Light microscopic histology of achilles tendon ruptures. A comparison with unruptured tendons

We studied biopsies from the Achilles tendons of patients undergoing open repair for a subcutaneous rupture of their Achilles tendons (27 men, 11 women; mean age, 45.3 +/- 13.8 years) and specimens of Achilles tendons from persons with no known tendon ailments (43 men, 3 women; mean age, 64.2 +/- 9.7 years). Histologic examination was performed using stained slides that were interpreted using a semiquantitative grading scale assessing fiber structure and arrangement, rounding of the nuclei, regional variations in cellularity, increased vascularity, decreased collagen stainability, hyalinization, and glycosaminoglycan. We gave up to three marks for each of these variables, with 0 being normal and 3 being maximally abnormal. All the histology slides were assessed twice in a blinded manner; the agreement between two readings ranged from 0.56 to 0.87 (kappa statistics). The score of ruptured tendons was significantly greater than the average score of control tendons (20.5 +/- 3.6 versus 6.5 +/- 2.1), and there was significantly higher degeneration in the ruptured tendons. Nonruptured Achilles tendons, even at an advanced age, and ruptured Achilles tendons are clearly part of two distinct populations. Using these staining techniques, light microscopic degeneration is not a feature of tendons from healthy, older persons.     

Similar histopathological picture in males with Achilles and patellar tendinopathy

PURPOSE: To ascertain whether there are differences in the histopathological appearance of tendinopathic Achilles and patellar tendons. METHODS: In males, we studied biopsies from tendinopathic Achilles (N = 28; average age 34.1 yr) and patellar tendons (N = 28; average age 32.1), Achilles tendons (N = 21; average age 61.8 yr) from deceased patients with no known tendon pathology, and patellar tendons (N = 15; average age 28.3) from patients undergoing anterior cruciate ligament reconstruction. Hematoxylineosin stained slides were interpreted using a semiquantitative grading scale (0: normal to 3: maximally abnormal) for fiber structure, fiber arrangement, rounding of the nuclei, regional variations in cellularity, increased vascularity, decreased collagen stainability, and hyalinization. All slides were assessed blindly twice, the agreement between two readings ranging from 0.170 to 0.750 (kappa statistics). RESULTS: The highest mean score of tendinopathic Achilles tendons was not significantly different from that of tendinopathic patellar tendons (11.6 +/- 5 and 10.4 +/- 3, respectively). The ability to differentiate between an Achilles tendon and a patellar tendon was low. CONCLUSIONS: Tendinopathic Achilles and patellar tendons show a similar histological picture. It was not possible to identify whether a specimen had been harvested from an Achilles or a patellar tendon on the basis of histological examination. The general pattern of degeneration was common to both tendinopathic Achilles and patellar tendons. A common, as yet unidentified, etiopathological mechanism may have acted on both these tendon populations.     

Chondral metaplasia in calcific insertional tendinopathy of the Achilles tendon.

OBJECTIVE: To ascertain whether tendon samples harvested from patients with calcific insertional Achilles tendinopathy showed features of failed healing response, and whether abnormal quantities of type II collagen had been produced in that area by these tenocytes. DESIGN: Comparative laboratory study. DESIGN: University teaching hospitals. PATIENTS: Tendon samples were harvested from eight otherwise healthy male individuals (average age 47.5+/-8.4 years, range 38 to 60) who were operated for calcific insertional Achilles tendinopathy and from nine male patients who died of cardiovascular events (mean age 63.1+/-10.9 years) while in hospital. INTERVENTIONS: Open surgery for calcific insertional Achilles tendinopathy. MAIN OUTCOME MEASURE: Semi-quantitative histochemical, immunohistochemical, and immunocytochemical methods to ascertain whether tendinopathic tendons were morphologically different from control tendons, and whether abnormal types of collagen were produced. RESULTS: Tenocytes from tendons from patients with calcific insertional Achilles tendinopathy exhibit chondral metaplasia, and produce abnormally high quantities of collagen type II and III. CONCLUSIONS: The altered production of collagen may be one reason for the histopathological alterations described in the present study. Areas of calcific insertional Achilles tendinopathy have been subjected to abnormal loads. These tendons may be less resistant to tensile forces. Further studies should investigate why some tendons undergo these changes.     

