Validity and Reliability of a Laser Pointer Device to Assess Knee Proprioception in Healthy and Active Individuals.
Héctor González-Pons, Elena Muñoz-Gómez, Sara Mollà-Casanova and 3 others
A laser pointer device showed acceptable consistency for measuring knee proprioception at 15° closed-chain and 50° open-chain flexion, but not at the other two positions.
Tested in 25 healthy adults only.
Key findings
1The laser pointer device correlated moderately with a digital inclinometer in all four knee positions tested, with the strongest agreement at 50° open-chain flexion (r = 0.824) and the weakest at 50° closed-chain (r = 0.404).
2Reliability was acceptable in only two of four positions: 50° open-chain (inter-rater ICC 0.54, intra-rater ICC 0.65) and 15° closed-chain (inter-rater ICC 0.62, intra-rater ICC 0.58). The remaining two positions showed no meaningful reliability (ICC 0.10 to 0.24).
3All participants were healthy and active. The authors note that people with knee pathology may be unable to perform the single-leg squat required for the closed-chain test, and the sample of 25 may have reduced statistical power.
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What it does not show
Only healthy, active adults were tested. The authors note that people with knee pathology may be unable to perform the single-leg squat needed for the closed-chain test, so the device has not been validated in the population that most needs proprioception assessment. Sample size was 25, which the authors acknowledge may have reduced statistical power and widened the confidence intervals around the reliability and validity estimates. Intra-rater reliability was assessed for only one of the two evaluators. The reference standard was a digital inclinometer with 0.3° precision, not a laboratory gold-standard system such as an isokinetic dynamometer or 3D motion capture. Only two knee flexion angles (15° and 50°) were tested in each chain, so the device's performance at other angles is unknown.
Declared interests
Funded by the Spanish Government (PID2021-125694OB-I00, co-financed by EU FEDER), the Generalitat Valenciana (CIAICO/2021/215 and CIAICO/2024/107), and the Ministry of Science, Innovation and Universities (FPU23/01464). The authors declare no conflicts of interest. No commercial sponsor designed the study or wrote the manuscript.
The easy way to misread this
Do not read this as a general validation of the laser pointer for knee proprioception. It was reliable in only two of the four positions tested, and every participant was healthy and active. The authors themselves say people with knee pathology may not be able to perform the required movements, so there is no evidence here that the device works in the patients who most need a proprioception screen.
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 →