- Design
- randomised pilot study with instrumented crutch tips in both arms and feedback enabled in one
- Population
- 20 patients prescribed partial weight-bearing after lower extremity fracture surgery, 10 per arm
- Primary outcome
- percentage of steps within 10% of the prescribed weight-bearing target
- Effect
- 73.6% with feedback against 21.1% without (P<0.01); System Usability Scale 84.25; no device-related complications
Twenty patients with lower limb fractures prescribed partial weight-bearing were randomised to crutch tips that gave real-time feedback on loading, or to identical crutch tips with the notifications switched off - so both groups had their loading recorded and only one group knew it. Compliance was defined as the percentage of steps falling within 10% of the prescribed target.
The feedback group kept to target on 73.6% of steps; the control group on 21.1% (P<0.01). Usability scored 84.25 on the System Usability Scale, which is in the excellent range, and there were no device-related complications. Satisfaction assessed by video interview was high.
Twenty patients is a pilot and the effect size should not be quoted precisely; the trial also cannot show that better adherence produced better healing, which is the outcome anyone actually cares about. But the control arm figure is the finding, and it does not depend on the device at all. Patients given a standard partial weight-bearing instruction, with standard teaching, complied on one step in five. Every fixation decision that rests on a patient protecting a limb for six weeks rests on that number. Whether the answer is a feedback device - which has a cost, and is not available in most Indian settings - or better teaching and repeated demonstration, the problem is now measured rather than assumed.
- Assume partial weight-bearing instructions are largely not followed unless something reinforces them
- Where a construct genuinely depends on protected loading, consider whether a different fixation choice would be safer than relying on adherence
- Use demonstration and re-demonstration as the low-cost intervention; feedback devices are not widely available
- Do not quote the 73.6% figure as an expected result - this is a 20-patient pilot
- Note that adherence, not healing, was the outcome; no clinical benefit has been shown
Why it matters
It measures, rather than assumes, the adherence that a large part of fracture management silently depends on.
Don't overread it
A 20-patient pilot measuring adherence only - no fracture healing, alignment or functional outcomes were assessed.
The statistics, in plain English
With ten patients per arm, the gap between 73.6% and 21.1% is large enough to be convincing in direction while the precise figures will not replicate - a pilot of this size gives a signal, not an estimate. The design deserves credit: both arms wore the measuring device and only one received feedback, so the control figure is measured behaviour rather than self-report, which is what makes it believable. The missing outcome is healing: adherence is a process measure, and no link to union or loss of position was tested.
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