The 2026 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS) took place from March 2 to March 6 in New Orleans. The event gathered thousands of musculoskeletal specialists to discuss the latest research on bone, joint, and surgical care. One study presented at the conference raised important concerns about the safety of testosterone replacement therapy for patients undergoing knee replacement surgery.
Researchers found that people who used testosterone therapy before total knee arthroplasty may face higher risks of infections, blood clots, and other serious complications. The findings add to growing scientific discussions about hormone therapy and its effects on surgical outcomes.
Testosterone replacement therapy, often called TRT, has become increasingly common in recent years. The hormone is naturally produced in the body and plays an important role in muscle growth, bone health, and sexual function. However, synthetic testosterone is widely prescribed to treat conditions such as low testosterone levels, menopause related symptoms, decreased libido, and muscle loss.
According to data cited during the conference, prescriptions for testosterone therapy increased dramatically from about 7.3 million in 2019 to more than 11 million in 2024. This rise has sparked interest among researchers who want to understand how hormone therapy affects patients who undergo major surgeries.
Orthopaedic surgeons are particularly interested because total knee replacement procedures continue to increase globally. In the United States alone, experts expect more than one million knee replacements each year by 2030.
Total knee arthroplasty, commonly known as knee replacement surgery, is a procedure used to treat severe joint damage caused by arthritis, injury, or degenerative disease. During the operation, surgeons replace damaged cartilage and bone with artificial components that restore joint movement and reduce pain.
While the procedure is considered highly effective, complications can occur. These may include infections, blood clots, implant instability, or the need for revision surgery. Identifying risk factors before surgery is essential for improving patient outcomes.
The study presented at the meeting analyzed medical records from 13,250 patients who underwent primary total knee arthroplasty. Researchers used a national electronic health record database to track health outcomes for up to five years after surgery.
The investigation was conducted by medical students Argen Omurzakov and Arsen M. Omurzakov, with senior author Brian Chalmers. The researchers examined whether patients who used testosterone in the 12 months before surgery experienced different outcomes compared to those who did not.
To ensure a fair comparison, the study used a statistical technique called propensity score matching. This method balanced patient characteristics such as age, sex, race, obesity, smoking status, cardiovascular disease, diabetes, kidney disease, and other health factors.
The result was one of the largest analyses to date exploring the connection between testosterone therapy and knee replacement complications. Notably, the research also included a near equal number of male and female patients.
The study found that testosterone users experienced higher rates of several serious complications after surgery.
Within the first three months after surgery, testosterone therapy users showed increased rates of:
For example, pulmonary embolism occurred in 1.6 percent of testosterone users compared with 1.2 percent of non users.
After one year, additional complications were more common among testosterone users. These included:
Researchers also observed increased problems involving the knee implant itself.
Patients who used testosterone therapy were more likely to experience complications around the prosthetic joint, including:
These risks remained elevated even five years after the initial procedure.
While the study does not prove that testosterone directly causes complications, researchers suggested several biological mechanisms that may explain the association.
First, testosterone therapy has been linked in previous research to higher risk of blood clot formation. Blood clots can lead to conditions such as deep vein thrombosis and pulmonary embolism.
Second, testosterone may influence the way bones remodel and integrate with surgical implants. Successful joint replacement requires a process called osseointegration, where surrounding bone tissue grows around the artificial implant. If this process is disrupted, the implant may loosen over time.
Third, hormones can affect the immune system. Changes in immune function may alter how the body responds to infections and how tissues heal after surgery.
The study authors also noted that testosterone could influence the body's microbiome, which plays a role in immune responses and healing processes.
Another significant aspect of the research was the inclusion of women in the study population. Women account for approximately 60 percent of knee replacement surgeries in the United States, and that number is expected to grow.
Testosterone therapy is sometimes used by women to address menopause symptoms, improve sexual function, or increase muscle mass. Because earlier studies focused mainly on men, the new data provides a broader understanding of how hormone therapy may affect both sexes.
The findings suggest that doctors may need to evaluate testosterone therapy more carefully before scheduling knee replacement surgery. Patients using hormone treatments might benefit from additional screening or monitoring.
However, researchers emphasized that further studies are needed before making definitive clinical recommendations. The results highlight an association between testosterone use and complications, but they do not establish direct causation.
Patients should always consult their healthcare providers before starting or stopping any hormone therapy, particularly if they are planning to undergo surgery.
This study builds on earlier work that examined testosterone therapy in patients undergoing shoulder replacement surgery. As more people use hormone treatments, orthopaedic researchers are increasingly exploring how these therapies influence surgical outcomes.
Understanding these relationships can help surgeons improve patient selection, reduce complication risks, and optimize recovery after joint replacement procedures.
The research presented at the 2026 orthopaedic conference demonstrates the importance of large scale data analysis in identifying potential risk factors that might otherwise go unnoticed.
The 2026 meeting of the American Academy of Orthopaedic Surgeons highlighted critical new findings about testosterone therapy and knee replacement surgery. According to the presented research, patients who use testosterone within a year before total knee arthroplasty may face higher risks of infections, blood clots, implant complications, and revision surgery.
Although further investigation is required to confirm the biological mechanisms involved, the study provides valuable insight for both patients and healthcare providers. As hormone therapy becomes more common worldwide, understanding its effects on surgical outcomes will remain a priority for orthopaedic research.
This article is for informational and educational purposes only. It does not provide medical advice, diagnosis, or treatment recommendations. Readers should consult qualified healthcare professionals for personalized medical guidance regarding hormone therapy, knee replacement surgery, or any related health concerns.
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