Understanding adaption to load is essential for prevention and treatment of tendinopathy/tendinosis. Cytokine release in response to load is one mechanism involved in mechanotransduction. The cytokine tumor necrosis factor alpha (TNF-α) is implicated in tendinosis and can induce apoptotic effects via tumor necrosis factor receptor 1 (TNFR1). The complete absence of information concerning the TNF-α system in Achilles tendon is a limitation as mid-portion Achilles tendinosis is very frequent. Purpose: To examine expression patterns of TNF-α and its two receptors (TNFR1 and TNFR2) in human Achilles tendinosis and control tissue and to biochemically confirm the presence of TNF-α in tendinosis tissue. Methods: TNF-α and TNFR1 mRNA were detected via in situ hybridization. TNF-α, TNFR1, and TNFR2 were demonstrated immunohistochemically. Apoptosis markers were utilized. ELISA was used to detect TNF-α. Results: TNF-α and TNFR1 mRNA was detected in tenocytes of both tendinosis and control tendons. Tenocytes from both groups displayed specific immunoreactions for TNF-α, TNFR1, and TNFR2. The widened/rounded tenocytes of tendinosis samples exhibited the most intense immunoreactions. Apoptosis was detected in only a subpopulation of the tenocytes in tendinosis tissue. TNF-α was measurable in tendinosis tissue. Inflammatory cells were not seen. Conclusion: This is the first evidence of the existence of the TNF-α system in the human Achilles tendon. Findings are confirmed at mRNA and protein levels as well as biochemically. The TNF-α system was in principle confined to the tenocytes. The connection between tenocyte morphology and the expression pattern of TNF-α, TNFR1, and TNFR2 suggests that the TNF-α system may be involved in tenocyte activation in Achilles tendinosis.

Physical activity affects the pain symptoms for Achilles tendinosis patients. Brain-derived neurotrophic factor (BDNF), tumor necrosis factor-alpha (TNF-α) and their receptors have been detected in human Achilles tendon. This pilot study aimed to compare serum BDNF and soluble tumor necrosis factor receptor I (sTNFRI) levels in Achilles tendinosis patients and healthy controls and to examine the influence of physical activity, and BMI and gender, on these levels. Physical activity was measured with a validated questionnaire, total physical activity being the parameter analyzed. Physical activity was strongly correlated with BDNF among tendinosis women [Spearman's rho (ρ)=0.90, P<0.01] but not among control women (ρ=-0.08, P=0.83), or among tendinosis and control men. Physical activity was significantly correlated with sTNFRI in the entire tendinosis group and among tendinosis men (ρ=0.65, P=0.01), but not in the entire control group or among control men (ρ=0.04, P=0.91). Thus, the physical activity pattern is related to the TNF and BDNF systems for tendinosis patients but not controls, the relationship being gender dependent. This is new information concerning the relationship between physical activity and Achilles tendinosis, which may be related to pain for the patients. This aspect should be further evaluated using larger patient materials.

Introduction Treatment of midportion Achilles tendinopathy has been known to be difficult. Recent ultrasound(US) and Doppler(CD) findings (high blood flow outside ventral tendon), together with results of immunohistochemical analyses (marked presence of blood vessels accompanied by nerve fascicles in the ventral peritendinous tissue) have led to new treatment approaches like sclerosing polidocanol injections, where US and CD-guided injections in the region with high blood flow and nerves outside the tendon have shown good results. However, for satisfying pain relief multiple injection treatments were often needed. Therefore, based on the same principles as for the sclerosing injections, a more radical and one stage mini-surgical procedure has been invented. Methods 107 patients (66 men, 41 women), mean age 43 years (range 24-77), with tendinosis in 125 Achilles tendons were, in local anaesthesia, treated with a US+CD-guided new surgical approach outside the ventral tendon. Pain during tendon loading activity (VAS) and satisfaction with treatment, were evaluated. Results Before surgery, the mean VAS was 77. After surgery (follow up mean 18 months, range 6-33) the mean VAS was 2 in 111 tendons (89%) from satisfied patients back in full Achilles tendon loading activity. Conclusions US+CD-guided scraping/tenolysis in the region with rich vascularity and innervation outside the ventral tendon

In international studies, higher prevalence of persistent pain has been reported in indigenous populations compared to majority populations. The present study aimed to determine the prevalence of persistent pain within a Sami and a non-Sami population in northern Norway, with adjustment for the confounding factors of age, sex, marital status, education, income, mental health, smoking status and ethnic background. Using SAMINOR 2 survey data including Sami and non-Sami populations, we analysed 5,546 responses, from individuals aged 40-79 years, to questions concerning persistent pain (≥ 3 months). In total, 2,426 (43.7%) participants reported persistent pain with differences between Sami women and non-Sami women (44.1% versus 51.1%, respectively), but none between Sami men and non-Sami men (38.7% versus 38.2%, respectively). Elderly Sami women were less likely to report persistent pain than were elderly non-Sami women. In men, no ethnic differences in pain were observed according to age-group. Marital status, education levels, household income, psychological distress, and smoking status did not influence the association between ethnicity and pain. Pain severity and location did not differ between Sami and non-Sami participants. In this study, we found only minor ethnic differences in persistent pain. Similar living conditions and cultural features may explain these findings.