Baczkowicz D, et al. - In this study, researchers assessed 100 candidates to elaborate the behavior of normal and pathological synovial joints during motion with/without weight bearing and also to assess the efficiency of open (OKC) and closed (CKC) kinetic chains between healthy and deteriorated joints. They recorded an almost vibrationless motion of the physiological, unloaded patellofemoral joint (PFJ) articular surfaces in OKC. They suggested chondral lesions as an increased friction-related, aggravating factor of arthrokinematic motion quality (AMQ), crucial in CKC movements under load. Although, they characterized OKC and CKC conditions by large impact sizes, providing an effective test frame for distinguishing the physiological knees and joints with chondral lesions.