The minimum required overlap length for tendon transfer A biomechanical study on human tendons

Area of Science:

• Orthopedic surgery
• Biomedical engineering
• Tendon biomechanics

Background:

• Tendon transfer surgeries require stable tenorrhaphy for successful outcomes.
• Adequate tendon overlap is crucial for achieving sufficient tensile strength.
• The Woven-Fridén (WF) tenorrhaphy is a novel technique offering potential advantages over the Pulvertaft method.

Purpose of the Study:

• To evaluate the biomechanical properties of the Woven-Fridén (WF) tenorrhaphy.
• To determine the optimal tendon overlap for achieving sufficient tensile strength in WF tenorrhaphy.
• To compare the tensile strength of WF tenorrhaphy with varying overlaps to native tendons.

Main Methods:

• Performance of WF tenorrhaphies with 1.5 cm, 2 cm, and 3 cm tendon overlaps.
• Tensile testing to assess biomechanical properties, including ultimate load and stiffness.
• Derivation of a formula to quantify the relationship between tendon overlap and ultimate load.

Main Results:

• A 2 cm tendon overlap in WF tenorrhaphy achieved a mean ultimate load of 217 N, indicating sufficient tensile strength.
• Increasing overlap beyond 3 cm yielded diminishing returns in tensile strength.
• Calculated ultimate load for 4 cm overlap (397 N) approached the maximal load of native tendons (435 N).

Conclusions:

• The Woven-Fridén (WF) tenorrhaphy demonstrates promising biomechanical properties for tendon repair.
• A 2 cm tendon overlap is sufficient for achieving adequate stability in WF tenorrhaphy.
• The WF technique offers a potentially superior alternative to established methods like the Pulvertaft technique.