Variation in external rotation moment arms among subregions of supraspinatus, infraspinatus, and teres minor muscles.

A rotator cuff tear causes morphologic changes in rotator cuff muscles and tendons and reduced shoulder strength. The mechanisms by which these changes affect joint strength are not understood. This study's purpose was to empirically determine rotation moment arms for subregions of supraspinatus, infraspinatus, and for teres minor, and to test the hypothesis that subregions of the cuff tendons increase their effective moment arms through connections to other subregions. Tendon excursions were measured for full ranges of rotation on 10 independent glenohumeral specimens with the humerus abducted in the scapular plane at 10 and 60 degrees . Supraspinatus and infraspinatus tendons were divided into equal width subregions. Two conditions were tested: tendon divided to the musculotendinous junction, and tendon divided to the insertion on the humerus. Moment arms were determined from tendon excursion via the principle of virtual work. Moment arms for the infraspinatus (p < 0.001) and supraspinatus (p < 0.001) were significantly greater when the tendon was only divided to the musculotendinous junction versus division to the humeral head. Moment arms across subregions of infraspinatus (p < 0.001) and supraspinatus (p < 0.001) were significantly different. A difference in teres minor moment arm was not found for the two cuff tendon conditions. Moment arm differences between muscle subregions and for tendon division conditions have clinical implications. Interaction between cuff regions could explain why some subjects retain strength after a small cuff tear. This finding helps explain why a partial cuff repair may be beneficial when a complete repair is not possible. Data presented here can help differentiate between cuff tear cases that would benefit from cuff repair and cases for which cuff repair might not be as favorable.     

Effect of hyperdry amniotic membrane in preventing tendon adhesion in a rabbit model

BackgroundNo anti-adhesive materials are currently in clinical use for orthopaedic surgery. We developed a hyperdry amniotic membrane (HD-AM) for easy storage and transplantation as amniotic membrane. The purpose of this study was to examine the application of HD-AM to reduce peritendinous adhesions without impairing tendon healing.MethodsWe randomly divided 3 digits (2nd, 3rd, and 4th digits) from each rabbit into three groups: a tendon repair group; a tendon repair with HD-AM group (HD-AM group); and a control group (cast only). The effects of HD-AM on peritendinous adhesions and tendon healing were examined using microscopic, histological, and mechanical analyses in a rabbit flexor digitorum profundus tendon model.ResultsAdhesions on macroscopic evaluation of the tendon repair site were significantly smaller in the HD-AM group than in the tendon repair group. Little adhesion formation or foreign body reactions were seen by on histologic evaluation in the HD-AM group. Range of motion following tendon repair was significantly better in the HD-AM group than in the tendon repair group. Maximal tensile strength required to pull the tendon from the site of adhesion was significantly smaller in the HD-AM group than in the tendon repair group. As for tendon repair site, no significant difference was seen between the tendon repair and HD-AM groups.ConclusionsHD-AM prevented peritendinous adhesion macroscopically, pathologically, and mechanically without impairing the sutured tendon. HD-AM has already been clinically applied in neurosurgery, ophthalmology, and otolaryngology, and clinical application as an anti-adhesive materials may be achieved in the future.     

A biomechanical analysis of suture materials and their influence on a four-strand flexor tendon repair

