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.     

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.     

Tenocytes from ruptured and tendinopathic achilles tendons produce greater quantities of type III collagen than tenocytes from normal achilles tendons. An in vitro model of human tendon healing

Type I collagen is the main collagen in tendons; type III collagen is present in small amounts. Ruptured Achilles tendons contain a significantly greater proportion of type Ill collagen, which predisposes them to rupture. We used an in vitro model to determine whether tenocytes from Achilles tendons that were ruptured (N = 22), nonruptured (N = 7), tendinopathic (N = 12), and fetal (N = 8) show different behavior. Samples of Achilles tendon were digested with collagenase and the released tenocytes were collected. Primary tenocyte cultures were established and subsequently cultured onto glass coverslips. Once a confluent monolayer was obtained, the cell populations were "wounded" by scraping a pipette tip along the surface. The cultures were further incubated for either 1, 4, 8, 12, 16, or 24 hours, and production of types I and II collagen was assessed by immunostaining. In cultures from ruptured and tendinopathic tendons, there was increased production of type Ill collagen. Athletic participation places excess stress on the Achilles tendon, which could potentially lead to areas of microtrauma within the tendon. These areas may heal by the production of type III collagen, which is an abnormal healing response. Accumulation of such episodes of microtrauma could resuit in a critical point where the resistance of the tissue to tensile forces is compromised and tendon rupture occurs.     

Immediate Achilles tendon response after strength training evaluated by MRI

PURPOSE: To evaluate the tendon response after acute strength training in chronic Achilles tendinosis using magnetic resonance imaging (MRI). METHODS: Twenty-two patients (44 Achilles tendons, 15 males, 8 patients with bilateral symptoms) with a median age of 45 yr (range 28-57 yr) were included in the study. In all patients, both Achilles tendons were examined with MRI before and immediately after a standardized training program. The most painful side underwent 6 sets and 15 repetitions of heavy-loaded eccentric training. The contralateral tendons underwent only concentric loading during the training program. The tendon volume and the intratendinous signal were evaluated and calculated by MRI using a seed-growing technique. RESULTS: The immediate response of eccentric loading on the symptomatic tendons resulted in a 12% increase of the tendon volume, evident on T2-WI, from 7.8 +/- 2.0 to 8.8 +/- 2.7 cm3 (P < 0.001), and a 31% increase of the intratendinous signal evident on PD-WI, from 221 +/- 74 to 278 +/- 78 signal units (SU) (P < 0.001). The corresponding sequences on the contralateral concentrically loaded tendons showed an increase of 17% of tendon volume, from 6.1 +/- 1.5 to 7.0 +/- 1.6 cm3 (P < 0.001), and an increase of 27% of the intratendinous signal, from 170 +/- 55 to 211 +/-57 SU (P < 0.001). There was no significant difference of the mean of the increased tendon volume and the intratendinous signal between the eccentrically heavily loaded symptomatic tendons and the concentrically loaded contralateral tendons. CONCLUSIONS: Both eccentric and concentric loading of the Achilles tendon resulted in increased total tendon volume and intratendinous signal. This increase may be explained by a higher water content and/or hyperemia in the Achilles tendon during and/or immediately after strength training of the gastrocnemius-soleus complex.     

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.     

Effect of habitual exercise on the structural and mechanical properties of human tendon, in vivo, in men and women