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.     

The role of vasculature and angiogenesis for the pathogenesis of degenerative tendons disease

More than 100 years ago Wilhelm Roux (1895) introduced the term "functional adaptation to anatomy and physiology". Compared with other organ systems the functional adaptation processes are best identifiable in the locomotor system, like for example in the two types of tendons: traction and gliding tendons. Traction tendons are tendons where the direction of pull is in line with the direction of the muscle (e.g. Achilles tendon). Gliding tendons (e.g. tibialis posterior tendon) change direction by turning around a bony or fibrous hypomochlion. In this region the tendon is subjected to intermittent compressive and shear forces and the extracellular matrix consists of avascular fibrocartilage. Avascularity is considered to be a key factor for the etiology of degenerative tendon disease. The repair capability after repetitive microtrauma is strongly compromised in avascular tissue of gliding tendons. Reduced vascularity is not a specific feature of gliding tendons; several studies have shown that the number and size of blood vessels are largely shortened in the waist of the Achilles tendon. However, histological biopsies from degenerated Achilles tendons and Doppler flow examinations revealed a high blood vessel density in patients with degenerative tendon disease. Angiogenesis is mediated by angiogenic factors and recent studies have shown that the vascular endothelial growth factor (VEGF) is highly expressed in degenerative Achilles tendons, whereas VEGF expression is nearly completely downregulated in healthy tendons. Several factors are able to upregulate VEGF expression in tenocytes: hypoxia, inflammatory cytokines and mechanical load. Since VEGF has the potential to stimulate the expression of matrix metalloproteinases and inhibit the expression of tissue inhibitors of matrix metalloproteinases tissue inhibitor of metalloproteinases (TIMP) in various cell types (e.g. endothelial cells, fibroblasts, chondrocytes), this cytokine might play a significant role for the pathogenetic processes during degenerative tendon disease. An animal experiment in the rabbit has shown that local injection of VEGF reduced the material properties of the Achilles tendon. These experimental findings are in accordance with clinical results that a locally administered (in the area with neovascularization) sclerosing drug (Polidocanol) has a beneficial effect on chronic mid-portion Achilles tendinosis. In conclusion, decreased and increased vascularity might be involved in the pathogenesis of degenerative Achilles tendon disease.     

Adhesion and collagen production of human tenocytes seeded on degradable poly(urethane urea)

Purpose

The aim of this study was to investigate whether human tenocytes taken from ruptured quadriceps tendon could be seeded on a biodegradable polycaprolactone-based polyurethanes (PU) urea scaffold. Scaffold colonization and collagen production after different culture periods were analyzed to understand whether tenocytes from ruptured tendons are able to colonize these biodegradable scaffolds.

Methods

Human primary tenocyte cultures of ruptured quadriceps tendons were seeded on PU scaffolds. After 3, 10 and 15 days of incubation, the samples were stained with haematoxylin and eosin and were examined under white light microscopy. After 15 and 30 days of incubation, samples were examined under transmission electron microscope. Total collagen accumulation was also evaluated after 15, 30 and 45 days of culture.

Results

After 15 and 30 days of culture, tenocyte-seeded scaffolds showed cell colonization and cell accumulation around interconnecting micropores. Tenocyte phenotype was variable. Collagen accumulation in seeded scaffolds demonstrated a progressive increase after 15, 30 and 45 days of culture, while control non-seeded scaffolds show no collagen accumulation.

Conclusion

These results showed that human tenocytes from ruptured quadriceps tendon can be seeded on polycaprolactone-based PU urea scaffolds and cultured for a long time period (45 days). This study also showed that human tenocytes from ruptured tendons seeded on PU scaffolds are able to penetrate the scaffold showing a progressively higher collagen accumulation after 15, 30 and 45 days of incubation. This study provides the basis to use this PU biodegradable scaffold in vivo as an augmentation for chronic tendon ruptures and in vitro as a scaffold for tissue engineering construct.     

