Is MIO-RSA Noninferior to BIO-RSA When it Comes to Mechanical Implant Stability?

Migration of glenoid component from baseline until 24 months

CT-based motion analysis (CTMA) will be used to measure the 3-dimensional migration pattern of the glenoid components to assess the stability of the prostheses up to two years after implantation. The motion analysis includes measurement of translation along three orthogonal axes and rotations around two orthogonal axes. CTMA is a marker-free motion analysis, and the images are obtained on a standard CT-machine. Analysis and computation of motion data are performed using proprietary software at Sectra AB (collaborating partner) CTMA is a relative new method to measure implant migration. The precision of the measurements is 0.08-0.15 mm for translation and 0.23-0.54º for rotation, therefore, CTMA is capable of measuring very small movements of the implant relative to the surrounding bone.

Change in WOOS Index

The Western Ontario Osteoarthritis of the Shoulder (WOOS) index is a patient-reported, disease-specific questionnaire for the measurement of the quality-of-life in patients with osteoarthritis. There are 19 questions divided into four domains: Physical symptoms, sports and work, lifestyle and emotions. Each question is answered on a visual analogue scale ranging from 0 to 100. The overall score ranges from 0 to 1900, with 1900 being the worst. For ease of interpretation, the scores are often converted to a percentage of the maximum score.

Change in Constant-Murley Score

The CMS is a multi-item functional scale assessing pain, ADL, ROM and strength of the affected shoulder. Its score ranges from 0 to 100 points, representing worst and best shoulder function, respectively. The test is divided into subjective and objective components. Two subjective: pain and activities of daily living (ADL) and two objective: range of motion (ROM) and strength. The subjective components can receive up to 35 points and the objective 65. Pain and ADL are answered by the patient; ROM and strength require a physical evaluation and are answered by the orthopaedic surgeon or the physiotherapist.

Change in EuroQol-5

he widely used EuroQol-5 (EQ-5D-5L) will be used to measure health-related quality of life. The EQ5D-5L consists of two parts: A descriptive system (Mobility, self-care, usual activities, pain/discomfort and anxiety/depression) and the EQ-VAS that record patients self-rated health on a visual analog scale that range from 0 -100, higher levels indicate better self-rated health. The descriptive system can be converted to a single summary index number where lower levels indicate poorer health related quality of life.

Change in range of motion

The patient's active and passive range of motion (ROM) in the affected shoulder will be measured by an experienced physiotherapist with a long-legged goniometer. The directions measured will be flexion, abduction, external rotation and internal rotation, measured in degrees and/or physical landmarks.