Suture Purchase Research Articles

All-Endoscopic Modified Krackow Suture for Proximal Hamstring Repair

Surgical repair of proximal hamstring injuries can relieve pain and restore lower extremity function in active individuals. Whereas traditional surgical techniques are performed via an open approach, more recent endoscopic proximal hamstring repair techniques have proven safe, effective, and potentially associated with fewer complications than open repair. One theorized disadvantage of existing endoscopic techniques is reduced security at the suture-tendon interface, as compared to open surgery, during which a running suture technique, such as a Krackow stitch, may be employed. In this article, we present a technique for increasing suture purchase by performing an all-endoscopic, running, locking stitch during proximal hamstring repair.

Effects of a Q Suture Technique as a Core Suture on Resistance to Gap Formation and Tensile Strength in an Ex Vivo Porcine Flexor Tendon Model

The Q suture has been reported to be an effective alternative to conventional peripheral sutures in tendon repair. Whether the Q method can be used as a core suture rather than a peripheral suture by adjusting the purchase length is unknown. We tested a double Q suture technique with variable purchase length and studied its effects on gap formation and tensile strength using an exvivo model. Forty pig flexor tendons were repaired using the double Q sutures with purchase lengths of 2, 4, 6, and 8 mm. Twenty tendons repaired using the double Tsuge and double Kessler sutures with an 8-mm purchase length were used as controls. The tendons were subjected to cyclic loading and load-to-failure. The number of tendons that formed an initial or 2-mm gap between the tendon ends, gap distance at the repair site, stiffness, and ultimate strength were recorded. During cyclic loading, the double Q suture with a 4-8-mm purchase had fewer tendons form an initial or 2-mm gap and a smaller gap size at the repair site than the Tsuge and Kessler sutures. The stiffness of the double Q suture with a 6-8-mm purchase length and Tsuge suture was greater than those of the double Kessler suture. The double Q suture with a 2-mm purchase length had smaller ultimate strength than the other sutures. The Q suture may be an effective tendon repair method whose role can be converted between peripheral and core sutures via adjusting the suture purchase length. With an optimal suture length of 4-6 mm, the double Q method had tensile resistance superior to 4-strand core sutures. The double Q suture may be a viable option as a core suture in flexor tendon repair when the purchase length is appropriately adjusted.

Ex Vivo Biomechanical Assessment of a Novel Multi-Strand Repair of Canine Tendon Lacerations.

This study aimed to evaluate the effect of increasing the number of suture strands traversing the transection site, level of suture purchase and depth of suture penetrance on the biomechanical properties of repaired gastrocnemius tendons. Thirty-eight adult cadaveric gastrocnemius tendons were randomized, transected and repaired with either two-, four- or six-strand locking multi-level repair. Tensile loads required to create a 1 and 3 mm gap, yield, peak and failure loads and failure mode were analysed. Significance was set at p < 0.05. Mean ± standard deviation yield, peak and failure force for six-strand repairs was 90.6 ± 22.1 N, 111.4 ± 15.2 N and 110.3 ± 15.1 N respectively. This was significantly greater compared with both four-strand (55.0 ± 8.9 N, 72.9 ± 7.8 N and 72.1 ± 8.2 N) and two-strand repairs (24.7 ± 8.3 N, 36.5 ± 6.0 N and 36.1 ± 6.3 N) respectively (p < 0.001). Occurrence of 3 mm gap formation was significantly less using six-strand repairs (p < 0.001). Mode of failure did not differ between groups with all repairs (36/36; 100%) failing by suture pull-through. Pattern modification by increasing the number of suture strands crossing the repair site, increasing points of suture purchase from the transection site and depth of suture penetrance is positively correlated with repair site strength while significantly reducing the occurrence of gap formation in a canine cadaveric model. Additional studies in vivo are recommended to evaluate their effect on tendinous healing, blood supply and glide resistance prior to clinical implementation.

Barbed sutures versus conventional tenorrhaphy in flexor tendon repair: An ex vivo biomechanical analysis.

