Inclusion Criteria:  age >16 years; clinical diagnosis of bilateral intra-articular disorder; clinical criteria for bilateral TMJ arthroscopy; magnetic resonance imaging (MRI) assessing the intra-articular derangement  Exclusion Criteria:  The exclusion criteria included any history of previous TMJ surgical intervention or any facial trauma within the last 4 weeks prior the study. Severe medical problems or mental illness, and pregnancy were also exclusion criteria