PURPOSE: Flexor tendon repair strength depends on the suture technique and the suture material used. Configurations that incorporate locking loops prevent sutures from pulling through the tendon but typically fail because of suture breakage. The choice of suture material therefore influences repair strength. This study investigated the mechanical properties of 5 nonabsorbable 4-0 suture materials (monofilament nylon, monofilament polypropylene, braided polyester, braided stainless steel wire, and braided polyethylene) and evaluated their performance when used in a locking 4-strand flexor tendon repair configuration. METHODS: Five samples of 2 strands of each suture type were tested mechanically to determine the material stiffness and ultimate load. In addition, 50 fresh porcine flexor tendons were divided and repaired with each of the 5 suture materials using a 4-strand single-cross technique. Gap force, ultimate strength, and stiffness were measured to compare biomechanical performance. RESULTS: All repairs failed by suture rupture at the locking loop. Fibrewire and stainless-steel sutures and repairs were significantly stronger and stiffer than the other suture types. The results for Prolene and Ethibond were similar in the tendon repair groups with respect to gap and ultimate forces although Ethibond provided significantly increased repair stiffness. Nylon sutures and repairs consistently produced the poorest mechanical performance in all outcome measures. CONCLUSIONS: Suture material strongly influences the biomechanical performance of multistrand tendon repairs and is an important consideration for the surgeon. Fibrewire and stainless steel are the most biomechanically suitable suture materials for flexor tendon repair whereas nylon is the least suitable. Further developments in suture materials are important for advancements in flexor tendon repair strength.     

Enzymatic changes in the healing rat achilles tendon

The tenotomized rat Achilles tendon has been used as a medium to study the biochemical response of tendons to injury. Injury to one part of the tendon produces changes characteristic of repair throughout the entire length of the tissue. During the first 12–36 hr following tenotomy, glycolysis, the pentose shunt, and the citric-acid-cycle enzymes are stimulated throughout the tendon, with enrichment of marker enzymes associated with new collagen and mucopolysaccharide formation. The most significant changes in these enzyme patterns and in the levels of lysosomal enzymes changes which are indicative of repair or remodeling of the tendon occurred during the first 6 weeks following injury and are most marked near the site of tenotomy.     

移植部分鹅足囊修复腱鞘预防指屈肌腱粘连

目的 探讨指屈肌腱损伤修复后重建腱鞘预防肌腱粘连的手术方法.方法 对78例屈肌腱损伤患者,按手术方法的不同随机分为2组.治疗组39例指屈肌腱损伤修复后切取自体部分鹅足囊修复腱鞘,重建腱鞘的完整,使之形成一完整的闭合鞘管并注入玻璃酸钠.对照组不修复腱鞘.结果 经6～38个月临床随访,按TAM手指功能评价治疗组：优21例,良11例,中6例,差1例,优良率82.1%;对照组优良率51.3%,差异有显著性（Х^2=8.34,P=0.004）.结论 切取部分鹅足囊移植修复并应用具有营养和润滑作用的玻璃酸钠,能有效预防指屈肌腱修复后的粘连,是实用的手术方法.     

Effects of direction of tendon lacerations on strength of tendon repairs

PURPOSE: We compared the tensile strength of different repair configurations on tendons with oblique and transverse lacerations. METHOD: Seventy-two fresh pig flexor tendons were divided randomly and repaired using the modified Kessler, the cruciate, or the 4-strand Massachusetts General Hospital (MGH) repair methods. The tendons were lacerated either transversely or obliquely. They were repaired with conventional and oblique suture repairs. The 2-mm gap formation force and ultimate strength were determined as biomechanical performance for each repair. RESULTS: The gap formation and ultimate strength of the tendons vary with orientations of tendon lacerations and suture methods. In the tendons repaired with the modified Kessler or the cruciate methods, the 2-mm gap formation and ultimate strength of obliquely cut tendons were significantly lower than those of transversely cut tendons. The obliquely placed modified Kessler or cruciate sutures significantly improved the repair strength in the tendons with an oblique laceration. In the tendons repaired with the MGH method, no statistical differences were found in the repair strength of obliquely and transversely lacerated tendons. CONCLUSIONS: The direction of tendon lacerations affects strength of certain repair configurations. The nonlocking modified Kessler or the cruciate tendon repairs are weakened considerably when the tendon laceration is oblique but their mechanical performance is strengthened by re-orienting the repair strands to lie parallel to the laceration. The cross-locked configuration of the MGH repair is not affected by the obliquity of the tendon laceration.     

