This Level IV case series evaluated scapulothoracic kinematics in 34 patients with chronic, unreduced type III AC dislocation. The study asked whether scapular dyskinesis and SICK scapula syndrome develop as sequelae of this injury. It is the first study to examine scapulothoracic biomechanical consequences specifically in this population.
When you evaluate a patient who has been living with a chronic type III AC separation and complains of periscapular pain or limited overhead function, dyskinesis is almost certainly present. This paper established that 70% of these patients have it, yet prior studies on conservative vs. Surgical management of type III AC injuries never accounted for scapular dyskinesis as a driver of poor outcomes.
In practice: screen every chronic type III AC patient for dyskinesis with arms at rest. You do not need X-rays or provocative positioning — the resting exam is equally sensitive.
If you find dyskinesis (asymmetry >1.5 cm or >5°), check for the full SICK constellation: scapular malposition, inferomedial border prominence, coracoid pain, and dyskinesis. A SICK Scapula Rating Scale score below 5 predicts preserved overhead function; scores of 5-10 mean painful but possible overhead use; scores above 10 mean the patient cannot reliably elevate above 90°.
First-line treatment is rehabilitation targeting scapular muscle rebalancing per the Kibler-McMullen protocol. Surgery for the AC joint alone will not resolve dyskinesis if the muscular dysfunction is not addressed.
This Level IV case series evaluated scapulothoracic kinematics in 34 patients with chronic, unreduced type III AC dislocation. The study asked whether scapular dyskinesis and SICK scapula syndrome develop as sequelae of this injury. It is the first study to examine scapulothoracic biomechanical consequences specifically in this population.
When you evaluate a patient who has been living with a chronic type III AC separation and complains of periscapular pain or limited overhead function, dyskinesis is almost certainly present. This paper established that 70% of these patients have it, yet prior studies on conservative vs. Surgical management of type III AC injuries never accounted for scapular dyskinesis as a driver of poor outcomes.
In practice: screen every chronic type III AC patient for dyskinesis with arms at rest. You do not need X-rays or provocative positioning — the resting exam is equally sensitive.
If you find dyskinesis (asymmetry >1.5 cm or >5°), check for the full SICK constellation: scapular malposition, inferomedial border prominence, coracoid pain, and dyskinesis. A SICK Scapula Rating Scale score below 5 predicts preserved overhead function; scores of 5-10 mean painful but possible overhead use; scores above 10 mean the patient cannot reliably elevate above 90°.
First-line treatment is rehabilitation targeting scapular muscle rebalancing per the Kibler-McMullen protocol. Surgery for the AC joint alone will not resolve dyskinesis if the muscular dysfunction is not addressed.