Biomechanic comparison of the Teno Fix tendon repair device with the cruciate and modified Kessler techniques

PURPOSE: To compare the mechanical behavior of a novel internal tendon repair device with commonly used 2-strand and 4-strand repair techniques for zone II flexor tendon lacerations. METHODS: Thirty cadaveric flexor digitorum profundus tendons were randomized to 1 of 3 core sutures: (1) cruciate locked 4-strand technique, (2) modified Kessler 2-strand core suture technique, or (3) Teno Fix multifilament wire tendon repair device. Each repair was tested in the load control setting on a Instron controller coupled to an MTS materials testing machine load frame by using an incremental cyclic linear loading protocol. A differential variable reluctance transducer was used to record displacement across the repair site. Cyclic force (n-cycles) to 1-mm gap and repair failure was recorded using serial digital photography. RESULTS: There was no significant difference in differential variable reluctance transducer displacement between the cruciate, modified Kessler, and Teno Fix repairs. The cruciate repair had greater resistance to visual 1-mm repair-site gap formation and repair-site failure when compared with the Kessler and Teno Fix repairs. No significant difference was found between the modified Kessler repair and the Teno Fix repair. In all specimens, the epitenon suture failed before the core suture. Repair failure occurred by suture rupture in the 7 cruciate specimens that failed, with evidence of gap formation before failure. Seven of 10 modified Kessler repairs failed by suture rupture. All of the Teno Fix repairs failed by pullout of the metal anchor. CONCLUSIONS: The Teno Fix repair system did not confer a mechanical advantage over the locked cruciate or modified Kessler suture techniques for zone II lacerations in cadaveric flexor tendons during cyclic loading in a linear testing model. This information may help to define safe boundaries for postoperative rehabilitation when using this internal tendon repair device.     

Comparison of modified Kessler and Yotsumoto-Dona suture: A biomechanical study on porcine tendons

Abstract

There is a need for a strong suture technique that allows early active mobilisation after repair of flexor tendons, but the best method has not yet been found. The aim of this study was to compare the modified Kessler suture biomechanically with a newer, two–strand suture. Eighteen porcine tendons were cut and repaired according to either the grasping modified Kessler suture or the combined side-locking loop technique (Yotsumoto) and interlocking horizontal mattress suture (Dona). The specimens were tested linearly to failure. The 2 mm gap force, yield force, ultimate force, stiffness, energy to yield, and energy to failure were all significantly higher (p value = 0.005, 0.003, <0.001, 0.001, 0.004, and 0.001, respectively) in the Yotsumoto-Dona group (median values (IQR): 30.9 (28.1-39.5) N, 82.7 (64.9-114.1) N, 82.7 (76.6-114.1) N, 12.5 (10-14.5) N/mm, 0.45 (0.2-0.5) J, and 0.45 (0.35-0.5) J) than in the modified Kessler group (25.8 (12.2-28.1) N, 35 (24.6-54.4) N, 50.9 (34.4-55.1) N, 7 (5.8-91) N/mm, 0.09 (0.06-0.18) J, and 0.21 (0.18-0.28) J). All Yotsumoto-Dona specimens had a yield force exceeding 35 N, while in the Kessler group only four did. The early yielding rate was 6/9 and 2/9 in the modified Kessler and the Yotsumoto-Dona groups, respectively (p = 0.15). Most of the core sutures failed by breakage, but three Yotsumoto knots loosened. All the simple running and six of the Dona epitendinous sutures failed predominantly by pulling-out, and by breakage at the intersections in three of the latter. The relatively easy two-strand Yotsumoto-Dona suture is likely to withstand the loads of active finger flexion, whereas the modified Kessler suture is probably not.     

Strength analysis and comparison of the Teno Fix Tendon Repair System with the two-strand modified Kessler repair in the Achilles tendon