Prevention of peritendinous adhesions following flexor tendon injury with seprafilm

Peritendinous adhesions are the most important complication of flexor tendon injury. In this study, Seprafilm was used for the prevention of peritendinous adhesions following flexor tendon repair. Seprafilm Bioresorbable Membrane (Genzyme Corporation, Cambridge, MA) contains sodium hyaluronate and carboxymethyl cellulose. Thirty New Zealand white male rabbits were divided equally into 3 groups. In all groups, the deep flexor tendon of the third finger of the left back foot was cut and repaired by Kessler-Tajima suture technique. In the first study group following tendon repair, Seprafilm was wrapped around the repaired tendon. In the second study group, sodium hyaluronate gel was injected to the operation field after tendon repair. In the control group, no external material was applied to the field. The study groups had better range of motion. Histopathologically, study groups had less adhesions compared with the control groups. As a result, it was concluded that in rabbit the peritendinous adhesions following flexor tendon repairs could be lowered with Seprafilm and hyaluronic acid.     

Distal attachment of flexor tendon allograft: A biomechanical study of different reconstruction techniques in human cadaver hands

We compared the mechanical force of tendon‐to‐bone repair techniques for flexor tendon reconstruction. Thirty‐six flexor digitorum profundus (FDP) tendons were divided into three groups based upon the repair technique: (1) suture/button repair using FDP tendon (Pullout button group), (2) suture bony anchor using FDP tendon (Suture anchor group), and (3) suture/button repair using FDP tendon with its bony attachment preserved (Bony attachment group). The repair failure force and stiffness were measured. The mean load to failure and stiffness in the bony attachment group were significantly higher than that in the pullout button and suture anchor groups. No significant difference was found in failure force and stiffness between the pullout button and suture anchor groups. An intrasynovial flexor tendon graft with its bony attachment has significantly improved tensile properties at the distal repair site when compared with a typical tendon‐to‐bone attachment with a button or suture anchor. The improvement in the tensile properties at the repair site may facilitate postoperative rehabilitation and reduce the risk of graft rupture. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1720–1724, 2013     

The effect of muscle excursion on muscle recovery after tendon repair in a neglected tendon injury: A study in rabbit soleus muscles

We attempted to determine whether muscle excursion observed during operation can be a prognostic indicator of muscle recovery after delayed tendon repair in a rabbit soleus model. Eighteen rabbits underwent tenotomy of the soleus muscles bilaterally and were divided into three groups according to the period from tenotomy to repair. The tendons of each group were repaired 2, 4, and 6 weeks after tenotomy. The excursion of each soleus muscle was measured at the time of tenotomy (baseline), at 2, 4, 6 weeks after tenotomy, and 8 weeks after tendon repair. The amount of muscle recovery after tendon repair in terms of muscle excursion independently depended on the timing of repair and on the muscle excursion observed during repair. The regression model predicted that the muscle excursion recovered on average by 0.6% as the muscle excursion at the time of repair increased by 1% after adjusting for the timing of repair. This study suggests that measuring the muscle excursion during tendon repair may help physicians estimate the potential of muscle recovery in cases of delayed tendon repair. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:74–78, 2011     

Quadrizeps- und Patellasehnenrupturen

Ruptures of the quadriceps or patellar tendon are uncommon but extremely relevant injuries. Early diagnosis and surgical treatment with a stable suture construction are mandatory for a good postoperative clinical outcome. The standard methods of repair for quadriceps and patellar tendon injuries include the placement of suture loops through transpatellar tunnels. Reinforcement with either a wire cerclage or a PDS cord is used in patellar tendon repair. The PDS cord can also be applied as augmentation in quadriceps tendon repair. In secondary patellar tendon repair an autologous semitendinosus graft can be used. For chronic quadriceps tendon defects a V-shaped tendon flap with a distal footing is recommended. The different methods of repair should lead to early functional postoperative treatment. The clinical outcome after surgical treatment of patellar and quadriceps tendon ruptures is mainly good.     

