Assessing shoulder disability in orthopaedic specialist care: introducing the Copenhagen Shoulder Abduction Rating (C-SAR)

Key points

1. 01The C-SAR test combines how high the arm can lift (abduction range of motion) and pain during the movement to rate disability as Mild, Medium, or Severe in about 10 seconds.
2. 02Among 325 specialist-care patients, adhesive capsulitis carried the highest disability and glenohumeral injury (instability or labral injury) the lowest.
3. 03C-SAR could be applied to 82% of rotator-cuff related patients but was not usable for adhesive capsulitis or glenohumeral injury.
4. 04Mild versus Medium C-SAR groups differed strongly on questionnaire disability, but Medium versus Severe separated clearly only on the function sub-scale.
5. 05C-SAR showed excellent inter-tester reliability in a separate sample (weighted kappa 0.84).

How it was conducted

Design

Cross-sectional study of a consecutive cohort in secondary (specialist orthopaedic) care over 3 months

Participants

325 consecutive adults referred for shoulder disorders at a public outpatient clinic in Denmark

Groups

Diagnostic categories (subacromial impingement, glenohumeral injury, complete rotator-cuff tear, adhesive capsulitis, other) and C-SAR subgroups (Mild, Medium, Severe)

Index test

C-SAR, based on active abduction range of motion (digital inclinometer) plus pain during testing on a 0-10 scale

Reference standard

Shoulder Pain and Disability Index (SPADI) total and the SPADI-pain and SPADI-function sub-scales

Analysis

ANCOVA models comparing SPADI scores across diagnoses and across C-SAR subgroups, with effect sizes reported

What they found

• Most patients had subacromial impingement (65%, n=211); other categories were glenohumeral injury (9%), adhesive capsulitis (7%), complete rotator-cuff tear (6%), and other (14%).
• Adhesive capsulitis scored worse than subacromial impingement on SPADI total (mean diff. 11 points, 95%CI 1 to 21, ES 0.5, p=.025) and SPADI-function (mean diff. 15 points, 95%CI 4 to 26, ES 0.6, p=.009), but not SPADI-pain (mean diff. 10 points, 95%CI 0 to 20, ES 0.4, p=.059).
• Glenohumeral injury scored better than all other groups on every SPADI measure (ES 0.8 to 1.4, p<.01).
• C-SAR disability rating was possible for 212 of 281 patients (75%) across the four categories, and for 187/229 (82%) of rotator-cuff related patients.
• In the merged subacromial impingement and rotator-cuff tear group, C-SAR was Severe for 34% (n=64), Medium for 30% (n=56), and Mild for 36% (n=67).
• Mild versus Medium C-SAR differed by 21 SPADI points (95%CI 15 to 27, ES 1.0, p<.0001), with the same large gap on SPADI-pain (20 points, ES 1.0) and SPADI-function (21 points, ES 1.0).
• Medium versus Severe C-SAR differed significantly only on SPADI-function (mean diff. 9 points, 95%CI 2 to 16, ES 0.4, p=.017), not SPADI total (ES 0.3, p=.085) or SPADI-pain (ES 0.1, p=.536).
• C-SAR inter-tester reliability was excellent in a separate sample of 20 patients (weighted kappa 0.84, 95%CI 0.68 to 1.00).

Limitations

• Cross-sectional design with no follow-up, so it cannot show that C-SAR predicts outcomes or guides treatment.
• C-SAR could not be used for adhesive capsulitis or glenohumeral injury, and several diagnostic groups were too small for full analysis.
• No prior sample size calculation, and Medium versus Severe groups separated on only one sub-scale, raising doubt about that boundary.
• Single Danish specialist clinic with a convenience set of assessors, limiting how widely the results generalize.

Why it matters

For patients

If you have shoulder pain from impingement or a rotator-cuff tear, a clinician may now use a quick arm-lift test to gauge how much your shoulder is limiting you instead of a long questionnaire.

For clinicians

C-SAR offers a fast, reliable bedside rating of disability for rotator-cuff related shoulder disorders, but should not be relied on for frozen shoulder or instability and does not cleanly separate medium from severe cases.

For readers

This is early single-site validation showing a simple test tracks questionnaire-measured disability, not yet evidence that using it changes care or outcomes.