6-strand Technique Research Articles

Biomechanical analysis of a new 8-strand technique for flexor tendon repair

We sought to compare the strength and rupture sites of a new 8-strand suture technique with those of an established 6-strand flexor tendon repair through biomechanical analysis. This new 8-strand suture pattern places minimal suture material in the remodeling zone and focuses on protecting the knot, a well-known weak point of the suture construct. The knot was buried within the tendon so as to not interfere with tendon gliding. In a biomechanical simulation, strength and rupture sites were compared with those of the 6-strand repair. We repaired a total of 54 porcine flexor tendons using one of the two techniques (n=27 each). Tensile strength at 2-mm gap formation and ultimate failure load were determined. Afterwards, we dissected the tendons to identify the rupture site of the suture material. The new 8-strand suture had a significant higher ultimate load to failure (87.7N) and 2-mm gap load (71.6N) compared to the 6-strand technique (57.7N and 45.9N) (P<0.001). Whereas the rupture site of the core suture in the 6-strand technique was mainly located next to the knot (81.5%), the suture seemed to fail independently from this weak spot in the 8-strand technique (11.1%). This new 8-strand technique achieves a strong flexor tendon repair in a biomechanical model. Additional cross-locking on either side of the knot seems to contribute to the repair's strength. The resulting higher ultimate failure load and 2-mm gap load may allow more aggressive active motion-based postoperative rehabilitation.

Zone II Flexor Tendon Repair in a 13-Month-Old: Report of a Complication

Despite early cautions against the primary repair of zone II flexor tendon injuries, recent advances in surgical technique and suture materials have allowed such repairs to become commonplace. The 6-strand repair technique is rarely applied to the young pediatric population, however, to our knowledge, no English-language articles have described this method of primary repair in zone II of children less than 2 years old. A 13-month-old male presented flexor digitorum profundus repair after lacerating it in zone II on a sharp aluminum can. The tendon was repaired with a 6-strand technique, using a 4.0 Fiberloop for the core suture and 6.0 Prolene for the epitendinous suture. Approximately four months after surgery, the patient developed a palmar collection at the level of his middle phalanx and a serosanguinous sinus tract at the distal interphalangeal crease. During the revision surgery, the inspection of the repaired tendon revealed a small gap filled with scar tissue. There was no evidence of new fistula formation at his final visit one month after the second procedure. After the revision, the patient could move his digit with minimal loss of range of motion at the distal interphalangeal joints. Unfortunately, he was subsequently lost to follow up. This surgical technique was selected to provide a strong repair that would allow the early postoperative movement. In retrospect, a 6-strand repair with braided suture is not ideal in young children as the bulky suture can cause a foreign-body reaction and possibly extrude through the skin. Additionally, the immobilization with a long-arm cast remains a valuable tool after tendon repair in infants who cannot voluntarily restrict their movements.

Flexor Tendon Repair in Zone II With 6-Strand Techniques and Early Active Mobilization

Flexor Tendon Repair in Zone II With 6-Strand Techniques and Early Active Mobilization

Flexor Tendon Repair in Zone II With 6-Strand Techniques and Early Active Mobilization

There are many biomechanic studies of 6-strand suture techniques for active mobilization, but few reports have described the clinical outcome in zone II flexor tendon lacerations. We discuss the clinical results of zone II flexor tendon repair using 2 of these techniques followed by controlled early active mobilization. Six-strand sutures using the number 1 technique by Yoshizu or a triple-looped suture technique were used to repair flexor tendons in 27 fingers from 21 consecutive patients. Fingers were mobilized by combining active extension and passive or active flexion in a protective splint for the first 3 weeks after surgery. The follow-up period averaged 13 months. Based on the original Strickland criteria, the results were excellent in 17 fingers, good in 9, and fair in 1. The average flexion was 62 degrees for distal interphalangeal joints and 91 degrees for proximal interphalangeal joints. None of the repaired tendons ruptured. The 6-strand flexor tendon suture technique followed by controlled active mobilization protected with a dorsal splint is safe, produces no ruptures, and achieves very good results in zone II flexor tendon laceration repair. Therapeutic, Level II.