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AAOS Now

Published 8/1/2014
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Amber Blake

Telemetric Implants Provide “Inside” Look at Impact of Shoes

What if something as simple as selecting the right footwear could improve the prognosis for individuals with knee osteoarthritis (OA)? Two members of the Orthopaedic Research Society (ORS)—Prof. Georg Bergmann and Prof. Georg Duda of the Julius Wolff Institut, Charité–Universitätsmedizin, in Berlin—are trying to determine whether picking the right shoe can make the difference between comfort and worsening joint pain.

Their ‘Loading and Movement’ team wants to learn what effect different footwear has on knee joint loading. The team has developed special instrumented implants for the hip, shoulder, knee, and spine. These implants are based on total joint replacement implants currently in wide clinical use. The implants have been modified to include sensors and a telemetry system. To date they have implanted nearly 50 patients with these devices.

These specialized instrumented implants enable the researchers to directly measure the forces inside the joint while the patient is performing various activities. In the past, these forces could only be estimated.

To date, nine patients with telemetered knee implants have been enrolled in the team’s OA knee study. The researchers began by measuring knee joint loading during activities of daily living, including walking, stair climbing, and sitting down. They then investigated the effects that different footwear had on the forces generated within the joint.

For example, patients who wore advanced running shoes shoed a reduction in maximum forces measured at the knee. However, when the patients wore dress shoes, the forces measured at the knee actually increased. Additional studies are needed to determine whether the pain relief patients felt was due to the reduction in maximum forces measured when wearing these shoes.

The team plans to share their data via the open access database OrthoLoad (www.orthoload.com). They are convinced that the results of their research will be valuable not only to patients with OA, but also to shoe designers, implant designers, orthopaedists, physical therapists, and athletes.

The ‘Loading and Movement’ team also includes Dr. Ines Kutzner, Verena Schwachmeyer, Dr. Alwina Bender, Dr. Friedmar Graichen, Mr. Philipp Damm, and Mr. Jörn Dymke.

Amber Blake is the ORS Communications Manager. She can be reached at blake@ors.org or 847-823-5770.

References

  1. Bergmann G, Bender A, Graichen F, et al: Standardized loads acting in knee implants. PLoS One 2014;9(1):e86035. doi: 10.1371/journal.pone.0086035. eCollection 2014.
  2. Kutzner I, Heinlein B, Graichen F, et al: Loading of the knee joint during activities of daily living measured in vivo in five subjects. J Biomech 2010;43(11):2164-2173. doi: 10.1016/j.jbiomech.2010.03.046.