Flexor Tendon Repair Using a New Looped Six- and Eight-Strand Technique-A Biomechanical Analysis.

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Sports Medicine

Background:

• Tendon injuries are common, leading to significant socioeconomic costs.
• Current flexor tendon repairs have high re-rupture rates (3.1-11.7%).
• Existing repairs balance tensile strength with repair bulk, often using four core strands and epitenon sutures.

Purpose of the Study:

• To evaluate six- and eight-strand looped core suture techniques for flexor tendon repair.
• To determine if these techniques provide sufficient tensile strength to omit epitenon sutures.
• To compare these novel techniques against the conventional four-strand Adelaide repair regarding strength and bulk.

Main Methods:

• 120 human flexor digitorum profundus tendons were harvested.
• Tendons were repaired using six groups: Adelaide (4-strand) ± epitenon, 6-strand ± epitenon, and 8-strand ± epitenon.
• Repairs were tested for load to failure using axial tensile loading, and cross-sectional area (CSA) changes were measured.

Main Results:

• Eight-strand looped sutures without epitenon achieved tensile strength comparable to the Adelaide repair with epitenon, with less increase in CSA.
• Six-strand looped sutures with epitenon showed similar strength to higher-strand techniques.
• Suture breakage was the primary failure mode across groups.

Conclusions:

• An eight-strand looped core suture without epitenon offers a strong, less bulky alternative for flexor tendon repair.
• Six-strand looped sutures with epitenon provide adequate strength with potentially less tissue manipulation.
• Findings support individualized flexor tendon repair strategies based on biomechanical needs and clinical context.