Epitendinous Suture Research Articles

Epitendinous Suture Techniques in Extensor Tendon Repairs—An Experimental Evaluation

The tension-band principle might be relevant to extensor tendon repairs, and a dorsal-only Silfverskiöld epitendinous repair is stronger and stiffer than more conventional techniques in vitro. We aimed to evaluate the strength and stiffness of the strongest epitendinous sutures described, using an in vitro model that subjects the repair to angular force over a pulley, thereby creating a tension-band model. Silfverskiöld dorsal-only epitendinous extensor tendon repairs in porcine foot tendons (n = 8) were compared to reverse (buried) Silfverskiöld (n = 8), Halsted (n = 8), and interrupted horizontal mattress (IHM) repairs (n = 6) in vitro with a tensiometer around a 45° pulley. Thirty tendons total were tested to assess the force required for 2-mm gapping and ultimate tensile strength. The IHM repair had a significantly higher ultimate tensile strength (43 N; SD, 10 N) than the other repairs, which had strengths between 27 N (SD, 4 N) and 31 N (SD, 7 N). The IHM was also significantly more resistant to gapping than the Silfverskiöld and Halsted repairs. Interlocking horizontal mattress, dorsal-only extensor tendon repairs were significantly stronger and more resistant to gapping than Silfverskiöld and Halsted repairs. Other repairs were still strong and resistant to gapping in comparison to previously published data for conventional repairs. The IHM is a relatively difficult technique to perform, and it remains to be seen whether the additional strength translates to clinical benefits over the easier Silfverskiöld technique.

Flexor Tendon Repair With a Knotless Barbed Suture: A Comparative Biomechanical Study

To test the hypothesis that a flexor tendon repair with only a knotless barbed suture technique provides a repair with a greater maximal load to failure and 2-mm gapping resistance than a traditional technique using a 4-strand core plus a running-locking epitendinous suture. We assigned 41 fresh-frozen cadaveric flexor digitorum profundus tendons for repair by either a traditional technique using a 4-strand core (Tajima and horizontal mattress) plus a running-locking epitendinous suture (n = 20) or a bidirectional barbed suture technique using a knotless, 4-strand core secured with 3 transverse passes (n = 21). A biomechanical study was performed on each tendon-suture construct and the tendons were linearly distracted to failure at 100 mm/min. The maximal tensile load to failure, 2-mm gapping tensile load, and mode of failure were determined and statistically compared. The average maximal load to failure was not significantly different between the traditional repair (48 ± 12 N) and the barbed suture repair (50 ± 14 N). The average 2-mm gapping load was also insignificantly different between the traditional repair (42 ± 12 N) and the barbed suture repair (32 ± 9 N). The traditional repair failed by knot unraveling and suture rupture 35% and 65% of the time, respectively. The barbed suture repair failed by suture pull-out and rupture 67% and 33% of the time, respectively. The average load to failure by suture rupture was insignificantly different between the traditional repair (51 ± 13 N) and the barbed suture repair (63 ± 16 N). The average load to failure by knot unraveling using the traditional repair was 43 ± 11 N, whereas the average load to failure by suture pull-out using the barbed suture repair was 43 ± 8 N. The barbed suture repair did not demonstrate a significant difference in maximal load to failure and 2-mm gapping resistance compared with the traditional method of repair. This study examines the biomechanical differences between 2 types of flexor-tendon repair, which can help guide the surgical management for these injuries.

Repair of Flexor Carpi Radialis Tendon Laceration at the Wrist in a Professional Ice Hockey Player