Pathological tendons maintain sufficient aligned fibrillar structure on ultrasound tissue characterization (UTC)

Structural disorganization in the tendon is associated with tendinopathy, with little research investigating whether disorganization overwhelms the overall structural integrity of the tendon. This study investigated the mean cross‐sectional area (CSA) of aligned fibrillar structure as detected by ultrasound tissue characterization (UTC) in the pathological and normal Achilles and patellar tendons. Ninety‐one participants had their Achilles and/or patellar tendons scanned using UTC to capture a three‐dimensional image of the tendon and allow a semi‐quantification of the echopattern. The mean CSA of aligned fibrillar structure (echo type I + II) and disorganized structure (echo type III + IV) was calculated based on UTC algorithms. Each tendon was classified as either pathological or normal based solely on gray‐scale ultrasound. The mean CSA of aligned fibrillar structure was significantly greater (P ≤ 0.001) in the pathological tendon compared with the normal tendon, despite the pathological tendon containing greater amounts of disorganized structure (P ≤ 0.001). A significant relationship was observed between the mean CSA of disorganized structure and anteroposterior diameter of the Achilles (R² = 0.587) and patellar (R² = 0.559) tendons. This study is the first to show that pathological tendons have sufficient levels of aligned fibrillar structure. Pathological tendons may compensate for areas of disorganization by increasing in tendon thickness.     

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.     

Ruptured Achilles tendons show increased lectin stainability

PURPOSE: To ascertain whether lectins could be a useful tool for investigation of the extracellular matrix of degenerated and normal tendons. METHODS: Hematoxylin-eosin-stained slides were assessed blindly using a semiquantitative grading scale for fiber structure, fiber arrangement, rounding of the nuclei, regional variations in cellularity, increased vascularity, decreased collagen stainability, hyalinization, and glycosaminoglycan, with a pathology score giving up to three marks per each of the above variables, with 0 being normal and 3 being maximally abnormal. For lectin staining with Aleuria aurantia, Canavalia ensiformis, Galanthus nivalis, Phaseolus vulgaris, Arachis hypogea, Sambucus nigra, and Triticum vulgaris, assessment of staining on a scale from 0 (no staining) to 5 (strong staining) was performed blindly. RESULTS: The mean pathology sum score of ruptured tendons (N = 14; average age 46.5 yr, range 29-61) was significantly greater than the mean pathology score of the control tendons of Achilles tendons from individuals with no known tendon pathology (N = 16; average age 62.5 yr, range 49-73) (pathology score: 18.5 +/- 3.2 vs 6.1 +/- 2.3). Four of the seven lectins used exhibited significantly positive results. CONCLUSIONS: Ruptured tendons were histologically significantly more degenerated than control tendons. Ruptured tendons showed different lectin staining properties than nonruptured ones. This difference may have resulted from posttranslational changes in the extracellular matrix producing alterations in the biochemistry of the tendon, which might interfere with the interaction with the lateral sugar residues of the collagen molecules or cause steric blockade.     

Ultrashort echo time MR imaging with off‐resonance saturation for characterization of pathologically altered Achilles tendons at 3 T

Off‐resonance radiofrequency saturation pulses applied prior to regular excitation in MR sequences can be used to modify signal contrast based on magnetization transfer and direct saturation effects. Clinical applicability and value of ultrashort echo time sequences combined with off‐resonance saturation pulses was tested in 16 healthy and 14 tendinopathic as well as paratendinopathic Achilles tendons in vivo at 3 T. A 3D ultrashort echo time sequence in combination with a gaussian off‐resonance saturation pulse (frequency offset: 1000–5000 Hz) was used to modify the detectable MR signal intensity from the Achilles tendon. Off‐resonance saturation ratio was calculated as the relative reduction in signal intensity under selective off‐resonance saturation in relation to a reference measurement without any saturation pulse. Off‐resonance saturation ratio in tendons of healthy volunteers ranged from 0.52 ± 0.06 (1000 Hz) to 0.24 ± 0.02 (5000 Hz), whereas symptomatic tendinopathic tendons (0.35 ± 0.04 to 0.17 ± 0.02) and asymptomatic tendinopathic tendons (0.41 ± 0.06 to 0.21 ± 0.02) showed significantly lower mean off‐resonance saturation ratio values. Off‐resonance saturation ratio values might provide a sensitive and quantitative marker for assessment of pathological microstructure alterations of the Achilles tendon. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.     

