Chronic Achilles tendon pain treated with eccentric calf-muscle training

Injuries involving the Achilles tendon and manifested as chronic tendon pain are common, especially among recreational athletes. In a pilot study on a small group of patients with chronic painful mid-portion Achilles tendinosis, eccentric calf-muscle training was shown to give good clinical results. The aim of this prospective study was to investigate if the previously achieved good clinical results could be reproduced in a larger group of patients, and also to investigate the effects of eccentric calf-muscle training in patients with chronic insertional Achilles tendon pain. Seventy-eight consecutive patients, having chronic painful Achilles tendinosis at the mid-portion (2–6 cm level) in a total of 101 tendons (55 unilateral and 23 bilateral), and thirty consecutive patients with chronic insertional Achilles tendon pain in 31 tendons (29 unilateral and one bilateral) were treated with eccentric calf-muscle training for 12 weeks. Most patients were recreational athletes. Evaluation of the amount of tendon pain during activity was recorded on a visual analogue scale (VAS), before and after treatment. In 90 of the 101 Achilles tendons (89%) with chronic painful mid-portion Achilles tendinosis, treatment was satisfactory and the patients were back on their pre-injury activity level after the 12-week training regimen. In these patients, the amount of pain during activity, registered on the VAS-scale (mean±SD), decreased significantly from 66.8±19.4 to 10.2±13.7. On the contrary, in only ten of the tendons (32%) with chronic insertional Achilles tendon pain was treatment satisfactory, with a significant decrease on the VAS-scale (mean±SD), from 68.3±7.0 to 13.3±13.2. Our conclusion is that treatment with eccentric calf-muscle training produced good clinical results in patients with chronic painful mid-portion Achilles tendinosis, but not in patients with chronic insertional Achilles tendon pain.     

Intratendinous glutamate levels and eccentric training in chronic Achilles tendinosis: a prospective study using microdialysis technique

Microdialysis has shown intratendinous glutamate levels to be significantly higher in Achilles tendons with painful tendinosis than in normal pain-free tendons, and treatment with eccentric training has shown good clinical results with diminished tendon pain during activity. In six patients with chronic painful Achilles tendinosis we performed microdialysis for 2 h, before and after the 12-week eccentric training program. The treatment was successful in all six patients, and the mean VAS score (amount of pain during Achilles tendon loading) decreased from 69 before treatment to 17 after treatment. There was no significant difference between the intratendinous glutamate levels before and after treatment. Our results offer no obvious neurophysiological explanation but showed that successful treatment with eccentric training was not associated with lowered intratendinous glutamate levels.     

Effects on neovascularisation behind the good results with eccentric training in chronic mid-portion Achilles tendinosis?

The background to the good clinical results reported using painful eccentric calf-muscle training as treatment for chronic painful mid-portion Achilles tendinosis is not known. Recently, using ultrasound and colour Doppler technique, we showed that painful tendinosis was associated with a local neovascularisation. Furthermore, in a pilot study, destroying these neovessels by sclerosing therapy cured the pain in most patients. Dynamic ultrasound and colour Doppler examination has shown that the flow in the neovessels stops during dorsiflexion in the ankle joint. Therefore, it was of interest to study the occurrence of neovascularisation before and after eccentric training. Forty-one tendons in 30 patients (22 men and 8 women, mean age 48 years) with chronic painful mid-portion Achilles tendinosis were examined with ultrasonography and colour Doppler, before and after 12 weeks of eccentric calf-muscle training. Before treatment, there was a local neovascularisation in the area with tendon changes (hypo-echoic areas, irregular fibre structure) in all tendons. At follow-up after treatment (mean 28 months), there was a good clinical result (no tendon pain during activity) in 36/41 tendons, and a poor result in 5/41 tendons. In 34/36 tendons with a good clinical result of treatment there was a more normal tendon structure, and in 32/36 tendons there was no remaining neovascularisation. In 5/5 tendons with a poor clinical result there was a remaining neovascularisation in the tendon, and in 2/5 tendons there were remaining structural abnormalities. In conclusion, in patients with chronic painful mid-portion Achilles tendinosis, a good clinical result after eccentric training seems to be associated with a more normal tendon structure and no remaining neovascularisation. Action on the area with neovessels during the eccentric training regimen might possibly be responsible for the good clinical results.     