The flexor carpi radialis is a wrist flexor and radial deviator with half the relative strength of flexor carpi ulnaris. In the majority of patients, the flexor carpi radialis tendon is expendable and is routinely used for various reconstructive procedures about the hand and wrist. Isolated flexor carpi radialis lacerations at the wrist are rare. Flexor carpi radialis tendon ruptures, which have been reported in association with distal radius fractures, longstanding osteoarthritis, and percutaneous treatment of scaphoid fractures, are usually treated non-operatively. We report a case of a traumatic laceration of the flexor carpi radialis tendon at the wrist in a professional ice hockey player. Surgical repair and rehabilitation using established principles for intrasynovial flexor tendon repair allowed return to sport at the professional level in 2 months.Tension-free core suture repair was performed with a modified-Kessler, 4-strand repair using a double-stranded 4-0 Supramid suture. A running epitendinous suture was then placed around the circumference of the tendon with 6-0 Prolene. Immobilization of the wrist in 20° of flexion was maintained for 2 weeks. Full active and passive digital motion was allowed immediately postoperatively and continued throughout the rehabilitation. Therapy was initiated at 2 weeks postoperatively with full passive wrist flexion and passive wrist extension to a dorsal block of 20°. At 4 weeks postoperatively, a dorsal splint was fabricated to keep the wrist in neutral. At this time, active extension to a dorsal block of zero and full passive flexion was allowed. Active wrist flexion without resistance was begun at 6 weeks, and full strengthening was allowed at 8 weeks postoperatively. The patient returned to sport at the professional level shortly thereafter. At latest follow-up, the patient has been able to fully participate in professional ice hockey without pain or functional limitation.

The tension band principle and angular testing of extensor tendon repairs

Extensor tendons in the finger are flat and not amenable to repair by core and epitendinous sutures. Mattress sutures and Kessler repairs without epitendinous stitching are often used for extensor tendon divisions in the fingers. Except when in full extension, the finger presents a series of curved surfaces (at each joint) to the tendon. It was hypothesized that extensor tendons are subject to the 'tension band' principle and that they might be amenable to repair by dorsal-only epitendinous sutures. A Silfverskiöld dorsal-only repair was compared with mattress and Kessler repairs invitro on a curvilinear testing apparatus. The epitendinous technique was found to be significantly more resistant to gapping and rupture, as well as more resistant to deformation (i.e. stiffer) than the conventional techniques.

A six-strand technique for zone II flexor-tendon repair in children younger than 2 years of age

Introduction A six-strand repair for zone II flexor-tendon repair in children younger than 2 years of age has not been reported in the literature because of the small size of the flexor tendon in this very young age group. Purpose The aim is to introduce the use of a six-strand repair in zone II flexor-tendon repair in children younger than 2 years of age. Methods A total of 12 children younger than 2 years, with 12 injured fingers, were treated over a 10-year period. A ‘profundus only’ repair was done using three separate ‘figure of eight’ core sutures and a continuous epitendinous suture. The repair site was bulky and ‘venting’ of the pulley system proximal to the repair site was done. The hand was immobilised for 3.5 weeks after surgery and then physiotherapy exercises were started. The final net range of motion at the interphalangeal joints was measured and the outcome was assessed as per the Strickland–Glogovac criteria. Results There were no ruptures. The final outcome in range of motion was excellent in nine children and good in the remaining three children. None of the children required tenolysis. Conclusion Our six-strand technique is an alternative technique for zone II flexor-tendon repair in children younger than 2 years of age, but the bulky repair site requires a ‘profundus only’ repair and ‘venting’ of the pulley system.

The Effect of Epitendinous Suture Technique on Gliding Resistance During Cyclic Motion After Flexor Tendon Repair: A Cadaveric Study

The Effect of Epitendinous Suture Technique on Gliding Resistance During Cyclic Motion After Flexor Tendon Repair: A Cadaveric Study

Flexor tendon repair in zone III

There is a paucity of the literature on the outcome of zone III flexor tendon injuries. In this paper, we report on the results of zone III flexor tendon repair in 35 consecutive adult patients with clean cut lacerations of both flexor tendons in 42 fingers. There were 25 men and 10 women with an average age of 32 years. Repair of both flexor tendons was performed using 'figure of eight' core sutures and a continuous epitendinous suture. Postoperatively, an immediate active range of motion protocol was applied to ensure full active extension of the interphalangeal joints. The results were assessed using the Strickland-Glogovac grading system. There were no ruptures. One patient with two injured fingers developed complex regional pain syndrome and the final outcome was fair in both fingers. In the remaining 34 patients (40 fingers), 33 patients (38 fingers) had an excellent outcome and the remaining patient (two fingers) had a good outcome.

Outcome of early active mobilization after flexor tendons repair in zones II-V in hand.

