Range-of-motion Analysis of Reverse Shoulder Arthroplasty (ROM)

Limited range-of-motion (ROM) is a common problem after reverse shoulder arthroplasty (RSA). The occurrence and magnitude depend on both surgical and patient-related factors. The most important surgical factor is the occurrence of impingement, which implicates collision between the humeral implant or bone and the scapula, limiting further motion. Patient-related factors such as scapula geometry and muscle function and activation also play an important role. Surgeons have to account for these factors when planning and implanting a RSA. Software models can support the surgeon during preoperative planning by using imaging data to simulate the ROM of a patient's shoulder after RSA. These software models allow for adaptation of the implant position during preoperative planning and, by this optimize the postoperative ROM. However, the models currently developed are limited in terms of ROM simulation and the factors the models take into account.

The impingement-free ROM in a RSA patient is defined as the rotational area the humeral liner can move through without colliding against the scapula or dislocating the joint. In a previous study, a new software model was developed that uses imaging data to compute and quantify the impingement-free ROM of a patient according to clinically relevant motions. Before this model can be used in clinical practice, a validation of the model's accuracy in predicting real RSA patient outcomes is required. Therefore, the first objective is to verify the model's ability to predict the ROM of the glenohumeral joint in real RSA patients. The investigators will investigate and quantify the ROM and joint angles of RSA patients with and without impingement with the help of EOS imaging and video motion analysis. The investigators can then compare model outputs with measured patient outcomes. Additionally, the investigators will investigate how well our software model can predict impingement in patients with known postoperative impingement. Currently, the software model uses a database of healthy shoulder kinematic motions to produce an objective ROM score for a RSA. However, it is not known if healthy shoulder kinematics are a suitable reference for quantifying and interpreting RSA kinematics. Glenohumeral motions of healthy subjects are already extensively described by Ludewig et al. Glenohumeral motions of RSA patients are not yet reported. Also, little is known about muscle activation patterns in RSA patients. The second objective is to describe muscle activation patterns and shoulder kinematics of RSA patients and compare our measured RSA kinematic motions to the healthy kinematic motion data currently used in the software model. Therefore, the investigators will perform instrumented 3D motion analysis in conjunction with electromyography measurements to incorporate muscle activation patterns into our RSA glenohumeral motion analysis. Our additional sub-objective is to compare muscle activation patterns between patients with and without limited ROM, with the goal of identifying differences between the two groups. The third objective is to identify patient-related and implant related factors that influence the ROM after a reversed shoulder arthroplasty. Therefore, the investigators will investigate clinical factors that could have effect on the ROM after RSA. The different factors (sex, birth year, Body Mass Index, generic score EQ-5D-3L, Tampa Schaal voor kinesofobia) will be analyzed both across and within patients with and without limited ROM with the goal of identifying their relation to ROM. The most important implanted related factor will also be investigated and analyzed both across and within groups: implant position in terms of glenoid component version, inclination and location of center of rotation.

a. non- limited ROM i. Endorotation control until lumbosacral level ii. Scapular plane abduction above 150° b. limited ROM i. Endorotation control lower then lumbosacral level ii. Scapular plane abduction under 150° Intervention: clinical data, imaging data, movement analysis, EOS measurements, ROM simulation

a. non- limited ROM i. Endorotation control until lumbar level ii. Scapular plane abduction above 150° b. limited ROM i. Endorotation control lower then lumbar level ii. Scapular plane abduction under 150° Intervention: clinical data, imaging data, movement analysis, EOS measurements, ROM simulation

Clinical Data: Registration of patient identity, sex and birth year, Body Mass Index, generic score EQ-5D-3L, Tampa Schaal voor kinesofobia and shoulder specific score like Constant Score, PROMS, ADLER, SST and postoperative ROM. Imaging Data: A preoperative and postoperative CT scan and 1-year postoperative radiograph (all three part of standard clinical practice) will be obtained. This data is used to extract the bone geometries and implant position. Movement Analysis: The subject should stand still followed by different motion tasks in the gait lab with collection of shoulder girdle kinematics and kinetics using a 14-camera VICON System. Stereo Radiographic EOS Measurements: Every subject included in the study will undergo a stereo radiographic EOS exam while quite standing with their arm in various positions (van Andel et al., 2008) . ROM simulation: With the developed ROM software, we will simulate the ROM of the 2 patient groups based on the available CT scan data.

The subject should stand still followed by different motion tasks in the gait lab with collection of shoulder girdle kinematics and kinetics using a 14-camera VICON System

Every subject included in the study will undergo a stereo radiographic EOS exam while quite standing with their arm in various positions (van Andel et al., 2008)

It is a questionnaire that gives an impression of the degree of pain-related fear in patients with low back pain (LBP) or fibromyalgia.

These parameters define the level of pain and the ability to carry out the normal daily activities of the patient

It is a measuring instrument that measures the functional limitations of the affected shoulder of patients with shoulder complaints

Inclusion Criteria: Adults with RSA operated in the University Hospitals Leuven, Belgium Ability and willingness of patient to attend follow-up visit and complete patient questionnaires Complete patient informed consent Preoperative CT-scan available Pain free RSA (VAS score ≤ 3) more than 1 year postoperative Exclusion Criteria: Only RSA patients with a functional RSA will be included, so patients with postoperative stiffness, pain, instability or pseudoparalysis will be excluded.