Determining the success of clinical outcomes for thumb immobilization compared to no thumb immobilization in adult non-displaced, non-surgically managed scaphoid fractures: A systematic review.

Only six studies, and the people in them were very different from one another: adults with a fresh scaphoid fracture, healthy volunteers and cadaver forearms were all analysed together. Half the included studies did not involve a single person living with a fracture. Two put casts on healthy volunteers for 30 minutes and one used cadaver forearms, so their results say little about recovery from a real injury. Two of the six studies were rated limited quality, with no reporting of who was blinded, how participants were allocated to a group, or how outcomes were measured. The studies used different casts, different outcome measures and no shared definition of when a fracture counts as united, so the results could not be pooled and direct comparison is difficult. All the studies came from the UK, the USA or Japan, and everyone was 16 or older with a stable fracture. People with displaced or open fractures, multiple injuries or surgery were excluded, so this says nothing about them. All six studies used casts rather than removable splints, which is what many therapists actually provide.

The authors declared no potential conflicts of interest and stated that they received no financial support for the research, authorship or publication of the article.

Do not read this as proof that leaving the thumb out of a cast improves healing. Most of the comparisons found no significant difference between the two casts. The one clear hand-function advantage came from healthy volunteers who wore the cast for 30 minutes, not from people with a fracture that was healing, and two of the six studies were rated limited quality.