Unveiling the hidden dynamics: patellar support tissue alterations in post-stroke rehabilitation.

Cross-sectional design: patients with different disease durations were compared to each other, so the 'temporal' pattern is an inference from between-group differences, not a tracked change in the same person over time. The authors state this explicitly. No healthy control group. The unaffected leg was used as the within-person reference, but the authors acknowledge that bilateral degenerative changes have been documented in post-stroke patients, so the 'unaffected' side may not represent true normal anatomy. The 60-day split point was chosen after examining the data (the authors describe it as arising from a prior examination of thickness and grayscale before the full analysis), which introduces a post-hoc element. The 'vertical power' and 'horizontal power' indices are explicitly described as exploratory, unvalidated, and not yet standardised biomechanical measures. Ultrasound was used rather than MRI; the authors note it may carry a higher risk of error for tendons and supporting ligaments. Tissue thickness and grayscale were measured, not tissue strength; the causal link between the two is acknowledged as unproven. Ischaemic and haemorrhagic strokes were not analysed separately, despite potentially different recovery trajectories. The age range of 30–80 years is broad and may introduce age-related degeneration bias. Single centre, single country, 70 patients; generalisability is limited.

Funded by the Yunnan Revitalization Talent Support Program (XDYC-MY-2022-0033) and the Education Department of Yunnan Province (2024J0350). No industry sponsor, no device or drug manufacturer involvement declared.

Do not read the 60-day split as proof that a patient's knee tissues will change in a predictable direction at two months post-stroke. The comparison was between two different groups of people (those who happened to be at 60 days or less versus those beyond), not a before-and-after measurement in the same individuals. The authors state plainly that the study cannot draw conclusions about longitudinal progression in individual patients, and the proposed rehabilitation strategies are labelled exploratory hypotheses, not evidence-based guidelines.