Biomechanical evaluation of a novel barbed suture pattern with epitendinous suture augmentation in a canine flexor tendon model

Biomechanical Comparison of a 3-Loop Pulley and a 4-Loop Pulley Suture for Tenorrhaphy in the Canine Gastrocnemius Tendon

OBJECTIVE

 The aim of this study was to compare a 3-loop pulley (3LP) suture pattern with a 4-loop pulley (4LP) suture pattern for the tenorrhaphy of the canine gastrocnemius tendon STUDY DESIGN:  Randomized, cadaveric, biomechanical study of 30 canine gastrocnemius tendons. Tendons were transected and repaired with either 3LP or 4LP suture pattern with 2-0 polypropylene. A tensile load was applied at 25 mm/min until construct failure. The load required to form a 1 mm gap, 3 mm gap and maximum load at failure was recorded and compared between groups.

RESULTS

 The estimated mean load to form a 1 mm gap for the 3LP and 4LP was 28.4 N (95% confidence interval [CI]: 24.0-32.6N) and 45.5 N (95% CI: 40.7-50.1N) respectively. The 4LP mean load to form a 1 mm gap was 17.1 N (95% CI: 11.7-22.5N) greater than the 3LP. The estimated mean load to form a 3mm gap for the 3LP and 4LP was 39.7 N (95% CI: 34.1-45.4N) and 55.0 N (95% CI: 49.3-60.9N) respectively. The mean load to form a 3mm gap was 15.3 N (95% CI: 8.5-21.9N) greater in the 4LP than the 3LP. The estimated mean load for failure in the 3LP and 4LP was 41.2 N (95% CI: 35.6-46.9 N) and 54.3 N (95% CI: 48.7-60.3 N) respectively.

CONCLUSION

 A 4LP pattern was biomechanically superior to a 3LP pattern, as demonstrated by a greater load required to form both a 1 and 3 mm gap and a greater load for failure CLINICAL SIGNIFICANCE:  A 4LP suture pattern better resists gap formation and requires greater load prior to construct failure compared with a 3LP, in this canine gastrocnemius model.

Comparison of the mechanical properties and anchoring performance of polyvinylidene fluoride and polypropylene barbed sutures for tendon repair

Polyvinylidene fluoride (PVDF) has been considered as an alternative suture material to replace polypropylene (PP) due to its superior biocompatibility and mechanical properties, but it has never been examined for use in barbed sutures, particularly for tendon repair. This study fabricated size 2–0 PVDF and PP bidirectional barbed sutures and compared their mechanical properties and anchoring performance in patellar tendons. The mechanical properties were evaluated via tensile testing, and the anchoring performance of the barbed sutures was assessed by a tendon suture pullout test. Sixty porcine patellar tendons were harvested, transected to mimic a full‐thickness injury, and repaired using a cross‐locked cruciate suturing technique. The ultimate tensile force was 60% higher for the PVDF barbed sutures (22.4 ± 2.1 N) than for the PP barbed sutures (14.0 ± 1.7 N). The maximum pullout force was 35% higher for PVDF barbed sutures (70.8 ± 7.8 N) than for PP barbed sutures (52.4 ± 5.8 N). The force needed to form a 2‐mm gap, indicative of repair failure, was similar between the PVDF (29.2 ± 5.0 N) and PP (25.6 ± 3.1 N) barbed sutures, but both were greater than the 2‐mm‐gap forces for non‐barbed sutures of the same size. In this study, PVDF barbed sutures provided better mechanical properties and improved tissue anchoring performance compared to the barbed PP sutures for porcine patellar tendon repair, demonstrating that PVDF monofilament sutures can be barbed and used effectively for tendon repair.

Selective Serotonin Reuptake Inhibitor Promotes Bone-Tendon Interface Healing in a Rotator Cuff Tear Rat Model

BACKGROUND

Selective serotonin reuptake inhibitor (SSRI) is believed to accelerate wound healing, and thus expected to have a positive effect on rotator cuff repair. We hypothesized that SSRI has a positive effect on the healing of the bone-tendon interface (BTI), and improved rotator cuff tear healing would be confirmed by mechanical strength measurements and histological assessment of the restored tendon.

METHODS

The study used 40 adult male Sprague-Dawley wild-type rats. The animals were divided into two groups: group-SSRI, the supraspinatus repair with SSRI injection group, and group-C, conventional supraspinatus repair only without SSRI. Biomechanical and histological analyses were performed 8 weeks after index rotator cuff surgery.

RESULTS

The ultimate load (N) was significantly higher in group-SSRI than in group-C (54.8 ± 56.9 Vs 25.1 ± 11.1, p = .031). In the histological evaluation, the Bonar score confirmed significant differences in collagen fiber density (group-C: 0.6 ± 0.5, group-SSRI: 1.1 ± 0.6, p = .024), vascularity (group-C: 0.1 ± 0.2, group-SSRI: 0.3 ± 0.4, p = .024) and cellularity (group-C: 1.7 ± 0.4, group-SSRI: 2.0 ± 0.0, p = .023) between the groups. Based on the total score, group-SSRI was significantly better compared with group-C (6.3 ± 2.7 Vs 4.3 ± 1.9, p = .019).

CONCLUSION

Our study demonstrated that SSRI could facilitate improved biomechanical and histological outcomes 8 weeks after rotator cuff repair in a rat model. Consequently, SSRI may improve healing after rotator cuff repair.