BACKGROUND: Various options exist for repair of Achilles tendon ruptures, yet a method that consistently provides sufficient gap resistance to allow early mobilization remains elusive. This study compares the mechanical performance of a modified Kessler repair with that of the Teno Fix Tendon Repair System (Ortheon Medical, LLC) in matched pairs of cadaver Achilles tendons. METHODS: The two-strand modified Kessler repair was selected as the control construct on the basis of literature review and physician interviews which identified it among the many options as a popular method for repair of acutely ruptured Achilles tendons. Test specimens were harvested from matched pairs of cadaver ankles. The tendons were transected 3.5 cm proximal to the calcaneal insertion and repaired with either the two-strand modified Kessler suture construct or the Teno Fix Tendon Repair System. Assignment to the modified Kessler or Teno Fix group was done randomly for the first member of each pair. All test and control repairs were performed by the same author to reduce variability. Evaluation of the repairs consisted of tensile strength testing and measurement of the gap formation and peak stresses. RESULTS: Gap and peak stress for the two-strand modified Kessler repair were 0.30 +/- 0.15 N/mm2 and 1.03 +/- 0.51 N/mm2, respectively. For the Teno Fix repairs the mean gap and peak stress values were 0.80 +/- 0.46 N/mm2 and 1.19 +/- 0.12 N/mm2, respectively. The mean gap formation stress was significantly higher in the Teno Fix repairs than in the control repairs (p < .0005). There was no significant difference in peak strength between the repairs (p < .10). CONCLUSIONS: The Teno Fix repair was superior to the modified Kessler repair. In the Teno Fix repairs, the gap formation stress was 67% of the peak tensile stress. In comparison, in the modified Kessler repairs, the gap formation stress was 29% of the peak stress. This can be correlated to the elastic property of the modified Kessler suture and the initial tightening of the suture around the tendon fibers. The Teno Fix system is nonelastic and is fully tensioned during installation. This lends to a more gap resistant repair.     

Tendon suture: surgical techniques

Tendon sutures belong to the bases of surgical activity. Particularly in the last decades these sutures experienced a substantial upswing by the introduction of new techniques and materials. Target is to reestablish the tendon function. In order to achieve this target, it requires knowledge of tendon healing. An outline of suture materials, in particular specific suture techniques as well as the subsequent treatment is given. With different localizations of the tendon lesions one deals.     

不剥离骨膜法肋骨钉内固定治疗多发肋骨骨折的随机对照研究

目的 分别运用Achillon吻合器和改良Kessler缝合法治疗急性闭合性跟腱断裂,随访比较患者的临床效果和功能恢复情况.方法从2009年3月至2012年2月,随机采用 Achillon吻合器微创修复与改良Kessler缝合法治疗49例急性闭合性跟腱断裂.其中Achillon 微创修复28例,改良Kessler法缝合21例.两组均无需行拇长屈肌或腓肠肌延长术.本研究平均随访21个月,分别在术后1周、第6个月、第12个月、随访结束期4个时间段,对两组患者的手术时间、住院时间、切口长度、踝关节运动范围、美国足踝外科协会（AOFAS）踝-后足疗效评分进行评价.结果在术后1周内,Achillon组发生1例神经损伤,改良Kessler组发生2例创口浅表感染,1例延迟愈合.两组并发症发生率差异无统计学意义（P=0.41）.在第6月,Achillon组AOFAS评分要优于改良Kessler组,第12月时两组无明显差异.术后两组踝关节运动范围,差异无统计学意义.截止随访结束时,所有患者均恢复到受伤前运动水平.结论两种缝合方法均能取得良好的疗效,相比改良Kessler缝合法,采用Achillon吻合器具有切口小、住院时间短、功能恢复快、术后美观等优点.     

TwinFix带线锚钉辅助改良Kessler法修补陈旧性跟腱断裂

目的 探讨TwinFix带线锚钉辅助改良Kessler法修补陈旧性跟腱断裂的临床疗效.方法 采用TwinFix带线锚钉辅助改良Kessler法修补陈旧性跟腱断裂患者11例,术中用改良Kessler法对位缝合跟腱断端,再用2枚TwinFix带线锚钉辅助固定断裂跟腱.术后予患侧下肢屈膝90°、踝跖屈30°位长腿石膏托固定,3周后改踝跖屈石膏托固定.结果 11例均获随访,时间3～18个月.患者均未发生切口延期愈合、感染、皮肤坏死和跟腱再断裂等并发症.采用Arner-Lindholm评分标准评价疗效:优7例,良3例,差1例.结论 TwinFix带线锚钉辅助改良Kessler法手术操作简便,是修补陈旧性跟腱断裂的有效方法.     

Meniscus suture techniques: a comparative biomechanical cadaver study

The primary stability of four common meniscus suture techniques was tested on human cadaver menisci. The test series was carried out under standard conditions (25 degrees C, 100% air humidity) using the Instron 1122 Tensometer. The tearing stress of different sutures was reproducible in different specimens dependent only on the suture technique. Knot-end techniques gave inferior results (tearing stress, 24 +/- 9 N) compared with arthroscopic techniques using a loop placed on the meniscus surface (tearing stress, 89 +/- 4 N). When an open meniscus repair is performed, a vertical stitching technique (tearing stress, 105 +/- 4 N) should be the preferred method. Horizontal sutures are weaker (tearing stress, 44 +/- 18 N).     

