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Randomized Controlled Trial
. 2025 Jan 30;25(3):825.
doi: 10.3390/s25030825.

Biofeedback's Effect on Orthosis Use: Insights from Continuous Six-Week Monitoring of Ankle Fracture Loading

Tobias Peter Merkle  1 , Nina Hofmann  1 , Christian Knop  1 , Tomas Da Silva  1
Affiliations
Randomized Controlled Trial

Biofeedback's Effect on Orthosis Use: Insights from Continuous Six-Week Monitoring of Ankle Fracture Loading

Tobias Peter Merkle et al. Sensors (Basel). .

Abstract

There is limited understanding of how well patients adhere to postoperative instructions following ankle surgery, particularly in outpatient settings regarding partial weight bearing (15-30 kg) and orthosis use. This study aims to assess orthosis compliance and load frequency over six weeks post-surgery using pressure-sensitive insoles, while also evaluating the effectiveness of continuous biofeedback. A total of 84 patients with isolated ankle fractures were enrolled. All participants were instructed to maintain partial weight bearing of 15-30 kg for six weeks with a lower leg orthosis equipped with insoles that continuously recorded daily step counts and maximum loads. In a prospective randomized design, the control group received no biofeedback, while the intervention group received audiovisual feedback whenever loads exceeded 20 kg. Adherence to the prescribed partial weight bearing and orthosis use was low in both groups, with only 10% of the control group wearing the orthosis by week three and overload occurring as early as week one. However, the implementation of biofeedback resulted in significant improvements in orthosis utilization (57.4% vs. 29.1%) and adherence to prescribed loading. The implementation of continuous biofeedback significantly enhanced adherence to prescribed loading and orthosis usage, highlighting its critical role in postoperative rehabilitation for ankle fractures.

Keywords: ankle fracture rehabilitation; biofeedback; continuous monitoring; orthosis compliance.

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Conflict of interest statement

The authors declare no conflicts of interest.

Figures

Figure 1
Figure 1
Flowchart of the study. The study ultimately included 34 patients in the control group and 42 patients in the intervention group.
Figure 2
Figure 2
A patient walking up a staircase using underarm crutches with the applied orthosis. The orthosis emits a clearly audible warning signal in addition to a red light.
Figure 3
Figure 3
Descriptive statistics of participant retention for the intervention and control groups, stratified by week. The accompanying table shows the percentage of orthoses worn per week, divided between the two groups. Paired comparisons between the intervention and control groups were conducted for each of the six weeks. The Wilcoxon signed-rank test was employed, as normal distribution was not assumed.
Figure 4
Figure 4
The loads for both groups per week. On the left side, we see the intervention group, and on the right side, the control group. Weeks 3–6 are shaded out in the control group, as no valid conclusions could be drawn due to the low wear duration in this group.
Figure 5
Figure 5
The percentage share of steps in the three load zones in both groups. Again, we have grayed out weeks 3–6 in the control group, as there were too few measurements to make a valid statement.
Figure 6
Figure 6
This figure presents descriptive statistics of pain perception for the intervention and control groups, separated by week. Postoperative pain levels were measured using the numeric rating scale (NRS). The data are presented as means and standard deviations. The Wilcoxon signed-rank test was used, as normal distribution of the data was not assumed.
Figure 7
Figure 7
The results of the Spearman’s rank correlation test used to determine correlations between pain sensations and the duration of orthosis wear.
See this image and copyright information in PMC

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