We examined whether long-term habitual training (a) was associated with differences in structural and mechanical properties in tendon in women and (b) yielded different tendon properties in men and women. Ten male runners, 10 female runners and 10 female non-runners were tested. Tendon cross-sectional area (CSA) and length of the patellar and Achilles tendon were determined with MRI. Ultrasonography-based measurement of tendon elongation and force during isometric contractions provided mechanical properties. Distal patellar and Achilles tendon CSAs were greater than the proximal part in all three groups (P<0.05). Weight-normalized Achilles tendon CSA were similar in trained (2.78+/-0.17 mm(2)/kg(3/4)) and untrained women (2.60+/-0.13 mm(2)/kg(3/4)), while that in trained men (3.77+/-0.27 mm(2)/kg(3/4)) was greater compared with trained women (P<0.01). Patellar tendon CSA were comparable in trained and untrained women, while that in trained men was greater compared with trained women (P<0.01). Patellar tendon stiffness was greater in male runners (3528+/-773 N/mm) compared with female runners (2069+/-666 N/mm) and non-runners (2477+/-381 N/mm), (P<0.01), but patellar tendon deformation, stress, strain and modulus were similar. These data indirectly suggest that the ability of Achilles and patellar tendons to adapt in response to habitual loading such as running is attenuated in women.     

Femoral press-fit fixation of the hamstring tendons for anterior cruciate ligament reconstruction

BACKGROUND: Press-fit fixation of patellar tendon-bone anterior cruciate ligament autografts is an interesting technique because no hardware is necessary. For hamstring tendon grafts, no biomechanical data exist of a press-fit procedure. HYPOTHESIS: Press-fit femoral fixation of hamstring tendons is mechanically equivalent to press-fit patellar tendon-bone fixation. STUDY DESIGN: Controlled laboratory study. METHODS: Patellar and hamstring tendons of 30 human cadavers (age, 53.8 +/- 18.0 years) were used. An outside-in press-fit fixation with a knot in the semitendinosus and gracilis tendons and an inside-out and outside-in fixation with the tendons wrapped around a bone block were compared with patellar tendon-bone press-fit fixation in 30 ovine femora. Constructs were cyclically strained and then loaded until failure. Maximum load to failure, stiffness, and elongation during failure testing and cyclical loading were investigated. RESULTS: The maximum load to failure was 561 +/- 309 N for the patellar tendon, 599 +/- 234 N for the semitendinosus/gracilis tendons knot construct, 678 +/- 231 for the semitendinosus/gracilis tendons bone construct inserted outside in, and 339 +/- 236 for the semitendinosus/gracilis tendons bone construct inserted inside out (inferior to the others; analysis of variance, Dunn test, P < .01). Stiffness of the constructs averaged 134 +/- 32 N/mm for the patellar tendon, 124 +/- 21 N/mm for the knot construct, 118 +/- 27 N/mm for the outside-in fixation, and 117 +/- 23 N/mm for inside-out fixation. Elongation during initial cyclical loading was 0.7 +/- 0.6 mm for the patellar tendon, 1.6 +/- 0.5 mm for the knot construct, 1.9 +/- 1.2 mm for the outside-in fixation, and 1.9 +/- 0.9 mm for the inside-out fixation (significantly larger for all semitendinosus/gracilis tendon techniques, P < .05). CONCLUSIONS: Failure loads for the semitendinosus/gracilis tendons bone construct inserted outside in and the semitendinosus/ gracilis tendons knot construct were within the confidence interval of the patellar tendon press-fit fixation. All semitendinosus/ gracilis tendon graft techniques exhibited larger elongation during initial cyclical loading than the patellar tendon graft. There was no difference in stiffness between all techniques. Clinical Relevance: Two of the 3 hamstring press-fit fixation techniques showed loads to failure similar to the patellar tendon fixation. Preconditioning of the constructs is critical. These results must be interpreted with care because of high standard deviations.     

