1H double-quantum-filtered MR imaging as a new tool for assessment of healing of the ruptured Achilles tendon.

1H double-quantum-filtered magnetic resonance imaging (DQF MRI) was applied to monitor the healing process of the Achilles tendons in rabbits after tenotomy. DQF MRI provides a new contrast, which is based on the non-zero average of the dipolar interaction caused by anisotropic motion of water molecules, determined mainly by their interaction with the ordered collagen fibers. Tissues are characterized by the dependence of their DQF signal on the DQ creation time, tau. With the use of DQF MRI, higher tissue contrast is obtained between tendon, bone, skin, and muscle. The tendons, which give weak signals in standard MRI techniques, are highlighted in the (1)H DQF image. The image changed dramatically during the healing process of the injured Achilles tendon. These changes matched the phases of the healing process. By using a tau-weighted contrast, the DQF images indicate the part of tendon that has not completely healed, even after the conventional MRI appeared normal. Magn Reson Med 42:884-889, 1999.     

Botulinum toxin improves reduced dorsiflexion after Achilles tendon surgery

Generally, outcome after surgical repair of complete Achilles tendon rupture is good. However, some patients have ongoing problems with dorsiflexion of the ankle joint. We report on eight patients, who did not achieve heel contact because of reduced ankle dorsiflexion 5 months after surgical repair of complete Achilles tendon rupture. All patients received at least three cycles of injections with 200–300 units of Botulinum toxin A (BOTOX^®) into the gastrocnemius and soleus muscle. Weakening of the triceps surae by Botulinum toxin allowed patients to perform the required exercises and to tolerate casting at night. Thus, all patients were able to tolerate plantigrade foot position 9 months after beginning of Botulinum toxin treatment. At final follow-up after 2 years, pain had significantly improved, and a mean dorsiflexion of 21° was reached. In conclusion, treatment of the calf muscles with BOTOX^® is a safe and effective method to improve restricted dorsiflexion in patients after Achilles tendon repair.     

High association between accessory soleus muscle and Achilles tendonopathy

Objective  This study investigated the association between accessory soleus muscle and abnormalities of the Achilles tendon. Materials and methods  The authors reviewed 15 consecutive cases with a diagnosis of accessory soleus muscle from a computerized database of ankle magnetic resonance (MR) examinations reported between January 1998 and January 2007. On review, two cases were eliminated because of an incorrect initial diagnosis: One patient had a low lying soleus attachment to the Achilles tendon, while the other had a prominent flexor hallucis longus tendon partially obliterating Kager’s fat. The remaining 13 cases with accessory soleus muscles were evaluated for Achilles tendon abnormalities. Results  There were 13 cases of accessory soleus muscles in 11 patients; two patients had bilateral accessory soleus muscles (the only study patients with bilateral MR examinations in our sample). There were five male and six female patients ranging from 15 to 81 years of age (mean 48). There were nine cases (69.2%) in which Achilles tendonopathy was associated with accessory soleus muscle, including tendonopathy of each Achilles tendon in the two patients with bilateral accessory muscles. Conclusion  In our small patient population, there was a high association between accessory soleus muscle and Achilles tendonopathy.     

Magnetic resonance imaging after operative repair of achilles tendon rupture

We performed a magnetic resonance imaging (MRI) study in 16 consecutive patients who had undergone open repair of a unilateral Achilles tendon rupture (ATR) at an average of 32.5 (SD 3.2) (range 29-36) months from the operation. We measured the widest antero-posterior diameter of the tendon, the longest distance between the insertion of the Achilles tendon on the calcaneum and the musculo-tendinous junction of the soleus muscle on the Achilles tendon, the distance between the insertion of the Achilles tendon on the calcaneum and the point of maximal width of the tendon. We also ascertained whether areas of altered signal were present in and around the tendon. The operated tendons were always significantly thicker than the non-operated ones. There was a non-significant trend for the other measurements to be greater in the operated tendons. In five patients, areas of dishomogeneous signal were present in the operated tendon. These areas were less than 25% of the antero-posterior diameter of the tendon, and were clinically silent. These findings probably represent normal features of long-term tendon healing following open repair of an ATR.     