Background:The functional outcome of a flexor tendon injury after repair depends on multiple factors. The postoperative management of tendon injuries has paved a sea through many mobilization protocols. The improved understanding of splinting techniques has promoted the understanding and implication of these mobilization protocols. We conducted a study to observe and record the results of early active mobilization of repaired flexor tendons in zones II–V.Materials and Methods:25 cases with 75 digits involving 129 flexor tendons including 8 flexor pollicis longus (FPL) tendons in zones II–V of thumb were subjected to the early active mobilization protocol. Eighteen (72%) patients were below 30 years of age. Twenty-four cases (96%) sustained injury by sharp instrument either accidentally or by assault. Ring and little finger were involved in 50% instances. In all digits, either a primary repair (n=26) or a delayed primary repair (n=49) was done. The repair was done with the modified Kessler core suture technique with locking epitendinous sutures with a knot inside the repair site, using polypropylene 3-0/4-0 sutures. An end-to-end repair of the cut nerves was done under loupe magnification using a 6-0/8-0 polyamide suture. The rehabilitation program adopted was a modification of Kleinert’s regimen, and Silfverskiold regimen. The final assessment was done at 14 weeks post repair using the Louisville system of Lister et al.Results:Eighteen of excellent results were attributed to ring and little fingers where there was a flexion lag of < 1 cm and an extension lag of < 15°. FPL showed 75% (n=6) excellent flexion. 63% (n=47) digits showed excellent results whereas good results were seen in 19% (n=14) digits. Nine percent (n=7) digits showed fair and the same number showed poor results. The cases where the median (n=4) or ulnar nerve (n=6) or both (n=3) were involved led to some deformity (clawing/ape thumb) at 6 months postoperatively. The cases with digital or common digital nerve involvement (n=7 with 17 digits) showed five excellent, two good, four fair, and six poor results. Complications included tendon ruptures in 2 (3%) cases (one thumb and one ring finger) and contracture in 2 (3%) cases whereas superficial infection and flap necrosis was seen in 1 case each.Conclusion:The early active mobilization of cut flexor tendons in zones II–V using the modified mobilization protocol has given good results, with minimal complications.

The Effect of Epitendinous Suture Technique on Gliding Resistance During Cyclic Motion After Flexor Tendon Repair: A Cadaveric Study

To investigate the effects of motion following repair with a modified Kessler core suture and 5 different epitendinous suture designs on the gliding resistance, breaking strength, 2-mm gap force, and stiffness of flexor digitorum profundus tendons in a human in vitro model. The flexor digitorum profundus tendons of the index, middle, ring, and little fingers of 50 human cadavers were transected and repaired with a 2-strand modified Kessler suture and assigned to 5 groups based on type of epitendinous suture design. The 5 epitendinous designs tested were a simple, running epitendinous suture whose knot was outside the repair (simple running KO); a simple, running epitendinous suture whose knot was inside the repair (simple running KI); a cross-stitch epitendinous suture; an interlocking, horizontal mattress (IHM) epitendinous suture; and a running-locking epitendinous suture. The tendon repair strength and 2-mm gap force were measured after 1,000 cycles of tendon motion. The resistance to gap formation, a measure of repair stiffness, was obtained from the force versus gap data. None of the repairs showed any gap formation after 1,000 cycles of tendon motion. The cross-stitch epitendinous suture, IHM epitendinous suture, and running-locking epitendinous suture all had significantly lower gliding resistance than the simple running KO epitendinous suture after 1 cycle. The simple running KI epitendinous suture had significantly lower gliding resistance than the simple running KO epitendinous suture after 100 cycles and 1,000 cycles. The differences for gap force at 2 mm and stiffness of the repaired tendon evaluation were not statistically significant. The cross-stitch epitendinous suture, IHM epitendinous suture, and running-locking epitendinous suture all had significantly higher maximal failure strength after 1,000 cycles than the simple running KI epitendinous suture. The cross-stitch, IHM, and running-locking epitendinous sutures had the best combination of higher strength and lower gliding resistance in this study. Although these findings suggest a potential for these suture types to be preferred as epitendinous sutures, these repairs should first be investigated in vivo to address their effect on tendon healing and adhesion formation.

