While total shoulder arthroplasty (TSA) is a generally successful procedure, glenoid loosening remains a common complication. Though the occurrence of loosening was related to patient-specific factors, biomechanical factors related to implant features may also affect the fixation of the glenoid component, in particular increased glenohumeral mismatch that could result in eccentric loads and translations. In this study, a novel test setup was used to quantify glenohumeral pressures for different motion patterns after TSA. Six cadaveric human shoulders were implanted with total shoulder replacements (Exactech, Inc., USA) and subjected to cyclic internal-external, flexion-extension and abduction-adduction rotations in a passive motion testing apparatus. The system was coupled to a pressure sensor system (Tekscan, Inc., USA) to acquire joint loads and to a Zebris system (Zebris Medical, GmbH, Germany) to measure joint kinematics. The specimens were subjected to a total of 2160 cycles and peak pressures were compared for each motion pattern.Background
Methods
