## 2 Materials and Methods
Inclusion Criteria:  
* Age between 18 and 85 years
* Underwent lower limb orthopaedic surgery, including the following:
* \(\  
* Ability to walk with or without assistance
* Provision of informed consent
* Exclusion Criteria:
* Severe cognitive impairment
* Neurological conditions affecting gait
* Pre-existing walking disability
* Foot size incompatible with the pressure insole
* Refusal to participate  
The recruitment was conducted at the Rehabilitation Clinic in Novaggio and the Physiatry Department of San Carlo Hospital in Bordighera. The recruiting physicians and physiotherapists were aware of the study protocol. Participants were randomly assigned to the intervention or control group. The digital insole used for measuring plantar pressure was GeBiom [15], GP MobilData-Go-tec (v.7, 48149 Munster, Germany), and the pressure measurement system was GP MobilData wireless. The software divided the plantar surface into several regions to evaluate the foot's load. The sensory feedback incentivator was designed and created from preformed rubber insoles with protruding automatic buttons, which provided feedback and encouraged sensitivity to the load. Four buttons were placed per insole in a vertical line along the heel, with the first button 2.5 cm from the end of the insole and the other three buttons spaced 1.5 cm apart along the midline. Depending on the load, the starting insole or three materials of variable density (foam rubber, 6 mm neoprene, or 8 mm neoprene) were used to increase the patient's sensitivity to proprioceptive stimuli and impose increased load on the limb (Figure 2). Before clinical use, each insole was statically calibrated on a custom hydraulic press equipped with a 0-500 N load cell (accuracy \(\pm\)0.5 N). Three polyurethane-foam inserts of increasing hardness (35, 45, and 60 Shore A; thickness 6 mm) were available and selected according to the participant's body mass. The insole was pre-loaded in 10 N steps; the tactile dome was adjusted until it collapsed at 20% \(\pm\) 1% of the individual's body weight, representing our protocol's prescribed partial weight-bearing limit. The procedure was repeated thrice per insole, yielding a coefficient of variation < 4%. The insoles were calibrated to apply a specific load on the heel before the material reached zero height, and the buttons provided distinct tactile feedback. The complete insole was placed inside the patient's shoe to provide sensory feedback on the correct load. The sensory feedback incentivator was used in the treatment group's evaluation and treatment phases. The evaluation protocol included collecting demographic data, medical history, and conducting physical examinations such as the Numeric Rating Scale (NRS) and the 6-Minute Walking Test (6 MWT) [16; 17; 18; 19; 20]. The study design was quasi-experimental, where the treated group received treatment with an incentivator while the control group did not receive any treatment. The primary outcome measure of the study was the change in loaded weight (\(\Delta\) loaded weight), defined as the difference between the theoretical weight and the actual weight measured at two time points: T0 (before the start of treatment) and T1 (at the end of hospitalisation). Statistical analysis compared the treatment and control groups regarding their \(\Delta\) loaded weight at T0 and T1. Specifically, values at T0 and T1 were compared using parametric tests when normality was met, or non-parametric alternatives: the \(t\)-test (or Student's \(t\)-test). A non-parametric test, the Wilcoxon-Mann-Whitney test for paired data, was also performed for confirmation. The significance level for both tests was set at \(p\) < 0.05, meaning that results at the 95 th percentile were considered valid, resulting in 95% confidence that the differences between the groups were significant. SPSS(r) v19.0 and Excel 2019 were used for data analysis.