Reliability of a portable device for measuring lower-limb muscle strength in patients who underwent total knee arthroplasty.
Kenta Kuwahara, Yuta Makino, Toshihiro Kato and 2 others
PMID 41328280WHAT IT FOUND
In 64 patients after total knee arthroplasty, a portable quadriceps strength device gave consistent readings within each therapist and between two therapists.
Use the best of three trials rather than the average.
Key findings
01In 64 patients after total knee arthroplasty, the device showed agreement values of 0.903 for Tester A and 0.889 for Tester B within each tester.
02Agreement between testers was 0.783 for the mean of three measurements and 0.818 for the maximum of three measurements.
03The maximum reading had error values of 0.132 kgf/kg and 35.1%, while the mean reading had error values of 0.138 kgf/kg and 39.6%.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study was done at one regional Japanese hospital, so it may not show how the device performs in other settings or patient groups. It did not test repeated measurements by the same tester on separate occasions, so the error for one tester over time is unknown. Only two experienced male physical therapists were tested, so tester experience, body size, or measurement skill may matter. Measurements were taken about 1 month after surgery, so reliability early after surgery or long after surgery is not shown.
Declared interests
No funding was received for this study, and the authors declared no conflicts of interest.
The easy way to misread this
Do not read this as proof that the device detects real strength change. The study tested agreement in 64 patients about 1 month after surgery, with two experienced male therapists. The smallest detectable change was 35.1% of the value when the maximum reading was used.
Summarised by AI from the full paper, without a clinician reviewing it. Check it against the source before it changes what you do. Read it on PubMed →