The twisted structure of the Achilles tendon unraveled: A detailed quantitative and qualitative anatomical investigation

The Achilles tendon (AT) consists of fibers originating from the soleus muscle (SOL), which lies deep, and the medial (GM) and lateral (GL) heads of the gastrocnemius muscle, which lie superficial. As the fibers descend toward the insertion of the AT, the individual subtendons twist around each other. The aim of this study was to investigate the twisted structure of the AT and its individual subtendons. Specimens of the AT, with preserved calcaneal bone and a fragment of the triceps surae muscle, were obtained from 53 fresh‐frozen, male cadavers (n=106 lower limbs). The angle of torsion of each of the AT's subtendons was measured using a specially designed and 3D‐printed tool. The mean distance between the most distal fibers of the triceps surae muscle and the superior border of the calcaneal bone was 60.77±14.15 mm. The largest component of the AT at the level of its insertion into the calcaneal bone is the subtendon from the GL (44.43%), followed by the subtendon from SOL (27.89%), and the subtendon from GM (27.68%). The fibers originating from the GM rotate on average 28.17±15.15°, while the fibers originating from the GL and SOL twist 135.98±33.58° and 128.58±29.63°, respectively. The torsion of superficial fibers (GM) comprising the AT is significantly lower than that of deeper fibers (GL and SOL). The cross‐sectional area of the AT is smaller at the level of the musculo‐tendinous junction than at the level of its insertion. This study illustrates the three types of the AT with differently twisting subtendons, as well as a generalized model of the AT. Types of AT torsion may potentially alter the biomechanical properties of the tendon, thus possibly influencing the pathophysiologic mechanisms leading to the development of various tendinopathies.     

Symptomatic accessory soleus muscle: report of 18 cases in athletes

AIM: The aim of this paper was to investigate the prevalence and sports distribution in athletes. METHODS: Six hundred and fifty radiographs of athletes affected by tenderness and exertional pain in the region of the Achilles tendon, were observed over a period of 30 years. The clinical and diagnostic imaging materials were reviewed. RESULTS: Eighteen cases of accessory symptomatic soleus muscle were diagnosed: in 10 cases using soft tissue radiographic technique, in 8 cases using, in sequence, exclusively ultrasound and magnetic resonance. CONCLUSIONS: The presence of an accessory soleus muscle has been considered a rare even incidental occurrence; the review of our cases, substantially different for the evident symptoms, showed a frequency in athletes of 2.77% in accordance with the results of the anatomical and clinical literature. US and MRI are the best diagnostic modalities especially in differentiating accessory soleus muscle from soft tissue tumors not rare in this anatomic region.     

CDMP-2 injection improves early tendon healing in a rabbit model for surgical repair

This study examines the hypothesis that cartilage-derived morphogenic protein-2 (CDMP-2) can improve tendon healing after surgical repair. We have previously found improved tendon healing by applying CDMP-2 in models for conservative treatment with mechanically loaded Achilles tendon defects in rats and rabbits. In this study, the patellar tendon was unloaded by patello- tibial cerclage and cut transversely in 40 rabbits. Two hours post-operative, the rabbits received a dose of 20 microg of CDMP-2 or vehicle injected into the hematoma. Specimens were harvested after 14 and 28 days and evaluated by biomechanical testing, radiography and histology. At 14 days, CDMP-2 caused a 65% increase in force at failure, a 50% increase in ultimate stress and a 57% increase in stiffness, as compared with controls. There was no effect on callus size. At 28 days, no differences between the treatment groups could be demonstrated. No bone or cartilage was found in any tendon or regenerated tissue at any time point. Thus, early tendon repair can be stimulated by CDMP-2 in an unloaded model. These results suggest that CDMP-2 might be of interest for clinical use as a complement to surgical treatment of tendon ruptures.     

