Kinematic and Radiographic Evaluation of Acromioclavicular Reconstruction with a Synthetic Ligament

Table 1

Rockwood and ISAKOS classifications for AC joint injury.

Classification	AC ligaments	CC ligaments	Deltoid and trapezius	Radiographic hallmark of AC joint and CC interval	Treatment
Rockwood I	Sprained	Intact	Intact	Intact but joint space may be may widened	Nonoperative; 6–12 weeks of rehabilitation
Rockwood II	Complete tear	Sprained	Possible partial detachment	CC interval <25% increase and disrupted AC joint	Nonoperative; 6–12 weeks of rehabilitation
Rockwood III	Complete tear	Disrupted	Likely detached from lateral clavicle	CC interval 25–100% increase	Controversial–usually non-op initially
ISAKOS IIIA	Complete tear	Disrupted	Likely detached from lateral clavicle	Clavicle not overriding on adduction view	Favors nonoperative
ISAKOS IIIB	Complete tear	Disrupted	Likely detached from lateral clavicle	Clavicle overriding on adduction view	Favors surgery
Rockwood IV	Complete disruption	Partial or complete disruption	Likely detached from lateral clavicle	AC joint dislocated; clavicle posterior into or through trapezius on axillary view	Surgery
Rockwood V	Complete disruption	Complete disruption	Likely detached from lateral clavicle	AC joint dislocated; extreme vertical incongruity between lateral clavicle and acromion; CC interval 100% to 300% increase	Surgery
Rockwood VI	Complete disruption	Intact and interval is decreased or reversed	Intact, partial, or complete detachment	AC joint dislocated; lateral clavicle displaced inferior to acromion and found in subacromial or subcoracoid space	Surgery

In a continuation of type VI, the clavicle is displaced inferior to the coracoid process, and the CC ligaments are completely torn.