Hormone therapy linked to knee ligament tear risk in midlife women
Women taking estrogen-containing hormone therapy had higher odds of knee ligament tears than matched controls, with an odds ratio of 1.26.
Researchers studied 384,582 women aged 40 to 55 to examine whether estrogen-containing hormone replacement therapy was linked to knee ligament tears. The retrospective observational cohort study used insurance claims from 2019 to 2023. Of the women included, 16,751 were taking hormone therapy. Researchers matched women exposed to supplemental estrogen with unexposed women and looked for subsequent tears of the anterior cruciate ligament, which helps stabilise the knee.
Women taking supplemental estrogen had higher odds of a tear than matched controls, with an odds ratio of 1.26. The analysis accounted for age, other medical conditions and whether women were approaching or had reached menopause.
Why it matters
Changing estrogen levels across women’s lives may relate to ligament injury risk. The researchers called for prospective studies to better characterise the relationship with hormone therapy.
Caveats
This observational study could not establish whether hormone therapy caused the injuries. It relied on insurance claims from women aged 40 to 55.
- Hormone replacement therapy
- Sex hormone signalling (oestrogen, androgen)
- Anterior cruciate ligament tear
- Comorbidity
- Humans
The paper
New England Baptist Hospital; Brigham and Women's Hospital
JB & JS Open Access, 11 Oct 2026
