A Patellofemoral Chondropathy Quantification from Vibroarthrography: A Preliminary Study

Abstract

Objective: To preliminarily investigate if the proposed parameter derived from the knee vibroarthrographic (VAG) signals, namely the VAG score, could potentially be used to quantify the patellofemoral chondropathy. Materials and Methods: Five subjects with meniscus injury as an indication for arthroscopy were recruited for the present preliminary crosssectional study. Prior to the arthroscopy, the Kujala scores were assessed and the knee VAG signals were recorded from all the subjects. Subjects were asked to actively perform the knee flexion-extension for three cycles in the supine position while recording the VAG signal. The proposed VAG score was defined as the power spectral density of the signal in the frequency of 450 to 1,000 Hz. Patellofemoral chondropathy was arthroscopically graded using French Society of Arthroscopy system (SFA) score and SFA category. Results: The SFA score was significantly strongly correlated with the VAG score (r=0.87, p=0.02) but not with the Kujala score (r=–0.79, p=0.11). Likewise, the SFA category was significantly correlated with the VAG score (r=0.98, p<0.01) but not with the Kujala score (r=–0.67, p=0.22). Conclusion: The proposed signal-based VAG score was demonstrated to be preliminarily able to better assess the patellofemoral chondropathy non-invasively, compared to the Kujala score, which is questionnaire-based. Keywords: Chondropathy; Vibroarthrographic signal; SFA score; SFA category; Kujala score