Authors of section

Authors

Anton Fürst, Christoph Lischer

Executive Editor

Jörg Auer

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Screw fixation

1. Principles

Anatomic reduction

Perfect anatomic reconstruction is essential for articular fractures to avoid the development of arthritic changes.

Trochlear ridge fractures of the talus - screw fixation

Stabilization

In most cases, two or three 3.5 or 4.5 mm cortex screws are sufficient to stabilize the fracture.

Trochlear ridge fractures of the talus - screw fixation

2. Preparation and approach

This procedure is performed with the patient placed in lateral recumbency and through stab incisions.

screw fixation

3. Arthroscopic evaluation

The arthroscope is introduced through a medial approach.

Trochlear ridge fractures of the talus - screw fixation

After arthroscopic evaluation of the fracture, the joint is flushed and the blood and small fragments removed.

Trochlear ridge fractures of the talus - screw fixation

4. Reduction

Most trochlear fractures are only slightly dislocated and reduction can be easily achieved by compression with blunt instruments.

Anatomic reduction is confirmed by intraoperative radiographs as well as arthroscopic evaluation.

Trochlear ridge fractures of the talus - screw fixation

When perfect reduction is achieved, it is temporarily held in place by a temporary interfragmentary K-wire.

Trochlear ridge fractures of the talus - screw fixation

5. Screw fixation

Preparation of the drill hole

A stab incision is made over the planned screw site followed by a 4.5 mm glide hole drilled perpendicular to the fracture plane from the dorsal aspect of the ridge. Penetration of the drill bit is continuously monitored radiographically or fluoroscopically.
Care is taken to avoid undue penetration of the parent portion of the bone with the glide hole.

Trochlear ridge fractures of the talus - screw fixation

Preparation of the thread hole

The 3.2 mm drill guide is inserted into the glide hole and the thread hole is prepared.

In most cases one cannot go through the entire talus and has to create a blind thread hole.

Trochlear ridge fractures of the talus - screw fixation

Countersinking

A deep countersink depression is prepared in the articular surface to accept the entire screw head.

Trochlear ridge fractures of the talus - screw fixation

Measuring screw length

A depth gauge is introduced to measure the required screw length.
With a blind hole, the screw should be 3-4 mm shorter than the measured depth.

Trochlear ridge fractures of the talus - screw fixation

Screw insertion

The hole is carefully tapped.

Trochlear ridge fractures of the talus - screw fixation

The first screw is inserted and thoroughly tightened.

Trochlear ridge fractures of the talus - screw fixation

One or two additional screws are inserted applying identical technique.

The arthroscopy portal and the stab incisions prepared for screw insertion are closed by simple interrupted skin sutures.

Trochlear ridge fractures of the talus - screw fixation

Radiographic confirmation of the final construct

Trochlear ridge fractures of the talus - screw fixation

6. Case example

Case example of a 16 year old Thoroughbred.

Trochlear ridge fracture of the talus - screw fixation

Fracture line as identified under arthroscopic supervision.

Trochlear ridge fracture of the talus - screw fixation

Drilling the glide hole.

Trochlear ridge fracture of the talus - screw fixation

Determining the screw length with the depth gauge.

Trochlear ridge fracture of the talus - screw fixation

Tapping of the thread hole.

Trochlear ridge fracture of the talus - screw fixation

Screw insertion.

Trochlear ridge fracture of the talus - screw fixation

7. Aftertreatment

A bandage is applied, the horse recovered, and maintained for two weeks. The bandage should be changed every 5 days.

The sutures are removed after 10 days.

The horse is kept in a stall for 4 weeks. Hand-walking exercises are indicated for another 4 weeks before the horse can be put back into training.

Follow-up x-rays are taken 8 weeks after surgery to evaluate fracture healing.

screw fixation

Radiographic control after two years. The fracture has healed completely and no signs of degenerative joint disease can be seen.

screw fixation