Why Repair the Subscapularis? A Logical Rationale

Tears of the subscapularis tendon are now more frequently recognized and are often associated with tears of the posterosuperior rotator cuff tendons. This has been facilitated by arthroscopic approaches, and repair techniques have been developed. In the setting of a rotator cuff repair, when a subscapularis tendon tear is found in continuity with a supraspinatus tendon tear, it is essential to recognize how the repair of both tendon tears can influence the overall security of the entire repair construct. When a repairable subscapularis tendon tear is left unrepaired, the function of the subscapularis muscle will be lost. In addition, the posterosuperior rotator cuff tear will be more difficult to repair, and it will be less securely repaired. When the subscapularis tendon is repaired initially, the posterosuperior rotator cuff repair can be more easily and more reliable achieved.     

Technique for repairing inguinal hernias with Marlex mesh

A technique using Marlex mesh for the repair of inguinal hernias is described. In this procedure the transversalis fascia is incised and a 1 inch strip of Marlex mesh is sutured as a cuff over the free edge of the conjoined tendon. The mesh-reinforced conjoined tendon is then sutured to Poupart's ligament. Continuous sutures of polypropylene monofilament are used both to affix the mesh cuff to the conjoined tendon and to suture the reinforced conjoined tendon to Poupart's ligament. Use of the mesh cuff results in a significant mechanical advantage and an exceptionally strong repair. This technique has been used in 72 patients since January 1979, with good results.     

Effects of locking area on strength of 2- and 4-strand locking tendon repairs

PURPOSE: The area of the tendon within the locking suture configuration of the modified Pennington repair is an important determinant of eventual tendon strength. This 2-strand repair's loop configurations encompass a large cross-sectional area of the tendon. Many recently proposed repairs, however, consist of locks in a number of narrow sites on the tendon surface and most are multistranded. It is not clear how the area within the locks affects tendon strength and whether the effects of locking areas change according to the number of repair strands. In this study we investigate the effects of locking area on repair strength of 2- and 4-strand tendon repairs. METHODS: Sixty-five fresh pig flexor tendons were divided equally into 6 groups and were transected completely. They were repaired with 2- or 4-strand techniques. The tendon-suture interface was a circle-locking junction and diameters of the locks were 1, 2, or 3 mm. The tendons were pulled in a tensile testing machine until failure of the repair and the mode of failure, 2-mm gap force, and ultimate strength were measured. RESULTS: In the tendons with either 2- or 4-strand repairs locks with a diameter of 2 or 3 mm had significantly greater gap formation force and ultimate strength than those of 1 mm. The gap formation and ultimate forces were not statistically different between tendons with locks of 2 or 3 mm in diameter. CONCLUSIONS: In both the 2- and 4-strand tendon repairs tested in this study repair strength increased as the diameter of locks of the repair increased from 1 mm to 2 or 3 mm. An increase in the diameter from 2 mm to 3 mm, however, did not increase the gap force and ultimate strength. These findings indicate that the cross-sectional area within the locks affects repair strength when the diameter of the locks is within a certain range (2 mm) and that further enlargement of the locking area does not increase strength.     

Rotator Cuff Repair: Patch the Shoulder

Rotator cuff tears are a common problem in our growing and aging population. Because of this, rotator cuff repair is consistently one of the most frequently performed operations by orthopaedic surgeons every year. Successful outcomes have been directly correlated to a successful repair to the tuberosity; however, healing rates have varied greatly depending on tear size, tear type, and tear chronicity. Despite advances in techniques and repair technology, healing rates have remained relatively stable.Improving the biology at the site of a rotator cuff repair has been proposed as a way of increasing healing rates. A recent bio-inductive patch has been introduced to improve the vascularity and collagen formation at the site of tendon repair. The implant is made from type I bovine collagen that is highly porous. It is nonstructural and does not provide any tensile strength. The patch improves collagen formation at the site of a repair, thus decreasing strain on the repaired tendon.Limited clinical trials involving the collagen patch have shown healing rates from 89% to 96% in small sample sizes. The patch has been successfully and safely applied in tear sizes ranging from partial thickness tears to massive tears, as well as primary and revision repair settings. To date, no adverse clinical reactions to the patch have been observed; however, no randomized clinical trials have been performed, and the patch is a significantly increased cost to the procedure.     

