Both active and inactive males in there 4th and 5th decade have increased risk of Achilles tendon ruptures. The literature in general is full of musculoskeletal injuries like this, that appear to have clear gender preferences, but offer biological or pathophysiological explanations have offered explanations for these documented observations.
In males conditions that accompany the aging process such as decreased muscle mass, body fat, osteoporosis, metabolism and libido are associated with declines in serum testosterone. Although the effect of estrogen levels on tendon size and architecture has been studied in females, the correlation of testosterone levels on tendons in males is unknown.
Serum free testosterone (FT) and total testosterone (TT) level were drawn in males with Achilles tendon rupture at time of injury and compared to healthy normal historical data as a means of evaluating if decreased sex hormone level is a risk factor for tendon injury. We hypothesized that males diagnosed with Achilles tendon ruptures will have lower FT and TT levels than age-matched normal levels in the literature.
The FT and TT levels of these injured men were directly compared to age matched historical data. The mean FT and TT levels, and 95% confidence intervals were then calculate from historical data and used to determine statistical significance.
15 males age 24-33, sixteen age 34-43, nine age 44-53 and two males age 54-63 had serum FT and TT levels recorded as part of their clinical care. All Males between 25-61 had statistically significant lower FT and TT levels compared to normal controls in the literature. Those in the 4th decade had largest difference in means compared to historical data.
All 42 males in our study were randomly and consecutively recruited as they presented for clinical management of their Achilles tendon injury. They all were found to have lower serum FT and TT that age-matched controls. Our findings suggest that low sex hormone levels in males maybe associated with the increased risk of Achilles tendon rupture. We are currently investigating the impact of low testosterone on the skeletal system in animal models.