Arthroscopically assisted percutaneous repair of fresh closed achilles tendon rupture by Kessler's suture

BACKGROUND: Achilles tendon ruptures are difficult to repair, and the healing rate is low due to this structure's anatomic and physiological characteristics. It is essential to develop new techniques to increase the healing rate and decrease the rate of complications. OBJECTIVE: To propose and evaluate a new percutaneous method of repairing fresh closed Achilles tendon ruptures by Kessler's suture under arthroscopy. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Twenty patients were followed at least 12 months in this study. First, the torn ends of the Achilles tendon were debrided during arthroscopy. Then percutaneous repair of the Achilles tendon was performed using Kessler's suture by an inside-out technique. All cases were followed up for an average range of 21 months (range, 12-36 months). All patients were evaluated by clinical examination, magnetic resonance imaging, and the Lindholm scale. RESULTS: The torn ends were well aligned and sutured after the debridement under arthroscopy. According to the Lindholm scale, excellent results were seen in 15 cases and good in 5 cases. No patients had complications such as nerve injury, infection, or re-rupture at follow-up. Magnetic resonance imaging results showed that the ruptured Achilles tendons were repaired and remodeled very well in all patients. CONCLUSION: The present method is an effective surgical technique for repair of a closed rupture of the Achilles tendon. The short-term follow-up results were good, and recovery time was short. Few complications were found in our study cases.     

The ultrasonographic appearance of the ruptured Achilles tendon during healing: a longitudinal evaluation of surgical and nonsurgical treatment,with comparisons to MRI appearance

This prospective, randomized trial compared healing characteristics of the Achilles tendon after surgical and nonsurgical treatment for complete rupture of the Achilles tendon. Fifty-eight patients were examined by ultrasonography after 6, 12, and 24 months and by magnetic resonance imaging after 12 months. A standardized protocol was used, and the outcome was correlated with clinical findings. Common findings 1 year after the injury were tendon thickening and moderate heterogeneity of the tendon. Peritendinous reactions, edema, and defects were present only in a minority of patients. There were no significant differences between the treatment groups in any of the evaluated parameters apart from the gliding function of the tendon, which was significantly less in the surgically treated group than in the nonsurgically treated group. No correlations were found between the radiological findings and the clinical parameters, such as muscle strength, endurance, and range of motion. We conclude that the roles of ultrasonography and magnetic resonance imaging during the healing process after Achilles tendon rupture are limited, due to a weak correlation with clinical findings.     

Reconstruction of chronic achilles tendon rupture with the use of interposed tissue between the stumps

BACKGROUND: The gap between the tendon stumps in chronic Achilles tendon rupture has reportedly been filled with interposed scar tissue. In the authors' clinical experience, this interposed tissue is often thick and resists tension, so they considered it was possible to use the interposed tissue for reconstruction of Achilles tendon rupture. HYPOTHESIS: Scar tissue interposed between the tendon stumps has the capacity to form tendon-like repair tissue in patients with chronic Achilles tendon rupture. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Six patients with chronic rupture of the Achilles tendon underwent tendon reconstruction with the use of interposed tissue between the stumps. The average time from the primary injury to surgery was 22 weeks (range, 9 to 30 weeks). Preoperative magnetic resonance imaging (MRI), histology of the interposed tissue, and clinical results were evaluated. The average postoperative follow-up period was 31 months (range, 24 to 43 months). RESULTS: Preoperative T2-weighted MRI in all cases revealed that chronically ruptured Achilles tendons were thickened and fusiform-shaped with diffuse intratendinous high-signal alterations throughout. Longitudinal high-signal bands were seen throughout the tendon, except at the musculotendinous junction and insertion on the calcaneus. Histologically, scar tissue interposed between the tendon stumps consisted of dense collagen fibers, and degenerative changes were not seen. After surgery, no patient had difficulty in walking or stair climbing, and all were able to perform a single-limb toe raise. The mean preoperative and postoperative American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot scores were 88.2 and 98.3 points, respectively; the difference was statistically significant (P = .0277). CONCLUSION: Interposed tissue between the tendon stumps is suitable for repair of chronic Achilles tendon rupture if preoperative MRI shows a thickened fusiform-shaped Achilles tendon with diffuse intratendinous high-signal alterations throughout.     

Histopathology in rabbit Achilles tendon after operative tenolysis (longitudinal fiber incisions)

The surgical treatment (tenolysis) of chronic Achilles tendinopathy is often successful. However, little is known about the postoperative intratendinous changes after this procedure. The study group consisted of 21 rabbits. Operative tenolysis was done in each case on one Achilles tendon (AT). The ATs of both legs were studied histologically and immunohistochemically using antibodies against collagen types I and III 2, 4 and 6 weeks postoperatively. Nine rabbits without operation served as controls. A significant uniform hypervascularization was noted in the entire operated tendon postoperatively, and this concurred with the contralateral nonoperated AT, but neither side showed changes in collagen fiber structure as judged by immunohistochemistry. We conclude that the tenolysis procedure triggers neoangiogenesis at the AT followed by increased blood flow and improved nutrition in the same. These changes could, at least partly, explain the often seen clinical success in surgically treated tendinopathy.     

