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All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.
1. Tendon repair using core suture and Q suture
<ol>
	<li>Mark the anterior surface of one of the tendon stumps with 2 points that are 10 mm from the cut tendon end, with each point locating one-fourth of the way from the left (point 1) and the right (point 2), respectively, in the medial-lateral direction (Figure 1A).</li>
	<li>Mark each of the left (point 3) and right (point 4) lateral surfaces of the tendon with one point that is 8 mm from the cut tendon end and locate in the middle in the anterior-posterior direction&#160;(Figure 1A). Determine all lengths with a Vernier calliper (rated accuracy of 0.02 mm).</li>
	<li>Repair the tendon with 4-0&#160;suture. Insert the needle into the cut surface of one tendon stump from the point that is in the middle in the anterior-posterior direction and one-fourth of the way from the left in the medial-lateral direction (Figure 1B). Pass the needle longitudinally through the tendon and withdraw the needle on the anterior surface of the tendon, exiting from point 1 (Figure 1B).</li>
	<li>Re-insert the needle obliquely from point 3 and pass it transversely toward point 4, creating a small loop at the lateral surface of the tendon (Figure 1C). Pull out the suture and re-insert the needle obliquely from point 2 and pass it longitudinally toward the cut end (Figure 1D,E).</li>
	<li>Insert the needle into the cut end of the other tendon stump and repair it with the same construct, forming a symmetrical repair (Figure 1F).</li>
	<li>Tighten the suture with 10% shortening of the tendon segment within the core suture. Tie the tendon ends together with 3 to 4 knots and complete the 2-strand core suture (Figure 1G).</li>
	<li>Repeat the operation once to complete the 4-strand core suture. Do not cut off the first core suture when performing the second core suture.</li>
	<li>Insert the same needle into the tendon anterior surface 2 mm away from the joined tendon end and pass through the full thickness of the tendon stump (Figure 2A).</li>
	<li>Withdraw the needle on the posterior surface of the tendon and re-insert the needle into the posterior surface of the tendon 2 mm away from the other side of the joined tendon end (Figure 2B).</li>
	<li>Pull out the suture from the anterior surface of the tendon and tie 3 knots to complete 1 Q suture (Figure 2C). Repeat the procedure to complete the second Q suture (Figure 2D).</li>
	<li>In the 2-strand and 4-strand core suture plus running group, add a running epitendinous suture of 9 to 10 stitches to the tendon ends using 6-0 suture. Keep a similar purchase of 1.5 mm and depth of 1 mm (Figure 2E,F,G).</li>
	<li>Keep the repaired tendon moist by wet gauzes before biomechanical testing.</li>
</ol>

q suture technique: a suturing technique to reduce gap formation and increase tensile strength in tendon repair

Source: Mao, W. F., et al., <a href="https://www.jove.com/v/61445">Using Q Suture to Enhance Resistance to Gap Formation and Tensile Strength of Repaired Flexor Tendons.</a> J. Vis. Exp. (2020).
In this video, we demonstrate suturing techniques &#8212; core suture and Q suture &#8212; to repair the foot flexor tendon in an ex vivo porcine model. Q sutures enhance the strength of the core suture in tendon repair and decrease gapping at the tendon repair site.

<img alt="Figure 1" src="/files/ftp_upload/20915/20915_Figure1.jpg" /> 
Figure 1: 2-strand core suture in tendon repair. 
(A) Surface of tendon stump was marked with point 1, 2, 3, and 4. (B-E) Core suture in one tendon stump was completed. (F) The entire core suture was completed. (G) Suture was tightened, and knots were tied.
<img al...

Q Suture Technique: A Suturing Technique to Reduce Gap Formation and Increase Tensile Strength in Tendon Repair

Source: Mao, W. F., et al., Using Q Suture to Enhance Resistance to Gap Formation and Tensile Strength of Repaired Flexor Tendons. J. Vis. Exp. (2020).
In ...

Tendons are connective tissue that attaches the muscles to bones. Damaged tendons can be repaired by stitching their cut ends using the core suturing technique. This procedure still leaves gaps between tendon ends. To reduce any remaining gaps, an additional suturing technique called Q suture is performed.
Begin by placing two incised porcine tendon stumps longitudinally next to each other. For core suturing, mark points at an appropriate distance from the cut tendon end on the anterior and lateral sides. These points help determine the path of the suture.
Insert a longitudinal suture from the cut end. Advance it toward one of the anterior marking points. Pull the suture out from this point. Reinsert it into the nearby lateral marking, making a loop. Pass the suture through the other two markings. Repeat the process with the other stump and knot the sutures to ligate two stumps.
After core suturing, insert the suture on the anterior side of one tendon stump. Loop it on the posterior side of the second stump, spanning the core suture. Withdraw the suture from anterior portion of the second stump. Tie the knots to complete one Q suture. Repeat the process on the opposite side to add the second Q suture.
The repaired tendon is ready for further applications.

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1.2K Views. Source: Mao, W. F., et al., Using Q Suture to Enhance Resistance to Gap Formation and Tensile Strength of Repaired Flexor Tendons. J. Vis. Exp. (2020). In this video, we demonstrate suturing techniques — core suture and Q suture — to repair the foot flexor tendon in an ex vivo porcine model. Q sutures enhance the strength of the core suture in tendon repair and decrease gapping at the tendon repair site. 

