Lengthening and locking: two ways to improve repair strength of obliquely lacerated tendons

PURPOSE: Oblique transections in tendons tend to reduce the strength of conventional repairs. We evaluated the effectiveness of lengthening longitudinal strand passage and adding locking components to improve the strength. METHODS: Seventy-six fresh pig flexor tendons were transected obliquely and repaired using either a modified Kessler (grasping) repair or a locking Kessler repair. Orientations of the strands within the tendon were varied among conventional, oblique, and lengthened. The 2-mm gap formation force and ultimate strength were tested as measures of biomechanical performance for each repair. RESULTS: The 2-mm gap formation force and ultimate strength with either grasping or locking repair were the weakest with a conventional repair, stronger with an oblique repair, and the strongest with a lengthened repair. The strength was significantly greater in oblique and lengthened locking repairs than in corresponding types of the grasping repair but was not different between the repairs with conventional configurations. CONCLUSIONS: Lengthening the repairs effectively improves the repair strength in obliquely lacerated tendons, in which strength of the conventional repairs diminishes owing to a decrease in the distance from sutures' grasping points to the laceration. Adding locking components increases the strength to oblique and lengthened repairs but does not add to the repairs with locking points that are not sufficiently away from the level of laceration.     

肌腱斜形损伤修复强度的研究

目的　研究斜形损伤对肌腱修复抗张强度的影响。方法　根据猪后蹄跖深屈肌腱切断的方向 (横形、斜形 )、缝合方法 (改良Kessler法、Cruciate法、MGH法 )及缝合方向 (横形、斜形 ) ,将 81根肌腱分为 9组 ,每组 9根。检测缝合后肌腱 2mm间隙形成的负荷、最大抗张强度、最大功耗。采用ANOVA进行统计分析。结果　斜形损伤后用Kessler法、Cruciate法作横形缝合时 ,其抗张强度显著小于横形损伤的修复强度 (P <0 .0 5 )。选用斜形缝合修复斜形损伤后 ,两者抗张强度均较横形缝合增大 (P <0 .0 5 )。斜形损伤用MGH法缝合对抗张强度的影响不显著。结论　肌腱斜形损伤后采用Kessler法和Cruciate法作斜形缝合 ,可明显提高修复后的抗张强度。     

Primary nerve repair: strength of repair with different gauges of nylon suture material

Cadaveric median nerves were divided and repaired with interrupted epineural sutures, as in normal clinical practice, using three different gauges of nylon monofilament material. Tensile testing of the nerve repairs showed that, of these three gauges, 9/0 (0.3 metric) sutures were preferable: gap formation at the repair site occurred at the highest force. Finer gauge (10/0) sutures snapped at a lower force, while thicker (8/0) sutures were less consistent and pulled out of the nerve tissue.     

Pullout strength of suture anchors used in rotator cuff repair

BACKGROUND: Surgical treatment of rotator cuff tears may be complicated by osteoporosis of the proximal part of the humerus. The purpose of this study was to determine whether pullout strength of suture anchors is affected by the location of the anchor placement and by bone mineral density. We hypothesized that higher bone mineral density is associated with higher pullout strength of suture anchors. METHODS: Peripheral quantitative computed tomography was used to measure total, trabecular, and cortical bone mineral density in different regions of the lesser and greater tuberosities in seventeen cadaveric humeri. Suture anchors were inserted into individual regions and subjected to cyclic loading. Repeated-measures analysis of variance was used to assess differences in bone mineral density and load to failure between regions of interest. Pearson correlation was used to determine the association between bone mineral density and pullout strength of suture anchors. RESULTS: Total, trabecular, and cortical bone mineral densities were an average of 50%, 50%, and 10% higher, respectively, in the proximal part of the tuberosities compared with the distal part (p < 0.01). Within the proximal part of the greater tuberosity, trabecular bone mineral density of the posterior region and cortical bone mineral density of the middle region were, on the average, 25% and 16% higher, respectively, than the densities in the other regions (p < 0.01). Load to failure in the proximal part of the tuberosities was an average of 53% higher than that in the distal part (p < 0.01). The lesser tuberosity showed, on the average, a 32% higher load to failure than did the greater tuberosity (p < 0.01). Within the proximal part of the greater tuberosity, loads to failure in the anterior and middle regions were, on the average, 62% higher than the load to failure in the posterior region (p < 0.01). Overall positive correlations were found between bone mineral density and load to failure (0.65 相似文献   