The effects of freezing on the tensile properties of repaired porcine flexor tendon

PURPOSE: When conducting complex testing of tendon repairs, it is essential that the samples are adequately preserved to prevent degradation. Freezing of samples is the most convenient method of preservation; however, there is no evidence in the literature to prove that freezing tendon before or after repair is acceptable. We aimed to prove that freezing tendons does not significantly alter the results of linear load-to-failure testing of tendon repairs. METHODS: After a power study, 150 tendons were harvested from porcine forelimbs and randomized into 5 groups of 30 tendons. After division, tendons were repaired using a Pennington modified core technique with a Silfverski?ld peripheral cross-stitch. Tendons in group 1 were divided, repaired, and tested within 3 hours postmortem. Tendons in group 2 were refrigerated at 4 degrees C for 24 hours prior to repair and testing. Tendons in group 3 were frozen at -25 degrees C for 3 months prior to repair and testing. Tendons in group 4 were frozen at -25 degrees C for 6 months prior to repair and testing. Tendons in group 5 were frozen at -25 degrees C for 6 months, repaired, refrozen for 1 month, and then tested. All repairs were linear load tested to ascertain the ultimate strength and force to produce 3-mm gap in the repair. RESULTS: Analysis of variance analysis of the results did not demonstrate any significant differences between groups. CONCLUSIONS: Freezing tendons both before and after suture repair is an acceptable method of preservation when investigating the force to produce 3-mm gap and ultimate strength of tendon repairs.     

天狼猩红染色法在肌腱胶原形态分析中的应用

目的 探讨天狼猩红染色法在肌腱胶原形态分析中的应用价值.方法 将30只10个月龄雄性Leghorn鸡随机分为A、B、C 组,每组10只.将每只鸡的左足第Ⅲ趾造成挤压撕脱伤模型,用改良Kessler缝合法缝接.A组、B组、C组分别于术后2周、4周、8周取材,对标本进行磷钨酸苏木素染色、天狼猩红染色、免疫组织化学染色等观察.结果 A组腱缝合段内的胶原纤维数量少,排列稀疏,以纤细的Ⅲ型胶原为主;B组腱缝合段内的胶原纤维数量较多,排列紊乱,Ⅰ、Ⅲ型胶原交错排列;C组腱缝合段内的胶原纤维数量多,以粗大的Ⅰ型胶原为主,成纤维细胞数量少,腱细胞成熟.结论 天狼猩红染色法在胶原纤维的染色中可在同一张切片中同时显示Ⅰ型和Ⅲ型胶原,是研究肌腱损伤修复中胶原纤维形态变化的重要染色方法.肌腱在愈合早期以纤细的Ⅲ型胶原为主,愈合晚期则以粗大的Ⅰ型胶原为主.

Abstract：

Objective To observe the applied value of Sirius red staining in the study on tendon repair. Methods Thirty ten-month old fowls were randomly divided into groups A, B and C (10 each group). The flexor tendon was cut off in the third toe then suture it.A group,B group,C group,respectively after 2 weeks,4 weeks,8weeks drawn and did the specimens biomechanical test,sirius red staining,immunohistochemical staining,the specimens were evaluated by means of macroscopic observation.Results A group within the section of tendon suture a small number of collagen fibers,arranged in sparse,thin collagen type Ⅲ to the main;B group within the section of tendon suture collagen fibers are more disordered,Ⅰ,Ⅲ collagen staggered;C group tendon suture paragraph quantity of collagen fibers,with thick main type Ⅰ collagen;a small number of fibroblasts,tendon cell maturation.Conclusion Sirius red staining of collagen fibers can be dyed simultaneously in the same slide show type Ⅰ and Ⅲ collagen,is to study the tendon collagen fibers in the repair of major staining.Tendon healing in the early to slim type Ⅲ collagen-based,healing late stage Ⅰ collagen-based thick.     

