Executive Editor: Chris Colton

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

Proximal phalanx - MCP joint - avulsion fracture

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Glossary

1 Principles top

Avulsion fracture of proximal phalanx MCP joint – Collateral ligament reattachment enlarge

Avulsion fractures

Avulsion fractures are the result of side-to-side (coronal) forces acting on the finger, putting the collateral ligament under sudden tension. The ligament is usually stronger than the bone, causing the ligament to avulse a fragment of bone at its insertion.
Avulsion fractures result in marked joint instability.
If the fracture is not displaced, nonoperative treatment is usually indicated (buddy taping to the adjacent finger). Displaced fractures, however, must be internally fixed.
In some circumstances, the fracture is severely comminuted with multiple tiny fragments. It may be preferable to excise the fragments and reattach the collateral ligaments directly to the bone.

View animation


Avulsion fracture of proximal phalanx MCP joint – Collateral ligament reattachment enlarge

Suture anchors or tunneling

Two alternative techniques are available for collateral ligament reattachment: suture anchors, or tunneling.
The advantage of suture anchors is the relative ease of the procedure. It is also a time-saving technique.
Tunneling is the more demanding procedure, but it is significantly less expensive.

2 Excision of the fragments top

Avulsion fracture of proximal phalanx MCP joint – Collateral ligament reattachment enlarge

Excise fragments

All comminuted fragments need to be removed in order to prevent osteoarthritis.
If any fragments remain attached to the ligament, they have to be excised with a fine scalpel.


Avulsion fracture of proximal phalanx MCP joint – Collateral ligament reattachment enlarge

Visualize the joint

Laterally deviate the phalanx in the opposite direction to gain maximal visualization of the joint (open book). Ensure that all bony fragments have been removed.

3 Option 1: suture anchor fixation top

Avulsion fracture of proximal phalanx MCP joint – Collateral ligament reattachment enlarge

Drill anchor hole

Keep the phalanx laterally deviated to visualize maximally the area of the fracture at the base of the phalanx.
Make a perforation of the same diameter as the anchor to be used, as close as possible to the subchondral bone.


Avulsion fracture of proximal phalanx MCP joint – Collateral ligament reattachment enlarge

Insert anchor

Insert the anchor according to the manufacturer’s instructions. Ensure that the whole anchor is completely buried in the bone.


Avulsion fracture of proximal phalanx MCP joint – Collateral ligament reattachment enlarge

Insert the sutures

Insert the sutures into the free end of the ligament.
Reapproximate the ligament to the phalanx and make a loop in each end of the thread as an anchoring pass. Tie a knot to secure the ligament to the phalanx.
Reattaching the ligament close to the subchondral bone will ensure a smooth surface for ideal mobility.


Avulsion fracture of proximal phalanx MCP joint – Collateral ligament reattachment enlarge

Pitfall

If the ligament is reattached too far from the joint surface, there is a sharp edge in the joint which may cause cartilage abrasion and eventually result in degenerative joint disease.

4 Option 2: tunneling top

Avulsion fracture of proximal phalanx MCP joint – Collateral ligament reattachment enlarge

Drill holes

A pair of parallel perforations, using a 1.0 mm drill or a K-wire, can be made as close as possible to the subchondral bone, angled from proximal to distal, and from palmar to dorsal, penetrating the opposite cortex.
A drill sleeve for soft-tissue protection is mandatory.


Avulsion fracture of proximal phalanx MCP joint – Collateral ligament reattachment enlarge

Insert sutures

4.0 nonresorbable, threaded sutures, with straight needles, are used.
Insert the sutures obliquely through the end of the ligament, make a loop in each end of the thread as an anchoring pass, and thread each needle through a drill hole.


Avulsion fracture of proximal phalanx MCP joint – Collateral ligament reattachment enlarge

Reapproximate the ligament

Make a small incision in the opposite side of the finger to retrieve the sutures. Cut off the needles, pull the sutures to approximate the ligament, and tie a knot over the cortical bone.

v1.0 2008-11-08