Biomechanical Comparison of Techniques to Reduce the Bulk of Lacerated Flexor Tendon Ends Within Digital Sheaths of the Porcine Forelimb

Zone II flexor tendon repairs may create a bulging effect with increased bulk and resistance to tendon gliding. A biomechanical time 0 study was performed to assess 2 methods of tendon antibulking for work of flexion and strength characteristics. We placed 24 fresh-frozen porcine forelimb tendons in a custom jig. Deep flexor tendon was sectioned just distal to the intact A1 and A2 pulleys. Specimens were divided into 3 groups before repair: group 1, nonmodified tendon; group 2, 30 degrees bilateral notch excised from both tendon ends; and group 3, triangular longitudinal central wedge excised from both tendon ends. All repairs used a 4-strand modified Kessler core suture and running circumferential epitendinous suture. Work of flexion, 2-mm gap formation, and ultimate load to failure were tested. Both antibulking techniques (groups 2 and 3) had significantly less work of flexion than group 1 (36.3 and 34.9 J vs 142.9 J, p < .001). There was no significant change in work of flexion between groups 2 and 3 (p > .05). There was no significant difference in terms of 2-mm gap formation among the 3 groups (p > .05). Groups 1 and 3 exhibited a significantly higher load to failure compared with group 2 (p < .05). The antibulking repair techniques used in this study decrease the work of flexion with no significant change in force to 2-mm gap formation. Group 2, however, did have significantly lower load to failure. These techniques might be beneficial in zone II flexor tendon injury, in which the tight annular pulley system restricts tendon gliding. However, this is a time 0 study and the potential adverse effects of increase tendon manipulation and trauma were not analyzed, which might increase adhesions and scar during the healing phase of tendon repair.

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.

Flexor tendon repair in children with zone 2 injuries: an innovative technique using autogenous vein

Objectives This is a new technique for tendon repair that may improve the results of existing methods. Methods The study is a nonrandomized retrospective study using historical (nonconcurrent) controls. From May 1994 to March 2004, 53 children aged 5 to 15 years requiring tendon repair (test group) were compared to 53 children conventionally repaired (control group). All patients had flexor tendon injuries, involving zone 2. In the test group (53 patients), a modified Kessler repairing of tendons with 4-0 prolene was used, followed by a core suture of running 7-0 nylon or prolene epitendinous suture. After the tendon repair, a segment of vein through which the tendon had been passed before or a vein patch used as a tendon sheath substitute was used to repair the sheath defects. The results during 6 months of follow-up were compared with those of the control group that were operated using the conventional technique (modified Kessler method). Results We assessed the results by measuring the range of motion of the metacarpophalangeal, distal interphalangeal, and proximal interphalangeal joints in the follow-up period and graded them as excellent, good, fair, and poor. In the test group, 86% were graded as excellent, 11% good, 3% fair, and 0% poor results; and in the control group, 0% were excellent, 12% good, 38% fair, and 50% poor results. The differences were significant ( P < .005). Conclusions Our preliminary results appeared encouraging when compared with the outcomes achieved by the conventional tendon repair technique. As the new technique decreases the need for intensive physiotherapy, it may serve as a substitute method for the conventional tendon repair and eventually become a standard technique in the future.

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.

The results of treatment for isolated zone 3 extensor tendon injuries

We evaluated late-term results of surgical repair and physical rehabilitation of isolated zone 3 extensor tendon injuries. Sixteen patients (13 males, 3 females; mean age 28 years; range 11 to 57 years) underwent surgical repair for isolated simple central slip injuries of zone 3 extensor tendon. Injuries involved the second, third, fourth, and fifth fingers in seven, three, two, and four patients, respectively. Primary tendon repair was performed in 14 patients. Two patients were treated after one week and two months following primary injury, respectively. Tendons were repaired by modified Kessler and epitendinous sutures in four patients, and by locking running suture in 12 patients. Following surgical repair, three patients underwent K-wire fixation in extension for two weeks, while 13 patients received the short arc motion protocol. The patients were assessed with respect to proximal interphalangeal (PIP) joint motion and extension loss. Functional results were assessed using the Strickland formula. The mean follow-up was 58 months (range 8 to 120 months). Full range of motion of the PIP joint was achieved in 15 patients (93.8%). The mean PIP joint motion was 98 degrees. One patient (6.3%) had an extension loss of 10 degrees in the range of motion of the PIP joint. There were no losses in the range of motion in three patients treated with K-wire fixation. The mean of the Strickland formula was 94.8% (range 74% to 100%), showing an excellent result in 15 patients (98.3%) and a good result in one patient (6.3%). All the patients returned to their pre-injury work status. None had buttonhole deformity or soft tissue complication. A proper suture technique combined with the short arc motion protocol provides good results in the treatment of isolated zone 3 extensor tendon injuries.

