Current pharmacological approaches to the treatment of tendinopathy.

INTRODUCTION: Tendinopathies are common in elite and recreational athletes: traditionally considered overuse injuries, they involve excessive tensile loading and subsequent breakdown of the loaded tendon. Many pharmacological treatments have been proposed for the management of tendinopathy, with no agreement regarding the overall best option available both for Achilles and patellar tendinopathy. AREAS COVERED: The present article reports the best scientific evidence regarding the efficacy and safety of different pharmacological treatments in different types of tendinopathy, focusing on Achilles and patellar tendinopathy, the conditions on which more studies have been published. EXPERT OPINION: No univocal evidence exists regarding the best non-operative management, which includes non-steroidal anti-inflammatory drugs, platelet-rich plasma, high volume image-guided injections, hyaluronic acid, and prolotherapy, for tendinopathy (in particular Achilles and patellar tendinopathies) as a suitable alternative to the commonly used eccentric loading rehabilitation regimen. It is unclear whether the combination of pharmacological substances with physical therapy would produce better results than physical therapy alone. There is an overall lack of published well-performed randomized controlled trials comparing the various options available for the management of tendinopathy, studying large cohorts of patients for adequately long follow-up periods and with well-validated standardized scores and scales.

Effect of androgenic-anabolic steroids and heavy strength training on patellar tendon morphological and mechanical properties.

Combined androgenic-anabolic steroids (AAS) and overloading affects tendon collagen metabolism and ultrastructure and is often associated with a higher risk of injury. The aim of this prospective study was to investigate whether such effects would be reflected in the patellar tendon properties of individuals with a history of long-term resistance training and AAS abuse (RTS group), compared with trained (RT) and untrained (CTRL) nonsteroids users. Tendon cross-sectional area (CSA), stiffness, Young's modulus, and toe limit strain were measured in vivo, from synchronized ultrasonography and dynamometry data. The patellar tendon of RT and RTS subjects was much stiffer and larger than in the CTRL group. However, stiffness and modulus were higher in the RTS group (26%, P < 0.05 and 30%, P < 0.01, respectively) than in the RT group. Conversely, tendon CSA was 15% (P < 0.05) larger in the RT group than in RTS, although differences disappeared when this variable was normalized to quadriceps maximal isometric torque. Yet maximal tendon stress was higher in RTS than in RT (15%, P < 0.05), without any statistical difference in maximal strain and toe limit strain between groups. The present lack of difference in toe limit strain does not substantiate the hypothesis of changes in collagen crimp pattern associated with AAS abuse. However, these findings indicate that tendon adaptations from years of heavy resistance training are different in AAS users, suggesting differences in collagen remodeling. Some of these adaptations (e.g., higher stress) could be linked to a higher risk of tendon injury.

Effect of prolotherapy on cellular proliferation and collagen deposition in MC3T3-E1 and patellar tendon fibroblast populations.

Proliferative therapy, or prolotherapy, is a treatment for damaged connective tissues involving the injection of a solution (proliferant) which causes local cell death and triggers the body's wound healing cascade. Physicians vary in their use of this technique; it is employed for ligaments but has also been investigated for tissues such as cartilage. Physicians also vary in treatment regiments using different dosses of the proliferant. This study evaluates several proliferant dosages develop an optimal dosage that maximizes cell and collagen regeneration. This study also looks at cell and collagen regeneration in response to proliferant exposure outside of the healing cascade. MC3T3-E1 cells and patellar tendon fibroblasts were exposed to various amounts of the proliferant P2G and monitored over several weeks. The results showed an inverse relationship between proliferant concentration and cell viability and collagen production in MC3T3-E1 cells. Following exposure, cell populations experienced an initial decrease in cell number followed by increased proliferation. Trichrome staining over 4 weeks showed an increase in collagen production after proliferant exposure. However the cell numbers and amounts of collagen from the treated groups never surpassed those of the untreated groups, although collagen production was comparable in fibroblasts. The results of this basic study show that there is an effective proliferant dosage and point to a local response to the proliferant that increases cell proliferation and collagen production separate from the wound healing cascade. This local response may not be adequate for complete healing and assistance from the body's healing cascade may be required.

Radix Dipsaci does not improve tendon healing in a rat model of patellar tendon donor site injury.

OBJECTIVE: To explore whether Radix Dipsaci (RD) exhibits beneficial effects on tendon healing. METHODS: An attempt was made to explore the in vitro effects of a hot water extract of RD on gene expression of procollagen Type I (COL1A1), procollagen Type III (COL3A1) and decorin in cultured tendon fibroblasts, and its in vivo effects in a well-established rat model of patellar tendon donor site injury. RESULTS: It was found that gene expression of COL3A1 and decorin in cultured tendon fibroblasts was significantly increased by RD, but that COL1A1 was not affected. In vivo studies showed that RD increased blood vessels in the wound but did not significantly affect the expression of COL1A1, COL3A1 and decorin at day 14 post-injury. The ultimate tensile stress of the healing tendon was not significantly improved by either local injection or oral administration of hot water extract of RD (P > 0.05). CONCLUSION: The present findings imply that RD per se does not significantly improve tendon healing. Further investigation of RD in a herbal formula may be necessary to test its efficacy in tendon injuries.

Effect of hyperbaric oxygen therapy on patellar tendinopathy in a rabbit model.

BACKGROUND: Hyperbaric oxygen therapy is a method for augmenting oxygen availability to tissues. This study investigated the effect of hyperbaric oxygen therapy on the collagenase-induced tendinopathy in the rabbit patellar tendon. METHODS: In this study, 13 rabbits were treated by ultrasound-guided injection of 0.025 mL collagenase into the patellar tendon at the right knee, with the left knee serving as a control condition. The rabbits were randomly divided into two groups. After tendinopathy had been confirmed by histologic examination 3 weeks after treatment, hyperbaric oxygen therapy was initiated for group 1. The hyperbaric oxygen therapy involved 30 daily sessions of 2.5 ATA for 120 minutes starting 6 weeks after treatment. The rabbits in group 2 were put in normobaric room air. Both groups were killed 10 weeks after treatment. Histologic examinations as well as mechanical and biochemical tests were performed after the animals were killed. RESULTS: The ultimate tensile load in the tendon that had hyperbaric oxygen therapy was 34.8% greater than that in the control tendon 10 weeks after treatment (p < 0.05). Hydroxyproline concentrations increased 82.2% simultaneously in the tendons that had hyperbaric oxygen therapy, as compared with the concentrations in the control tendons (p < 0.05). However, no statistical difference was found between the two groups in terms of pyridinoline concentration at the 10th week (p > 0.05). The histologic examination demonstrated an increase in blastlike tenocytes in group 1, with more mature phenotype, more organized collagen matrix, absence of myxoid degeneration, and increased vascularity at the 10th week, as compared with the control knee. CONCLUSIONS: The results validate the effectiveness of hyperbaric oxygen therapy in the treatment of tendinopathy. Hyperbaric oxygen therapy may increase collagen synthesis and collagen cross-link formation during the early healing process.