Flexor tendon repair in no-man's-land: results of primary repair with controlled mobilization

Fifty-three patients with 60 injuries within the digital sheath, which were treated with primary tendon repair by the Kleinert technique, had follow-up of 6 to 36 months after operation. Seventeen digits had isolated lesions of the profundus tendon and regained an average 38 degrees range of motion (ROM) in the distal interphalangeal (DIP) joint. Forty-three digits had injuries to both the profundus and superficialis tendons, 35 of which flexed within 2 cm from the distal palmar crease (81%), and 21 had a total active motion of at least 200 degrees (49%). The average active ROM in the DIP joint was 30 degrees. The results were superior to our own results with primary repair by the Verdan technique. Comparison with our own results after secondary tendon repair by the Kleinert technique showed that repair of isolated profundus lesions could be done primarily or secondarily within 1 month of injury with equally good results. Primary repair of double tendon lesions gave better results than secondary repair.     

Flexor tendon ruptures secondary to hamate hook fractures

Four patients with flexor tendon ruptures secondary to hook of the hamate fracture are described. None of the patients had the diagnosis of fracture made before tendon rupture. All patients were treated with excision of the fractured hook and tendon repair. The tendon repair was usually an end-to-side (Y junction) of the profundus of the small to the profundus of the ring finger. After operation, all patients were free of pain and returned to their preinjury activity levels, but most had some limitation of motion in the digit with the tendon repair. The complication of tendon rupture not uncommonly follows basilar hook of the hamate fractures. Treatment by excision of the fracture and end-to-side tendon repair produces satisfactory results. Range of motion after tendon repair seems to depend more on the patient's age and the amount of inflammation at the site of repair rather than on the method of tendon repair.     

A staged technique for the repair of the traumatic boutonniere deformity

A step-by-step approach to the systematic management of chronic boutonniere deformity due to trauma is presented. If surgical intervention is necessary, the problem should be approached one step at a time. The following stages are described: stage I, tendolysis of the extensor tendon and freeing of the transverse retinacular ligament; stage II, sectioning of the transverse retinacular ligament; stage III, tendon lengthening of the lateral bands over the middle phalanx; and stage IV, repair of the central extensor tendon. After managing 23 patients according to this plan, we have concluded that it is frequently unnecessary to automatically go through all four stages in treating chronic traumatic boutonniere deformity. We found that 17 patients were successfully managed by some combination of stages I, II, and III, and six patients received adequate treatment with stages I, II, and IV.     

Suture holding capacity of the Achilles tendon during the healing period: an in vivo experimental study in rabbits

BACKGROUND: Early motion and weightbearing is known to promote the healing of Achilles tendon repair. It is important to be informed about the repair strength for a secure rehabilitation. There are reports about the initial repair strength of Achilles tendons; however, they are mainly in vitro studies that represent the time zero strength of the repair. Softening of the tendon observed during the biological process of the tendon healing, which may effect the suture holding capacity and in turn the repair strength of the tendon has not been evaluated before. METHODS: In the current study, the suture holding capacity of rabbit Achilles tendon was observed at various times during the healing period. RESULTS: The suture holding capacity of the tendon at the end of the first and third weeks after surgery was found to be similar within 30% of the control tendon. However, at the end of the fourth week it was doubled reaching 65% of the control tendon. CONCLUSIONS: Intrinsic tendon insufficiency which causes a decrease in the suture holding capacity of the tendon may lead to pull-out of the suture material during the postoperative third week. This period is precarious for early motion and weightbearing since the suture holding capacity of the tendon doubled relative to the previous three weeks.