Authors of section

Authors

Jörg Auer, Larry Bramlage, Patricia Hogan, Alan Ruggles, Jeffrey Watkins

Executive Editor

Jörg Auer

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Screw fixation

1. Principles

Two-point fixation

When ever possible because of the size of the fracture fragment, two-point fixation is recommended, to ensure interfragmentary fixation and rotational stability.

Two-point fixation

Positioning and access

In lateral recumbency, the fragment should always be positioned uppermost.

Palmar/plantar eminence fractures of the proximal phalanx are usually reduced closed. Either small incisions or arthroscopic control are useful in assisting anatomic reduction.

Insertion of the screws is accomplished by means of stab incisions through the associated collateral ligament.

Lateral recumbency

2. Reduction

Achieving reduction

Minimally displaced fractures may require no reduction prior to internal fixation.

Displaced fractures must be reduced appropriately.

Either small incisions or arthroscopic control are useful in assisting anatomic reduction.
Flexion and manipulation of the fetlock joint is often needed to obtain reduction.

Reduction

Temporary fixation

Insertion of the screws is accomplished by means of stab incisions through the associated collateral ligament.

Temporary fixation

Prior to placement of the screws, temporary fixation using a 2 mm drill bit, a reduction forceps and/or radiodense markers is applied to radiographically identify the ideal position for the screw(s).

screw fixation

3. Fixation

Insertion of the first screw

The ideal position of the first screw is perpendicular to the fracture plane and as close as possible to the joint surface.

A second, usually more distal screw should be used if the fragment is large enough to accommodate two screws.

Insertion of the first screw

Number and size of screws

Interfragmentary fixation is usually first achieved with a 4.5 mm cortex screw inserted in lag fashion.

Subsequently either a 4.5 mm or 3.5 mm screw are inserted, depending on the fracture fragment size. In some instances, two 3.5 mm screws will be more appropriate than a single 4.5 mm screw.

Number and size of screws

4. Aftertreatment

Recovery

External coaptation is recommended for recovery from general anesthesia. The surgeon may prefer to use a temporary immobilization device that is removed immediately after recovery from anesthesia. Half-limb casts, if elected, should be removed shortly after recovery from anesthesia.

Prolonged cast immobilization is contraindicated, because it weakens the soft-tissue support to the fetlock joint. Normal fetlocks are stable during weight bearing, minimizing the tension on the collateral ligament. Bandaging to restrict flexion of the fetlock joint is useful.

Postoperative management and exercises

Postoperative management includes box stall confinement for 8 weeks with hand-walking exercise beginning 2-4 weeks postoperatively. The operative site is bandaged for 4 weeks after surgery and analgesics used for 10 days postoperatively.

screw fixation

Radiographic follow up

Fracture healing is followed radiographically at 8 weeks post surgery. If the fracture is healing satisfactorily small paddock exercise for 4 weeks followed by field exercise is prescribed. Additional radiographs are taken 12-16 weeks post surgery.

Return to training is typically 3-4 months post injury.

If significant collateral ligament injury is present, further rest combined with repeated ultrasonographic evaluations may be needed.

screw fixation