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.     

Eccentric training in patients with chronic Achilles tendinosis: normalised tendon structure and decreased thickness at follow up

OBJECTIVE: To prospectively investigate tendon thickness and tendon structure by ultrasonography in patients treated with eccentric calf muscle training for painful chronic Achilles tendinosis located at the 2-6 cm level in the tendon. METHODS: The patients were examined with grey scale ultrasonography before and 3.8 years (mean) after the 12 week eccentric training regimen. At follow up, a questionnaire assessed present activity level and satisfaction with treatment. RESULTS: Twenty six tendons in twenty five patients (19 men and six women) with a mean age of 50 years were followed for a mean of 3.8 years (range 1.6-7.75). All patients had a long duration of painful symptoms (mean 17.1 months) from chronic Achilles tendinosis before treatment. At follow up, 22 of 25 patients were satisfied with treatment and active in Achilles tendon loading activities at the desired level. Ultrasonography showed that tendon thickness (at the widest part) had decreased significantly (p<0.005) after treatment (7.6 (2.3) v 8.8 (3) mm; mean (SD)). In untreated normal tendons, there was no significant difference in thickness after treatment (5.3 (1.3) mm before and 5.9 (0.8) mm after). All tendons with tendinosis had structural abnormalities (hypoechoic areas and irregular structure) before the start of treatment. After treatment, the structure was normal in 19 of the 26 tendons. Six of the seven patients with remaining structural abnormalities experienced pain in the tendon during loading. CONCLUSIONS: Ultrasonographic follow up of patients with mid-portion painful chronic Achilles tendinosis treated with eccentric calf muscle training showed a localised decrease in tendon thickness and a normalised tendon structure in most patients. Remaining structural tendon abnormalities seemed to be associated with residual pain in the tendon.     

Significance of ultrasonographically detected asymptomatic tendinosis in the patellar and achilles tendons of elite soccer players: a longitudinal study

BACKGROUND: Chronic tendinosis of the Achilles or patellar tendons, or both, is one of the most frequent and severe conditions that affects athletes in sports such as soccer. It can often end an athlete's sports activity. HYPOTHESIS: Ultrasonography of asymptomatic tendons can be used to predict which athletes will develop tendon symptoms. STUDY DESIGN: Longitudinal study. METHODS: Using ultrasonography of the ankle and knee, we examined 54 elite soccer players in the top Danish soccer league before and after a single season (in January and December). RESULTS: At the start of the season, ultrasonography had revealed abnormalities in 29% of those examined. Eighteen percent (18 of 98 tendons) were observed to have abnormal sonographic findings in the patellar tendon at the initial examination in January. These athletes were found to have a 17% risk of developing symptomatic jumper's knee during the 12-month season. Eleven percent (11 of 96 tendons) were observed to have abnormal sonographic findings in the Achilles tendon at the initial examination; it was calculated that they had a 45% risk of developing symptoms of Achilles tendinosis. Only one of the players with normal tendons in January actually developed symptoms by the end of the season. CONCLUSIONS: For the first time it is now possible to identify risk factors for the development of serious tendon disorders in asymptomatic athletes. Future studies may be directed at developing preventive treatment to reduce the risk of chronic, therapy-resistant symptoms of tendinosis and ruptures.     

Superior short-term results with eccentric calf muscle training compared to concentric training in a randomized prospective multicenter study on patients with chronic Achilles tendinosis

In a previous uncontrolled pilot study we demonstrated very good clinical results with eccentric calf muscle training on patients with painful chronic Achilles tendinosis located at the 2-6 cm level in the tendon. In the present prospective multicenter study (Sundsvall and Ume?) patients with painful chronic Achilles tendinosis at the 2-6 cm level in the tendon were randomized to treatment with either an eccentric or a concentric training regimen for the calf muscles. The study included 44 patients, with 22 patients (12 men, 10 women; mean age 48 years) in each treatment group. The amount of pain during activity (jogging or walking) was recorded by the patients on a visual analogue scale, and patient satisfaction was assessed before and after treatment. The patients were instructed to perform their eccentric or concentric training regimen on a daily basis for 12 weeks. In both types of treatment regimen the patients were told to do their exercises despite experiencing pain or discomfort in the tendon during exercise. The results showed that after the eccentric training regimen 82% of the patients (18/22) were satisfied and had resumed their previous activity level (before injury), compared to 36% of the patients (8/22) who were treated with the concentric training regimen. The results after treatment with eccentric training was significantly better (P<0.002) than after concentric training. The good clinical results previously demonstrated in the pilot study with eccentric calf muscle training on patients with chronic Achilles tendinosis, were thus reproduced in this multicenter, showing superior results to treatment with concentric training.     

Trigger finger,tendinosis, and intratendinous gene expression

The pathogenesis of trigger finger has generally been ascribed to primary changes in the first annular ligament. In contrast, we recently found histological changes in the tendons, similar to the findings in Achilles tendinosis or tendinopathy. We therefore hypothesized that trigger finger tendons would show differences in gene expression in comparison to normal tendons in a pattern similar to what is published for Achilles tendinosis. We performed quantitative real‐time polymerase chain reaction on biopsies from finger flexor tendons, 13 trigger fingers and 13 apparently healthy control tendons, to assess the expression of 10 genes which have been described to be differently expressed in tendinosis (collagen type 1a1, collagen 3a1, MMP‐2, MMP‐3, ADAMTS‐5, TIMP‐3, aggrecan, biglycan, decorin, and versican). In trigger finger tendons, collagen types 1a1 and 3a1, aggrecan and biglycan were all up‐regulated, and MMP‐3and TIMP‐3 were down‐regulated. These changes were statistically significant and have been previously described for Achilles tendinosis. The remaining four genes were not significantly altered. The changes in gene expression support the hypothesis that trigger finger is a form of tendinosis. Because trigger finger is a common condition, often treated surgically, it could provide opportunities for clinical research on tendinosis.     

Tendinopathy and Doppler activity: the vascular response of the Achilles tendon to exercise

BACKGROUND: Intratendinous Doppler activity has been interpreted as an equivalent of neovessels in the Achilles tendon and as a sign of tendinosis (AT). AIM: To evaluate the vascular response as indicated by color Doppler activity after repeated loading of both symptomatic and non-symptomatic Achilles tendons. MATERIAL AND METHODS: Ten non-trained, healthy subjects ran 5 km. Ultrasound (US) Doppler activity was determined before and after the exercise. Eleven patients with chronic AT performed 3 x 15 heavy-load eccentric exercise. The Achilles tendons were scanned before and immediately after the exercise. RESULTS: Non-symptomatic: six Achilles tendons in five subjects had intratendinous Doppler activity before the exercise. All but two subjects (80%) had intratendinous Doppler activity after running. Symptomatic: all patients had Doppler activity in the tendons, with a median color fraction before eccentric exercise of 0.05 (range 0.01-0.33). The Doppler activity did not disappear after exercise. Tendons with a color fraction below the median at baseline increased significantly after the exercise (P=0.02). CONCLUSION: The mere presence of Doppler in the Achilles tendon does not per se indicate disease. Eccentric exercise does not extinguish the flow during or after one training session in patients with chronic AT.     

Is vasculo-neural ingrowth the cause of pain in chronic Achilles tendinosis?

The purpose of this study was to investigate where the pain comes from in chronic mid-portion Achilles tendinosis, by using ultrasonography and colour Doppler, immunohistochemistry, and diagnostic injections. Twenty-five tendons in 24 patients (mean age 47 years) with the clinical diagnosis of painful chronic mid-portion Achilles tendinosis, and 20 tendons in 14 controls (mean age 48 years) with pain-free Achilles tendons were examined with ultrasonography and colour Doppler. For the 25 painful tendons, a local anaesthetic was injected in the area with neovascularisation outside the ventral part of the tendon. Biopsies taken from tendinosis tissue in six patients were used for PGP 9.5 immunohistochemistry. A neovascularisation, inside and outside the ventral part of the area with tendon changes, was demonstrated in all painful tendinosis tendons, but not in any of the pain-free control tendons. After injection of the local anaesthetic towards the neovessels outside the ventral part of the tendon, the pain during tendon-loading activity was temporarily cured in all patients. The mean VAS-score for heel-raises decreased significantly from 75 mm to 6 mm. In biopsies, PGP 9.5 immunohistochemistry showed nerve structures in the vicinity of blood vessels. In conclusion, we demonstrate findings which support neovessels and accompanying nerves being the possible source of pain in chronic mid-portion Achilles tendinosis.     

