Value of additional acromioclavicular cerclage for horizontal stability in complete acromioclavicular separation: a biomechanical study.

PURPOSE

To evaluate whether isolated anatomical coracoclavicular (CC) ligament reconstruction with two suture-button devices provides equal horizontal acromioclavicular joint (ACJ) stability compared to additional ACJ suture tape cerclage.

METHODS

A servohydraulic testing machine was used to assess horizontal ACJ translation in 12 fresh-frozen human shoulders during 5,000 cycles of dynamic anteroposterior directed loading (70 N). Horizontal ACJ stability was assessed for native specimen (n = 6) and compared to specimen with dissected AC ligaments but intact CC ligaments (n = 6). After complete AC/CC dissection, an anatomical CC reconstruction was performed with two suture-button devices (n = 6) and compared to the additional ACJ suture tape cerclage (n = 6).

RESULTS

Native specimen showed an mean horizontal amplitude of 10.8 mm [standard deviation (SD) 3.29]. After 5,000 cycles of horizontal loading (70 N), mean amplitude increased by 1.5 mm (SD 0.75, p = 0.005). Specimen with dissected AC ligaments started at an mean amplitude of 14.1 mm (SD 4.11), which was increased by 0.9 mm (SD 0.56, n.s.) after loading. Initially, amplitude of specimen with anatomical CC reconstruction was 13.2 mm (SD 2.75), which increased by 2.9 mm (SD 1.45, p = 0.001) after loading. The specimen with additional AC cerclage initially showed an amplitude of 10.6 mm (SD 2.35). After loading, translation was increased by 3.0 mm (SD 0.97, p = 0.001). There was no failure of any surgical reconstruction in the tests.

CONCLUSION

The results of this study suggest that only combined AC and CC reconstruction can adequately re-establish physiological horizontal ACJ stability. Therefore, it is likely that a combined surgical procedure with double suture-button devices and AC suture tape cerclage can adequately re-establish horizontal AC joint stability in case of an acute injury (≥type Rockwood IV and may allow superior clinical outcomes for patients, especially if early functional rehabilitation is intended).