Evaluation of left-right difference of impulse in impact forces at stance phase: comparison of measurements on flat land and stairs.

The study included only 8 healthy subjects and 1 patient, so it cannot support clinical decisions. The stair age pattern was reported for healthy subjects aged 49 and older, but the paper did not show that this applies to patients or to ordinary clinical stair walking. The patient with KL grade 2 did not follow the stair age curve, and the authors say they cannot be certain because there was only one patient. The paper reports impulse measurements, not patient outcomes. The stair task used a 1 cm rise that subjects were not told about, so the result may reflect a disturbance protocol rather than usual stair use. The flat-ground measure did not track age, body weight, height, or BMI, so it did not show the expected risk pattern.

The authors declared no conflict of interest.

Do not treat the stair imbalance pattern as a validated clinical test. The age association came from 8 healthy people and 1 patient, and the patient did not follow the curve, so it cannot diagnose knee OA or guide treatment.