Abstract
Purpose
The remplissage technique of insetting the infraspinatus tendon and posterior joint capsule into an engaging Hill-Sachs lesion has gained in popularity. However, a standardized technique for suture anchor and suture placement has not been defined for this novel procedure. The purpose of this biomechanical study was to compare three remplissage techniques by evaluating their effects on joint stiffness and motion.
Method
Cadaveric forequarters (n=7) were mounted on a custom active biomechanical shoulder simulator. Three randomly ordered techniques were conducted: T1- anchors in the valley of the defect, T2- anchors in the rim of the humeral head; T3- anchors in the valley with medial suture placement. The testing conditions included: intact, Bankart, Bankart repair, and 15% & 30% HS lesions with repairs (T1, T2, T3). Outcome measures including internal-external range of motion and stability were recorded. Stability was quantified in terms of glenohumeral joint stiffness against an externally applied anterior force of 70N.
Results
In abduction, no significant reduction in range of motion was observed between any of the remplissage techniques compared to the intact for 15% defects. For 30% defects, T1 and T2 produced significant reductions (T1:14.36.7o, p=0.02; T2:20.79.8o, p=0.02), but T3 had the greatest mean reduction (26.816.6o, p=0.08) in range of motion.
In adduction, for the 15% defect, T1 did not cause a significant reduction in internal-external rotation range of motion; however, T2 reached and T3 approached a significant difference compared to intact (T2:10.75.8o, p=0.02 and T3:20.914.7o, p=0.06, respectively). For the 30% defect, T1 and T3 repairs significantly reduced range of motion (11.0–28.2o, p <= 0.05), while the reduction in motion following T2 repair was not significant (18.815.9o, p=0.3).
All three techniques were found to greatly increase joint stiffness when an external anterior force was applied in abduction and 60o of external rotation; however, no comparisons to the unrepaired defect or the intact state were significant. Additionally, T3 produced the greatest increases in stiffness followed by T1 and T2 (9.20 >= 7.06 >= 6.05 N/mm), but these differences were not significant.
Conclusion
All remplissage techniques were observed to decrease shoulder motion. Specifically, T3 was found to consistently produce the greatest mean reductions in rotation while T1 produced the smallest decreases. The remplissage procedure also produced increases in joint stiffness in all cases, with T3 producing the greatest increases; however, excessive variation may have prevented these findings from being statistically significant. The choice of remplissage technique does have an impact on joint stiffness and motion. Further biomechanical and clinical studies are required to determine the optimum technique that maximizes stability and motion.