Effect of eccentric training on the plantar flexor muscle-tendon tissue properties

PURPOSE: It has been shown that eccentric training can be effective in the rehabilitation of patients with Achilles tendonopathy. The mechanism behind these results is not clear. However, there is evidence that tendons are able to respond to repeated forces by altering their structure and composition, and, thus, their mechanical properties change. In this regard, the objective of the present study was to investigate whether eccentric training affects the mechanical properties of the plantar flexor's muscle-tendon tissue properties. METHODS: Seventy-four healthy subjects were randomized into two groups: an eccentric training group and a control group. The eccentric training group performed a 6-wk eccentric training program for the calf muscles. Before and after this period, all subjects were evaluated for dorsiflexion range of motion using universal goniometry, passive resistive torque of the plantar flexors, and stiffness of the Achilles tendon. Passive resistive torque was measured during ankle dorsiflexion on an isokinetic dynamometer. Stiffness of the Achilles tendon was assessed using a dynamometer, in combination with ultrasonography. RESULTS: The results of the study reveal that the dorsiflexion range of motion was significantly increased only in the eccentric training group. The eccentric heel drop program also resulted in a significant decrease of the passive resistive torque of the plantar flexors (from 16.423 +/- 0.827 to 12.651 +/- 0.617 N.m). The stiffness of the Achilles tendon did not change significantly as a result of training. CONCLUSION: These findings provide evidence that an eccentric training program results in changes to some of the mechanical properties of the plantar flexor muscles. These changes were thought to be associated with modifications to structure rather than to stretch tolerance.     

Neovascularisation in chronic painful patellar tendinosis—promising results after sclerosing neovessels outside the tendon challenge the need for surgery

Sclerosing injections targeting neovascularisation have been demonstrated to give promising clinical results in patients with chronic painful Achilles tendinosis. In this study, fifteen elite or recreational athletes (12 men and three women) with the diagnosis patellar tendinosis/Jumpers knee in 15 patellar tendons were included. All the patients had a long duration of pain symptoms (mean = 23 months) from the patellar tendon, and ultra-sonography + colour doppler examination showed structural tendon changes with hypo-echoic areas and a neovascularisation, corresponding to the painful area. The patients were treated with ultrasound and colour doppler-guided injections of the sclerosing substance Polidocanol, targeting the area with neovascularisation. At follow-up (mean = 6 months) after a mean amount of three treatments, there was a good clinical result in 12/15 tendons. The patients were back to their previous (before injury) sport activity level, and the amount of pain recorded on a VAS-scale had decreased significantly (VAS from 81 to 10). Our findings indicate that treatment with sclerosing injections, targeting the area with neovessels in patellar tendinosis, has the potential to cure the pain in the tendons and also allow the patients to go back to full patellar-tendon loading activity.     

Eccentric training of the gastrocnemius-soleus complex in chronic Achilles tendinopathy results in decreased tendon volume and intratendinous signal as evaluated by MRI

BACKGROUND: Satisfactory treatment results have been reported after eccentric calf muscle strength training in patients with chronic Achilles tendinopathy. HYPOTHESIS: Magnetic resonance imaging may be a useful adjunct in the evaluation of the effect of 3 months of eccentric calf muscle strength training. STUDY DESIGN: Prospective cohort study. METHODS: Using magnetic resonance imaging, the Achilles tendons were investigated in 25 patients (16 men and 9 women) ranging in age from 28 to 70 years (median, 51 years) before and after training. Five different magnetic resonance imaging sequences were used. Tendon volume and mean intratendinous signal were calculated using a new seed-growing technique showing 99.3% and 96.6% intraobserver reliability, respectively. The clinical outcome was categorized according to pain level and performance using a questionnaire completed by the patient. RESULTS: The eccentric training resulted in a 14% (mean) decrease of tendon volume measured on T1-weighted images, from 6.6 +/- 3.1 cm3 to 5.8 +/- 2.3 cm3 (P < .05). The intratendinous signal in the symptomatic Achilles tendon measured on proton density-weighted images decreased 23% (mean), from 227 +/- 77 signal units to 170 +/- 83 signal units (P < .05). The gadolinium contrast agent-enhanced images did not add further value compared with other sequences. CLINICAL OUTCOME: The clinical outcome was categorized as excellent in 10, good in 3, fair in 5, and poor in 8 patients. The Delta signal correlated significantly with the pain level (P < .05). CONCLUSIONS: Eccentric training resulted in decreased tendon volume and intratendinous signal and was correlated with an improved clinical outcome. Magnetic resonance imaging techniques can be used as an adjunct to clinical evaluation by monitoring morphologic effects in clinical treatment studies of Achilles tendinopathy.     

