Executive Editor: Rick Buckley, Chris Colton

Authors: Florian Gebhard, Phil Kregor, Chris Oliver

Patella Extraarticular avulsion fracture

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Glossary

1 Principles top

The reattachment of such a strong soft-tissue structure as the patellar tendon to the inferior pole of the patella, requires a technique which not only achieve an excellent suture hold in the tendon, but also preserves its vascularity. The Krackow suture realizes these goals.

2 Patient preparation and approach top

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Patient preparation

This procedure is normally performed with the patient in a supine position with the knee flexed 30°.


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Approach

For this procedure a mid-axial longitudinal approach is used.

3 Reduction and fixation top

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Fracture debridement

The knee joint and fracture lines must be irrigated and cleared of blood clots and small debris to allow exact reconstruction.

An image intensifier should always be available so that the final result can be checked in the AP and lateral planes.


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Krackow whip stitch

The Krackow whip stitch uses 2 or more locking loops inserted into each side of the patellar tendon. The Krackow whip stitch is stronger than the Kessler, or Bunnell, stitches that are used for repairing smaller tendons.

Open the patellar tendon retinaculum longitudinally. Insert two Krackow stitches of #5 non-absorbable suture into the patellar tendon, as illustrated.


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Make holes in the main fragment

Make 4 longitudinal drill holes in the proximal patellar fragment.


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Ligament fixation

Using a suture passer from proximal to distal, pull the free ends of the sutures through the proximal segment.

The sutures are then tightened and tied deep to the quadriceps tendon, with the knee in full extension.

Be sure that there is good contact between the tendon and the bone.


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Augmentation of patella ligament tendon repair - patella baja

To protect this suture repair during the healing process, a protective cerclage wire can be passed around the upper pole of the patella and through a transverse drill hole at the tibial tubercle.

This wire frequently breaks later, and it is best to remove it once healing is assured at 3-4 months.


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If the cerclage wire is tightened too tightly it will not be possible to flex the knee and a patella baja will occur.

This complication must be avoided and can cause severe limitation of knee flexion. If there is need for a cerclage wire to protect the patellar tendon, a patella baja can be produced by misjudging the exact length of the patellar tendon. The opposite knee will indicate the correct position of the patella as described under x-ray evaluation.

v2.0 2019-03-21