Marked pathological changes proximal and distal to the site of rupture in acute Achilles tendon ruptures

A laboratory study was performed to evaluate the histopathological features of the macroscopically intact portion of the Achilles tendon in patients undergoing surgery for an acute rupture of the Achilles tendon. Tendon samples were harvested from 29 individuals (21 men, 8 women; mean age: 46 ± 12) who underwent repair of an Achilles tendon tear tear, and from 11 male patients who died of cardiovascular events (mean age: 61). Three pieces of tendon were harvested: at the rupture site, 4 cm proximal to the site of rupture, 1 cm proximal to the insertion of the Achilles tendon on the calcaneum. Slides were assessed using a semiquantitative grading scale assessing fiber structure and arrangement, rounding of the nuclei, regional variations in cellularity, increased vascularity, decreased collagen stainability, and hyalinization. Intra-observer reliability of the subscore readings was calculated. The pathological features were significantly more pronounced in the samples taken from the site of rupture than in the samples taken proximally and distal to it (0.008 < P < 0.01). There were no significant differences in the mean pathologic sum-scores in the samples taken proximally and distal to the site of rupture. Unruptured Achilles tendons, even at an advanced age, and ruptured Achilles tendons are clearly part of two distinct populations, with the latter demonstrating histopathological evidence of failed healing response even in areas macroscopically normal.     

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.     

Neovascularisation in Achilles tendons with painful tendinosis but not in normal tendons: an ultrasonographic investigation

Chronic Achilles tendinosis is a condition with unknown aetiology and pathogenesis, most often, but not always, associated with painful nodular thickening of the tendon. In this investigation, 28 tendons (21 patients) with a painful nodule located at the 2-6 cm level in the tendon, and 20 normal (pain-free) tendons, were examined with grey-scale ultrasonography combined with colour Doppler examination. In all tendons with a painful nodule, but not in any of the normal pain-free tendons, neovascularisation was seen in the area with tendon changes (localised widening of the tendon with focal hypo-echoic areas). In tendons with advanced changes, vessels were seen through the entire widened part of the tendons, and both arterial and venous blood flows were registered. The neovascularisation found in this investigation might have implications on the pathogenesis of chronic Achilles tendinosis.     

肌肉包埋法旷置大段裸露跟腱的初步报告

目的 探讨肌肉包埋法旷置大段裸露跟腱的手术方法和疗效.方法 本组21例跟腱断裂合并跟区皮肤缺损,16例合并胫腓骨粉碎骨折及动脉、神经损伤,13例合并休克,6例合并骨盆骨折,2例合并同侧开放性股骨骨折,3例合并肝脾破裂.急诊手术固定骨折,修复动脉、神经损伤,修复肝脾破裂;清创后小腿三头肌包埋、旷置跟腱.二次手术修复跟腱和跟区皮肤缺损.结果 跟腱与肌肉组织紧密粘连,外膜新鲜有光泽,腱性组织坚韧有力,无变黑、坏死、液化和感染.二次手术后随访15～27个月,平均18个月.疗效评定为优15例,良4例,差2例,优良率为90%.皮瓣均成活,伤口Ⅰ期愈合,跟腱无再次断裂.结论 肌肉包埋法可以有效避免跟腱暴露所致的缺血坏死和感染,为Ⅱ期手术提供条件.     