Calf muscle atrophy and Achilles tendon healing following experimental tendon division and surgery in rats

We used a rat model to study the effects of immobilization of the calf muscle-tendon complex after an experimental Achilles tendon repair. Immobilizations of the complex in either a relaxed or tensioned position were compared by histochemical and morphometric analyses at the site of the tendon injury as well as in the gastrocnemius and soleus muscle bellies. The type of immobilization did not affect the healing of the tendon injury because no reruptures occurred in either of the treatment groups and the average tendon end-to-end distance did not differ between the groups. However, immobilization in a relaxed position led to a significantly more extensive fiber atrophy in the calf muscles. In clinical practice, these results suggest that rehabilitation after Achilles tendon surgery can be early and gradually tension- and load-increasing without a significant increase in the risk of rerupture of the tendon.     

A new surgical method to treat chronic ruptures and reruptures of the Achilles tendon

In patients with a chronic rupture or rerupture of the Achilles tendon, the recommended treatment is surgical. Various surgical techniques have been reported in the literature; however, the outcome is rarely evaluated with a sufficiently long follow-up, using appropriate end-points. The purpose of this study was to evaluate the subjective and objective outcome following a new surgical treatment for chronic rupture or rerupture of the Achilles tendon using augmentation with a free gastrocnemius aponeurosis flap. A total of 28 consecutive patients (22 male and 6 female) with a mean (SD) age of 46 (10.4) years were evaluated at a median (range) of 29 (12-117) months after surgery. The surgical technique involved making a single incision and then using a free gastrocnemius aponeurosis flap to cover the tendon gap after an end-to-end suture. The patients were evaluated using the Achilles tendon rupture score (ATRS) and a detailed questionnaire relating to symptoms, physical activity and satisfaction with treatment. The functional evaluation consisted of a validated test battery measuring different aspects of muscle/tendon function of the gastrocnemius/soleus and Achilles tendon complex. The median (range) ATRS was 83 (24-100). There were no reruptures. In terms of surgical complications, there was one deep infection, three wound closure complications and deep venous thrombosis in two patients. All but one patient returned to work within 6 months of surgery. Sixteen (57%) patients were satisfied with the treatment. There was a significant decrease in the level of physical activity after the injury compared with before the injury (p = 0.004). Of the 25 patients who participated in recreational sports prior to injury, 13 (52%) returned to the same activity level after treatment. In terms of jump performance, no significant differences were found between the healthy and injured sides. There was, however, a significant decrease in strength, in terms of both concentric and eccentric-concentric toe raises and the toe-raise test for endurance compared with the healthy side. The use of a free gastrocnemius aponeurosis flap to treat chronic ruptures and reruptures of the Achilles tendon rendered a good overall subjective and objective outcome in the majority of patients. The use of a single incision in combination with a free flap augmentation produced favourable results.     

