Correction: Geiger et al. Monitoring of Hip Joint Forces and Physical Activity After Total Hip Replacement by an Integrated Piezoelectric Element. Technologies 2024, 12, 51

The authors wish to make the following corrections to their paper [1]:

In the original publication there was an error in the average percentage deviation across activities for the activity-independent and activity-dependent determination of actual maximum hip joint force. The average percentage deviation across activities for the activity-independent determination should be 0.87 ± 7.29% instead of 2.49 ± 13.16% and for the activity-dependent determination should be 0.18 ± 3.96% instead of 0.87 ± 7.28%. This results in the following corrections.

• Abstract:

“The maximum forces on the THR could be determined via activity-independent determinations with a deviation of 0.87 ± 7.29% and activity-dependent calculation with 0.18 ± 3.96% deviation.”

2.

Section 3.1. Maximum Hip Joint Reaction Forces:

“The absolute and percentage deviations of the calculated maxima from the actual maximum values applied using the second-degree polynomial regression equation are shown in Figure 4. The maxima of the activities jogging, stance, sit down, and knee bend were generally estimated to be lower, while those of the remaining activities were estimated to be higher than the actual force. The average percentage deviation is 0.87 ± 7.29%.”

“Figure 5 shows the absolute and percentage deviations between the maximum forces calculated by linear regression and the actual maximum forces applied to the THR. The median here is close to zero for almost all activities, both for the absolute and percentage deviations, and lower for all activities than when all maxima are calculated using second-degree regression. Furthermore, the 25th and 75th percentiles of all activities are below ±4%; for the activities of jogging, stairs up, and stairs down, they are even below ±1.5%. The total mean and standard deviation are 0.18 ± 3.96%.”

3.

Section 4. Discussion:

“The maximum forces acting on the THR calculated using a second-degree polynomial regression equation show deviations of 0.87 ± 7.29% of the actual maximum forces. This relatively high deviation may be due to the previously described factors influencing the level and rate of the applied hip joint forces on the transmission and the calculation of the forces on the piezo element.”

“A calculation of the maximum forces using the linear, activity-dependent regression shows a clear minimization of the deviation from the actual maximum forces for all activities. The average deviation was 0.18 ± 3.96%.”

The authors apologize for any inconvenience caused and state that the scientific conclusions are unaffected. The average percentage deviation across all activities for the activity-dependent and activity-independent determination of the actual maximum hip joint force using the voltage output of a piezoelectric element integrated into a total hip replacement stem is lower after the correction, which further reinforces the potential for using the piezoelectric element as a sensor for hip joint forces.

This correction was approved by the Academic Editor. The original publication has also been updated.