Reliability and validity of 3D limb scanning for ankle-foot orthosis fitting.

Only 30 healthy, able-bodied adults took part, so none had the deformities, swelling, scars or standing difficulties that bring real patients to an AFO clinic. The scans captured the surface of the limb, not the bone underneath, and nobody compared a scan with a plaster cast of the same limb, so it is not known how the scanned shape compares with the method it might replace. The reliability of collecting the scan itself between different people holding the scanner was not tested. Only the software measurements taken from completed scans were compared between raters. One low-cost scanner in one clinic was studied, and the scanning procedure followed what one of the authors already does in practice. There is no agreed clinical range of acceptable measurement error, so the authors' judgement of what counts as close enough is not benchmarked against anything.

The authors state that none of them has a potential conflict of interest. No funding source is named anywhere in the paper, including in the section headed funding and conflicts of interest. The paper notes that the scanning software is already sold and used in clinics without established reliability or validity data, and the authors' practical recommendation about how much measurements can be expected to vary draws on the clinical experience of one of the authors as well as on the study data.

Do not take this as evidence that scanning improves AFO fitting or patient outcomes. The study measured limb dimensions on 30 healthy adults, never made or fitted an orthosis from the scans, and never compared a scanned device with a cast one.