循环训练模式对兔跟腱末端区组织形态学的影响

目的 观察循环训练对兔跟腱末端区组织形态学的影响,探讨循环训练对训练性末端病的预防作用.方法 72只日本大耳白兔随机分为正常对照组、跑步训练组、跳跃训练组、循环训练组(n=18),各组于第2、3、4、6、8、10周时随机处死3只动物,取双侧后足跟腱末端区组织,光镜下观察病理形态学变化,进行病理学评分及统计学分析.结果 光镜观察显示,跳跃训练模式下末端区组织腱纤维部分和纤维软骨部分受损严重;跑步训练模式下末端区组织腱纤维部分受损严重,纤维软骨部分受损较轻;与跳跃训练组及跑步训练组比较,循环训练模式下末端区组织损伤明显减轻.跳跃训练组第2、3、4、6、8、10周时跟腱末端区组织病理学评分分别为1.17±0.12、2.19±0.15、3.23±0.20、4.66±0.16、4.71±0.18、4.63±0.13,而跑步训练组分别为1.16±0.13、1.15±0.14、2.18±0.12、2.99±0.15、3.98±0.16、4.01±0.12,跳跃训练组病理学评分升高早于跑步训练组,且从第3周起其分值即明显高于跑步训练组(P＜0.05),两组评分差异主要源于潮线的变化.循环训练组第2、3、4、6、8、10周时跟腱末端区组织病理学评分分别为1.13±0.14、1.16±0.17、1.15±0.13、2.18±0.13、2.17±0.12、2.92±0.11,早期阶段病理学评分与正常对照组比较无明显差异,在训练晚期(6周以后)评分升高,但其分值低于跳跃训练组及跑步训练组(P＜0.05),且评分改变主要源于腱周组织和潮线的病理学变化.结论 循环训练可以为跟腱末端区组织塑形改建提供充分的修复时间,降低末端区组织受损程度.应用循环训练法不仅可有效预防末端病的发生,还可促进末端区组织的塑形改建,增强其抗损伤能力.     

Repair of Achilles tendon ruptures with a polylactic acid implant: assessment with MR imaging

An investigational tendon repair device composed of a polymer of lactic acid (PLA) is currently undergoing multicenter clinical trials for use in repairing rupture of the Achilles tendon. The advantages of the PLA device include high tensile strength and the induction of a rapid proliferative tissue response resulting in a shorter rehabilitation period than with conventional surgical repair. We reviewed 16 MR examinations performed in 10 patients 3-35 months after repair to characterize the MR appearance. All 16 T1-weighted sagittal images revealed a thickened fusiform tendon with streaks of moderate signal within the tendon corresponding to the PLA device and its surrounding collagenogenic response. The double-echo T2-weighted axial images at the mid tendon level demonstrated progressive changes in the signal pattern of the central portion of the tendon that reflected the maturation of the healing tendon. All tendons repaired with PLA implants were uniformly hypertrophied relative to the contralateral normal side because of the induced proliferative collagenogenic ingrowth. Two follow-up MR examinations were performed in six patients and showed mean reductions in tendon caliber of 24% and 30% at the mid and inferior levels. MR imaging of the Achilles tendon repaired with PLA implants shows a diffusely thickened tendon with streaks of signal within the tendon that distinguish it from tendons repaired by conventional techniques.     

Electromyographic analysis of an eccentric calf muscle exercise in persons with and without Achilles tendinopathy

ObjectivesTo compare surface electromyographic (EMG) activity of the gastrocnemius and soleus muscles between persons with and without Achilles tendinopathy (AT) during an eccentric muscle exercise in different knee joint positions.DesignRepeated measures design.SettingResearch laboratory.ParticipantsParticipants (n = 18) diagnosed with AT and 18 control subjects were recruited.Main outcome measuresGastrocnemius and soleus muscle activity was examined by surface (EMG) during extended and flexed knee joint conditions while performing the eccentric training technique. The EMG data were expressed as a percentage of a maximum voluntary contraction (MVC).ResultsEMG activity was notably higher (mean difference: 10%, effect size: 0.59) in those subjects with AT. Irrespective of the presence of AT, there was a significant interaction effect between muscle and joint position. The gastrocnemius muscle was significantly more active in the extended knee condition and soleus muscle activity was unchanged across joint positions.ConclusionsThe results indicated that the presence of AT influenced calf muscle activity levels during performance of the eccentric exercise. There were differences in muscle activity during the extended and flexed knee conditions. This result does support performing Alfredson, Pietila, Jonsson, and Lorentzon (1998) eccentric exercise in an extended knee position but the specific effects of the knee flexed position on the Achilles tendon during eccentric exercise have yet to be determined, particularly in those with AT.     

