Acromioclavicular reconstructions with hamstring tendon grafts: a comparative biomechanical study

The surgical treatment of chronic acromioclavicular injuries remains controversial. There is increasing use of autogenous tendon grafts to perform these reconstructions. This study examined the mechanical properties of differing configurations of these grafts. Mechanical testing of acromioclavicular joint reconstructions was performed with a screw and soft tissue washer for tendon fixation, a simple loop of tendon tied to itself, and a bio-interference screw for tendon fixation, with and without a loop of nonabsorbable suture for reinforcement. The bio-interference screw fixation, with reinforcement by a loop of nonabsorbable suture, gave the highest load to failure among the group (502N +/- 177), which was not significantly different from the intact ligaments (705 N +/- 132), although it was significantly less stiff than the intact group (57.2 N/mm +/- 12.6 and 109.7 N/mm +/- 32.6, respectively). All other reconstructions had an ultimate load and stiffness which were significantly less than that of the intact specimens.     

Fixation of tendon grafts for collateral ligament reconstructions: a cadaveric biomechanical study

PURPOSE: To compare the biomechanical properties of 4 methods of fixation of tendon grafts to bone as used for ligament reconstructions. METHODS: Thirty-two metacarpals were harvested from fresh-frozen cadavers and stripped of soft tissue. Flexor tendons were harvested from the same cadavers and cut into 2-mm-wide strips. Each tendon was fixed to a metacarpal head at the site of origin of a collateral ligament. Four different methods of fixation were tested. In group 1 the tendon was fixed to the bone with a 4.0-mm Arthrex bio-tenodesis interference screw (Arthrex, Inc., Naples, FL). In group 2 the tendon was passed through a bone tunnel and fixed with a 3.2-mm mini-Acutrak screw (Acumed, LLC, Hillsboro, OR) that was inserted in interference mode. In group 3 the tendon was passed through a bone tunnel and fixed with sutures tied over a polyethylene button. In group 4 the tendon was fixed with a mini-Mitek bone suture anchor (Mitek Worldwide, Norwood, MA). All specimens were clamped into a linear loading machine and loaded until failure. Statistical analysis was performed by 1-way analysis of variance testing. RESULTS: The differences in maximal tensile strength and stiffness were statistically significant when comparing any 2 groups. The Arthrex biotenodesis interference screw was the strongest and stiffest fixation method, followed by the Acutrak screw inserted in interference mode. Next was the suture tied over a button method. The mini-Mitek bone suture anchor was the weakest. CONCLUSIONS: Interference screw fixation of tendons to bone has statistically significant higher pullout strength and stiffness than 2 other commonly used fixation methods. The use of interference screws for fixation of tendon grafts to bone for hand ligament reconstructions is a promising new surgical technique.     

Acromioclavicular reconstruction using autogenous semitendinosus tendon graft: results of revision surgery in chronic cases

Revision surgery of acromioclavicular dislocation is challenging owing to the altered anatomic relationships and the lack of stabilizing structures. In this study, an autogenous semitendinosus tendon graft was used for revision acromioclavicular stabilization, aiming at anatomic coracoclavicular reconstruction, as these patients had previously undergone a Weaver-Dunn procedure, which failed. Twelve patients were followed up clinically and radiographically for a mean of 49.5 months. The primary diagnosis was acromioclavicular joint dislocation Rockwood type III in 6, type IV in 4, and type V in 2 cases. At follow-up, the mean Constant score averaged 76.4 points. Pain relief was statistically significant (P < .01). Radiologic coracoclavicular distance and posterior displacement of the lateral clavicle in the Rockwood type IV cases decreased significantly (P < .01). We conclude that with this new technique of autogenous semitendinosus tendon graft replicating the anatomic ligamentous properties, good to excellent results can be achieved in revision cases of acromioclavicular reconstruction.     

