The Goutallier Classification is evaluated using MRI images to assess fatty infiltration and muscle degeneration in the rotator cuff. It has a categorial grading system from stage 0 to 4.

Based on MRI images, the investigator classifies the rotator cuff of each subject. Thereby, a higher classification means more fatty infiltration.

The tendon quality of each subject is graded based on MRI images using a categorial scoring system.

The following classification can be used: Normal, Intact with edema/regularity, Partial tearing and/or abnormal tissue, Complete Tear/Abnormal.

The ASES score is a patient-reported outcome measure survey which is completed by all subjects. It is used to assess shoulder function and pain. Based on the answers, a final score between 0 and 100 can be achieved. Thereby, higher scores indicate better shoulder function and less pain.

The SANE score is a patient-reported outcome measure used to assess a patient's perception of their shoulder function. It consists of a single question and each subject has to rate their shoulder function on a scale from 0% to 100%. Thereby, higher percentages indicates better shoulder function.

The VAS Score is a patient-reported outcome measure used to assess pain intensity. All patients rate their pain on a horizontal line ranging from 0 to 10. Thereby, a higher score indicates greater pain intensity.

The VR-12 is a patient-reported outcome measure assessing physical and mental health of the subjects. Based on their answers, the subjects can reach a score between 0 and 100, with a higher score indicating better health.

The subject's active ROM (based on the objective ASES score) is assessed using a goniometer. During an outpatient visit at the investigators facility, forward flexion, external rotation, abducted external rotation, abducted internal rotation and internal rotation will be evaluated. The unit of measure is degrees.

If subjects are unable to return for an in person visit, an optional self-assessment of these range of motion form will be provided for electronic completion.

The strength of each subject will be evaluated (based on objective ASES) using a manual muscle testing device or other dynamometers. Thereby, external rotation strength, subscapularis strength-belly press and the constant score strength will be evaulated. The unit of measure will be kilograms or pounds.

The Constant-Murley Score will be assessed optionally. The score requires an outpatient visit at the investigator's facility and covers questions and functional assessments to assess pain, activity levels, range of motion and strength. The range of motion is assessed using a goniometer in degrees and the strength using a manual muscle testing device (or other dynamometers) in kilogram. The subjects can reach points between 0 and 100, whereby a higher score indicates better function.

(Serious) Adverse Events, (Serious) Adverse Device Effects and Device Deficiencies will be reported by the research staff as soon as they occur.