深低温冷冻保存同种异体肌腱移植修复陈旧性跟腱断裂研究

目的：探讨深低温冷冻保存同种异体肌腱移植修复陈旧性跟腱断裂的临床效果。方法2010年1月-2012年9月收治急性创伤所致跟腱断裂一期未行修复导致的陈旧性跟腱断裂患者共32例,缺损长度3-6（4.6±1.0）cm,手术所用肌腱为经过深低温处理的同种异体胫前肌肌腱。在跟腱远端和近端用2-0可吸收抗菌薇乔采用双束 Kessler 法端端吻合,术后常规跖屈20-30°位固定踝关节,足背肢具或石膏板固定4-6 w。3例合并皮肤缺损者,行腓肠神经营养皮瓣转移覆盖创面。术后采用美国足踝外科协会（ AOFAS）踝与后足评分行疗效评价。结果术后32例均获随访1年以上,平均随访（15.0±3.5）个月,其中29例切口Ⅰ期愈合,2例切口Ⅱ期愈合,1例因为排异反应取出移植肌腱由于疤痕愈合未行再次肌腱移植,目前可以正常行走。术后踝关节功能恢复良好,AOFAS 足踝评分从术前（50.5±5.5）分提高到术后（90.5±6.5）分。结论修复陈旧性跟腱断裂可用深低温冷冻保存同种异体肌腱,手术效果可,并可避免取自体腱造成二次损伤和并发症,患者更容易接受,移植物可长期保存,但长期效果仍需长期随访。     

Achilles tendon rupture: experimental results on spontaneous repair in a sheep-model

We studied the course of spontaneous healing of Achilles tendons in a sheep model after transection and partial resection of the tendon by means of histological and biomechanical analyses. In 18 sheep used for another animal study the operated knee had to be excluded from weight-bearing; therefore the Achilles tendons were transected and for 1.5 cm partially resected in the middle substance of the tendon. For evaluation these spontaneously healed tendons (n = 18) were compared with the contralateral noninvolved tendons (n = 18). Specimens were analyzed 3, 6, and 12 months postoperatively by means of histology, polarized light, angiography, and mechanically analyzing the specific tensile strength and absolute tensile strength. We found that in all animals the resected tendon healed spontaneously. All animals exhibited a normal gait pattern at least 6 weeks postoperatively. Histologically, the tendinous area of healing demonstrated after 3 months a fibrous collagenous tissue with a loose fiber orientation. The cross-sectional area had at 3 months increased to maximum but decreased later. Concomitantly the fiber orientation improved with time and 12 months after transection the specimens showed a nearly normal histological structure of the healed tendon. Biomechanically the specimens exhibited a rather low specific rupture force after 3 months (28.8% of normal tendons) and 6 months (30.2%) but increased after 12 months (56.7%). In regard to the resulting total rupture force the decrease in the spontaneously healed tendons was less (75.6% after 3 months, 56.1% after 6 months, 81.18% after 12 months), because the cross-sectional area of the healing tendon had significantly (P < 0.05) increased to maximum after 3 and 6 months. Sheep Achilles tendons thus healed spontaneously without any immobilization. The initial healing mechanism is thickening of the scar tissue with improvement of the fiber orientation towards a tendonlike structure within 1 year. Parallel to this, the specific rupture force increased and the thickness of the newly tendonlike area decreased.     

Improved healing of transected rabbit Achilles tendon after a single injection of cartilage-derived morphogenetic protein-2

BACKGROUND: Achilles tendon ruptures in humans might be treated more efficiently with the help of a growth factor. Cartilage-derived morphogenetic protein-2 has been shown to induce formation of tendon-like tissue. HYPOTHESIS: Cartilage-derived morphogenetic protein-2 has a positive effect on mechanical parameters for tendon healing in a rabbit model with Achilles tendon transection. STUDY DESIGN: Controlled laboratory study. METHODS: The right Achilles tendon of 40 rabbits was transected without tendon suture. Cartilage-derived morphogenetic protein-2 (10 micro g) or vehicle control (acetate buffer) was injected locally 2 hours postoperatively. All tendons were tested biomechanically at 8 and 14 days, and treated tendons were histologically and radiographically evaluated at 56 days. RESULTS: At 14 days, both failure load and stiffness of treated tendons were increased by 35%. The treated tendons had significantly larger callus size at 8 and 14 days. Histologic and radiographic examination showed no signs of ossification in the treated tendons after 56 days. CONCLUSIONS: A single injection of cartilage-derived morphogenetic protein-2 led to a stronger and stiffer tendon callus than that in the controls without inducing bone formation. Clinical Relevance: Similar results from a larger animal model would suggest a possible future use of cartilage-derived morphogenetic protein-2 in the treatment of human Achilles tendon ruptures.