BackgroundThe management of flexor tendon injuries has evolved in recent years through industrial improvements in suture materials, refinements of repair methods, and early rehabilitation protocols. However, there is no consensus on the ideal suture material and technique. This study was conducted to compare the tensile strength, repair time, and characteristics of 4-strand cruciate, modified Kessler, and 4-strand horizontal intrafiber barbed sutures for flexor tenorrhaphy with a 12-mm suture purchase length in an animal model.MethodsThe right third deep flexors of 60 adult Leghorn chicken feet were isolated and repaired with a 12-mm suture purchase length. The tendons were randomly assigned to three groups of equal number (n=20 each). Groups 1 and 2 received 4-strand cruciate and modified Kessler repair with conventional suture materials, respectively. A 4-strand horizontal intrafiber barbed suture technique was used in group 3. The repaired tendons were biomechanically tested for tensile strength, 2-mm gap resistance, and mode of failure. Repair times were also recorded.ResultsThe maximum tensile strength until failure was 44.6±4.3 N in group 1, 35.7±5.2 N in group 2, and 56.7±17.3 N in group 3. The barbed sutures were superior to the other sutures in terms of the load needed for 2-mm gap formation (P<0.05). Furthermore, the barbed sutures showed the shortest repair time (P<0.05).ConclusionsThis study found that 4-strand horizontal intrafiber barbed suture repair with a 12-mm purchase length in a chicken flexor tendon injury model showed promising biomechanical properties and took less time to perform than other options.

New Developments Are Improving Flexor Tendon Repair.

New developments in primary tendon repair in recent decades include stronger core tendon repair techniques, judicious and adequate venting of critical pulleys, followed by a combination of passive and active digital flexion and extension. During repair, core sutures over the tendon should have sufficient suture purchase (no shorter than 0.7 to 1 cm) in each tendon end and must be sufficiently tensioned to resist loosening and gap formation between tendon ends. Slight or even modest bulkiness in the tendon substance at the repair site is not harmful, although marked bulkiness should always be avoided. To expose the tendon ends and reduce restriction to tendon gliding, the longest annular pulley in the fingers (i.e., the A2 pulley) can be vented partially with an incision over its distal or proximal sheath no longer than 1.5 to 2 cm; the annular pulley over the middle phalanx (i.e., the A4 pulley) can be vented entirely. Surgeons have not observed adverse effects on hand function after judicious and limited venting. The digital extension-flexion test to check the quality of the repair during surgery has become increasingly routine. A wide-awake surgical setting allows patient to actively move the digits. After surgery, surgeons and therapists protect patients with a short splint and flexible wrist positioning, and are now moving toward out-of-splint freer early active motion. Improved outcomes have been reported over the past decade with minimal or no rupture during postoperative active motion, along with lower rates of tenolysis.

Effect of the Optimal Asymmetry on the Strength of Six-Strand Tendon Repair: An Ex Vivo Biomechanical Study

To evaluate the mechanical properties of a 6-strand core suture repair with asymmetric purchase in the 2 tendon ends, in comparison with a repair with symmetric suture purchases. Under cyclic loading of the tendons, we recorded the fatigue strength (Forces× Cycles) of a 6-strand flexor tendon repair with different symmetry in the lengths of suture purchase in 60 porcine tendons. The symmetric repair was made with 3 groups of parallel Kessler repairs of equal suture purchase (10 mm from the cut end) in the 2 tendon stumps. The asymmetric core suture repairs were then made with a Kessler repair of equal suture purchase (10 mm from the cut end) in the 2 tendon stumps, and shifting 2 other Kessler repairs by 1, 2, 3, 4, or 5 mm, respectively, along the longitudinal axis of the tendon in relation to the first (symmetric) Kessler repair. The core repairs with 2 mm or more asymmetry in suture purchases in 2 tendon ends showed significantly greater fatigue strength compared with those with symmetric suture placement. The core repairs with 3 mm or more asymmetry in suture purchases in 2 tendon ends showed significantly smaller gaps compared with those with symmetric suture placement. The core repairs with 3 mm or more asymmetry in suture purchases in 2 tendon ends generated increased fatigue strength and reduced gap sizes compared with those with symmetric suture placement in an exvivo porcine model. An asymmetric core suture repair with 3 mm or more difference in purchase length may allow for earlier rehabilitation and reduce the risk of postoperative complications.