A comparative analysis of the six-strand double-loop flexor tendon repair and three other techniques: a human cadaveric study

The ideal zone II flexor tendon repair would be easy to perform, cause minimal scarring, and be strong enough to allow early active motion. A 6-strand loop suture technique devised by the senior author (T.M.T.) was studied in vitro. Forty flexor tendons were harvested from fresh-frozen human hands and divided into 4 groups of 10 tendons each. Each group of tendons was repaired with a specific technique: group 1, the modified Kirchmayr (modified Kessler) technique; group 2, the single-loop 2-strand technique described by Tsuge; group 3, Tsai's double-loop 4-strand modification of Tsuge's technique; and group 4, Tsai's double-loop 6-strand modification of Tsuge's technique. Gap resistance of each repair technique was recorded on a computer using a Differential Variable Reluctance Transducer (MicroStrain, Burlington, VT) and on videotape to record first gap formation, 1-mm and 2-mm gap formation, and maximum load. Statistically significant differences between groups were as follows: at first gap formation between the 2-strand and 6-strand loop suture techniques, and at maximum load between the modified Kessler and 4-strand, modified Kessler and 6-strand, 2-strand and 4-strand, and 2-strand and 6-strand loop suture techniques. The 6-strand double-loop suture technique had a higher tensile strength than the other techniques, as measured in this model at each stage in our experiment. The 6-strand double-loop suture technique simplifies flexor tendon repair. It improves the repair's strength and its resistance to gapping without increasing tendon handling or bulk. This increased repair strength allows us to pursue a more aggressive rehabilitation program.     

Dacron augmentation of a free patellar tendon graft: A biomechanical study

The mechanical characteristics of a knitted 8-mm Dacron tube used as augmentation for patellar tendon strips was analyzed and compared with ligament augmentation device (LAD) tendon strips. The failure load was found to be the same (approximately 320 N) for both types of ligament augmentations. The typical failure mode in the Dacron augmentations was rupture of the Dacron tube proximal to the proximal bone fragment. The LAD augmentations failed at the suture line. The Dacron composite was stiffer than the LAD composite at low loads, but both composites became stiffer after two load cycles to 40 N with stress relaxation. At the end of the second stress relaxation cycle, the remaining load was significantly higher for the Dacron composite. During the second 2-min stress relaxation period, the Dacron composite lost 23% and the LAD composite lost 28% of the applied load. The stiffness and the elongation to failure was the same for both composites. The study showed that the Dacron tube may have possibilities similar to the LAD for use as an augmentation device.     

Zone II tendon repairs augmented with autogenous dorsal tendon graft: a biomechanical analysis

We investigated the biomechanical properties of a new technique for tendon repair that reinforces a standard suture with an autogenous tendon graft. A dynamic in situ testing apparatus was used to test 40 flexor digitorum profundus tendons harvested from fresh-frozen cadaver hands. The tendons were cut and repaired using 1 of 4 suture techniques: 2-strand modified Kessler, 4-strand modified Kessler, 6-strand modified Savage, and 2-strand modified Kessler augmented with autogenous dorsal tendon graft. The augmented repair uses 1 slip of the flexor digitorum superficialis tendon secured to the dorsal surface of the repair site with a continuous stitch. Ultimate tensile strength, resistance to gap formation, and work of flexion were measured simultaneously on an in situ tensile testing apparatus. No significant difference in tensile strength was found between the augmented repair and the 6-strand Savage repair. The augmented repair and the 6-strand Savage repair showed significantly greater ultimate tensile strength than the 2- and 4-strand repairs. The augmented repair had significantly greater resistance to 2 mm gap formation than the other 3 repairs. We were unable to show a significant difference in work of flexion between the repairs with the numbers tested (n = 10). Our findings suggest that the augmented repair is strong enough to tolerate the projected forces generated during active motion without dehiscence or gap formation at the repair site.     