Video: Q Suture Technique: A Suturing Technique to Reduce Gap Formation and Increase Tensile Strength in Tendon Repair - Concept

Murine Flexor Tendon Injury and Repair Surgery

Tendon connects skeletal muscle and bone, facilitating movement of nearly the entire body. In the hand, flexor tendons (FTs) enable flexion of the fingers and general hand function. Injuries to the FTs are common, and satisfactory healing is often impaired due to excess scar tissue and adhesions between the tendon and surrounding tissue. However, little is known about the molecular and cellular components of FT repair. To that end, a murine model of FT repair that recapitulates many aspects of healing in humans, including impaired range of motion and decreased mechanical properties, has been developed and previously described. Here an in-depth demonstration of this surgical procedure is provided, involving transection and subsequent repair of the flexor digitorum longus (FDL) tendon in the murine hind paw.&#160;This technique can be used to conduct lineage analysis of different cell types, assess the effects of gene gain or loss-of-function, and to test the efficacy of pharmacological interventions in the healing process. However, there are two primary limitations to this model: i) the FDL tendon in the mid-portion of the murine hind paw, where the transection and repair occur, is not surrounded by a synovial sheath. Therefore this model does not account for the potential contribution of the sheath to the scar formation process. ii) To protect the integrity of the repair site, the FT is released at the myotendinous junction, decreasing the mechanical forces of the tendon, likely contributing to increased scar formation. Isolation of sufficient cells from the granulation tissue of the FT during the healing process for flow cytometric analysis has proved challenging; cytology centrifugation to concentrate these cells is an alternate method used, and allows for generation of cell preparations on which immunofluorescent labeling can be performed. With this method, quantification of cells or proteins of interest during FT healing becomes possible.

Flexor tendons in the hand are commonly injured, leading to impaired hand function. However, the scar-tissue healing response is not well characterized. A murine model of flexor tendon healing is demonstrated here. This model can enhance overall understanding of the healing process and assess therapeutic approaches to improve healing.

Tendon connects skeletal muscle and bone, facilitating movement of nearly the entire body. In the hand, flexor tendons (FTs) enable flexion of the fingers ...

JoVE Journal

Medicine

Effects of Allogeneic Platelet-Rich Plasma (PRP) on the Healing Process of Sectioned Achilles Tendons of Rats: A Methodological Description

This article describes the experimental procedures used to observe if PRP can positively affect tendon healing. There are 4 main steps to follow: induce a lesion in the Achilles tendon; prepare PRP and inject it (or the saline solution); remove the tendon; and perform biomechanical, molecular, and histological evaluations. At each step, all the procedures and methods are described in detail, so they can be reproduced easily.
Achilles tendons have been surgically sectioned (removal of a 5-mm long section). Afterwards, PRP or saline solution was injected to study whether PRP has a positive effect on the healing of the tendon. Three groups of 40 animals (a total of 120 rats were used in this study) were subdivided into 2 subgroups: PRP injection group and a saline injection control group. Rats were sacrificed at increasing time points (Group A: 5 days; Group B: 15 days; Group C: 30 days) and tendons were removed. 90 tendons underwent biomechanical testing before performing transcriptomic analysis and the 30 remaining tendons were submitted to histological analysis.

Effects of Allogeneic Platelet-Rich Plasma PRP on the Healing Process of Sectioned Achilles Tendons of Rats: A Methodological Description

This protocol describes the evaluation process of healing tendons in rats that have been injected with allogeneic platelet rich plasma (PRP) or saline solution after removing part of the Achilles tendon. The progress of tendon healing is evaluated at several time points using different types of analyses.

This article describes the experimental procedures used to observe if PRP can positively affect tendon healing. There are 4 main steps to follow: induce a ...

Evaluation of Stem Cell Therapies in a Bilateral Patellar Tendon Injury Model in Rats

Regenerative medicine provides novel alternatives to conditions that challenge traditional treatments. The prevalence and morbidity of tendinopathy across species, combined with the limited healing properties of this tissue, have prompted the search for cellular therapies and propelled the development of experimental models to study their efficacy. Umbilical cord matrix-derived mesenchymal stem cells (UCM-MSC) are appealing candidates because they are abundant, easy to collect, circumvent the ethical concerns and risk of teratoma formation, yet resemble primitive embryonic stem cells more closely than adult tissue-derived MSCs. Significant interest has focused on chitosan as a strategy to enhance the properties of MSCs through spheroid formation. This paper details techniques to isolate UCM-MSCs, prepare spheroids on chitosan film, and analyze the effect of spheroid formation on surface marker expression. Consequently, creation of a bilateral patellar tendon injury model in rats is described for in vivo implantation of UCM-MSC spheroids formed on chitosan film. No complication was observed in the study with respect to morbidity, stress rising effects, or tissue infection. The total functional score of the operated rats at 7 days was lower than that of normal rats, but returned to normal within 28 days after surgery. Histological scores of tissue-healing confirmed the presence of a clot in treated defects evaluated at 7 days, absence of foreign body reaction, and progressing healing at 28 days. This bilateral patella tendon defect model controls inter-individual variation via creation of an internal control in each rat, was associated with acceptable morbidity, and allowed detection of differences between untreated tendons and treatments.

This paper describes the preparation and evaluation of umbilical cord matrix-derived mesenchymal stem cells spheroids with a bilateral patellar tendon defect model in a rat. This model was associated with an acceptable morbidity and was found to detect differences between untreated and treated tendons, and between the two treatments tested.

Regenerative medicine provides novel alternatives to conditions that challenge traditional treatments. The prevalence and morbidity of tendinopathy across ...

Q Suture Technique: A Suturing Technique to Reduce Gap Formation and Increase Tensile Strength in Tendon Repair

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