Criterion-Related Validity of Knee Joint-Position-Sense Measurement Using Image Capture and Isokinetic Dynamometry

<jats:p><jats:italic><jats:bold>Context:</jats:bold></jats:italic> Clinicians require portable, valid, and cost-effective methods to monitor knee joint-position-sense (JPS) ability. <jats:italic><jats:bold>Objective:</jats:bold></jats:italic> To examine the criterion-related validity of image-capture JPS measures against an isokinetic-dynamometer (IKD) procedure. <jats:italic><jats:bold>Design:</jats:bold></jats:italic> Random crossover design providing a comparison of knee JPS measures from image capture and IKD procedures. <jats:italic><jats:bold>Participants:</jats:bold></jats:italic> 10 healthy participants, 5 female, age 28.0 ± 13.29 y, mass 60.3 ± 9.02 kg, height 1.65 ± 0.07 m, and 5 male, 29.6 ± 10.74 y, mass 73.6 ± 5.86 kg, height 1.75 ± 0.07 m. <jats:italic><jats:bold>Main Outcome Measures:</jats:bold></jats:italic> The dependent variables were absolute error scores (AES) provided by 2 knee directions (flexion and extension). The independent variables were the method (image capture and IKD). <jats:italic><jats:bold>Results:</jats:bold></jats:italic> There was no significant difference between clinical and IKD AED into knee-extension data (<jats:italic>P</jats:italic> = .263, <jats:italic>r</jats:italic> = 0.55). There was a significant difference between clinical and IKD AES into knee-flexion data (<jats:italic>P</jats:italic> = .016, <jats:italic>r</jats:italic> =.70). <jats:italic><jats:bold>Conclusions:</jats:bold></jats:italic> Analysis of photographic images to assess JPS measurements using knee flexion is valid against IKD techniques. However, photo-analysis measurements provided a lower error score using knee-extension data and thus may provide an optimal environment to produce maximal knee JPS acuity. Therefore, clinicians do not need expensive equipment to collect representative JPS ability.</jats:p>