Thumb metacarpophalangeal joint ligament reconstruction with a triangular tendon graft in posttraumatic chronic instability

The purpose of this study was to report the results of static triangular ligament reconstruction, in thumb metacarpophalangeal (MCP) joint chronic posttraumatic laxity using a tendon graft with a proximal apex in ten patients. The mean postoperative follow-up was 40.2 months. The mean postoperative thumb MCP joint stress testing was 43° less than before surgery, and 6.5° less than in the non-injured hand. The mean range of flexion was 10.5° lower in the operated thumb than in the contralateral one, and the mean range of extension was 8° lower. Minimal differences in the values of the Kapandji score, grip and key-pinch strength were found. The preoperative pain became an occasional discomfort after surgery. All patients had a subjective sense of stability until final follow-up. All patients returned to their work or daily activities. LEVEL OF EVIDENCE IV: For therapeutic studies investigating the results of treatment.     

Acromioclavicular joint reconstruction using the Nottingham Surgilig: a preliminary report

Eleven patients with a chronic acromio-clavicular joint disruption underwent acromio-clavicular joint stabilisation using the Nottingham Surgilig and were followed up clinically and radiologically for an average of 24 months post operation. The mean post-operative Constant score was 83.1, the Imatani score was 81.2 and the Walsh score was 14.1. Eighty-two per cent of patients were satisfied with the operation. There was one case of rupture through the central portion of the Surgilig, and following laboratory analysis, the ligament has been modified since. In 4 patients there was evidence of loosening of the screw but only one complained of this being a problem. This short-term outcome analysis of the Nottingham Surgilig is the first such report outside the Nottingham unit where the prosthesis was originally developed. Our results are encouraging and justify further use and evaluation of this relatively new technique.     

同种异体肌腱重建喙锁和肩锁韧带治疗肩锁关节脱位

目的 介绍应用同种异体肌腱重建喙锁和肩锁韧带治疗肩锁关节脱位的临床疗效.方法 2010年2月至2012年2月,对6例肩锁关节脱位患者,应用同种异体肌腱“V”形重建喙锁和肩锁韧带,并跟踪随访其疗效.随访包括调查患者总体满意度,观察患肩外形,测量肩关节活动度,摄片评价肩锁关节复位维持情况,使用Constant-Murley肩关节评分和美国加州大学洛杉矶分校(UCLA)评分系统评价患肩功能,视觉模拟评分法(VAS)了解患者疼痛情况.结果 术后平均随访时间为18个月,患者总体满意度为83.3％,所有患者肩关节外形正常,平均前屈上举163.5°、外展上举147.2°,Constant-Murley评分平均95.3分、UCLA评分平均32.8分、VAS评分平均0.3分.结论 应用同种异体肌腱修复重建喙锁和肩锁韧带治疗肩锁关节脱位,符合生物力学要求,术后随访疗效满意,是一种有效的治疗方法.     

Flexor tendon repair using a new suture technique: a comparative in vitro biomechanical study

Introduction  

The purpose of this experimental study was to evaluate the biomechanical characteristics of two new four-strand core suture techniques for flexor tendon repair.     

单根肌腱多韧带重建治疗急性第一腕掌关节脱位

目的：探讨桡侧腕长伸肌腱重建第一腕掌关节周围4束韧带治疗急性第一腕掌关节脱位的临床疗效。方法：自2008年12月至2012年10月,对4例急性第一腕掌关节脱位的患者切开复位后采用单根桡侧腕长伸肌重建关节周围4组韧带,即背侧韧带,掌侧韧带,桡背侧韧带,第一、二掌骨间韧带;其中男3例,女1例;平均年龄38．7岁（22~63岁）。术后根据X线片、JAMAR握力测试、拇指关节活动范围（rangeofmotion,ROM）、活动时疼痛视觉模拟评分（visualanaloguescale,VAS）等指标评价手术效果。结果：所有患者获随访,时间6~40个月,平均19个月。术后伤口均I级愈合。术后1、3、6个月x线片未见第一腕掌关节脱位复发,关节间隙无明显狭窄退变。JAMAR握力测试患侧恢复至健侧的60％N90％。ROM测定3例屈伸、收展活动恢复正常,1例内收受限。拇指活动时疼痛VAS评分0-1分。结论：对于急性第一腕掌关节脱位,桡侧腕长伸肌腱重建关节周围韧带可恢复关节稳定性,改善功能。     

