Estradiol Supplementation and Rotator Cuff Repair

Injuries to the rotator cuff are among the most common musculoskeletal complaints and are increasing in incidence. Multiple studies have demonstrated that rotator cuff repair (RCR) improves outcomes for rotator cuff tears. Over 500,000 RCRs are performed in the US annually. When both surgical and non-operative treatment are included, rotator cuff injuries cost the United States over $5 billion dollars annually. After RCR, tendon healing fails to occur in \>20% of patients. Improving tendon healing is thus a critical barrier to success. The field has arrived at a consensus that improving tendon biology is the key to improving tendon healing. Our prior human and animal research demonstrates that estradiol deficiency contributes to rotator cuff injuries and poor outcomes after RCR and estradiol supplementation improves RCR healing and outcomes. With this study we propose to translate these promising and compelling findings into improved clinical care of patients with rotator cuff injuries. Estradiol deficiency can be treated with hormone therapy (HT), which is widely utilized, well-tolerated, inexpensive, and FDA approved. In this study, we will conduct a phase II study of the efficacy and feasibility of HT within the setting of RCR. We hypothesize that compliance and response rates will be high while adverse events will be infrequent and equally common with estradiol patches and placebo patches. We also hypothesize that outcomes and healing will be better in the HT group than the control group. To test these hypotheses, we will conduct a randomized, placebo-controlled, double-blinded clinical trial to measure recruitment and retention rates, compliance with treatment, response to treatment of serum hormone levels, estimated effect size for power calculations, and adverse events. Postoperatively, we will evaluate validated patient-reported outcomes and tendon healing and rotator cuff muscle volumes utilizing magnetic resonance imaging. If efficacy and tolerability are demonstrated, a future large, multi-center, randomized clinical trial will be warranted. We expect these data will support the use of estradiol as a promising approach to improved healing and outcomes, supporting a future, larger, well-powered, multi-centered randomized clinical trial with longer follow-up. Such a study could improve the treatment of people with rotator cuff injuries, thereby decreasing a source of significant disability. If our hypotheses are confirmed, it would shift the paradigm on the treatment of problems with tendons and their attachments to bone throughout the body.