February 20, 2019

Good Morning,

Today, I have a great article about the improvements and durability of hip and knee replacements. It's amazing how they have advanced over time!

Learn about this and more interesting stories from the scientific community in today's issue.

Until Next Time,
Erin

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*-- Hip and knee replacements show high durability, study shows --*

Most hip replacements last well after the surgery was performed, a new study says.

About six in 10 hip replacements performed 25 years ago have remained in place, according to a new study published Thursday in The Lancet. Additionally, 89 percent were still in place 15 years later and 70 percent lasted 20 years.

"Over two million hip and knee replacements have been performed in the UK since 2003 and patients often ask clinicians how long their hip or knee replacement will last, but until now, we have not had a generalizable answer," Jonathan Evans, a researcher at the Bristol Medical School and study lead author, said in a news release.

This new research also shows that durability comes along with knee replacement surgery. About 90 percent of total knee replacements and 72 percent of unicondylar knee replacements last for roughly 20 years.

"Previous studies have been based on much smaller samples. At best, the NHS has only been able to say how long replacements are designed to last, rather than referring to actual evidence from multiple patients' experiences of joint replacement surgery," Evans said. "Given the improvement in technology and techniques in the last 25 years, we expect that hip or knee replacements put in today may last even longer."

Hip replacements, however, can come with some risk. A recent study found that 14 percent of hip surgeries end with an infection.

The National Institutes of Health estimate that one million total joint arthroplasty surgeries occur each year. They project that number to shoot up to nearly four million by 2030.

One study also shows that getting text messages boosts the moods of people who recently received hip replacements.

"This information is incredibly useful to me as a researcher to understand the life course of people undergoing joint replacement," said Michael Whitehouse, Reader in Trauma and Orthopaedics at the Bristol Medical School and study senior co-author. "Additionally, as a clinician, it gives me the information that I need, to give my patients a reliable and evidence-based answer to one of the questions they consider most important when deciding whether it is the right time for them to have a joint replacement."

*-- Geologists use tide gauge measurements to track tremors --*

Geologists have developed a method to track tremors using water level measurements recorded by tide gauges.

Today, scientists use GPS to track the elevation changes caused by episodic tremors and slow slip earthquakes, but the Global Positioning System has only been in operation since 1995. Researchers have been tracking water levels for much longer.

The new analysis technique -- detailed this week in the journal Bulletin of the Seismological Society of America -- could allow researchers to probe pre-GPS tide gauge data for unique seismic patterns called episodic tremor and slip events, or ETS.

"The part of the fault that is slipping during [an episodic tremor and slip] can't be totally locked, because it is experiencing periodic slow earthquakes, so that area sort of defines the edge of what could theoretically slip, producing destructive seismic waves, during a megathrust earthquake," lead author Sequoia Alba of the University of Oregon said in a news release.

Episodic tremor and slip patters can help scientists better understand the nature of large, tension-filled fault lines and, perhaps, better gauge the risk of a large earthquake.

"How destructive [a megathrust earthquake] would be to the people and cities of the Pacific Northwest will depend largely on where on the interface the earthquake happens -- in this case, how far inland it happens -- because the intensity of shaking is dependent on distance," Alba said. "If the part of the fault that slips during an earthquake is beneath the ocean floor miles out to sea, for example, that will be less damaging to cities like Portland and Seattle than if the slip patch is directly beneath those cities."

Alba and her colleagues surveyed water level data collected by tide gauges along the Pacific Northwest Coast -- gauges anchored in the Juan de Fuca Strait and Puget Sound, as well as in the coastal waters of Port Angeles, Port Townsend, Neah Bay and Seattle.

As land uplifts, the water levels should appear to drop. Scientists built a model to identify uplift patterns caused by episodic tremors and slow slip earthquakes. Researchers compared with GPS data collected between 1995 and 2011, to see if their efforts were successful.

While scientists weren't able to use the water level data to identify individual episodic tremor and slip events, they were able to locate groups of episodic tremor and slip events.

Oddly, scientists weren't able to locate similar episodic tremor and slip signatures among tide gauge data between 1980 to 1995.

"Our results are too preliminary to characterize how ETS changes, or if ETS was present during the pre-GPS era, but there does appear to have been a change," scientist wrote in their paper.