半腱肌腱与同种异体肌腱解剖重建踝关节外侧副韧带治疗慢性踝关节不稳的疗效比较

目的比较自体半腱肌腱与同种异体肌腱重建踝关节外侧副韧带治疗慢性踝关节不稳的临床疗效。方法回顾性分析自2012-06—2014-12在踝关节镜联合小切口下分别应用同种异体肌腱与自体半腱肌腱解剖重建踝关节外侧副韧带治疗慢性踝关节不稳68例。半腱肌腱组35例,异体肌腱组33例。比较2组手术时间、住院时间、手术费用,以及末次随访时VAS评分、AOFAS评分、IKDC评分、距骨倾斜角和距骨前移距离。结果 68例均获得13~38(22.7±5.2)个月随访。半腱肌腱组手术时间明显长于异体肌腱组,但在住院时间和手术费用方面优于异体肌腱组,差异有统计学意义(P0.05)。2组末次随访时VAS评分、AOFAS评分、IKDC评分、距骨倾斜角和距骨前移距离比较差异无统计学意义(P0.05)。结论同种异体肌腱与自体半腱肌腱重建踝关节外侧副韧带治疗慢性踝关节不稳均能获得良好临床疗效,临床中可根据患肢膝关节健康状况、运动期望值及经济承受能力综合分析,个体化选择移植物。     

Flexor tendon graft attachment: a review of methods and a newly modified tendon graft attachment

A review of the described methods of attachment of flexor tendon grafts to the distal phalanx is presented. The authors advocate the previously described method of attachment consisting of passage of the tendon graft through the pulp with anchorage to the nail. A new modification of this technique is presented, facilitating accurate dissection and placement of the graft with minimal trauma.     

Glenohumeral joint motion after medial shift of the attachment site of the supraspinatus tendon: a cadaveric study

During a rotator cuff repair, it is ideal to reattach the torn edge of the cuff tendon back to the greater tuberosity. However, with massive tears where the torn edges are too retracted to be reattached to the greater tuberosity, they may have to be reattached somewhere more medial. It is clinically important to know how far medially one can shift the reattachment site without sacrificing function of the shoulder. Ten fresh, previously-frozen cadaveric shoulders were used. Medial shift of the supraspinatus tendon was simulated by placing the suture anchors along lines 3, 10, or 17 mm medial to the cuff attachment site. The ranges of glenohumeral motion were measured using a goniometer with a constant torque applied to the humerus. All motions, except for internal rotation at 60 degrees of abduction, were significantly restricted by medial shift of 10 mm or more compared with that of the intact shoulder. We conclude that significant restriction of joint motion occurs when a bony trough is created more than 10 mm medial to the cuff attachment site.     

Biomechanical analyses of the human flexor tendon adhesion models in the hand: A cadaveric study

Patients with longstanding trigger finger may develop flexion contracture at the proximal interphalangeal (PIP) joint that persists even after division of the A1 pulley. The purpose of this study was to explore the hypothesis that flexion deformity of the PIP joint in advanced trigger finger is caused by severe adhesion between the flexor digitorum superficialis (FDS) and the flexor digitorum profundus (FDP) tendons. Ten freshly frozen cadaveric hands were used in the experiments. After preparation of the extrinsic flexor, extrinsic extensor, and intrinsic muscle tendons, we applied weights to the flexor tendons and minimal tension to the extrinsic extensor and intrinsic muscle tendons. We then measured the initial flexion angles of the metacarpophalangeal (MCP) and PIP joints. Next, we measured the flexion angles of the MCP and PIP joints as increasing tension was applied to the extrinsic extensor and intrinsic muscle tendons, respectively. We repeated these experiments after constructing flexor tendon adhesion model. The initial flexion angles of the MCP and PIP joints were greater in the adhesion model, as were the average tensions required for full extension of these joints. Our results suggest that adhesion between two flexor tendons contributes to progression of flexion deformity in the PIP joint. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:717–725, 2015.