Acoustic emission and angular movement variations from early adulthood healthy knees to late adulthood osteoarthritic knees.

From sit-stand-sit movements performed by healthy and osteoarthritic knees in three different age bands, this paper presents the investigation of the relationship between joint angular movement measured using electro-goniometers and acoustic emission measured using piezoelectric sensors. By partitioning joint movement in each sit-stand-sit cycle into sub-movement phases based on ascending and descending as well as acceleration and deceleration, the statistical analysis reveals aged and osteoarthritic knees exhibiting increased asymmetry and more variable angular movement compared with young and age-matched healthy knees, particularly in the descending-deceleration phase. With further evidence of a clear difference in the number of acoustic emission events detected from different knee groups, the study suggests the descending-deceleration phase likely to be most informative for quantitative assessment of knee aging and condition.