Asymmetric six-strand core sutures enhance tendon fatigue strength and the optimal asymmetry.

Under cyclic loading, we recorded the fatigue strength of a six-strand tendon repair with different symmetry in the lengths of suture purchase in two stumps of 120 dental rolls and in 30 porcine tendons. First, the strengths of the repairs with 1, 2, 3, 4 and 5 mm asymmetry were screened using the dental rolls. The asymmetric core suture repairs were then made with a Kessler repair of equal suture purchase (10 mm) in two tendon stumps, and shifting two other Kessler repairs by 1, 3 or 5 mm, respectively, along the longitudinal axis of the tendon in relation to the first (symmetric) Kessler repair. The core repairs with 3 mm or more asymmetry in suture purchases in two tendon ends showed significantly greater fatigue strength and significantly smaller gaps compared with 1 mm asymmetry in core suture repair. Our results support that asymmetric placement of core sutures in two tendon ends favour resisting gapping at the repair site and 3 mm or more asymmetry is needed to produce such beneficial effects.

INFLUENCE OF DIFFERENT LENGTH OF CORE SUTURE PURCHASE AMONG SUTURE ROW ON THE STRENGTH OF 6-STRAND TENDON REPAIRS

In multi-strand suture methods consisting of several suture rows, the different length of core suture purchase between each suture row may affect the strength of repairs. We evaluated the influence of the different length of core suture purchase between each suture row on the strength of 6-strand tendon repairs. Rabbit flexor tendons were repaired by using a triple-looped suture technique in which the suture purchase length in each suture row was modified. Group 1, all lengths are 8-mm. Group 2, all lengths are 10-mm. Group 3, two are 10-mm and one is 8-mm. Group 4, one is 10-mm and two are 8-mm. The repaired tendons were subjected to load-to-failure test. The gap strength was significantly greater in Group 1 and Group 2 than in Group 3 and Group 4. This study demonstrates that maintaining equal core suture purchase lengths of each suture row increases the gap resistance.

Thermal capsulorrhaphy: a modified technique for breast pocket revision.

Scant attention has been paid to breast capsule revision after augmentation mammaplasty. Dissatisfaction with traditional techniques prompted the senior authors to develop a thermal capsulorrhaphy (TC) technique to obliterate excess breast pocket space using ball cautery followed by barbed suture closure. The authors propose a new periprosthetic technique for pocket closure, present a corresponding guide for surgical and postoperative management, and provide results of their retrospective review. Medical records were reviewed for all patients who underwent TC after cosmetic augmentation mammaplasty during a 5-year period, for whom clinical photographs were available from at least 1 year postoperatively. Operating details and complications were documented. Outcomes were rated a success, partial success, or failure, based on analysis of the photographs. Of the 157 TC cases (41 unilateral, 58 bilateral) with a mean follow-up of 2 years, 141 (90%) outcomes were successful, 4 (2%) were partially successful, and 12 (8%) had failed. There were 16 complications: 10 over- or undercorrections and 1 episode each of hematoma, capsular contracture, slight deformity, nipple sensitivity, exposed suture knot, and suture abscess. The efficacy of TC derives from the symbiosis of stitches and heat: capsulorrhaphy reinforces apposition of the damaged walls, and cautery contracts and thickens the capsule, thus reducing dead space and improving suture purchase. Initially popularized in shoulder surgery, TC is even better suited for breast pocket closure due to superior visibility and maneuverability, more aggressive practices, and the lack of similar complications. Postoperative stabilization and guideline compliance are essential to successful revision. 4.

