The Impact of Suture Caliber and Looped Configurations on the Suture-Tendon Interface in Zone II Flexor Tendon Repair

Minimally Invasive Suture Technique Pull-out to Repair the Acute Flexor Tendons in Zone II of the Hand

Objective:  To evaluate the safety and effectiveness of a modified pull-out suture technique in patients undergoing primary repair surgery for injuries to the flexor tendons of the fingers with Total Active Motion (TAM) as the primary outcome. Method:  A total of 29 patients (38 fingers) were chosen from both sexes, aged between 18 and 65 years with clean acute tendon laceration occurring within 15 days, in the Verdan's zone II of flexor tendon in the hand, when only the deep flexor tendon was sutured, either associated or not with digital nerve injury. The patients were operated on using the proposed technique and evaluated at 3, 9 and 24-weeks PO. The primary outcome was the assessment of Total Active Movement (TAM) and 3 classifications were employed: Strickland, IFSSH and Buck-Gramcko. Results:  We observed a total active motion (TAM) of 209.3 °at the end of 24 weeks; 83.0% of Good and Excellent results by the Modified Strickland Classification, 93% of Excellent results by the IFSSH Classification, and 97% of Good and Excellent results using the Buck-Gramcko Classification. There were no cases of rupture, but tendon adhesion was observed in 3 fingers. Conclusion:  The present suture technique proved to be safe and effective with a low rate of complications, obtaining an excellent functional result in terms of total active mobility, according to the evaluations and classifications used.

Comparison of Clinical Outcomes of Endoscope-Assisted Technique and Conventional Surgery in Zone 2 Flexor Tendon Repair

PURPOSE

The purpose of the study was to compare clinical outcomes between patients who underwent endoscope-assisted flexor tendon repair and those who underwent conventional surgery.

METHODS

Patients were divided into 2 groups. Group 1 (endoscope-assisted surgery) included 21 patients (27 fingers) and group 2 (conventional surgery) included 19 patients (25 fingers). Outcomes assessed included the mean total active motion, Strickland classification, prevalence of rerupture, tenolysis requirement, and infection rate.

RESULTS

The mean total active motion was 152.3° in group 1 and 134.7° in group 2, which was significantly higher in group 1 compared to group 2. An excellent or good outcome was achieved in 25 (92.5%) of the fingers in group 1 as opposed to 17 (68%) fingers in group 2.

CONCLUSIONS

We conclude that endoscope-assisted surgery is an alternative method for tendon surgery, enables a minimally invasive approach, and provides a favorable range of motion.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Strength, bulk and surgery time of ex situ versus in situ flexor tendon repair in a cadaveric model

The purpose of this study was to compare strength, bulk and time of repair of human cadaveric flexor digitorum profundus tendons repaired in situ versus ex situ. Ninety-six human cadaveric flexor digitorum profundus tendons were transected 5 mm distal to the A2-pulley and randomized to 2-strand, 4-strand or 6-strand repairs. We found no significant differences in repair strength between in situ and ex situ repairs, but repair strength increased with increasing number of strands. The cross-sectional area of the repair was not significantly related to the number of strands, but 4- and 6-strand in situ repairs were bulkier than ex situ repairs. In situ repair took longer, and repair time increased with increasing number of strands. We suggest that cadaveric studies of flexor tendon repair should be performed in situ in order to better mimic the clinical reality of tissue handling and repair bulkiness.

Beyond the Core Suture: A New Approach to Tendon Repair

Despite significant improvements in zone II flexor tendon repair over the last 2 decades, function-limiting complications persist. This article describes 2 novel repair techniques utilizing flexor digitorum superficialis (FDS) autografts to buttress the flexor digitorum profundus (FDP) repair site without the use of core sutures. The hypothesis being that the reclaimed FDS tendon autograft will redistribute tensile forces away from the FDP repair site, increasing overall strength and resistance to gapping in Zone II flexor tendon injuries compared with the current clinical techniques.

Methods

Two novel FDP repair methods utilizing portions of FDS have been described: (1) asymmetric repair (AR), and (2) circumferential repair. Ultimate tensile strength and cyclical testing were used to compare novel techniques to current clinical standard repairs: 2-strand (2-St), 4-strand (4-St), and 6-strand (6-St) methods. All repairs were performed in cadaveric sheep tendons (n = 10/group), by a single surgeon.

Results

AR and circumferential repair techniques demonstrated comparable ultimate tensile strength to 6-St repairs, with all 3 of these techniques able to tolerate significantly stronger loads than the 2-St and 4-St repairs (P < 0.0001). Cyclical testing demonstrated that AR and circumferential repair were able to withstand a significantly higher total cumulative force (P < 0.001 and P = 0.0064, respectively) than the 6-St, while only AR tolerated a significantly greater force to 2-mm gap formation (P = 0.042) than the 6-St repair.

Conclusion

Incorporating FDS as an autologous graft for FDP repair provides at least a comparable ultimate tensile strength and a significantly greater cumulative force to failure and 2-mm gap formation than a traditional 6-St repair.

Effects of a Q Suture Technique on Resistance to Gap Formation and Tensile Strength of Repaired Tendons: An Ex Vivo Mechanical Study

PURPOSE

The repair of digital flexor tendons following laceration should aim to prevent gapping at the repair site and restore the tensile strength of the tendons to facilitate postoperative movement. We present here a simple Q suture and test its effects on gap formation and tensile strength of the repaired tendons.

METHODS

Sixty porcine tendons were repaired with 3 2-strand sutures (Kessler, Kessler plus 2Q, and Kessler plus running sutures) and 3 4-strand sutures (double Kessler, double Kessler plus 2Q, and double Kessler plus running sutures). The specimens were subjected to a cyclic loading. At each cycle, the number of tendons that initiated gapping or formed a 2-mm gap at the repair site was determined. After the cyclic load testing, the gap distance between tendon ends and the ultimate strength of the repaired tendons was measured.

RESULTS

In both 2-strand and 4-strand tendon repairs, augmentation by insertion of the 2Q sutures reduced the number of tendons that showed 2-mm gaps ends during loading. Compared with the single Kessler and Kessler plus running sutures, Kessler plus 2Q suture significantly increased the ultimate strength of the tendon repair. Compared with the double Kessler and double Kessler plus running sutures, double Kessler plus 2Q suture significantly decreased the gap distance at the repair site after cyclic loading.

CONCLUSIONS

The Q suture technique effectively enhances the resistance to gap formation of 2-strand and 4-stand tendon repair. It also improves the tensile strength of 2-strand Kessler repairs.

CLINICAL RELEVANCE

The Q suture is a simple technique that can resist gap formation and strengthen the tensile strength of the repaired tendons in the laboratory setting.