using-q-suture-to-enhance-resistance-to-gap-formation-tensile

Using Q Suture to Enhance Resistance to Gap Formation and Tensile Strength of Repaired Flexor Tendons

Peripheral epitendinous sutures are believed to enhance core suture strength in tendon repair and decrease the risk of gapping between tendon ends. Here Q ...

Affiliated Hospital of Nantong University

The actions of growth factors during healing of injured flexor tendons are not well characterized, although information pertinent to some individual growth factors is available. We studied gene expression and protein production of a number of growth factors at several time points during the early healing period in a chicken model.

Tendon healing in vivo: gene expression and production of multiple growth factors in early tendon healing period.

Release of part of the A2 pulley has been suggested to improve function after zone II primary flexor tendon repairs. The purpose of this study was to measure the effect of A2 pulley release compared with pulley preservation on repaired tendon gliding resistance and rupture in the early postoperative period in a chicken model.

Effect of A2 pulley release on repaired tendon gliding resistance and rupture in a chicken model.

Transforming growth factor (TGF)-beta is considered to be responsible for the formation of scars such as adhesions around healing digital flexor tendons. We proposed to deliver microRNAs (miRNAs) to silence expression of the TGF-beta1 gene and to investigate the effectiveness of miRNAs in down-regulation of the TGF-beta1 gene in vitro and in vivo.

Effectiveness of microRNA in Down-regulation of TGF-beta gene expression in digital flexor tendons of chickens: in vitro and in vivo study.

Cellular proliferation is accompanied by cellular apoptosis. In the healing digital flexor tendon, molecular events concerning cellular apoptosis have not been investigated. This study aimed to investigate the relationship between cellular apoptosis and proliferation in early tendon healing.

Molecular events of cellular apoptosis and proliferation in the early tendon healing period.

Cellular apoptosis might be an important molecular event in the middle or late healing periods of intrasynovial tendons, but this has not been studied. We aimed to investigate cellular apoptosis and corresponding cellular proliferation in the middle and late healing stages of intrasynovial tendons.

Cellular apoptosis and proliferation in the middle and late intrasynovial tendon healing periods.

Tendons repaired with varying amounts of tension result in different degrees of shortening of the tendon segment within core sutures, which may affect tensile strengths. We aimed to investigate the effects of tension across the repair site on gap formation forces and ultimate strength.

Effects of tension across the tendon repair site on tendon gap and ultimate strength.

Early flexor tendon healing is characterized by peak cellular apoptosis of both inflammatory and tendon cells in the first week, followed by progressively greater tenocyte proliferation in the second and third weeks. Tenocyte apoptosis is a predominant event, but proliferation of tenocytes is minimal in the middle and late healing periods. Edematous subcutaneous tissues, edema of the tendon, the intact annular pulleys, and extensor tendons all greatly contribute to the resistance. Careful consideration of the contributing factors and dynamics offers insight into strategies to reduce repair rupture and maximize tendon gliding through surgery and postoperative motion protocols.

Tendon healing, edema, and resistance to flexor tendon gliding: clinical implications.

Adhesion formation is closely related to tendon-gliding function. We aimed to investigate apoptosis (programmed cell death) in adhesions and tendons and study its relationship to the mechanics of adhesions and healing tendons.

Apoptosis in adhesions and the adhesion-tendon gliding interface: relationship to adhesion-tendon gliding mechanics.

To evaluate the biomechanical properties of an asymmetric core suture for tendon repair.

The effect of asymmetric core suture purchase on gap resistance of tendon repair in linear cyclic loading.

Sustained gene delivery could be particularly necessary in modulating gene expression in healing intrasynovial tendons and may be a promising approach for preventing adhesions.

Effective modulation of transforming growth factor-β1 expression through engineered microRNA-based plasmid-loaded nanospheres.

Letter Regarding "A 10- or 12-Strand Core Suture in a Flexor Tendon in Zones I, II, and III".

Rupture of the repair and adhesion around a tendon are two major problems after tendon surgery. Novel biological therapies which enhance healing and reduce adhesions are goals of many investigations. Gene therapy offers a new and promising approach to tackle these difficult problems. In the past decade, we sought to develop methods to augment tendon healing and reduce tendon adhesion through gene therapy.

Gene therapy strategies to improve strength and quality of flexor tendon healing.