The Effect of Asymmetric Core Suture Purchase on Gap Resistance of Tendon Repair in Linear Cyclic Loading

To evaluate the biomechanical properties of an asymmetric core suture for tendon repair. Sixty porcine flexor tendons were repaired with 3 different 4-strand sutures using different core suture purchases: 2 sets of identical purchases of 10 mm, 2 sets of asymmetric purchases (8 mm proximal/distal stump and 12 mm distal/proximal stump), and 2 sets of identical purchases of 12 mm. The tendons were subjected to the cyclic loading for 20 cycles. The number of tendons with gaps at each cycle, elongation of gap area between tendon ends and tendon segment, gap formation forces, and ultimate strengths were recorded. Tendons repaired with the asymmetric core suture purchases had the smallest gaps during cyclic loading. The elongation of gaps and tendon segments were significantly smaller than those with symmetric suture purchase of 10 or 12 mm. The asymmetric core suture repair had significant higher gap resistance forces than the symmetric suture repair at the final loading cycle. A 4-strand core suture repair with asymmetric purchases on the tendon stumps generated greater gapping resistance than that with an equal length of suture purchase. The asymmetric core suture purchase may be a practical measure to improve gapping resistance and fatigue strength when the suture purchase meets essential length requirements.

Flexor tendon injuries in the child

This review aims to highlight the differences in the management of flexor tendon injuries between children and adults. These include differences in epidemiology, anatomy, classification, diagnosis, incisions and skin closure, the size of the flexor tendons, technical aspects of zones I and II repairs, core suture purchase length, rehabilitation, results, and complications of primary flexor tendon repair. Finally, one- versus two-stage flexor tendon reconstruction in children is reviewed.

Suture Purchase Length: A Biomechanical Study of Flexor Tendon Repair in Newborn Lambs

We aimed to determine the effect of core suture purchase on repair strength of flexor tendon lacerations in newborn lambs as a model for pediatric tendon repairs. The dimensions of flexor tendons in these lambs are similar to those of children younger than 2 years. Thirty-six flexor tendons were harvested from newborn lambs. The tendons were cut transversely and repaired using a single figure-of-eight core suture using 5-0 polypropylene. The 36 tendons were divided into 9 groups (n = 4 tendons in each group) according to the length of the core suture purchase: 2, 3, 4, 5, 6, 7, 8, 9, or 10 mm. The initial gap force and ultimate strength of the repairs were studied using a computerized tensometer. There were no significant differences between core suture purchase lengths 2, 3, 4, and 5 mm for both initial gap and ultimate strength. Similarly, there were no significant differences between purchase lengths 6, 7, 8, 9, and 10 mm for both initial gap and ultimate strength. However, there was a significant difference between the former and the latter groups. The optimal core suture purchase length in flexor tendon repair of newborn lambs was 6 mm. However, this length may be too much of a purchase when applied clinically in children younger than 2 years.

Intrasynovial flexor tendon repair: A biomechanical study of variations in suture application in human cadavera

To improve the functional outcomes of intrasynovial tendon suture, prior experiments evaluated individual technical modifications used in the repair process. Few studies, however, have assessed the combinatorial effects of those suture modifications in an integrated biomechanical manner, including a sample size sufficient to make definitive observations on repair technique. Two hundred fifty-six flexor tendon repairs were performed in human cadavera, and biomechanical properties were determined. The effects of five factors for flexor tendon repair were tested: core suture caliber (4-0 or 3-0), number of sutures crossing the repair site (four- or eight-strand), core suture purchase (0.75 or 1.2 cm), peripheral suture caliber (6-0 or 5-0), and peripheral suture purchase (superficial or 2 mm). Significant factors affecting the properties of the repair were the number of core suture strands and the peripheral suture purchase. The least significant factors were core suture purchase and peripheral suture caliber. The choice of core suture caliber affected the properties of repair marginally. Based on these results, we recommend that surgeons continue to focus on multi-strand repair methods, as the properties of eight-strand repairs were far better than those of four-strand repairs. To resist gap formation and enhance repair strength, a peripheral suture with 2 mm purchase is also recommended. Finally, since core suture caliber affected some biomechanical properties, including the failure mode, a 3-0 suture could be considered, provided that future in vivo studies can confirm that gliding properties are not adversely influenced.