A comparison of suture and tubulization nerve repair techniques in a primate.

This study compared standard methods of nerve repair, epineurial or perineurial sutures with a technique termed fascicular tubulization using a biodegradable polyglycolic acid tube in a nonhuman primate model. Electrophysiologic analysis demonstrated that the percentage of proximal axons that conducted across the repair site did not significantly differ among the three techniques while epineurial suture repairs were associated with significantly longer conduction delays across the repair site compared with the other two techniques. Even though fascicular tubulization using the current polyglycolic acid tube resulted in regeneration equal to the currently perceived best suture repair technique, associated technical problems with the current tube design indicate that this fascicular tubulization technique cannot, at present, be considered as an alternative to present clinically used nerve suture techniques.     

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.     

Comparison between tenocutaneous suture and Kessler suture techniques in treating acute closed Achilles tendon rupture

BackgroundTo compare the effectiveness of tenocutaneous suture and conventional Kessler suture techniques in treating acute closed Achilles tendon rupture.MethodsA total of 33 patients with acute closed Achilles tendon rupture who were admitted to our hospital from February 1998 to December 2008 underwent repair with either a tenocutaneous suture or Kessler suture technique. All patients were followed up for 1–5 years (mean, 3 years).ResultsAccording to the American Orthopaedic Foot and Ankle Society ankle–hindfoot scale, the excellence rate was 91% in the Kessler suture group and 98% in the tenocutaneous suture group, with a significant difference between groups.ConclusionOur tenocutaneous suture technique is an effective method for treating Achilles tendon rupture. It has certain advantages compared with the conventional incision method and is worthy of wide clinical application.     

Flexor tendon repair using shape memory alloy suture: a biomechanical evaluation

The purpose of the current study was to test in vitro a new shape memory alloy suture for flexor tendon repair. Forty fresh-frozen human anatomic flexor superficialis and profundus tendons were divided and repaired via the cruciate four-strand technique using one of two suture materials (the shape memory alloy suture and the 4-0 Ethibond suture). The forces required to cause a 1, 2, and 3 mm gap, ultimate load to failure, and repair stiffness were compared. Twenty specimens of each suture material also were tensile tested for load to failure, tensile strength, and elongation at failure. The shape memory alloy suture had a significantly higher mean resistance force to 1, 2, and 3 mm gap formation than the 4-0 Ethibond suture (47 N versus 31 N, 51 N versus 36 N, and 57 N versus 41 N, respectively). The shape memory alloy suture repair was 40% stronger than the 4-0 Ethibond suture (61.9 +/- 8.8 N versus 44.3 +/- 10.6 N). Repair with the shape memory alloy suture was significantly stiffer than repair with the 4-0 Ethibond suture (8.1 +/- 1.0 N/mm versus 6.1 +/- 0.9 N/mm). The load to failure and tensile strength of the shape memory alloy suture were significantly higher than that of the 4-0 Ethibond suture. The values of elongation for the two materials were not significantly different. The results of the current study suggest that the shape memory alloy suture may be superior to the 4-0 Ethibond suture in resisting gap formation in the range of forces generated in the early rehabilitation protocol and may be the future material of choice for tendon repairs.     

The strength of the 6-strand modified Kessler repair performed with triple-stranded or triple-stranded bound suture in a porcine extensor tendon model: an ex vivo study

PURPOSE: To investigate the biomechanic influence of triple-stranded sutures and the spatial arrangement of the strands on the strength of the 6-strand Pennington modified Kessler repair. METHODS: In the present ex vivo study of pig extensor tendons 2 techniques were used: (1) triple-stranded suture (3 suture strands in the same needle) and (2) triple-stranded bound suture (3 suture strands in the same needle that were bound together, parallel to each other, side by side). The repairs were subjected to static tensile testing. RESULTS: The 6-strand modified Kessler repair performed with triple-stranded bound suture reached significantly higher yield force, ultimate force, and both partial and total 1-, 2-, and 3-mm gap forces compared with the repairs performed with triple-stranded suture. The stiffness and strain values at the yield point and at the ultimate point did not differ significantly. CONCLUSIONS: This experimental study introduces a way to improve the strength of the tendon repair. The triple-stranded bound suture significantly increased both the gap resistance and ultimate force of the 6-strand modified Kessler repair. We assume the improvements are due to increased holding capacity of the locking loops. The triple-stranded bound suture is easy to use and avoids several problems associated with traditional multistrand repairs. Further studies are needed before clinical use can be considered.