外伤性跟腱撕裂的MRI诊断

目的：评价磁共振(MRI)对外伤性跟腱撕裂的诊断价值。方法：收集经删检查并由手术证实的外伤性跟腱撕裂患者10例，回顾、分析其MRI表现。结果：10例患者均诊断正确(敏感性100％，特异性100％)。其中完全性撕裂8例，不完全性撕裂2例；撕裂发生在跟腱中上段2例、跟腱中段7例、跟腱下段1例；MRI主要表现为肌腱增粗10例，肌腱内信号增高10例，宽径／前后径比值缩小8例，肌腱连续性中断9例，断端分离、肌腱缩短3例。跟腱周围软组织肿胀及积液9例。结论：MRI能够直接显示跟腱的形态及其内部结构．对跟腱撕裂的术前诊断具有很高的敏感件和特异性．     

Functional anatomy of the Achilles tendon

The Achilles tendon is the strongest and thickest tendon in the human body. It is also the commonest tendon to rupture. It begins near the middle of the calf and is the conjoint tendon of the gastrocnemius and soleus muscles. The relative contribution of the two muscles to the tendon varies. Spiralisation of the fibres of the tendon produces an area of concentrated stress and confers a mechanical advantage. The calcaneal insertion is specialised and designed to aid the dissipation of stress from the tendon to the calcaneum. The insertion is crescent shaped and has significant medial and lateral projections. The blood supply of the tendon is from the musculotendinous junction, vessels in surrounding connective tissue and the osteotendinous junction. The vascular territories can be classified simply in three, with the midsection supplied by the peroneal artery, and the proximal and distal sections supplied by the posterior tibial artery. This leaves a relatively hypovascular area in the mid-portion of the tendon where most problems occur. The Achilles tendon derives its innervation from the sural nerve with a smaller supply from the tibial nerve. Tenocytes produce type I collagen and form 90% of the cellular component of the normal tendon. Evidence suggests ruptured or pathological tendon produce more type III collagen, which may affect the tensile strength of the tendon. Direct measurements of forces reveal loading in the Achilles tendon as high as 9 KN during running, which is up to 12.5 times body weight.     

Effect of ultrasound therapy on the repair of Achilles tendon injuries in rats

The purpose was to determine the effects of selected regimens of ultrasound therapy on the rates of repair of injured Achilles tendons of rats. Specific dependent variables examined were tendon breaking strength and rate of collagen formation. A puncture technique was used to induce injuries to both Achilles tendons of rats. Continuous ultrasound was administered to the left tendon for 4 min per treatment session at an intensity of 1.5 W.cm-2. Rats were sacrificed 2, 5, 9, 15, and 21 d following injury for measurement of tendon breaking strength and 3 and 5 d postinjury for analysis of collagen synthesis. Breaking strength was defined as the minimum force required to completely rupture the tendon. Collagen synthesis was indicated by the conversion of labeled proline to hydroxyproline. The breaking strengths of the treated tendons were significantly greater than strengths of the untreated tendons 5, 9, 15, and 21 d postinjury. Collagen synthesis was increased in the treated tendons compared with the untreated tendons 5 d postinjury. The results indicate that ultrasound treatment increases the rate of repair of injured Achilles tendons of rats. The results are also consistent with an association between increased collagen synthesis and greater breaking strength during tendon repair.     