Anchor Suture Technique for Muscle Belly Repair

Upper extremity lacerations occur frequently. Although surgical indications for tendon repair are widely accepted, indications for repairing the midsubstance of muscles are not as clear. As the standard of care for muscle repair is absent, there are a variety of techniques available to the treating surgeon. In this study, we describe a technique used on several patients seen in our orthopedic practice. The use of orthogonally placed anchor sutures allows for more reliable suture passes and purchase in the muscle belly compared with simple end-to-end approximation. Furthermore, our technique does not introduce excessive foreign material as has been suggested by previous techniques.

The Effects of Core Suture Purchase on the Biomechanical Characteristics of a Multistrand Locking Flexor Tendon Repair: A Cadaveric Study

To determine the effects of suture purchase on work of flexion (WOF), 2-mm gap force, and load to failure on the combination cross-locked cruciate-interlocking horizontal mattress (CLC-IHM) flexor tendon repair in zone II. A total of 33 fresh-frozen cadaveric fingers were mounted in a custom jig, and the flexor digitorum profundus of each finger was fixed to the mobile arm of a tensile strength machine. Initial measurements of WOF were obtained. Each tendon was repaired with the CLC core suture, randomly assigned to placement of 3, 5, 7 or 10 mm from the cut edge of the tendon, and completed with the IHM circumferential suture. After the repair was completed, measurements of WOF were repeated. Each finger was cycled 1000 times. After each 250 cycles, gapping was recorded, and WOF was measured again. Change in WOF (WOF after repair - WOF of intact tendon) was calculated. Tendons were then dissected from the fingers and linearly tested for 2-mm gap force and ultimate load to failure. The group repaired at 10 mm had the lowest percent increase in WOF (5.2%), the highest 2-mm gap force (89.8 N), and the highest ultimate load to failure (111.5 N). The group repaired at 3 mm had the highest percent increase in WOF (22.1%), the lowest 2-mm gap force (54.6 N), and the lowest ultimate load to failure (84.6 N). A 10-mm suture purchase is the recommended distance for optimal performance for the CLC-IHM combination repair method. This method with a 10-mm suture purchase has a low increase in WOF, high strength, and high resistance to gapping, and it should be strong enough to tolerate early motion.

A new technique of flexor profundus repair in the distal part of zone I: inclusion of the palmar plate

Flexor profundus lacerations in the distal part of zone I are usually treated by tendon reinsertion into bone. We present a modified technique in which three 'figure of eight' sutures include the palmar plate in the distal purchase. Inclusion of the palmar plate significantly strengthens the tensile strength of the repair and this was confirmed biomechanically in an experimental study. In a prospective clinical study, 15 patients with clean-cut complete lacerations of the profundus tendon in the distal part of zone I underwent the modified repair technique of three separate 'figure of eight' sutures with the palmar plate included in the suture distally and 7 mm suture purchase proximally, with postoperative immediate active motion that ensured full active extension of the interphalangeal joints. There were no ruptures or infections. At final follow-up 12-25 weeks after surgery, the mean range of motion at the distal, proximal, and combined interphalangeal joints was 66 degrees, 100 degrees and 166 degrees respectively. All patients achieved an excellent or good outcome.

What is the Significance of Tendon Suture Purchase?