Achilles tendon adaptation during strength training in young adults

PURPOSE: Tendons are specialized musculoskeletal structures responsible for transferring forces between muscles and bones. To maintain joint mechanics and structural integrity, tendons must adapt to changes in mechanical loading, but little is known about the interaction between muscle and tendon adaptations in vivo. We tested the hypothesis that tendons adapt to changes in muscle strength to maintain strains within a preferred operating range. METHODS: The right lower leg of 10 male subjects, age 24.9 +/- 3.4 yr (mean +/- SD), mass 78.1 +/- 9.7 kg, and height 176.5 +/- 7.2 cm, were tested before and during weeks 1, 2, 4, 6, and 8 of an 8-wk ankle plantar flexion strength training program. Subjects performed isometric plantar flexion efforts slowly ramping up from rest to a maximum effort. Plantar flexion force, Achilles tendon deformation, and cross-sectional area were measured. Triceps surae muscle force (assumed equal to Achilles tendon force), normalized force, and Achilles tendon stress and strain were calculated. Achilles tendon strains during maximum plantar flexion efforts (epsilon(max)) were compared between weeks to test the hypothesis. Repeated-measures ANOVA was used to test for significant changes during the 8 wk, with alpha = 0.05 used as the criterion for significance. RESULTS: There were no significant differences in the group's mean percent or absolute change in epsilon(max) (P = 0.607 and 0.351, respectively) despite a 21.4% average increase in muscle strength during the 8 wk. CONCLUSIONS: This is the first study that quantifies Achilles tendon strain throughout a strength training program. Findings indicate that the Achilles tendon adapts quickly to muscle strength training and experiences relatively little change in peak strain despite large increases in muscle strength.     

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.     

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.     

Normative Achilles and patellar tendon shear wave speeds and loading patterns during walking in typically developing children

BackgroundMotion analysis is commonly used to evaluate joint kinetics in children with cerebral palsy who exhibit gait disorders. However, one cannot readily infer muscle-tendon forces from joint kinetics. This study investigates the use of shear wave tensiometry to characterize Achilles and patellar tendon forces during gait.Research QuestionHow do Achilles and patellar tendon wave speed and loading modulate with walking speed in typically developing children?MethodsTwelve typically developing children (9–16 years old) walked on an instrumented treadmill with shear wave tensiometers over their Achilles (n = 11) and patellar (n = 9) tendons. Wave speeds were recorded at five leg length-normalized walking speeds (very slow to very fast). Achilles and patellar tendon moment arms were measured with synchronized ultrasound and motion capture. The tendon wave speed-load relationship was calibrated at the typical walking speed and used to estimate tendon loading at other walking speeds.ResultsCharacteristic Achilles and patellar tendon wave speed trajectories exhibited two peaks over a gait cycle. Peak Achilles tendon force closely aligned with peak ankle plantarflexor moment during pushoff, though force exhibited less modulation with walking speed. A second peak in late swing Achilles loading, which was not evident from the ankle moment, increased significantly with walking speed (p < 0.001). The two peaks in patellar tendon loading occurred at 12 ± 1% and 68 ± 6% of the gait cycle, matching the timing of peak knee extension moment in early stance and early swing. Both patellar tendon load peaks increased significantly with walking speed (p < 0.05).SignificanceThis is the first study to use shear wave tensiometry to characterize Achilles and patellar tendon loading during gait in children. These data could serve as a normative comparison when using tensiometry to identify abnormal tendon loading patterns in individuals who exhibit equinus and/or crouch gait.     

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.     

Age-related differences in the properties of the plantar flexor muscles and tendons

PURPOSE: The purpose of this study was to determine age-related differences in the human plantar flexor muscles and tendon. METHODS: Four age groups--a 20-yr group (20-27 yr, N = 19), 30-yr group (31-38 yr, N = 15), 50-yr group (46-57 yr, N = 10) and 70-yr group (62-77 yr, N = 15)--volunteered to take part in the present study. Muscle thickness, strength, and activation level (using twitch-interpolation technique) of plantar flexor muscles were measured. Elongation of the Achilles tendon was determined using ultrasonography while subjects performed ramp isometric plantar flexion up to the voluntary maximum. RESULTS: No significant difference in relative muscle thickness (to limb length) was observed among the four age groups. Muscle strength and activation level of the 20-yr group were significantly higher than those of the 50- and 70-yr groups (activation levels were not measured in the 70-yr group), and maximal strain (elongation/initial tendon length) of the Achilles tendon decreased with aging. Although there were no differences in muscle strength and activation levels between the 20- and 30-yr groups, maximal strain of the Achilles tendon of the 30-yr group was already lower than that of the 20-yr group (P = 0.062). CONCLUSION: These results suggest that the processes of age-related changes in the muscle and tendon are different. Furthermore, the differences in age-related changes of muscle and tendon might play a role in the frequency of Achilles tendon ruptures among men in their 30s.     