Tendon injury during limb motion is common. Damaged tendons heal poorly and frequently undergo unpredictable ruptures or impaired motion due to insufficient innate healing capacity. By basic fibroblast growth factor (bFGF) or vascular endothelial growth factor (VEGF) gene therapy via adeno-associated viral type-2 (AAV2) vector to produce supernormal amount of bFGF or VEGF intrinsically in the tendon, we effectively corrected the insufficiency of the tendon healing capacity. This therapeutic approach (1) resulted in substantial amelioration of the low growth factor activity with significant increases in bFGF or VEGF from weeks 4 to 6 in the treated tendons (p < 0.05 or p < 0.01), (2) significantly promoted production of type I collagen and other extracellular molecules (p < 0.01) and accelerated cellular proliferation, and (3) significantly increased tendon strength by 68-91% from week 2 after AAV2-bFGF treatment and by 82-210% from week 3 after AAV2-VEGF compared with that of the controls (p < 0.05 or p < 0.01). Moreover, the transgene expression dissipated after healing was complete. These findings show that the gene transfers provide an optimistic solution to the insufficiencies of the intrinsic healing capacity of the tendon and offers an effective therapeutic possibility for patients with tendon disunion.

Basic FGF or VEGF gene therapy corrects insufficiency in the intrinsic healing capacity of tendons.

Suture knots between tendon stumps may not benefit tendon repairs

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.

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

Tendon stem/progenitor cells (TSPCs) are considered to be promising seed cells for tendon regeneration. Previous studies reported that a low seeding density favors TSPC growth, while a high seeding density favors tenocyte growth. We aimed to distinguish TSPCs from tenocytes by seeding tendon-derived cells at a density gradient. Here, tendon-derived cells were isolated from flexor digitorum profundus (FDP) tendons of mice and seeded at the initial densities of 50/cm2, 500/cm2, 5000/cm2, and 50 000/cm2. We found that distinct cell colonies were formed from cells with initial seeding densities of 50/cm2 and 500/cm2, but colonies were not discernable for cells seeded at 5000/cm2 and 50 000/cm2. There was a positive correlation between cell proliferation rate and seeding density, but a negative correlation between cell senescence and seeding denstity. The cell proliferation rate decreased gradually during serial passages. All cells exhibited restricted differentiation potentials, and expressed stem cell markers and relatively high levels of tenogenic markers without notable differences among cells seeded at different densities. We concluded that a pure population of TSPCs could not be isolated from mouse digital flexor tendons through culturing cells at a density gradient. Cells seeded at low densities had very limited proliferative ability and did not show more prominent stem cell characteristics when compared with cells seeded at high densities.

Article	Year
Tendon healing in vivo: gene expression and production of multiple growth factors in early tendon healing period. The Journal of hand surgery\| PubMed ID: 19084187	2008
Effect of A2 pulley release on repaired tendon gliding resistance and rupture in a chicken model. The Journal of hand surgery\| PubMed ID: 19643293	2009
Effectiveness of microRNA in Down-regulation of TGF-beta gene expression in digital flexor tendons of chickens: in vitro and in vivo study. The Journal of hand surgery\| PubMed ID: 19969188	2009
Molecular events of cellular apoptosis and proliferation in the early tendon healing period. The Journal of hand surgery\| PubMed ID: 20117302	2010
Cellular apoptosis and proliferation in the middle and late intrasynovial tendon healing periods. The Journal of hand surgery\| PubMed ID: 22209211	2012
Effects of tension across the tendon repair site on tendon gap and ultimate strength. The Journal of hand surgery\| PubMed ID: 22386548	2012
Tendon healing, edema, and resistance to flexor tendon gliding: clinical implications. Hand clinics\| PubMed ID: 23660053	2013
Apoptosis in adhesions and the adhesion-tendon gliding interface: relationship to adhesion-tendon gliding mechanics. The Journal of hand surgery\| PubMed ID: 23660197	2013
The effect of asymmetric core suture purchase on gap resistance of tendon repair in linear cyclic loading. The Journal of hand surgery\| PubMed ID: 24630942	2014
Effective modulation of transforming growth factor-β1 expression through engineered microRNA-based plasmid-loaded nanospheres. Cytotherapy\| PubMed ID: 25457276	2015
Letter Regarding "A 10- or 12-Strand Core Suture in a Flexor Tendon in Zones I, II, and III". The Journal of hand surgery\| PubMed ID: 26612641	2015
Gene therapy strategies to improve strength and quality of flexor tendon healing. Expert opinion on biological therapy\| PubMed ID: 26853840	2016
Basic FGF or VEGF gene therapy corrects insufficiency in the intrinsic healing capacity of tendons. Scientific reports\| PubMed ID: 26865366	2016
Suture knots between tendon stumps may not benefit tendon repairs The Journal of hand surgery, European volume\| PubMed ID: 30326798	2018
Effects of a Q Suture Technique on Resistance to Gap Formation and Tensile Strength of Repaired Tendons: An Ex Vivo Mechanical Study. The Journal of hand surgery\| PubMed ID: 31451319	2020
Growth and stem cell characteristics of tendon-derived cells with different initial seeding densities: an in vitro study in mouse flexor tendon cells. Stem cells and development\| PubMed ID: 32443957	2020

Ya Fang Wu

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