Journal of Hand Surgery

Long-term outcomes of closed reduction and percutaneous pinning for the treatment of distal radius fractures. Glickel SZ, Catalano LW, Raia FJ, Barron OA, Grabow R, Chia B. J Hand Surg Am. 2008;33:1700–1705.

Optimizing Achilles Tendon Repair: Effect of Epitendinous Suture Augmentation on the Strength of Achilles Tendon Repairs

Epitendinous suture augmentation has been shown to increase gap resistance and overall strength in flexor tendon repairs of the hand. The purpose of this study was to evaluate the effect of various suture augmentation techniques in Achilles tendon repair. Eighteen fresh-frozen cadaveric Achilles tendons were transected and repaired with a 4-strand Krackow core stitch. Suture augmentation was performed with 3 figure-of-eight stitches in 6 specimens and a running cross-stitch weave in 6 specimens. The other 6 specimens were not augmented. Each tendon was loaded to failure on an MTS. Force to failure (defined as peak force or force at 5 mm gapping), gapping resistance, stiffness, and elongation were compared. Force to failure (p < 0.001), stiffness (p < 0.01) and gapping resistance (p < 0.05) were increased by suture augmentation. Additionally failure force and gapping resistance for the cross-stitch augmentation was higher than the figure-of-eight augmentation (p < 0.05). Cross-stitch augmentation of Achilles tendon repair yields a stronger and stiffer repair with greater resistance to gapping. Achilles tendon repairs augmented with a cross stitch weave will be able to withstand substantially higher forces than non-augmented repairs.

Tensile Strength of Modified 4-Strand Cruciate Technique for Transversely or Obliquely Lacerated Tendons

To assess the tensile strength of the modified 4-strand cruciate technique for obliquely lacerated tendons, and to compare the findings with the strength of transversely lacerated tendons repaired at various grasping depths. 60 porcine front foot tendons were evenly divided into 4 groups. In groups 1 to 3, tendons were transversely lacerated and repaired with grasping points at both ends away from the laceration by 5 mm, 10 mm, and 15 mm respectively. In group 4, tendons were obliquely lacerated and repaired with a grasping point 5 mm away from the laceration on one end and 15 mm on the other. All tendons were repaired with a modified 4-strand core suture and continuous epitendinous suture, and then tested to failure in a tensile machine. The tensile strength in group 1 was significantly lower than that in the other 3 groups (p<0.005). The tensile strength in group 4 was not significantly different from groups 2 and 3. The tensile strength of modified 4-strand cruciate repair configuration is not weakened in obliquely lacerated tendons; the grasping point at one end of the tendon being 15 mm away from laceration provides sufficient strength to compensate for the relatively weak 5-mm end. So long as one grasping point is away from the laceration site by 10 mm, the ultimate tensile strength of the transversely lacerated tendons appears acceptable. The modified 4-strand cruciate repair is safe to use for repairing obliquely lacerated tendons.

Bone Marrow-Derived Mesenchymal Stem Cells Influence Early Tendon-Healing in a Rabbit Achilles Tendon Model

