Effect of synergistic wrist motion on adhesion formation after repair of partial flexor digitorum profundus tendon lacerations in a canine model in vivo.

BACKGROUND: Therapy employing passive finger flexion and active finger extension with the wrist fixed in flexion is commonly used after flexor tendon repair. However, this method of rehabilitation may not produce full tendon excursion because of buckling of the tendon within its sheath with passive flexion. Studies of cadavera suggest that the use of synergistic wrist and finger motion may improve tendon gliding. The purpose of this study was to assess the effects of passive digital motion, performed with either wrist fixation or synergistic wrist motion, on adhesion and gap formation after flexor tendon repair. METHODS: Sixty-six dogs were randomly allocated to two groups. In each group, two flexor digitorum profundus tendons of one forepaw were partially (80%) lacerated and then repaired with a modified Kessler suture. In each group, a different postoperative therapy (wrist fixation or synergistic motion) was performed twice daily. The dogs were killed at one week, three weeks, or six weeks after surgery, and the repaired tendons were evaluated to determine the adhesion grade and adhesion breaking strength. RESULTS: The synergistic motion group had a significantly lower adhesion grade and significantly less adhesion breaking strength than the wrist fixation group at three and six weeks (p < 0.05). At one week, there was no significant difference between the two therapy groups (p > 0.05). CONCLUSIONS: Passive digital flexion and extension with synergistic wrist motion was an effective therapy after repair of partial zone-2 lacerations in a canine model.     

Eight-strand core suture technique for repair of intrasynovial flexor tendon lacerations

The concept of intrinsic tendon healing, the idea that tendons can heal primarily without the ingrowth of fibrous adhesions from the surrounding fibrous flexor sheath, has been validated both experimentally and clinically. The goals of the surgical treatment of intrasynovial digital flexor tendon lacerations are twofold: 1) to achieve a primary tendon repair of sufficient strength so as to prevent repair site gap elongation and possible rupture, and 2) to prevent the formation of intrasynovial adhesions that cause loss of tendon excursion within the flexor tendon sheath. It is well accepted that repair site strength, both at time zero and within the first 6 postoperative weeks, is directly related to the number of core suture strands crossing the repair site. The factor that limits more widespread use of multistrand suture techniques remains the surgeon's ability to perform the repair while also minimizing trauma to the tendon stumps and the circumferential epitenon. We describe an 8-strand core suture technique used at our institution that has been tested ex-vivo, in-vivo in canines, and used in human subjects over the last 4 years with excellent results.     

A biomechanical analysis of the modified Tsuge suture technique for repair of flexor tendon lacerations

Thirty-six flexor tendons from fresh frozen cadavers were randomized to three types of repairs: a Kessler-Tajima, a 4-strand modified Tsuge, and a 6-strand modified Tsuge. All repairs were accompanied by a standard epitendinous suture. The repaired tendons were then tested to initial gap and ultimate failure in an Instron machine. The average forces to ultimate failure were 31.8 N (SD, 8.8), 48.4 N (SD, 10.7), and 64.2 N (SD, 11.0) respectively. The 6-strand modified Tsuge suture was significantly stronger than the other repairs and the 4-strand modified Tsuge was significantly stronger than the 2-strand Kessler-Tajima. The 6-strand and 4-strand modified Tsuge repairs appear strong enough to withstand the forces generated during early active range of motion flexor tendon rehabilitation protocols. Clinical trials are required to evaluate the usefulness of these repairs.     

The effect of fibrin glue on tendon healing and adhesion formation in a rabbit model of flexor tendon injury and repair

Abstract

Fibrin glue has been widely used in a variety of surgical procedures to promote haemostasis and tissue bonding. It can also be used as a cell carrier for stem cells on tendons. However, the data about the effect of fibrin glue on flexor tendon healing is very limited. The present study examined the role of fibrin glue TISSEEL® in a rabbit model of flexor tendon injury. The rabbits were killed 3 or 8 weeks after the operation. The range-of-motion of the fingers and biomechanical properties of tendons were measured and compared between the control group and TISSEEL-treated group. The findings have shown that the range-of-motion in the TISSEEL-treated group was significantly different from that of the control group at 3 weeks after the operation. However, there is no significant difference in range-of-motion at 8 weeks after the operation. Moreover, there is no significant difference in biomechanical properties between the control group and TISSEEL-treated group. The results indicate that TISSEEL may attenuate adhesion formation at the early stage of flexor tendon repair. However, there is no significant effect on biomechanical features during tendon repair. In conclusion, this study has shown that it may be safe to use TISSEEL in tissue engineering applications for tendon regeneration and healing.     

A biomechanical analysis of a new interlock suture technique for flexor tendon repair.

Using a computerised tensometer, both the gap-producing and breaking forces of a new interlocking suture for flexor tendon repair were compared to the modified Kessler and the Strickland techniques. 30 porcine deep flexor tendons were used in each group and all repairs were performed with 3/0 polypropylene sutures. The interlock technique withstood gap-producing and breaking forces significantly better than the modified Kessler and Strickland techniques. Also, the gap-producing force was closer to the breaking force with the interlock technique than with the other two techniques.     

