Chronic tendon pain--implications for treatment: an update.

Area of Science:

• Orthopedics
• Pain Medicine
• Regenerative Medicine

Background:

• Chronic Achilles tendinosis is associated with high concentrations of the neurotransmitter glutamate.
• The role of glutamate in tendinosis pain requires further investigation.
• Neovascularization is observed in painful tendinosis tendons.

Purpose of the Study:

• To evaluate the importance of intra-tendinous glutamate concentrations in chronic Achilles tendinosis pain.
• To investigate the association between neovascularization and pain in chronic Achilles tendinosis.
• To assess the efficacy of sclerosing treatment for tendinosis-related pain.

Main Methods:

• Microdialysis was used to measure glutamate levels before and after treatment.
• Ultrasonography and color Doppler techniques identified neovascularization.
• A pilot study involved injecting Polidocanol to destroy neovascularization.
• Immunohistochemical analysis of biopsies and diagnostic injections were performed.

Main Results:

• No significant difference in glutamate levels was found in patients who became pain-free after treatment.
• Neovascularization was present in painful tendinosis tendons but not in normal tendons.
• Sclerosing treatment of neovascularization resulted in pain relief in 8/10 patients.
• Biopsies revealed nerve structures near blood vessels in the affected area.
• Local anesthesia temporarily relieved pain in all patients.

Conclusions:

• Glutamate levels are not the primary cause of pain in chronic Achilles tendinosis.
• Neovascularization, along with associated nerves, is likely responsible for tendinosis pain.
• Locally administered sclerosing agents like Polidocanol show potential for curing chronic Achilles tendinosis pain.