Braided hamstring tendons for reconstruction of the anterior cruciate ligament. A biomechanical analysis

BACKGROUND: In an effort to improve the strength and stiffness of anterior cruciate ligament grafts, several authors have advocated alterations of graft structure and orientation, including braiding the tendons in hamstring tendon grafts. HYPOTHESIS: Braiding hamstring tendons does not increase graft strength and stiffness. STUDY DESIGN: Controlled laboratory study. METHODS: Sixteen hamstring tendon and 21 bone-patellar tendon-bone grafts were harvested from 12 cadavers and divided into three groups: 1) braided four-strand hamstring tendon, 2) unbraided four-strand hamstring tendon, and 3) bone-patellar tendon-bone. All grafts were placed under a 50-N preload on a servohydraulic testing device and were tensioned to failure. RESULTS: The strength and stiffness of the tested specimens averaged 427 +/- 36 N and 76 +/- 10 N/mm, respectively, for braided specimens, 532 +/- 44 N and 139 +/- 18 N/mm for unbraided specimens, and 574 +/- 46 N and 158 +/- 15 N/mm for patellar tendon specimens. There was a 20% decrement in hamstring tendon graft tensile strength and a 45% decrease in stiffness after braiding because of the suboptimal multidirectional orientation of individual tendons within the braided grafts. CONCLUSIONS: In vitro braided hamstring tendon grafts demonstrated mechanically inferior strength and stiffness characteristics compared with unbraided hamstring tendon grafts and patellar tendon grafts. CLINICAL RELEVANCE: Braiding of hamstring tendon grafts provides no mechanical advantage in anterior cruciate ligament reconstruction.     

Functional capability is enhanced with semitendinosus than patellar tendon ACL repair

The patellar and semitendinosus tendon autograft are the two most common techniques that orthopedic surgeons use to reconstruct the anterior cruciate ligament (ACL). It has not been established, however, whether either of these techniques provides a greater functional advantage to the patient. PURPOSE: To identify patients' functional capabilities after reconstruction of the ACL with a patellar or semitendinosus tendon autograft. METHODS: Forty male soccer players volunteered for the study and were assigned to three homogeneous groups: individuals who had patellar tendon reconstruction (N = 15), individuals who had semitendinosus tendon reconstruction (N = 15), and a control group (N = 10). All patients had undergone surgery 2 yr before this study and received the same rehabilitation training. The testing procedures included measurement of thigh circumference, maximal isometric strength of quadriceps and hamstrings, two- and one-legged jump, squat and gait analysis. Kinetic, kinematic, and electromyographic data were collected. RESULTS: The patellar tendon group exhibited lower (P < 0.05) coactivation of the agonist and antagonist muscles around the knee joint during the squat movement and lower stabilization- and landing degrees during the jumps. Furthermore, the patellar tendon group had a shorter stance phase and reached the first vertical maximum later with the impaired leg while walking (720.2 +/- 15.6 ms vs 740.3 +/- 14.3 ms, and 24.3 +/- 0.64% vs 22.9 +/- 0.74% of stance phase), which was not observed in the semitendinosus tendon and control groups. CONCLUSION: Functional performance is compromised in patients who undergo a patellar tendon graft compared with a semitendinosus graft, possibly due to an altered activation of the quadriceps and hamstring muscles.     

High-resolution MR imaging of the asymptomatic Achilles tendon: new observations.