Remodeling of the gliding surface after flexor tendon repair in a canine model in vivo.

Maintaining a smooth lubricated surface between the flexor tendon and sheath after tendon repair is very important for restoration of digit function. We studied the tendon surface after tendon repair mechanically in a canine model in vivo by measuring frictional force. One hundred and twenty flexor digitorum profundus (FDP) tendons were lacerated to 80% of their cross-section and repaired with either a modified Kessler (MK) or Becker (MGH) repair. The postoperative therapeutic regimen was either synergistic wrist and digit motion (SWM) or passive digit flexion and extension with the wrist fixed in 45 degrees of flexion (FIX). The dogs were sacrificed at one, three, or six weeks postoperatively. Thirty six FDP tendons from normal paws served as the control group, with each control tendon tested in two different conditions: intact and immediately after partial laceration and repair (0 time), making a total of five different timing points (intact, 0 time, one week, three weeks, and six weeks) for each repair type and each postoperative therapy. Frictional force between tendon and proximal pulley was evaluated after breaking any adhesions. Compared to intact tendons, friction was significantly increased immediately after tendon repair. The friction of the MK repair was significantly less than that of the MGH repair at all time and therapy groups, except at six weeks in the SWM group. For the MGH repair, at six weeks friction in the SWM group was significantly less than friction in the FIX group. This study showed that postoperative tendon gliding depends on the method of tendon repair and the postoperative therapy regimen. Furthermore, we have demonstrated that the gliding surface after tendon repair remodels with time.     

Adhesion formation after flexor tendon repair: comparison of two- and four-strand repair without epitendinous suture.

Increased handling, increased bulk at the repair site and an increase in external suture material may affect adhesion formation and gliding after tendon repair. A previous study(1) showed no significant difference in biomechanical or histopathological measurement of adhesion formation in two- and four-strand repairs combined with an epitendinous suture in the chicken model. In the present study, the flexor digitorum profundus tendon of the middle toe of 47 broiler chickens was cut and repaired with either a single (two-strand) or double (four-strand) modified Kessler core suture without epitendinous suture and immobilised for four weeks. Adhesion formation was measured by biomechanical testing or quantitative and qualitative histopathology. Biomechanical and histological data showed no differences between two- and four-strand repairs. Results did not differ from the previous study which used an epitendinous suture. Adhesion formation is not necessarily increased when multi-strand techniques are used, nor by the placement of an epitendinous suture if care is taken with surgical technique. Individual healing response introduces more variability than an increase in tendon handling by an experienced surgeon.     

指屈肌腱修复后早期主动活动防止粘连

指屈肌腱损伤是一种常见损伤,修复后常产生不同程度的粘连,阻碍肌腱的滑动,从而影响手指功能.肌腱粘连发生后常需施行松解术,目前早期控制性主、被动活动是一种有效的防止术后肌腱粘连的方法.     

指屈肌腱缝合早期主动活动预防肌腱粘连

目的 观察指屈肌腱Ⅱ区缝合后早期主动活动预防肌腱粘连的治疗效果。方法 采用核心津下套圈缝合联合周边Halsted缝合法临床治疗71例98指,术后早期主动活动,定期随访,将随访结果与其他缝合方法进行对应分析比较。结果 优良率达97．8％。在随访期各阶段本法均优于其他缝合方法。结论 津下套圈核心缝合联合Halsted周边缝合术后可早期主动活动,粘连率低,疗效显著。     

Direct end-to-end repair of flexor pollicis longus tendon lacerations.

Between 1976 and 1986, 38 consecutive acute isolated flexor pollicis longus lacerations were repaired. This study excluded all replanted or mutilated digits and all lacerations with associated fracture. Average follow-up was 26 months. Tendon rehabilitation was standardized. Range of motion and pinch strength were measured postoperatively. Seventy-four percent (28/38) of the flexor pollicis longus injuries occurred in zone II. Neurovascular injury occurred in 82% of the lacerations, and this correlated with the zone of tendon injury. In 21% of the patients (8/38) both digital nerves and arteries were transected. Postoperative thumb interphalangeal motion averaged 35 degrees and key pinch strength was 81% that of the uninjured thumb. One rupture occurred in a child. Laceration of the flexor pollicis longus is likely to involve damage to neurovascular structures, and repair may be necessary. Direct end-to-end repairs within the pulley system do at least as well as delayed tendon reconstruction and do not require additional procedures.     

Effects of indomethacin on adhesion formation after repair of zone II tendon lacerations in the rabbit

The flexor digitorum profundus tendon of the second medial toe of the hind foot was completely divided and repaired in zone II in 30 New Zealand white rabbits. Half of the animals received indomethacin solution (1 mg/kg/day) injected subcutaneously 2 hours before operation and daily for 4 weeks. The remaining 15 animals received daily injection of the same volume of saline solution. At 4 weeks the animals were killed and measurements were made of the angular motion of the distal interphalangeal joint and the excursion of the tendon. The animals treated with indomethacin had a greater tendon excursion and angular rotation of the joint than the control animals, implying a suppression of adhesions.     

