Release and reattachment of the coracoacromial ligament: a cadaveric study

The purpose of this study was to examine the anatomy and ability to reattach the coracoacromial ligament (CAL) after acromioplasty. Twenty-eight fresh cadaveric shoulder specimens were dissected, and the CAL dimensions and pattern of attachment were examined. The ability to reattach the CAL to the anterior acromion after acromioplasty was investigated, comparing release along the anterior acromion (traditional anterior acromioplasty) versus subperiosteal elevation from the acromial undersurface. The influence of CAL length, acromial "type," and amount of acromioplasty on reattachment were examined. In 96% of the specimens (27 of 28) confluent medial and lateral bands of the CAL insertion along the acromion precluded "selective" release. The ability to anatomically reattach the CAL was directly related to the method of ligament release (anterior release versus subperiosteal elevation) (p < 0.0001). When directly released from along the anterior acromion, the CAL could not be anatomically reattached in any specimen. Nonanatomic reattachment to a more medial anterior acromial insertion site, however, was possible in 22 (79%) of 28 specimens. Reattachment required an average medial positioning of 60% (range 16% to 88%) along the anterior acromion from the anterolateral tip. Six (21%) specimens could not be reattached despite attempted medial positioning. In contrast, when subperiosteally elevated from the anterior inferior acromion, the CAL was reattachable in all specimens, anatomically in 26 (93%) of 28. The two nonanatomic reattachments required medially reattaching the ligament's normal acromial insertion by an average of 30%. There was no relationship between specimen sex, age, presence of rotator cuff tear, type of acromion, and CAL reattachment. The confluent anatomy of the CAL does not permit "selective" release of discretely identifiable portions of the CAL (i.e., the lateral band). In cases in which CAL restoration is important, careful subperiosteal elevation from the acromial undersurface will facilitate anatomic reattachment. Standard release of the CAL from the anterior acromion precludes anatomic, and in some cases any, reattachment of the CAL.