Helical cutting as a new method for tendon-lengthening in continuity.

Area of Science:

• Orthopedic surgery
• Biomedical engineering
• Tendon biomechanics

Background:

• Surgical tendon lengthening often requires complete transection, compromising tendon continuity.
• Existing methods like z-plasty have limitations in achieving maximal length while preserving structural integrity.

Purpose of the Study:

• To develop and evaluate a new helical cutting technique for tendon lengthening.
• To assess the potential for increased tendon length and preserved continuity compared to conventional methods.

Main Methods:

• Forty bovine Achilles tendons were used, with 30 subjected to helical cuts at varying angles (60°, 45°, 30°).
• Tendon sections were either left unsutured or repaired with mattress stitches.
• Conventional z-plasty and untreated tendons served as controls.
• Uniaxial tension testing was performed to assess failure behavior.

Main Results:

• Helical cutting allowed for a wide range of length increases and tensile strengths, dependent on the helical angle.
• A 30° helical cut achieved a maximal length increase of 279% but had lower tensile strength (30 N).
• A 60° helical cut resulted in 212% length increase with significantly higher tensile strength (222 N).

Conclusions:

• Helical cutting preserves tendon continuity, unlike z-plasty.
• This technique enables greater tendon lengthening than z-plasty.
• Helical cutting offers adjustable tensile load resistance based on the chosen helical angle.