Docter (2019) — The Relationship Between the Critical Shoulder Angle and the Incidence of Chronic, Full-Thickness Rotator Cuff Tears and Outcomes After Rotator Cuff Repair: A Systematic Review

The Relationship between the Critical Shoulder Angle and the Incidence of Chronic, Full-Thickness Rotator Cuff Tears and Outcomes after Rotator Cuff Repair: a Systematic Review

·Arthroscopy·2019·52 citations·Shoulder & Elbow

This systematic review examines whether the critical shoulder angle (CSA), a radiographic measure of scapular morphology, relates to rotator cuff disease. It asks two questions: does a larger CSA increase the incidence of chronic full-thickness tears, and does it affect outcomes after rotator cuff repair? Twelve comparative studies (Level II-IV) were pooled qualitatively.

Study Snapshot

Design

Systematic review

Setting: Multinational studies (systematic review)

Funding: None reported

Objective

Whether a greater CSA increases full-thickness rotator cuff tear incidence but not outcomes after repair

Outcome(s)

CSA association with tear incidence and post-repair re-tear/function

Subjects

12 comparative studies

7Tear
5Repair

Inclusion

Clinical comparison study
English language
CSA vs tear or repair outcomes

Exclusion

Reviews, narratives, abstracts
Grouped partial- and full-thickness tears
Non-clinical studies

Follow-up

RCR studies 24-33 months

Statistics

Kappa coefficientMINORS scoringForest plot

Key Findings

A greater CSA is associated with chronic, full-thickness rotator cuff tears. Tear groups showed CSA values of 33.9-41.0 vs 27.3-37.3 in controls, with mean differences of 2.2 to 9.0. Most included studies reached statistical significance.
A larger CSA (>38) sharply raises re-tear risk after repair. Garcia reported 14.8x greater odds of re-tear, Scheiderer reported OR 3.78 (95% CI 1.05-13.58, P=.042), and Li found 15% vs 0% re-tear (P=.03). This is the strongest surgical signal in the review.
Despite higher re-tear rates, CSA did not affect functional outcomes. Three studies found no significant difference at 2 years in ASES, UCLA, Constant, or VAS scores between large and small CSA groups.
ROM and strength were also unaffected by CSA. Forward elevation (P=.191), abduction (P=.917), and abduction strength (P=.507) showed no significant differences.
Measurement reliability is a real problem. Chalmers found only 326 of 1,552 radiographs were of sufficient quality to measure CSA, suggesting differences may partly reflect measurement error.
The evidence base is weak, with mean MINORS scores of 14.8/24 (tear studies) and 17.2/24 (repair studies). Studies scored particularly low on prospective data collection and baseline group equivalence.

Board PearlA larger critical shoulder angle correlates with rotator cuff tears and higher re-tear rates, but does not change functional outcomes after repair.

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Supplemental

The Relationship between the Critical Shoulder Angle and the Incidence of Chronic, Full-Thickness Rotator Cuff Tears and Outcomes after Rotator Cuff Repair: a Systematic Review

Docter, Leroux, et al.·Arthroscopy·2019·52 citations·Shoulder & Elbow

The Relationship between the Critical Shoulder Angle and the Incidence of Chronic, Full-Thickness Rotator Cuff Tears and Outcomes after Rotator Cuff Repair: a Systematic Review

Study Snapshot

Key Findings

Images

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The Relationship between the Critical Shoulder Angle and the Incidence of Chronic, Full-Thickness Rotator Cuff Tears and Outcomes after Rotator Cuff Repair: a Systematic Review

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Key Findings

Images

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The Relationship between the Critical Shoulder Angle and the Incidence of Chronic, Full-Thickness Rotator Cuff Tears and Outcomes after Rotator Cuff Repair: a Systematic Review

Study Snapshot

Key Findings

Images

Related Articles

The Relationship between the Critical Shoulder Angle and the Incidence of Chronic, Full-Thickness Rotator Cuff Tears and Outcomes after Rotator Cuff Repair: a Systematic Review

Study Snapshot

Key Findings

Images

Related Articles