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.     

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.     

Correlation of procollagen (I) with prostate specific antigen and bone scan for the diagnosis of bone metastases in patients with prostate carcinoma

Procollagen (I) carboxyterminal propeptide (PICP) is a metabolite of procollagen, a precursor molecule of collagen type I, which accounts for more than 90% of the organic matrix of the bones. Serum PICP levels indicate the rate of bone collagen synthesis and therefore the osteoblastic activity. In this study we evaluate the clinical usefulness of serum PICP as an indicator of bone metastases in patients with prostate cancer in relation to bone scan and to prostate specific antigen (PSA) measurements. We found no similar study in the literature relating these three tests. Seventy-eight patients (median age 63+/-4,3 years) with prostate adenocarcinoma were examined. The diagnosis was confirmed histologically. Bone metastases were diagnosed in 42 (54%) of them assessed by bone scans (Group A), while the remaining 36 patients (46%) had no bone metastases (negative bone scans and X-rays) (Group B). We also examined 21 patients with benign prostate hyperplasia as a control group (Group C). All patients had serum PICP measurements, bone scans with (99m)Tc-MDP and PSA measurements. None of them had a history of disease or of using drugs known to affect bone metabolism. Serum levels of PICP were assayed by a radioimmunoassay (RIA) kit (Orion Cooperation, Farmos Diagnostics, Finland). Serum PSA was also tested by a RIA kit (Tandem-R, Hybritech Inc, USA). PICP levels in Group A were 265+/-89 microg/l, in Group B 128+/-39 microg/l and in Group C patients 110+/-48 microg/l. High levels of PICP above 170 microg/l, were diagnostic of bone metastases with sensitivity 54%, specificity 93% and accuracy 84%. In comparison, PSA levels above 4 ng/ml were also diagnostic with a sensitivity of 68%, specificity of 91% and accuracy 88%. Patients with low levels of PICP, lower than 90 microg/l, n=31, had no bone metastases. The positive prognostic value of bone scan was 74% with a sensitivity of 76%, specificity of 58% and accuracy 71%. Positive bone scans combined with very high levels of PICP and PSA, had positive prognostic value 97%, with sensitivity of 78%, specificity of 96% and accuracy 97%, while bone scans with levels of PICP lower than 170 microg/l, had positive prognostic value of 32%. Levels of PICP and PSA were significantly higher in patients with prostate cancer and bone metastases in comparison to patients with benign prostate hyperplasia (P<0.0001) respectively. Also, levels of PICP and PSA were higher in patients with prostate cancer without metastases as compared to prostate hyperplasia (P<0.0005 and P<0.0001 respectively) (Wilcoxon-Mann-Whitney test). When metastases were more extensive, PICP levels were higher than PSA. It is concluded that PICP as a marker of osteoblastic activity is useful for diagnosing bone metastases of prostate adenocarcinoma but when co-evaluated with PSA and the bone scan, the diagnostic accuracy of these three diagnostic procedures is much higher.     

