“Effects only make sense if they are beneficial”

Coxa Train evaluation study

From Bauerfeind Life Magazin on 16.06.2021

Story Check Hannah Steingrebe from Karlsruhe Institute of Technology (KIT) is in charge of the study to evaluate the new CoxaTrain brace when worn by subjects suffering from osteoarthritis of the hip.

  • The study focuses on the effects of the CoxaTrain on gait as a key to successful treatment for patients.
  • The study design includes investigations regarding restrictions in walking ability, proprioception and everyday functioning.
  • In order to map complex biomechanics, precise measurement systems and models for calculating joint kinematics and dynamics as well as a joint angle reproduction test are used.

How does the Coxa Train change the dynamics and kinematics in the hip joint? Hannah Steingrebe, Movement Scientist and Study Director at Karlsruhe Institute of Technology (KIT), is examining the modified biomechanics in cases of osteoarthritis of the hip. This includes observing the influence of the new brace on gait.   

Hannah Steingrebe, Study Director at Karlsruhe Institute of Technology (KIT), Germany.

ife: What goal are you pursuing with your study?

Hannah Steingrebe: We’re interested in the subjects’ limitations with regard to walking ability, proprioception and everyday functioning. In addition, we want to uncover the changes or effects from using the Coxa Train, for example relating to gait. For this, we’re examining patients with clinically relevant osteoarthritis of the hip – with clear inclusion and exclusion criteria to ensure a homogeneous sample and a clearly defined study design. 

What do you know so far about gait – with and without braces?

Hannah Steingrebe: We know that osteoarthritis of the hip limits the range of motion, compared with healthy people. The leg cannot be sufficiently bent or extended, it doesn’t fully swing during walking. The duration of the swinging and standing phases is reduced because of the pain. To compensate for this, the pelvis permanently tilts up and to the side, with the known consequences for the SI joint region. Those affected will start to limp. Something that has surprised me was that there are only few braces for the hip, unlike for the knee. That’s why there aren’t many studies about the effect of braces on gait – and they feature only few biomechanical analyses and often small sample sizes. 

How does your study take account of the complex biomechanics associated with osteoarthritis?

Hannah Steingrebe: There are mechanoreceptors in many structures affected by osteoarthritis. In order to determine to what extent possibly impaired proprioception contributes to gait abnormalities, we try to find out the subjects’ proprioception using a joint angle reproduction test, for example. If I’m not aware of the exact position my joint is in, I won’t be able to control it effectively with my muscles. We will also assess findings relating to everyday activities, such as taking the stairs or going around corners while wearing the Coxa Train, while not only looking at the hip joint, but also considering its adjacent joints. Osteoarthritis isn’t an isolated process. That’s why we need several levels of examinations, precise measuring systems and current models for calculating joint kinematics and dynamics. 

And you need the right brace?

Hannah Steingrebe: That’s what we’re trying to find out. But I can tell you this much: we haven’t had any compliance problems during our testing phase.


No symptoms during everyday activities

Wolfgang Klein, electrical engineer, Nordic Walking enthusiast and test subject of the Coxa Train study conducted at KIT

life: You are suffering from osteoarthritis of the hip. How has your condition progressed?

Wolfgang Klein: For a long time, I have been able to control the osteoarthritis pain in my knees and fingers with diet and exercise. In early 2018, I suddenly started experiencing severe pain in my right hip. It radiated all the way into my leg, and I could hardly walk for a while. Physicians diagnosed me with grade-2 osteoarthritis of the hip. With physiotherapy and three weeks of rehabilitation, I stopped feeling pain at rest. One thing that has remained, though, is a slight feeling of pressure in the right side of my buttocks as soon as I walk longer distances. In 2019, Prof. Sell examined me for the study and diagnosed osteoarthritis on both hips, more severe on the right than the left, with pain radiating into the sacroiliac joints. 

What was wearing the Coxa Train like?

Wolfgang Klein: When the measurements were taken while wearing the Coxa Train, I didn’t have any problems with my right hip when walking, climbing stairs and going around corners. During the seven test days, I wore the brace for at least eight hours each day and again, didn’t have any problems with everyday activities. When walking and hiking, though, I still had that familiar feeling of pressure after about a kilometer or two. This may have been down to my posture to help relieve pain. I thought the fit and comfort of the Coxa Train were excellent. Putting it on and taking it off were also easy.

What’s your impression of the new brace?

Wolfgang Klein: In general, I can say that I like the Coxa Train for strenuous activities. I could also imagine that the feeling of pressure might disappear if I wore it on both sides.

Images: Bauerfeind, Langer, Udo Schönewald

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