Biomechanical Effect of Dermal Allograft or Bone Block Augmentation on Standard Labral Repair in a Time-Zero Cadaveric Model of Glenoid Bone Loss

Abstract

Purpose

To biomechanically evaluate the stability of a labral repair technique using dermal augmentation (DA) compared with standard labral repair (SLR) and bone block augmentation (BBA) in the context of subcritical glenoid bone loss in a cadaveric model.

Methods

Eight cadaveric shoulder specimens were disarticulated and dissected, leaving only labral tissue. The specimens were secured to custom fixtures with 60° of glenohumeral abduction, 30° of external rotation, 20° of scapular anterior tilt, and 40 N of glenohumeral compression. In a repeated-measures design, the specimens were tested in 5 states: native, defect (with 15% glenoid bone loss), SLR, DA, and BBA. Dislocation was performed at 1 N/s over the anterior-inferior rim. Maximum load and distance to dislocation were recorded and statistically analyzed.

Results

Maximum loads for the defect state and SLR were significantly less than those for the native state (P = .005 and P = .008, respectively) and BBA (P = .014 and P = .022, respectively). The distance to dislocation decreased significantly for the defect state (P < .001) and SLR (P < .001) compared with the native state. The distance to dislocation for the defect state, SLR, and DA was significantly reduced compared with BBA (P < .001, P < .001, and P < .001, respectively). The distance to dislocation was significantly greater for DA than for the defect state (P < .001) and SLR (P = .001).

Conclusions

Dermal allograft repair showed similar biomechanical characteristics to the native state and showed an increased distance to dislocation and higher forces at dislocation compared with SLR. BBA restored the distance to dislocation and resulted in non-significantly increased maximum loads when compared with the native state.

Clinical Relevance

DA of labral repair is an alternative procedure for subcritical glenoid bone loss that potentially mitigates adverse effects from bone grafting. Future clinical investigation is warranted.