Back

A Tale of Time in Tendon Healing

Swedish scientists report a decrease in strength of healing tendons when patients use COX-2 inhibitors during the early post-operative period. The "patients" in this study were rats divided into groups. All rats had a small piece of the Achilles tendon surgically removed.

Some rats were given saline injections for the first five days after surgery. Others got parecoxib, a COX-2 inhibitor. COX-2 inhibitors are used to reduce inflammation without causing bleeding stomach ulcers. The researchers also studied two other groups of rats. Saline or parecoxib were used from day six until day 14. In a rat's short life, this is equal to giving them COX-2 inhibitors during the later phase of healing.

Studies show that inflammation in the first few days after trauma is good. It seems to help normal repair of damaged tissue. Later in the healing process, the tissues start to remodel and form cross-links needed for strength. The authors of this study say that inflammation should be stopped in this remodeling phase. COX-2 inhibitors taken in the later phase may be helpful.

These researchers aren't sure how to translate this information from rats to humans. Rats live a much shorter time compared to humans. A week in the life of a rat is equal to a month in humans. It's unclear if the phases of inflammation, healing, and remodeling are the same in rats and humans.

It may be necessary to avoid COX-2 inhibitors during the first 10 days of tendon healing in humans. More study is needed to find out how these drugs affect humans in the early period after tendon injury.

References: Olena Virchenko, MD, et al. Parecoxib Impairs Early Tendon Repair but Improves Later Remodeling. In The American Journal of Sports Medicine. October/November 2004. Vol. 32. No. 7. Pp. 1743-1747.

Back