# Effect of an Innovative Biofeedback Insole on Patient Rehabilitation after Total Knee Arthroplasty
## 3 Results  
No patients needed to quit the study or modify the rehabilitation protocol due to insole-related complications. No patients had post-surgical problems. The clinical outcomes were comparable to the ones obtained from the patients we habitually treat in our orthopedic department with the same surgical technique, surgeon, and rehabilitation program, although with wide interpersonal variability, as shown by the standard deviation (due to the small study cohort of 30 patients versus the 303 control patients). The patients' mean pre-operative NRS value was 6.71 \(\pm\) 1.94, which remained almost constant after 5 days post-op (6.08 \(\pm\) 1.93) (\(p\) = 0.301) but decreased significantly to 4.10 \(\pm\) 3.11 after 30 days (\(p\) = 0.043). The average post-operative standard KSS score was 53.33 \(\pm\) 6.44, while the functional KSS score was 65.42 \(\pm\) 23.11, a remarkable interpersonal difference (\(p\) = 0.047). At day 5 post-surgery, the standard KSS score decreased to 49.55 \(\pm\) 19.55 (not significantly, \(p\) = 0.241), while the functional score reduced significantly to 11.72 \(\pm\) 10.71 (\(p\) = 0.0001). This was still widely variable in relation to the functional starting conditions at time 0. At day 10 post-op, the patients' average KSS score was stable (50.73 \(\pm\) 11.71), while the functional score improved significantly to 45.55 \(\pm\) 9.40 (\(p\) = 0.0032). After skin suture removal and wound dressing renewal (from advanced to standard dressing) on day 14 post-op, standard KSS score rose to 63.00 \(\pm\) 15.03 (\(p\) = 0.0532) at day 15 and the functional KSS component to 49.09 \(\pm\) 11.36 (\(p\) = 0.011), while after a final control on day 30, the discharged patient cohort had means of 78.88 \(\pm\) 12.89 (\(p\) = 0.001) and 71.42 \(\pm\) 15.20, respectively. The WOMAC scores confirmed a similar pattern and increased from 45.69 \(\pm\) 15.96 pre-op to 51.37 \(\pm\) 15.05 on day 5, then significantly decreased definitively to 14.29 \(\pm\) 7.52 in the final evaluation on day 30 (\(p\) = 0.001). The Tinetti gait score showed that, after initial difficulty maintaining a correct debambulation pattern with respect to the recommended load range, all patients reached a normal gait according to direct therapist evaluation and Tinetti test scores. In fact, they started from a pre-operative mean value of 8.08 \(\pm\) 2.88, went to 5.08 \(\pm\) 1.88 on day 5, 6.50 \(\pm\) 1.57 on day 10, and 7.67 \(\pm\) 1.37 on day 15, and then had a definitive value of 9.43 \(\pm\) 1.90 (Table 1). In the first post-operative days, all patients found it impossible to meet the touch-down weight-bearing load, corresponding to a load of 10-20% bodyweight without walking alterations (flexed knee, ankle plantar flexion with forefoot footing) or gait pattern modifications from a continuous walking march to a stepping march (such as little jumps). Only four patients on the third day post-op could walk normally with a load between 30% and 50% of their bodyweight. Furthermore, we recorded that load beyond 80-90% of bodyweight was not detectable during dynamic gait. Patients behaved as though they were applying full load (i.e., 100% bodyweight). Only one patient did not correctly load because of a neurological quadriceps deficit resulting from a previous lumbar disc herniation.