The Use of the Anterior Labral Circumferential Onlay Technique to Reconstruct the Anterior Labrum and Biomechanically Restore Glenohumeral Joint Stability.

BACKGROUND

A labral injury contributes to glenohumeral instability. The Anterior Labral Circumferential Onlay Technique (ALCOT) reconstructs the labrum using the long head of the biceps tendon.

HYPOTHESIS

The ALCOT would restore glenohumeral joint stability in a cadaveric model without glenoid bone loss (1) comparable to the native state and (2) comparable to the Latarjet procedure.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 10 fresh-frozen cadaveric shoulders were tested using a 6 degrees of freedom robotic arm in 5 consecutive states: (1) native, (2) capsular repair, (3) labral tear, (4) ALCOT, and (5) Latarjet procedure. Biomechanical testing consisted of 80 N of anteroinferior force and 50 N of compression in 90° of humerothoracic abduction. Lateral displacement of the humeral head and the force ratio during a dislocation were measured.

RESULTS

The mean lateral translation of the humeral head during a dislocation in the native state was 6.5 ± 2.2 mm and decreased to 5.4 ± 2.4 mm in the labral tear state ( < .001). The mean lateral translation of the humeral head was restored to 6.4 ± 2.2 mm ( > .99) with the ALCOT, showing no difference from the native state. The Latarjet procedure restored the mean force ratio during a dislocation to 1.3 ± 0.6 but failed to restore lateral translation, with a value of 5.6 ± 2.8 mm ( = .003 vs native; = .94 vs labral tear). The mean force ratio was 1.8 ± 0.1 in the native state, decreased to 1.1 ± 0.4 in the labral tear state, and was 1.4 ± 0.4 ( < .27) with the ALCOT, showing no difference from the native state.

CONCLUSION

The ALCOT is a novel technique for labral reconstruction that may have a role in the treatment of anterior glenohumeral instability in the setting of a deficient labrum without bone loss. In this study, the ALCOT restored the force ratio and lateral translation of the humeral head compared to the native state. The Latarjet procedure restored the force ratio but not lateral translation of the humeral head compared to the native state.

CLINICAL RELEVANCE

This study proposes and biomechanically validates the ALCOT as a surgical technique for labral reconstruction that may have a role in treating patients with chronic anterior shoulder instability in the setting of a deficient labrum.