the ligament proximally when it is attached to the lunate, and distally when it is attached to the scaphoid.

4 Option top

Carpal bones - Perilunate - Scapholunate dissociation - Ligament repair enlarge

If bone anchors are not available, the avulsed ligament is attached using sutures which are passed through small tunnels drilled into the proximal pole of the scaphoid, as illustrated.

5 Anatomical reduction top

Carpal bones - Perilunate - Scapholunate dissociation - Ligament repair enlarge

Use the two joysticks to extend the scaphoid, flex the lunate, and then close the gap.


Carpal bones - Perilunate - Scapholunate dissociation - Ligament repair enlarge

A pointed reduction clamp helps to secure the reduction temporarily.
Confirm reduction using image intensification.


Carpal bones - Perilunate - Scapholunate dissociation - Ligament repair enlarge

Both bones are secured in position by transfixation with two K-wires inserted percutaneously from scaphoid to lunate.
Again, confirm the position of both wires using image intensification.

6 Ligament repair top

Carpal bones - Perilunate - Scapholunate dissociation - Ligament repair enlarge

Afterwards, the sutures are tied to the bone anchor.


Carpal bones - Perilunate - Scapholunate dissociation - Ligament repair enlarge

If the ligament is torn in the mid-substance, directly repair with resorbable sutures.


Carpal bones - Perilunate - Scapholunate dissociation - Ligament repair enlarge

Cut the K-wires and bend them so they rest underneath the skin.

v1.0 2008-11-08