Immersive visualization of movement in patients with hemophilic ankle arthropathy. Multicenter, single-blind, randomized clinical trial.

Patients were not blinded to their group assignment, which could introduce bias in self-reported pain scores. The use of analgesic medication was not monitored during the study, so differences in pain relief could be partly due to unrecorded drug use. The intervention used patients' own smartphones with varying screen sizes and operating systems, rather than a standardized headset, which may affect the consistency of the immersive experience. The study population was restricted to those with severe hemophilia and significant joint damage, so results may not generalize to milder phenotypes.

The work was financially supported by Roche Farma, S.A., a company that manufactures hemophilia treatments. The authors declared no other conflicts of interest and stated that the funder had no role in the design, conduct, or reporting of the study.

Do not assume the intervention caused the pain reduction through physical movement or muscle strengthening. The patients only watched a video and did not move their ankles or imagine the movement, so the effect is likely neurological or attentional rather than musculoskeletal.