Passive and active rehabilitation for partial lacerations of the canine flexor digitorum profundus tendon in zone II.

The purpose of this study was to compare the effect of unrestricted active versus passive mobilization on the gliding function and structural properties (ultimate load and stiffness) of repaired and nonrepaired canine flexor digitorum profundus tendons following partial laceration at 1 week. Using a radiographic method, normalized tendon gliding of the flexor digitorum profundus tendon adjacent to the metacarpal bone and total joint rotation were shown to be significantly greater in passive than in active tendons. Each group differed from their control group, however, by an average of only 5%. Both rehabilitation (active vs. passive) and treatment (repair vs. nonrepaired) of the partial tendon laceration significantly affected gap formation. Both active rehabilitation and repair of the laceration significantly increased gap formation compared with passive rehabilitation and nonrepair of the partial laceration. Rehabilitation did not significantly affect the normalized ultimate loads and stiffness in the passive and active groups but the nonrepair groups displayed significantly higher ultimate loads and stiffness than the repair groups.     

Advantages of "epitenon first" suture placement technique in flexor tendon repair.

A carefully performed flexor tendon repair should not result in enlargement of the tenorrhaphy. However, many current repair techniques using a core suture followed by an epitendinous suture have this drawback. A technique of placing the epitenon suture first, followed by the core suture, is discussed, and the advantages of the technique are emphasized.     

Short-term assessment of optimal timing for postoperative rehabilitation after flexor digitorum profundus tendon repair in a canine model.

Abstract The purpose of this study was to compare the short-term outcome following flexor tendon repair for postoperative rehabilitation commencing on day 1 (a common clinical choice) versus day 5 (the day on which, with postoperative immobilization, the initial gliding resistance is least in this model) in an in vivo canine model. Work of flexion (WOF) and tendon strength were evaluated following tendon laceration and repair in 24 dogs sacrificed 10 days postoperatively. Starting postoperative mobilization at day 5 resulted in no tendon ruptures compared with tendon ruptures in four of the dogs (33%) in the group subjected to mobilization starting at day 1. While there was no statistically significant difference in WOF between groups at day 10, there was a trend toward lower resistance favoring the day 5 start group, and the statistical power to detect a difference in WOF was diminished by the ruptures in the day 1 group. We conclude that starting rehabilitation on day 5, when initial gliding resistance is lower, may have an advantage over earlier starting times, when surgical edema and other factors increase the initial force requirements to initiate tendon gliding. We plan further studies to evaluate the longer-term benefits of this rehabilitation program.     

Evaluation of suture caliber in flexor tendon repair

This biomechanical study investigated the effect of suture caliber variation on tensile strength in 3 types of 2-strand flexor tendon repairs. Each type of repair was constructed with 5-0, 4-0, 3-0, and 2-0 braided polyester suture. Linear distraction was performed on 120 repaired human cadaveric flexor digitorum profundus tendons until tensile failure occurred. Ten trials of each repair construct were tested. Analysis of variance revealed significant main effects of caliber and technique. Mean repair strength increased as suture caliber increased. A 4-0 suture was 66% stronger than a 5-0 suture, a 3-0 suture was 52% stronger than a 4-0 suture, and a 2-0 suture was 51% stronger than a 3-0 suture. The technique effected repair strength only with the larger 2-0 and 3-0 suture calibers, which tested the technique's capacity to hold the tendon.     

A new core suture technique for flexor tendon repair: biomechanical analysis of tensile strength and gap formation

The purpose of this study was to test in vitro a new flexor tendon suture technique that has been developed to withstand the in vivo forces of active tendon motion. This new core suture technique involves locking loops in the form of a cross stitch. The new technique was tested for ultimate tensile strength and gap formation in cadaver human flexor tendons on a tensile testing machine. The new technique proved significantly stronger than the modified Kessler core suture.     

一种新型肌腱周边缝合方法的生物力学研究

目的通过比较连续周边缝合(Running)、Cross-stitch、Halsted及一种新型肌腱周边缝合方法的生物力学特性,为该方法的临床应用提供理论依据。方法将36根新鲜成年猪后蹄Ⅱ区屈肌腱随机分成4组,分别用连续周边缝合(Running)、Cross-stitch、Halsted及一种新型肌腱周边缝合方法进行修复。将缝合好的肌腱等速拉伸至完全断裂,并用材料力学测定仪(Instron4411)测定2-mm间隙形成负荷、最大负荷,计算断裂功耗。结果新型肌腱周边缝合法的2-mm间隙形成负荷为(53.2±6.0)N、最大负荷为(68.8±6.9)N、刚度为(6.6±0.7)N/mm,为各组中最高;断裂功耗为(0.784±0.075)J与Halsted法相近,高于Cross-stitch及Running法。结论该新型肌腱周边缝合法的生物力学强度高于目前临床应用的Running、Cross-stitch、Hal-sted法,能提供较大的抗张强度、有效抵御间隙形成、操作简便,有利于肌腱早期主被动功能锻炼。