Apolipoprotein A1 distribution pattern in the human Achilles tendon

Metabolic factors such as cholesterol appear to play an important role in the development of Achilles tendinopathy. There is, however, no morphologic proof explaining the link between high cholesterol and tendinopathy. As apolipoprotein A1 (Apo‐A1) is essential for reverse cholesterol transport, it may be related to cholesterol overload in tendon. Nothing is known about Apo‐A1 expression in tendon tissue. We examined the distribution of Apo‐A1 protein in biopsies from normal and tendinopathy‐affected human Achilles tendons, and APOA1 mRNA production from cultured human hamstring tenocytes. Specific immunoreactions for Apo‐A1 were detected. The tenocytes showed specific Apo‐A1 immunoreactions. These reactions were usually distinct in the tendinopathy specimens. While the tendinopathy specimens often showed granular/small deposit reactions, the slender tenocytes of control specimens did not show this pattern. The magnitude of Apo‐A1 immunoreactivity was especially marked in the tendinopathy specimens, as there is a high number of tenocytes. Reactions were also seen in the walls of blood vessels located within the tendon tissue proper of both the normal and tendinopathy tendons and within the peritendinous/fatty tissue of the tendinopathy tendons. The reactions were predominantly in the form of deposit reactions within the smooth muscle layer of the vessel walls. Cultured hamstring tenocytes produced APOA1 mRNA. We demonstrated the presence of Apo‐A1 in human tendon tissue. This suggests there may be a link between Achilles tendinopathy and cholesterol metabolism. We hypothesize that Apo‐A1 may be important for tenocyte and blood vessel function within tendons.     

关节镜辅助下经皮Kessler缝合法修复新鲜闭合跟腱断裂

目的介绍并评价关节镜辅助下经皮Kessler缝合法修复新鲜闭合跟腱断裂的临床效果。方法本组26例均为闭合性新鲜跟腱断裂，关节镜证实均为跟腱完全断裂，首先在关节镜下清理跟腱断端间的瘢痕组织和凝血块，使跟腱断端对合整齐，然后在关节镜监视下采用由内向外的穿针技术，经皮Kessler缝合修复断裂的跟腱。所有患者均得到了随访，平均随访18个月（6-36个月）。随访包括常规的临床评价和MRI检查，并按Amer Lindholm评分标准进行术后疗效评定。结果按Amer Lindholm评分标准，本组优18例，良8例，优良率100％。全部患者无神经损伤，术后无感染，随访期内无跟腱再次断裂发生。MRI显示全部患者跟腱均得到了良好的修复且塑形好。结论关节镜辅助下经皮Kessler缝合法修复新鲜闭合跟腱断裂是一种较为理想的方法，具有术后疗效优良、功能恢复迅速、无明显术后并发症等优点。     

Androgenic-anabolic steroids associated with mechanical loading inhibit matrix metallopeptidase activity and affect the remodeling of the achilles tendon in rats

BACKGROUND: The indiscriminate use of anabolic-androgenic steroids has been shown to induce pathologic changes in the Achilles tendon in several situations. PURPOSE: To study tendon remodeling in rats treated with anabolic-androgenic steroids combined with an exercise program. STUDY DESIGN: Controlled laboratory study. METHODS: Wistar rats were grouped as follows: sedentary (group I), injected with anabolic-androgenic steroids only (group II), trained only (group III), and trained and injected with anabolic-androgenic steroids (group IV). The trained groups performed jumps in water: 4 series of 10 jumps each, with an overload of 50% to 70% of the animal's body weight and a 30-second rest interval between series, for 6 weeks. Anabolic-androgenic steroids (5 mg/kg) were injected subcutaneously. Activity of matrix metallopeptidases, a marker for tendon remodeling, was analyzed in tissue extracts by zymography on gelatin-sodium dodecyl sulfate-polyacrylamide gel electrophoresis. RESULTS: Morphological analyses of tendons showed that in group II, the most external layer that covers the tendon was thicker with aggregation of the collagen fibers, suggesting an increase in collagen synthesis. In group IV, an inflammatory infiltrate and fibrosis in tendons as well as a pronounced increase of the serum corticosterone level were observed. This training protocol upregulated matrix metallopeptidase activity, whereas anabolic-androgenic steroid treatment strongly inhibited this activity. The appearance of lytic bands with molecular masses of approximately 62 and 58 kDa suggests the activation of matrix metallopeptidase-2. CONCLUSION: Anabolic-androgenic steroid treatment can impair tissue remodeling in the tendons of animals undergoing physical exercise by down-regulating matrix metallopeptidase activity, thus increasing the potential for tendon injury. CLINICAL RELEVANCE: Since the AAS abuse is so widespread, a better comprehension of the pathological effects induced by these drugs may be helpful for the development of new forms of therapy of AAS-induced lesions.