Evaluation of a protocol on the basis of physical therapy and biomechanics for rating the indication of microprocessor-controlled prosthetic joint systems of the lower limb

Status:

completed 05/2018

Aims:

The latest developments in prosthetic knee joints are microprocessor-controlled fitting parts that offer features such as stance phase locking and swing phase control. However, these advancements also lead to a considerable increase in the cost of prosthesis fitting. The medical necessity for such an aid only exists if the compensation of disability cannot be achieved to the same extent with a less expensive and equally suitable aid. It is often difficult to determine necessity because there are no objective test procedures for this. The aim of an indication test is to determine the "functional gain" achieved by a new prosthetic restoration. The functional gain consists of seven criteria: safety, relief, divided attention, speed, effort, gait pattern, walking aid. A generalized test procedure should be developed which can be used for indication. This should be objective, cost-effective and feasible in every center of excellence.

Activities/Methods:

58 patients (18-75 years) were recruited from March 2014 to March 2017. In the course of a one-week in-patient stay, the subjects underwent complex functional testing in physiotherapy and gait analysis to determine kinematics (Vicon, Oxford) and kinetics (force plate, AMTI) with the existing prosthesis fitting part. A 4-day gait school and a final re-testing in physiotherapy and the gait laboratory were held after the new prosthetic joint was adapted. A subjective assessment of the patient was also collected and a final medical examination carried out. The parameters within each and between both subjective physiotherapy values and objective instrumental movement analysis data were evaluated, in order to develop and test a physiotherapeutic and generally valid test procedure for assessing gait pattern after prosthesis treatment. The direct comparison of the parameters was carried out using a correlation analysis. The differences between the two measurements could be calculated for nominal scaled data using a univariate ANOVA. A correlation was calculated for metric data sets.

Results:

Comparison of the evaluation of several parameters, summarized in individual core criteria, showed a lack of agreement between the measurement results. This switched to a direct comparison of individual parameters. Within measurement values, significant large effect strengths were measured in gait speed (r= -0.416 to -0.767), and significant mean effect strengths were measured in step length difference (0.368), Duchenne (0.339), upper body fluctuation (0.307) and vaulting (0.494) on flat terrain. Between both measurement dates, the change was evaluated equally only in step length difference on the plane (p = 0.001) and speed on uneven ground (p = 0.000 to 0.009).

Discussion: The results showed that the measurements in the gait laboratory were insufficiently consistent with the physiotherapy observations, however, complex movement sequences could not be measured in the gait analysis. The assessment of the seven criteria of functional gain should be made, considering of gait analysis data after several days of gait training, by a physician and a therapiest experienced in dealing with amputees. The seven test criteria and movement sequences performed in physiotherapeutic testing make sense and should be maintained.

Last Update: