Electronic Thesis and Dissertation Repository


Doctor of Philosophy


Health and Rehabilitation Sciences


Dr. Joy C MacDermid


Rotator cuff repairs are done in patients who failed to achieve functional improvement with conservative management for rotator cuff tears. This thesis focuses on prognostic factors that predict outcomes after rotator cuff repair (RCR) and change in functional range of motion (ROM) and muscle endurance before and after RCR. A meta-analysis was performed to statistically analyze all available evidence in the literature concerning prognostic factors that determine outcome after RCR. Based on this study, several factors were identified that had significant and moderate effects on outcomes after RCR. Two prospective studies were conducted to analyze change in functional ROM and muscle endurance after RCR. The first study followed patients pre-op, 3 and 6 months after RCR. Patients performed 2 trials of 5 activities selected from Disabilities of Arm, Shoulder and Hand questionnaire. The activities were captured using 2D video motion system and analysed using Dartfish software. This study showed excellent intra-rater reliability while using the 2D video analysis system with improvement in ROM during all activities when compared before and after surgery with significant improvement in 2 activities when compared at different time points. A prospective study to evaluate muscle endurance at 6 months after surgery was done using an endurance protocol on the Biodex system and compared with age- and gender-matched controls. Results of this study indicated that changes in muscle performances as measured by average isokinetic torque and total work before and after the protocol did not indicate muscle fatigue in patients after RCR and in the control group. We also analysed the psychometric properties of Simple shoulder test (SST) using the Rasch model to assess its fit to the model and to examine the stability of the findings at different time points. Our results indicated that a number of properties of SST were supported and it appeared to be robust when tested against the Rasch model. Local dependency between light and heavy objects being lifted overhead fits with their conceptual overlap. Unless corrected some gender bias may exist on the lifting item.