Repairs have been performed on porcine flexor tendons and subjected to tensile stress measurements to determine the effects and mechanism of core suture purchase (the length of the suture bite). Eighty-four pig trotter flexor profundus tendons were divided and repaired using four lengths of core suture purchase (1.33, 1, 0.66 and 0.33 cm) using a double modified Kessler repair (four strands, two knots) with a peripheral epitendinous suture. Tendon purchase was achieved by either bilateral equal purchase lengths or with one tendon purchase at a fixed depth of 1 cm. A separate group of tendons were incubated in blood for 24 hours to simulate the wound environment prior to testing. Tensile tests demonstrated a progressive increase of repair strength with purchase length. With the exception of the 0.33 cm group, video analysis demonstrated the mode of failure as suture failure and not due to suture pullout. Therefore, the increase in breaking strength cannot be attributed to a better grip of the tendon ends, but to the mechanical characteristics of the suture polymer. The tendency for the incubated tendons to fail more consistently by pullout rather than suture failure, particularly in the shorter purchase lengths, emphasises the importance of studying tendon purchase in vivo. The significance of ex vivo mechanical testing should be considered with caution.

What is the Significance of Tendon Suture Purchase?

Repairs have been performed on porcine flexor tendons and subjected to tensile stress measurements to determine the effects and mechanism of core suture purchase (the length of the suture bite). Eighty-four pig trotter flexor profundus tendons were divided and repaired using four lengths of core suture purchase (1.33, 1, 0.66 and 0.33 cm) using a double modified Kessler repair (four strands, two knots) with a peripheral epitendinous suture. Tendon purchase was achieved by either bilateral equal purchase lengths or with one tendon purchase at a fixed depth of 1 cm. A separate group of tendons were incubated in blood for 24 hours to simulate the wound environment prior to testing. Tensile tests demonstrated a progressive increase of repair strength with purchase length. With the exception of the 0.33 cm group, video analysis demonstrated the mode of failure as suture failure and not due to suture pullout. Therefore, the increase in breaking strength cannot be attributed to a better grip of the tendon ends, but to the mechanical characteristics of the suture polymer. The tendency for the incubated tendons to fail more consistently by pullout rather than suture failure, particularly in the shorter purchase lengths, emphasises the importance of studying tendon purchase in vivo. The significance of ex vivo mechanical testing should be considered with caution.

Biomechanics and Histology of Intact and Repaired Digital Nerves: An In Vitro Study

To investigate the biomechanical properties of intact and repaired cadaver digital nerves. Ultimate tensile failure strength and stiffness were determined in 67 human cadaver digital nerves. Total nerve area, fascicular area, and nonfascicular (connective tissue) area were determined from the metacarpophalangeal to the distal interphalangeal joint in another 35 axial nerve sections to determine regional anatomic variation. Thirty-eight additional digital nerves were transected, and epineural repairs were performed using simple, interrupted sutures. Suture number (2 vs 4), gauge (8-0 vs 9-0), and purchase length (1 mm vs 2 mm) were used in various combinations, and then the repaired nerves were pulled to failure. The mechanism of repair-site failure was determined for each suture. In situ tension of the intact digital nerves was measured during passive metacarpophalangeal and proximal interphalangeal joint motion in another 19 intact digital nerves. There were no significant differences in failure load or stiffness with respect to the radial or ulnar nerves within a finger or between fingers. The primary tactile side of the finger tended to have a larger diameter digital nerve. Digital nerve failure was more common proximally than distally. Intact digital nerves failed at 6 N with a stiffness of 1 N/mm. Histologic analysis showed that fascicular area and total area decreased from proximal to distal, whereas the nonfascicular-to-fascicular area ratio increased. Four epineural sutures were statistically stronger than 2 sutures. Suture purchase length and gauge did not affect repair strength. The 8-0 nylon sutures failed primarily by cut-out, whereas the 9-0 sutures failed by cut-out or breakage. Repaired nerves failed at 1 to 2 N. Maximal metacarpophalangeal joint hyperextension resulted in 4 N of digital nerve tension. When the metacarpophalangeal joint was not hyperextended, proximal interphalangeal joint motion did not generate tension. Similar to flexor tendons, the number of suture strands crossing the repair site was the most important variable affecting digital nerve repair strength in this cadaveric model.

Influence of Core Suture Purchase Length on Strength of Four-Strand Tendon Repairs

Influence of Core Suture Purchase Length on Strength of Four-Strand Tendon Repairs