Comparing The Outcome of Large-Diameter vs Small-Diameter Glenospheres in Primary Reverse Shoulder Arthroplasty

Degrees of movement the participant is able to independently lift arm upward to the ceiling, while keeping elbow straight. Normal movement for forward elevation is 180 degrees.

Degrees of movement the participant is able to independently rotate arm up, while keeping arm at 0 degrees of abduction. Normal movement for external rotation is 90 degrees.

Shoulder abduction strength was measured using manual testing where strength was graded as: (1) paralysis; (2) contraction with no ability to resist gravity; (3) weak but able to resist gravity; (4) weak but able to resist the examiner; (5) normal.

Shoulder external rotation strength was measured using manual testing where strength was graded as: (1) paralysis; (2) contraction with no ability to resist gravity; (3) weak but able to resist gravity; (4) weak but able to resist the examiner; (5) normal.

Shoulder internal rotation strength was measured using manual testing where strength was graded as: (1) paralysis; (2) contraction with no ability to resist gravity; (3) weak but able to resist gravity; (4) weak but able to resist the examiner; (5) normal.

The Oxford Shoulder Score (OSS) is a patient reported questionnaire that includes 12 descriptors of pain and disability for shoulder ailments and related quality of daily activities. Each descriptor rating ranges from 0 to 4, with 4 representing the best (no pain, no difficulty with activity) and 0 is the worst (unbearable pain, extreme difficulty with activity). The score is calculated from the summation of all 12 descriptors, for a total range of 0 to 48, where a higher score reflects the best outcome (less pain and difficulty with activity) and a lower score reflects a worse outcome (more pain and difficulty with activity).

A self-assessment that measures pain and ability to perform daily activities.The questionnaire is divided into 2 components, a single pain question and 10 questions on function of daily living.The total score is weighted 50% for pain and 50% for function. Pain is ranked from 0-10, where 0 is no pain and 10 is unbearable pain.The total pain score is calculated by subtracting the result of this question from 10 and multiplying by 5.The function score is calculated from the sum of 10 questions on daily living.The 10 questions are scored from 0-3, where 0=unable to perform daily activity and 3=no difficulty with daily activity.The individual function scores are summed for a maximum functional score of 30.This functional score is then multiplied by 5/3 to make the maximum functional score out of 50 possible points.The pain and function scores are then added together to obtain the final score out of 100.The final score ranges from 0 to 100, where higher scores correlate to better outcomes.

The Quick DASH (disabilities of the arm, shoulder and hand) questionnaire is an 11 item self-reported participant questionnaire that measures physical function and symptoms in individuals experiencing musculoskeletal disorders of the upper limb. Each item is scored 1-5 where 1 reflects no pain or difficulty with activities and 5 reflects extreme pain or difficulty with activities. All individual scores are then summed and averaged to produce a score out of five. The score is then transformed to a score out of 100 by subtracting one and multiplying by 25. The final score ranges from 0 to 100, where a higher resulting score reflects more pain and greater disability while a lower score reflects less pain and disability.

Shoulder pain values reported by participants will be assessed using the 10cm Visual Analogue Scale (VAS). The VAS line will be 10 cm long with two endpoints representing 0 (no pain) and 10 (worst possible pain). Participants will identify their pain level by indicating a point on the line between each end. That point will be measured from the "No pain" end, and the number of centimeters will be reported as the pain score.

Patient satisfaction with the outcome of the surgery measured by on a scale from 1-10, where 1 is not at all satisfied and 10 is very satisfied.