Cyclic loading of olecranon fracture fixation constructs.

Area of Science:

• Orthopedic Surgery
• Biomechanics
• Trauma Care

Background:

• Olecranon fractures and osteotomies often face fixation challenges, including nonunion and loss of stability, despite reported good outcomes.
• Existing fixation methods lack comprehensive evaluation under clinically relevant cyclic loading conditions.
• The study addresses the need for robust testing of olecranon fixation techniques under physiologic stress.

Purpose of the Study:

• To evaluate and compare the stability of various olecranon fracture fixation techniques.
• To assess fixation performance under simulated physiologic cyclic loads.

Main Methods:

• Ten cadaveric elbows underwent simulated 50% transverse olecranon fractures.
• Fixation methods tested included intramedullary and cortically fixed tension bands, and a 7.3-mm cancellous screw with and without a tension band.
• Cyclic loading simulated active range of motion and pushing up from a chair; displacement was measured.

Main Results:

• Fixation using the 7.3-mm cancellous screw, with or without a tension band, demonstrated superior stability, approximately five times better than Kirschner wire techniques.
• The addition of a tension band to the intramedullary screw enhanced fixation stability.
• The AO tension band construct did not achieve compression across the osteotomy gap in any tested configuration.

Conclusions:

• A 7.3-mm screw combined with a tension band provides superior fixation for simulated displaced transverse olecranon fractures compared to Kirschner wire constructs or screw-only fixation.
• The study findings challenge the traditional AO tension band principle's efficacy in olecranon fracture fixation.
• Postoperative management should consider limiting active range of motion to prevent fracture distraction.