This study measured how often each Bigliani acromial shape appears on MRI in different shoulder populations. It compared 47 asymptomatic controls, 30 surgically proved impingement shoulders, and 34 full-thickness rotator cuff tears. The question: does a hooked acromion track with rotator cuff disease, and can MRI reliably show it?
When you read a shoulder MRI, classify the acromion on the sagittal oblique slice just lateral to the AC joint, where the acromion is longest. Use the Bigliani system: type 1 flat, type 2 curved, type 3 hooked. Apex in the anterior third means type 3. A hooked acromion should raise your suspicion for cuff pathology: it was present in 62% of full-thickness tears here versus 13% of normal shoulders.
Be careful with the causal story. This is cross-sectional data, so a hook is an association and possible risk marker, not proof that shape caused the tear. The authors themselves note the hook may be an acquired enthesopathy rather than a fixed congenital trait.
The practical link to management is the impingement-continuum model: identifying at-risk anatomy supports the rationale for anterior acromioplasty in selected Neer stage 2 patients to try to prevent progression to a full-thickness tear.
This study measured how often each Bigliani acromial shape appears on MRI in different shoulder populations. It compared 47 asymptomatic controls, 30 surgically proved impingement shoulders, and 34 full-thickness rotator cuff tears. The question: does a hooked acromion track with rotator cuff disease, and can MRI reliably show it?
When you read a shoulder MRI, classify the acromion on the sagittal oblique slice just lateral to the AC joint, where the acromion is longest. Use the Bigliani system: type 1 flat, type 2 curved, type 3 hooked. Apex in the anterior third means type 3. A hooked acromion should raise your suspicion for cuff pathology: it was present in 62% of full-thickness tears here versus 13% of normal shoulders.
Be careful with the causal story. This is cross-sectional data, so a hook is an association and possible risk marker, not proof that shape caused the tear. The authors themselves note the hook may be an acquired enthesopathy rather than a fixed congenital trait.
The practical link to management is the impingement-continuum model: identifying at-risk anatomy supports the rationale for anterior acromioplasty in selected Neer stage 2 patients to try to prevent progression to a full-thickness tear.