提高斜形损伤肌腱缝合强度的实验研究

目的探讨提高斜形肌腱损伤修复强度的有效方法。方法40根猪跖深屈肌腱按照切割方向及两端缝合距离随机分为4组:第1组肌腱为横形损伤,中心缝合边距为10mm;第2、3、4组肌腱为45°斜形损伤,中心缝合边距分别为4mm、7mm、10mm,10根肌腱,各组均采用改良Kessler法缝合。分别检测缝合肌腱的2mm间隙形成负荷、最大抗张强度及最大功耗,并采用ANOVA法进行统计分析。结果肌腱斜形损伤修复的强度显著低于用等长距离(20mm)缝合的横行损伤修复的强度(P<0.01),当其短边的缝合边距由4mm增大到7mm时,其修复的强度显著增大(P<0.01),但当短边的缝合边距增大到10mm时,其抗张强度与短边的缝合边距7mm相比增加不显著。结论在肌腱斜形损伤时,延长中心缝合边距是一种有效的提高肌腱修复强度的方法。     

指屈肌腱双环加强缝合法及其生物力学研究

目的：介绍作者设计的指屈肌腱双环加强缝合法。方法：用３６条人体指屈肌腱标本，行双环加强缝合法、改良Ｋｅｓｓｌｅｒ法、Ｌｅｅ法、Ｂｅｃｋｅｒ法和Ｓａｖａｇｅ法缝合肌腱，并进行生物力学测定比较。结果：５种缝合方法的平均抗拉强度分别为６７．５Ｎ、３５．８Ｎ、３６．７Ｎ、７４．７Ｎ、９６．８Ｎ。结论：双环加强缝合法操作简单，抗拉强度足够临床需要，术后可早期进行主动屈指活动，具有较大的安全系数     

Flexor tendon repair: significant gain in strength from the Halsted peripheral suture technique

A biomechanical study in vitro has evaluated a new modification of the core and peripheral suture technique for flexor tendon repair. Groups of repairs were conducted in cadaver tendons, using a core suture alone, a core suture with a simple running surface suture and a new modification involving a 'Halsted' horizontal mattress technique for the peripheral stitch. The Halsted modification increased the load at which a visible gap formed by 93%, the load at which a 2 mm gap formed by 77%, and the maximum strength by 89%. This increase was due to the technique; it did not depend on the suture material used. The bulk of the tendon repair was not significantly greater with the Halsted modification.     

The tensile strength of various peripheral circumferential repair techniques in canine flexor tendons

The purpose of this study was to evaluate the tensile strength of six peripheral circumferential suture techniques, using a variable number of suture strands. Transverse lacerations were made in 184 fresh frozen canine flexor profundus tendons and repaired using only a 6-0 Prolene circumferential suture. The six running suture techniques were: Simple, Simple-locking, Lembert, Halsted, Cross-stitch and Lin-locking, and 6, 10, 14, and 20 suture strands were used. For each technique, the tensile strength gradually increased with the increased number of suture strands. The tensile strength of the Lin-locking technique (19–34 N) was greater than that of the other techniques, followed by Cross-stitch (16–33 N), Halsted (10–25 N), Lembert (8–23 N), Simple (6–12 N), and Simple-locking (5–8 N). The Lin-locking had the best holding power, but it was technically the most complicated to place. The Cross-stitch had good tensile strength values. The Simple and the Simple-locking had the lowest tensile strengths. From the viewpoints of tensile strength and technical skill, the Cross-stitch may be preferable to other suture techniques.     

A safe and effective method for an immediate bronchopleural fistula repair

Bronchopleural fistula (BPF) is a well recognized and potentially fatal complication of major thoracic surgery and several strategies regarding its prevention and subsequent management have been described. An immediate BPF occurring intraoperatively after bronchial closure is a rare event and is usually treated by bronchial stump reamputation and/or hand-suture reinforcement by mattress suture, or myoplasty. We report a simple and successful technique, using azygous vein flaps, to repair an intraoperative BPF associated to a small bronchial dehiscence occurred after a right pneumonectomy in a 70-year-old diabetic man receiving induction chemotherapy treatment.     

