Robotics and knee replacements; benefits of tea, coffee

Medical Minutes

Newly discovered benefits of tea and coffee

Adding more tea and coffee drinking to your daily routine may reap some important hidden health benefits. Stroke and heart attack survivors can reduce multiple causes of death and prevent further cardiovascular events by drinking green tea, according to a new Japanese study. Researchers also found daily coffee consumption benefited heart attack survivors by lowering their risk of death after a heart attack and can prevent heart attacks or strokes in healthy individuals.

Previous research has examined the benefits of green tea and coffee on heart health in people without a history of cardiovascular disease or cancer. Researchers studied green tea and coffee consumption and all-cause mortality (meaning death from any cause) among persons with and without a previous stroke or heart attack.

“There is a strong need for scientific evidence on the lifestyles among survivors of stroke and heart attack, considering the rapidly aging population and the need to improve life expectancy following these cardiovascular events,” said study co-author Dr. Hiroyasu Iso, who is a professor of public health at Osaka University in Suita, Japan.

The researchers analyzed data from more than 46,000 participants between the ages 40 to 79 from the Japan Collaborative Cohort Study for Evaluation of Cancer Risk, which is a study conducted in 45 communities across Japan. Participants were asked to complete self-administered questionnaires that included information about demographics, lifestyle, medical history and diet. Researchers then analyzed the amount and frequency of green tea and coffee consumption.

When compared with participants who rarely drank green tea, stroke survivors who consumed at least seven cups of green tea daily lowered their risk of all-cause mortality by approximately 62%. Researchers did not observe a statistically significant association among participants without a history of stroke or heart attack. Heart attack survivors who drank one cup of coffee a day reduced their overall risk of death by approximately 22% when compared to those who did not regularly drink coffee.

People without a history of stroke or heart attack who consumed one or more cups of coffee a week had approximately a 14% lower risk of all-cause mortality compared to non-coffee drinkers. Most Americans drink black tea so there may be differences from those who regularly drink green tea.

“An important distinction to make is that in Japanese culture, green tea is generally prepared with water and without sugar. Additionally, coffee is prepared with water and occasionally milk and sugar,” said Dr. Iso. “The healthiest way to prepare these beverages is without an unnecessary amount of added sugars.”

Robotics for knee replacement surgery

In a career spanning more than two decades, orthopedic surgeon Dr. Geoffrey Westrich has seen numerous advances in joint replacement surgery that benefit patients. However, he thinks the promise of robotic-assisted knee replacement, which allows for an ultraprecise procedure, may be one of the most exciting new advances. A recent study by researchers in the United Kingdom found robotic-assisted total knee replacement was associated with decreased pain after surgery, improved early functional recovery and a shorter hospital stay.

Dr. Westrich, who specializes in knee and hip replacement, reached a milestone last year when he performed his 500th robotic-assisted knee replacement. He uses the MAKO robotic system, which is FDA-approved for both total and partial knee replacements.

“Joint replacement is highly successful in relieving arthritis pain and improving quality of life, and the robotic system allows us to really customize the procedure for each patient,” said Dr. Westrich. “The MAKO system allows for optimal alignment and positioning of the knee implant, as well as optimal ligament balancing, all critically important for the best outcome and long-term success of the surgery. Such precision could potentially lead to a longer-lasting knee replacement.”

Dr. Westrich says over the past few years he has seen more patients in their 40s and 50s with arthritis who are candidates for a knee replacement. The main concern for patients in this age group is that the implant may wear out over time. Although a knee replacement could last 20 years or even longer, it doesn’t last indefinitely. For younger individuals in particular, robotic-assisted surgery has made joint replacement an attractive option, as it could prolong the life of the implant, according to Dr. Westrich.

With a robotics approach, a CT scan is taken of the patient’s knee. The scan is then uploaded into the system software where a 3D model of the joint is created. The 3D model is used to plan and assist the surgeon in performing the joint replacement. In the operating room, the orthopedic surgeon controls a robotic arm that uses computer-guided mapping software, similar to GPS, integrated into the surgical instruments to position the implant in the knee joint.

The digital tracking system constantly monitors and updates the patient’s anatomy and enables the surgeon to make real-time adjustments to optimize implant placement, alignment, ligament balance and joint motion. This provides each patient with a personalized surgery tailored to his or her individual anatomy.

“With more accurate alignment and positioning, the implant should experience less wear and friction, and it could ultimately last longer,” said Dr. Westrich, who notes that studies will be needed to confirm this over the long term.

John Schieszer is an award-winning national journalist and radio and podcast broadcaster of The Medical Minute. He can be reached at

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John Schieszer is an award-winning national journalist and radio and podcast broadcaster of The Medical Minute.

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