The chronic painful Achilles and patellar tendon: research on basic biology and treatment

The etiology and pathogenesis of chronic tendon pain are unknown. Even though tendon biopsies having shown an absence of inflammatory cell infiltration, anti-inflammatory agents (non-steroidal anti-inflammatory drugs, corticosteroidal injections) are commonly used. We have demonstrated that it is possible to use intratendinous microdialysis to investigate human tendons, and found normal prostaglandin E2 (PGE2) levels in chronic painful tendinosis (Achilles and patellar) tendons. Furthermore, gene technological analyses of biopsies showed no upregulation of pro-inflammatory cytokines. These findings show that there is no PGE2-mediated intratendinous inflammation in the chronic stage of these conditions. The neurotransmitter glutamate (a potent modulator of pain in the central nervous system) was, for the first time, found in human tendons. Microdialysis showed significantly higher glutamate levels in chronic painful tendinosis (Achilles and patellar) tendons, compared with pain-free normal control tendons. The importance of this finding is under evaluation. Treatment is considered to be difficult, and not seldom, surgery is needed. However, recent researches on non-surgical methods have shown promising clinical results. Painful eccentric calf-muscle training has been demonstrated to give good clinical short- and mid-term results on patients with chronic painful mid-portion Achilles tendinosis. Good clinical results were associated with decreased tendon thickness and a structurally more normal tendon with no remaining neovessels. Using ultrasonography (US)+color Doppler (CD), and immunhistochemical analyses of biopsies, we have recently demonstrated a vasculo/neural (Substance-P and Calcitonin Gene-Related Peptide nerves) ingrowth in the chronic painful tendinosis tendon, but not in the pain-free normal tendon. A specially designed treatment, using US- and CD-guided injections of the sclerosing agent Polidocanol, targeting the neovessels outside the tendon, has been shown to cure tendon pain in pilot studies, in a majority of the patients. A recent, randomized, double-blind study verified the importance of injecting the sclerosing substance Polidocanol.     

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.     

In situ microdialysis in tendon tissue: high levels of glutamate, but not prostaglandin E2 in chronic Achilles tendon pain

This investigation was to our knowledge the first to use the microdialysis technique to study concentrations of substances in a human tendon. In four patients (mean age 40.7 years) with a painful nodule in the Achilles tendon (chronic Achilles tendinosis) and in five controls (mean age 37.2 years) with normal Achilles tendons (confirmed by ultrasonography) the local concentrations of glutamate and prostaglandin E₂ were measured under resting conditions. A standard microdialysis catheter was inserted into the Achilles tendon under local anesthesia. Sampling was performed every 15 min over a 4-h period. The results showed significantly higher concentrations of glutamate in tendons with tendinosis than in normal tendons (196 ± 59 vs. 48 ± 27 μmol/l, P < 0.05), and there were no significant changes in glutamate concentration over the period of investigation. There were no significant differences in the mean concentrations of prostaglandin E₂ (83 ± 22 vs. 54 ± 24 pg/ml) between tendons with tendinosis and normal tendons. In conclusion, in situ microdialysis appears a useful method to study certain metabolic events in tendon tissue. The higher concentrations of the excitatory neurotransmitter glutamate in Achilles tendons with a painful nodule may possibly be involved in the pain mechanism in this chronic condition. Furthermore, there were no signs of inflammation in the tendons with painful nodules, as indicated by the normal prostaglandin E₂ levels. Received: 30 March 1999 Accepted: 30 May 1999     

Hamstring injury occurrence in elite soccer players after preseason strength training with eccentric overload

The primary purpose of this study was to evaluate whether a preseason strength training programme for the hamstring muscle group - emphasising eccentric overloading - could affect the occurrence and severity of hamstring injuries during the subsequent competition season in elite male soccer players. Thirty players from two of the best premier-league division teams in Sweden were divided into two groups; one group received additional specific hamstring training, whereas the other did not. The extra training was performed 1-2 times a week for 10 weeks by using a special device aiming at specific eccentric overloading of the hamstrings. Isokinetic hamstring strength and maximal running speed were measured in both groups before and after the training period and all hamstring injuries were registered during the total observational period of 10 months. The results showed that the occurrence of hamstring strain injuries was clearly lower in the training group (3/15) than in the control group (10/15). In addition, there were significant increases in strength and speed in the training group. However, there were no obvious coupling between performance parameters and injury occurrence. These results indicate that addition of specific preseason strength training for the hamstrings - including eccentric overloading - would be beneficial for elite soccer players, both from an injury prevention and from performance enhancement point of view.