A new method for achieving compression in hindfoot arthrodesis

Area of Science:

• Orthopedic surgery
• Biomechanical engineering
• Podiatric medicine

Background:

• Achieving joint compression is crucial for successful hindfoot arthrodesis.
• Traditional lag screws offer eccentric compression, potentially limiting fusion efficacy.
• A novel post-and-screw construct aims to enhance compression distribution across the joint.

Purpose of the Study:

• To compare the biomechanical compression and clinical outcomes of a post-and-screw construct versus traditional lag screws in hindfoot arthrodesis.
• To evaluate the effectiveness of the post-and-screw technique in talonavicular fusions.

Main Methods:

• Biomechanical testing of the post-and-screw construct and traditional lag screws using synthetic bone models of the talonavicular joint.
• Cadaveric testing of the post-and-screw construct under simulated early weight-bearing conditions.
• Retrospective clinical comparison of 18 patients treated with the post-and-screw construct versus 18 patients treated with traditional lag screws for talonavicular fusion.

Main Results:

• The post-and-screw construct demonstrated more centralized compression in synthetic bone models compared to traditional screws.
• Neither construct provided sufficient strength to withstand early weight-bearing forces in cadaveric specimens.
• The clinical group using the post-and-screw construct experienced zero nonunions, while the traditional screw group had four nonunions.

Conclusions:

• The post-and-screw construct effectively distributes compression forces more uniformly across the arthrodesis site.
• Despite some biomechanical measures not being universally superior, the post-and-screw technique resulted in higher successful fusion rates in patients.
• This innovative construct shows potential for improved clinical outcomes in specific hindfoot arthrodesis scenarios and warrants further investigation.