A repaired tendon needs to be protected for weeks until it has accrued enough strength to handle physiological loads. Tissue-engineering techniques have shown promise in the treatment of tendon and ligament defects. The present study tested the hypothesis that bone marrow-derived mesenchymal stem cells can accelerate tendon-healing after primary repair of a tendon injury in a rabbit model. Fifty-seven New Zealand White rabbits were used as the experimental animals, and seven others were used as the source of bone marrow-derived mesenchymal stem cells. The injury model was a sharp complete transection through the midsubstance of the Achilles tendon. The transected tendon was immediately repaired with use of a modified Kessler suture and a running epitendinous suture. Both limbs were used, and each side was randomized to receive either bone marrow-derived mesenchymal stem cells in a fibrin carrier or fibrin carrier alone (control). Postoperatively, the rabbits were not immobilized. Specimens were harvested at one, three, six, and twelve weeks for analysis, which included evaluation of gross morphology (sixty-two specimens), cell tracing (twelve specimens), histological assessment (forty specimens), immunohistochemistry studies (thirty specimens), morphometric analysis (forty specimens), and mechanical testing (sixty-two specimens). There were no differences between the two groups with regard to the gross morphology of the tendons. The fibrin had degraded by three weeks. Cell tracing showed that labeled bone marrow-derived mesenchymal stem cells remained viable and present in the intratendinous region for at least six weeks, becoming more diffuse at later time-periods. At three weeks, collagen fibers appeared more organized and there were better morphometric nuclear parameters in the treatment group (p < 0.05). At six and twelve weeks, there were no differences between the groups with regard to morphometric nuclear parameters. Biomechanical testing showed improved modulus in the treatment group as compared with the control group at three weeks (p < 0.05) but not at subsequent time-periods. Intratendinous cell therapy with bone marrow-derived mesenchymal stem cells following primary tendon repair can improve histological and biomechanical parameters in the early stages of tendon-healing.

Bone Marrow-Derived Mesenchymal Stem Cells Influence Early Tendon-Healing in a Rabbit Achilles Tendon Model

Background: A repaired tendon needs to be protected for weeks until it has accrued enough strength to handle physiological loads. Tissue-engineering techniques have shown promise in the treatment of tendon and ligament defects. The present study tested the hypothesis that bone marrow-derived mesenchymal stem cells can accelerate tendon-healing after primary repair of a tendon injury in a rabbit model. Methods: Fifty-seven New Zealand White rabbits were used as the experimental animals, and seven others were used as the source of bone marrow-derived mesenchymal stem cells. The injury model was a sharp complete transection through the midsubstance of the Achilles tendon. The transected tendon was immediately repaired with use of a modified Kessler suture and a running epitendinous suture. Both limbs were used, and each side was randomized to receive either bone marrow-derived mesenchymal stem cells in a fibrin carrier or fibrin carrier alone (control). Postoperatively, the rabbits were not immobilized. Specimens were harvested at one, three, six, and twelve weeks for analysis, which included evaluation of gross morphology (sixty-two specimens), cell tracing (twelve specimens), histological assessment (forty specimens), immunohistochemistry studies (thirty specimens), morphometric analysis (forty specimens), and mechanical testing (sixty-two specimens). Results: There were no differences between the two groups with regard to the gross morphology of the tendons. The fibrin had degraded by three weeks. Cell tracing showed that labeled bone marrow-derived mesenchymal stem cells remained viable and present in the intratendinous region for at least six weeks, becoming more diffuse at later time-periods. At three weeks, collagen fibers appeared more organized and there were better morphometric nuclear parameters in the treatment group (p < 0.05). At six and twelve weeks, there were no differences between the groups with regard to morphometric nuclear parameters. Biomechanical testing showed improved modulus in the treatment group as compared with the control group at three weeks (p < 0.05) but not at subsequent time-periods. Conclusions: Intratendinous cell therapy with bone marrow-derived mesenchymal stem cells following primary tendon repair can improve histological and biomechanical parameters in the early stages of tendon-healing. Clinical Relevance: The findings of the present study have clinical importance as the early time-period during tendon-healing is crucial in the treatment of tendon injuries.

Comparison of tensile strength between 4 different epitendinous sutures

目的 研究缝针出入点距对合口距离对肌腱修复抗张强度的影响. 方法采用新鲜猪后肢跖深屈肌腱,将 40根肌腱分为 4组,每组 10根,横行切断,以改良 Kessler法缝合,周边加强,缝针出入点距断端距离分别为 4、 7、 10、 12mm,检测缝合后肌腱 2mm间隙形成的负荷,最大抗张强度,采用 ANOVA进行统计分析. 结果对肌腱的横断伤,以改良 Kessler法缝合修复时缝针出入点距断端的距离越大,肌腱的抗张强度越强,其中 4mm间距抗张强度明显低于其它三组( P< 0.05),而其它三组无明显统计学差异. 结论 肌腱横形损伤修复时,随着缝针出入点距断端的距离增大,其抗张强度有递增趋势。