Fuzzy clustering of gait patterns of patients after ankle arthrodesis based on kinematic parameters

Kinematic parameters for 10 normal subjects and 10 patients with ankle arth rodesis are grouped using the fuzzy cluster paradigm. The features chosen f or clustering are Euler angles of the sagittal plane in the hindfoot, the f orefoot and combined hindfoot and forefoot joints. Gait patterns are identi fied using information provided by cluster validity techniques. giving thre e, three and two clusters for the hindfoot, forefoot and combined hindfoot and forefoot joints, respectively. The cluster centers represent distinct w alking strategies adopted by normal subjects and patients after ankle arthr odesis. Utilizing angle values normalized by gait cycle. it is possible to classify any subject and to generate an individual's membership value for e ach of the clusters. The clinical utility of the fuzzy clustering approach is demonstrated with data for subjects with ankle arthrodesis, where change s in membership of the clusters provide an objective technique for measurin g changes of gait pattern after ankle arthrodesis. This approach can be ado pted to study other clinical entities where different cluster centers would be established using the algorithm provided in this study. (C) 2001 IPEM. Published by Elsevier Science Ltd. All rights reserved.