Abstract
Purpose
The remplissage procedure may be performed as an adjunct to Bankart repair to address an engaging Hill-Sachs defect. Clinically, it has been reported that the remplissage procedure improves joint stability but that it may also restrict shoulder range of motion. The purpose of this biomechanical study was to examine the effects of the remplissage procedure on shoulder motion and stability. We hypothesized that the remplissage procedure would improve stability and prevent engagement but may have a deleterious effect on motion.
Method
Eight cadaveric forequarters were mounted on a custom biomechanical testing apparatus which applied simulated loads independently to the rotator cuff muscles and to the anterior, middle and posterior deltoid. The testing conditions included: intact shoulder, Bankart defect, Bankart repair, 2 Hill-Sachs defects (15%, 30%) with and without remplissage. Joint range of motion and translation were recorded with an optical tracking system. Outcomes measured were internal-external rotation range of motion in adduction and 90 combined abduction, extension range of motion and stability, quantified in terms of joint stiffness and engagement, in abduction.
Results
With a 15% Hill-Sachs defect, the remplissage significantly reduced internal-external rotation in adduction (15.111.1, p=0.039), but not in abduction (7.79.0, p=0.380). In a 30% Hill-Sachs defect, the remplissage procedure significantly reduced internal-external rotation in adduction (19.57.8, p=0.001), and in abduction (12.28.6, p=0.03).
The remplissage procedure significantly enhanced stability in the 15% Hill-Sachs defect (4.74.0 N/mm, p=0.038), and in the 30% defect (3.93.2 N/mm, P=0.030) compared to the unrepaired defect. All of the unrepaired 30% defects engaged and the remplissage procedure successfully eliminated engagement in each case. However, impingement of the repair on the posterior glenoid with paradoxical posterior pivoting of the humeral head was observed in 50% of the specimens.
Conclusion
The remplissage procedure significantly augmented a Bankart repair in 15% and 30% Hill-Sachs defects and, in 30% Hill-Sachs defects, the remplissage successfully prevented engagement of the defect. The remplissage procedure, however, did significantly reduced shoulder internal-external rotation range of motion as reported clinically, and was also found to reduce extension in the two defect groups. During extension the intra-articular soft tissue bumper created by the remplissage procedure was found to impinge on the posterior glenoid rim and cause pivoting, which produced non-physiologic glenohumeral joint distraction. Therefore, the remplissage procedure stabilized the joint to a significantly greater degree than did a Bankart repair alone; however, it also significantly reduced shoulder range of motion.
