gms | German Medical Science

Objectives: The aim of our study was to evaluate a parameter considering femorotibial translation in osteoarthritic knees in three-dimensional (3D) gait analysis to improve diagnosis and understanding of the pathophysiology.

Methods: All tests were performed using an optical system(OptiTrak, Natural Point, USA) with a capture rate of 100 Hz and reflective markers. The range of femorotibial translation was measured during the loading response [1]. The offset corresponded to the translation of the thigh segment in the local coordinate system of the tibial plateau.

First, we performed a motion analysis on an anatomical model to detect differences between two calculating models for the virtual marker, representing the centre of the tibial plateau. Second, we recorded four gait trials gait on one subject including a minimum of 14 gait cycles to determine the reliability.

Third, we conducted a case-control study with n=40 participants to address knee osteoarthritis.We included 29 patientswith unicompartmental knee osteoarthritis who were scheduled for unicompartmental knee arthroplasty (UKA) and 11 young, healthy controls. All subject agreed to the study protocol and were equipped with 18 reflective markers. The gait analysis included walking on a treadmill at a self-selected velocity. The femorotibial translation was calculated from a customized lower body model (Visual 3D, C-motion). Spatiotemporal and kinematic data were collected and participants completed patient-reported outcome measures (PROM) questionnaires. Statistical analysis was performed using Student's t-test and Mann-Whitney U for statistical significance (p<0.05).

Results and conclusion: The calculations of the virtual centre of the tibial plateau revealed no significant differences between the methods. The difference in the range of femorotibial translation in the loading response was 0.13 mm ± 0.1 mm in average for all planes between the methods.

Repetitive testing on a single subject demonstrated a strong correlation (r=0.76) for femorotibial translation during loading response across all planes and recordings.

We found significant differences in PROMs, spatiotemporal and kinematic parameters (p<0.01) comparing patients with knee osteoarthrosis with healthy controls. There were no statistically significant differencesin the femorotibial translation during the loading response in all three planes between the groups.The data showed a large variance between participants.

The data demonstrates the typical changes in patient-reported outcome measures (PROMs) and spatiotemporal and kinematic data for patients diagnosed with knee osteoarthritis. However, the setup was unable to reveal any differences in femorotibial translation between the patients and the control group.