The TOTS (temporary outside traction suture): a new technique to allow easy suture placement and improve capsular shift in arthroscopic bankart repair

We describe a new technique to allow easy placement of anterior sutures and to improve the proximal capsular shift in arthroscopic anterior stabilization of the shoulder, which we call the temporary outside traction suture (TOTS). Two standard portals are used: posterior and anterosuperior. Using a curved suture hook, both the capsule and the labrum are perforated at approximately the 5-o’clock position, and a monofilament suture is passed through the tissues. The suture is first retrieved through the anterior canula and then placed outside the canula. After labrum detachment and glenoid preparation, 1 or 2 further inferior sutures can be placed before the first suture is retrieved inside the canula and used. The technique of the TOTS has many advantages. (1) It allows easy placement of the first suture before the anterior capsule and labrum have been released. This makes this step much more difficult due to the lack of tension in the anterior tissues and anterior subluxation of the humeral head. (2) It allows the surgeon to choose, with accuracy, the amount of capsule taken, according to the severity of the capsular lesions and the degree of capsular laxity. It can also allow anatomic recreation of the anterior band of the inferior glenohumeral ligament (IGHL). (3) By placing tension on the suture, it avoids damaging the anterior capsule and labrum with the shaver and burr while preparing the scapula neck and can aid with haemostasis. (4) Tension on the suture also allows one to easily place 1 or 2 further sutures in a lower position. (5) It avoids entangling the sutures in the canula. (6) It allows one to perform a capsular shift of approximately 10 to 15 mm when the traction suture is retrieved and implanted with an anchor in the 3- or even 2-o’clock position.     

The evolgate: a method to improve the pullout strength of interference screws in tibial fixation of anterior cruciate ligament reconstruction with doubled gracilis and semitendinosus tendons

Purpose:The goal of the study was to investigate the biomechanical properties of a new device for tibial fixation in arthroscopic anterior cruciate ligament reconstruction using doubled semitendinosus and gracilis tendons.Type of Study:Biomechanical study.Methods:This study compares the initial pullout strength, stiffness, and failure modes of 7 pairs of 4-strand human semitendinosus and gracilis grafts fixed to porcine tibias using either the Evolgate (Citieffe, Bologna, Italy) or 1 round threaded titanium interference screw. Structural tests of the graft fixation method tibia complexes were performed using a materials testing machine (MTS Bionix 855, Minneapolis, MN) at a strain rate of 50 mm/second.Results:The mean failure load was 1,237 ± 191 N for the Evolgate and 537 ± 65 N for the interference screw (P < .05) and the mean stiffness was 168 ± 37 N/m for the Evolgate and 105 ± 17 N/m for the interference screws (P ≤ .05). Although in all the cases fixed with the Evolgate failure occurred because of tendon rupture inside the tibial tunnel close to the fixation device, in 4 of the 7 cases fixed with interference screws, failure occurred because of tendon slippage at the fixation site.Conclusions:These results indicate that initial pullout strength of hamstring tendon graft interference screw fixation can be significantly increased using the Evolgate. In fact, because the screws purchase only in the cancellous bone, the Evolgate reinforces the walls of the tibial tunnel with a titanium involute, avoiding the loss of fixation strength related to the low density of the cancellous bone of the proximal metaphysis of the tibia.     

Vascular changes in flexor tendons after injury and repair: an experimental study.

Two groups of experiments were carried out on the profundus tendons of New Zealand rabbits: 1. Simple closed tenotomies at various levels along the digit. 2. Open tendon division followed by repair with a Bunnell criss-cross suture. At intervals after the operation injection studies were performed to outline the vascular pattern within the tendons. The results indicate that the circulation through the intratendinous vessels is precarious and it may be impaired both by tenotomy and by the presence of sutures. It is suggested that this may be an important factor in the pathogenesis of adhesions. The clinical implications are discussed.     

A simple and effective method to improve intrasplenic rat hepatocyte transplantation

Transplanted hepatocytes integrate, survive, and express their specific functions in the liver parenchyma. The aim of this study was to determine whether a large number of hepatocytes could move from the spleen to the liver when the cells are injected together with sodium nitroprusside, and if the improved hepatocyte migration may be related with portal vein dilatation. Wistar rats were transplanted in the spleen with fluorescent-labeled hepatocytes alone or together with sodium nitroprusside. At 1, 3, 6, and 24 h after the transplant, the liver from recipient animals was removed and morphometric analyses were performed. Portal and arterial pressures were also measured immediately after intrasplenic injection of a solution of sodium nitroprusside, hepatocytes alone, or hepatocytes plus sodium nitroprusside. Intrasplenically injected sodium nitroprusside produced a transient drop in arterial pressure and a sustained reduction in portal pressure. During hepatocyte transplantation it increased the number of transplanted cells migrating to the liver after 3 h. Sodium nitroprusside simultaneously injected with hepatocytes in the spleen allowed more cells to migrate into the liver of the host animal without risk in animal survival.     

Backstroke technique: an effective way to improve the healing of tibia fracture

To assess the method and results of applying a backstroke technique, we treated 43 patients with tibial shaft fracture using unreamed tibial nails (UTN). Of these patients, 27 suffered a closed fracture and 16 an open fracture. After the operation, the effect of treatment was evaluated: 42 of 43 cases were followed up from four to 18 months, averaging 13.6 months. The four-month and 12-month healing rates of open fracture were 54.6 and 80.9%, respectively, the former of which is significantly higher than the average rate of the AO/ASIF multicentre study. Our results indicate that applying a backstroke technique in treating tibial shaft fracture with UTN can improve the healing rate and reduce complications.

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Résumé Résumé: Afin d’apprécier la méthode et le résultat du traitement des fractures de la diaphyse tibiale avec un clou d’alignement, nous avons opéré 43 patients présentant une fracture de ce type. Parmi tous ces patients, 27 présentaient une fracture fermée, 16 une fracture ouverte. Après opération, les résultats du traitement ont été évalués. 42 patients sur 43 ont été suivis de 4 à 18 mois avec une moyenne de 13,6 mois. Le taux de consolidation des fractures à 4 mois et un an était respectivement de 54,6% et 80,9%. Ce taux est nettement supérieur à celui de l’étude multicentrique de l’AO/ASIF. Notre étude prouve que cette technique dans le traitement des fractures tibiales à l’aide d’un clou d’alignement UTN peut améliorer la consolidation et diminuer le nombre de complications.

     

Failure strength of a new meniscus arrow repair technique: Biomechanical comparison with horizontal suture

A new method for arthroscopic all-inside repair of vertical meniscus lesions by use of a biodegradable fixation device (“meniscus arrow”) has been developed, including a set of cannulas for easy insertion via standard arthroscopic portals. The technique is described. A study to test the fixation properties was performed in the laboratory. Twenty-four fresh frozen bovine medial menisci were defreezed and devided into three groups. In all menisci an artificial vertical lesion was created with a scalpel 3 mm from the peripheral rim. Repair in group I was done with a single horizontal Maxon-0 suture using an Acufex double-barrel cannula (Acufex Meniscal Stitcher; Acufex Microsurgical, Norwood, MA). A knot was tied on the capsular side. Repair in group II was made with one 13 mm Biofix Meniscus arrow (Bioscience Ltd, Tampere, Finland). In group III repair was performed like in group II but the menisci were incubated in isotonic saline at 21°C for 24 hours before testing. Menisci in group I and II were tested within 3 hours after defreezing. Prior to testing total separation of central and peripheral part of meniscus was performed. Thus only the repair site was tested. Pull-out tests to failure were made in a computer-based Nene M5 testing maschine with a cross-head speed of 5 mm/min. Median failure load in group I: 49 N (range 43 to 77 N), in group II: 53 N (range 42 to 65 N) and in group III: 54 N (range 35 to 74 N). No statistically significant difference in failure load was found between the groups. Thus initial failure strength for arrow-repaired bovine menisci is comparable to that of a horizontal suture