Stabilization of the clavicle after distal resection: a biomechanical study.

BACKGROUND

The potential destabilizing effect of distal clavicle resection has received limited attention.

HYPOTHESIS

Suturing the coracoacromial ligament to the undersurface of the distal clavicle after resection could counter clavicle instability.

STUDY DESIGN

Controlled laboratory study.

METHODS

The effect of ligament augmentation on posterior translation of the clavicle after resection was evaluated using 12 fresh-frozen cadaveric shoulders. Posterior clavicular displacement was measured after the application of a 70-N load under 4 different conditions: (1) the intact joint, (2) after distal clavicle resection, (3) clavicle resection plus acromioclavicular capsular ligament repair, and (4) clavicle resection plus acromioclavicular capsular ligament repair plus coracoacromial ligament augmentation.

RESULTS

Mean displacements for each of the test conditions were as follows: (1) 5.60 mm, (2) 7.38 mm, (3) 7.54 mm, and (4) 6.34 mm. A 32% increase in posterior translation was measured after resection compared to the intact specimen. No reduction in posterior displacement was noted after capsular repair; however, displacement decreased significantly when capsular repair was coupled with ligament augmentation.

CONCLUSIONS

Results suggest that the destabilizing effect of clavicle resection can be partially countered by the proposed ligament augmentation.

CLINICAL RELEVANCE

That the destabilizing effect of clavicle resection can be partially countered by the proposed ligament augmentation may be particularly relevant in cases of resection for posttraumatic arthritis after acromioclavicular separation in which some degree of preexisting acromioclavicular capsular attenuation and consequently acromioclavicular joint laxity may be presumed.