Abstract des Autors

Purpose: Regular physical activities are a keystone in the nonmedical and nonsurgical treatment of knee-osteoarthritis. However, the underlying mechanisms are still regarded as a black-box and a matter of debate. As potential candidates, two groups can be distinguished: First, joint-specific influences such as better biomechanical functioning and improvements in the quality of cartilage. Secondly, more unspecific effectors like anti-inflammatory cytokines and a central modulation of pain perception. In order to distinguish between these two groups the present study compared the training effects of knee-joint surrounding muscles (LBT), upper body muscles (UBT), and the combination of both (WBT). Methods: 372 physically inactive, adult knee-osteoarthritic patients of both sexes were enrolled in the multi-centered, controlled, and randomized training intervention. All three exercise groups fulfilled an 8-week circle-training intervention two times per week with a subjective intensity of 4 - 5 for the first five sessions (on a 0 = no effort to 10 = extreme effort scale). From the 6th to the 10th session, intensity was adjusted to 6 – 7 and thereafter to 7 – 8. The single training sessions were as follows. LBT: 4 devices, exercise net time (ENT) 20 min., UBT: 4 devices, ENT12 min., WBT 8 devices, ENT 28 min. Anthropometric data, comorbidities, regular physical activities, actual and former medical treatments, knee specific functionality, pain, stiffness, and health related physical and mental quality of life was evaluated at the beginning, after 4 weeks, and finally after 8 weeks by means of online-questionnaires. Main Results: Initially, pain and physical function correlated well with the Kellgren-Lawrence grades (p < 0,01). All three training interventions led to significantly increased functionalities (p < 0,0001) and physical qualities of life (p < 0,02). The pain-subscore of the Western Ontario and McMaster Universities Osteoarthritis Index was significantly reduced (p < 0,004). None of these improvements showed significant differences between groups, although there was a tendency of WBT to be superior to UBT and LBT. Conclusion: The positive effects of physical training regimens cannot be exclusively attributed to a knee-specific training effect since significant improvements also occurred in the UBT group.