Cyclical testing of zone II flexor tendon repairs.

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Hand Surgery

Background:

• Zone II flexor tendon lacerations pose significant challenges in hand surgery.
• Effective tendon repair is crucial for restoring function and enabling early mobilization.
• Existing repair techniques vary in biomechanical strength and suitability for early active motion.

Purpose of the Study:

• To compare the biomechanical properties of Kessler, Strickland, and modified Becker flexor tendon repairs.
• To evaluate the strength and gap resistance of these repairs under simulated physiological loading conditions.
• To determine the most suitable repair technique for facilitating early active motion protocols in flexor tendon healing.

Main Methods:

• Simulated zone II flexor tendon lacerations were created in cadaveric hands.
• Three repair techniques (Kessler, Strickland, modified Becker) were performed, augmented with epitenon sutures.
• Tendons underwent cyclic loading (100 cycles) followed by testing to failure using a tensiometer with a curvilinear model.

Main Results:

• No repaired tendons failed during the cyclic loading phase.
• The modified Becker repair exhibited significantly greater maximum load to failure and pinch force compared to Kessler and Strickland techniques.
• Average gapping after cyclic loading was minimal for all techniques, with Strickland showing 0.00 mm.

Conclusions:

• All three tested flexor tendon repair techniques demonstrated adequate strength for passive motion protocols.
• The modified Becker repair offers superior biomechanical strength, exceeding forces estimated for active motion during tendon healing.
• The modified Becker repair is recommended for its potential to allow earlier and safer active mobilization post-surgery.