OBJECTIVE: Our aim was to describe the normal appearance of the Achilles tendon and peritendinous tissues in asymptomatic active volunteers using high-resolution MR imaging. MATERIALS AND METHODS: One hundred clinically asymptomatic Achilles tendons were imaged at 1.5 T with axial high-resolution T1-weighted gradient-echo (fast low-angle shot [FLASH]) and short inversion time inversion recovery (STIR) sequences. The tendons, peritendinous tissues, tendon insertions, and musculotendinous junctions were separately evaluated by two observers. RESULTS: The average anteroposterior diameter (+/-SD) of the asymptomatic Achilles tendons was 5.2+/-0.73 mm. The anterior margin was flat or concave in all, except for 10 tendons that showed mild convexity. A wave-like bulge, which shifted from lateral to medial in the craniocaudal direction, was detected in the anterior margin of 56 tendons. The signal intensity was heterogeneous in 45 tendons. In these tendons, distal stripes or punctate foci were seen. A small (3 mm) intermediate intensity intratendinous region thought to represent tendon degeneration was detected in four cases on FLASH images. The retrocalcaneal bursae contained a prominent fluid collection in 15 cases. The paratenon was visualized in all cases on both FLASH and STIR images. CONCLUSION: High-resolution MR imaging depicts the Achilles tendon and peritendinous soft tissues in great detail. The normal anatomy of the asymptomatic Achilles tendon is variable. We postulate that the variability may be a potential source of diagnostic misinterpretation.     

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.     

钼靶摄影诊断跟腱、髌腱运动创伤

<正> 跟腱、髌腱及其附丽区损伤在运动创伤中较为常见,采用临床上使用的钨靶摄影,由于它产生的硬射线对软组织分辨率较差,不易清晰反映出肌腱、韧带等软组织的细节。1970年以来国外研究应用钼靶摄影诊断乳腺疾病,在1979年起国内开始了这方面报道,但仍以诊断乳腺疾病为主。我院1979年用于诊断运动创伤疾病,一年共摄片276张,发现它对显示跟腱、髌腱等软组织变化效果较好。现将临床使用和诊断依据作一介绍。     

Asymptomatic Achilles,patellar, and quadriceps tendinopathy: A longitudinal clinical and ultrasonographic study in elite fencers

Lower limb tendon changes detected at imaging are common among asymptomatic athletes. We aimed to prospectively assess the clinical status, tendon structure, and vascularity of lower limb tendons of elite fencers, and predict the risk of developing symptoms over time. Clinical examination, changes at ultrasonography (US), and Power Doppler (PD) flow of both the Achilles, patellar, and quadriceps tendon were assessed in 37 elite fencers in January 2007 and 3 years after. Two hundred and twenty‐two tendons were examined. At the last appointment, patellar tendons diagnosed as abnormal at baseline were more likely to develop symptoms than those normal at baseline (P < 0.05, Fisher's exact test), while US and PD abnormalities on Achilles and quadriceps tendons were no predictive for development of symptoms over years. A very low percentage of tendons diagnosed as normal at baseline (1.45%) showed US abnormalities at 3‐year follow‐up. In asymptomatic elite fencers, structural changes are relatively common at US and PD assessment of Achilles, quadriceps, and patellar tendons. It seems unlikely that additional PD investigations provide further information or change prognosis in patients with US diagnosis of tendinopathy.     

Neoinnervation in rotator cuff tendinopathy

The aim of this study was to determine whether there are more nerves in tendinopathic human tendon, and if so, where are they located. Tendon biopsies were collected from normal, tendinopathic, and torn human rotator cuff tendons and then analyzed using immunohistochemistry and antibodies against a general nerve marker (protein gene product 9.5, PGP9.5), a nerve regeneration marker (growth-associated protein 43, GAP43), and an endothelial cell marker (CD34). Nerve fibers exhibiting PGP9.5 or GAP43 immunoreactivity were often observed intimately in association with tiny blood vessels in the endotendineum of tendinopathic tendons. The expression of PGP9.5 and GAP43 were significantly higher in tendinopathic tendon compared with control tendon and torn tendon. These data support the hypothesis that early tendinopathy is associated with increases of newly grown nerve fibers and blood vessels inside and around tendinopathic tendon, and these may be the source of pain in tendinopathy.