A 3D finite element model for geometrical and mechanical comparison of different supraspinatus repair techniques

Abstract

Background: Contact pressure and contact area are among the most important mechanical factors studied to predict the effectiveness of a rotator cuff repair. The suture configurations can strongly affect these factors but are rarely correlated with each other. For example, there is a significant difference between the single-row technique and the transosseous or transosseous-like approaches in terms of footprint contact area coverage. A finite element model-based approach is presented and applied to account for various parameters (eg, suture pretension, geometry of the repair, effect of the sutures, geometry of the lesion) and to compare the efficacy of different repair techniques in covering the original footprint.

Methods: The model allows us to evaluate the effect of parameters such as suture configuration and position and suture pretension. The validity of such an approach was assessed in comparing 3 different repair techniques: single row, transosseous equivalent, and double row.

Results: Results from the application of the models show that the double-row and transosseous-equivalent techniques lead to progressive increase of the contact area compared with the single-row approach, supporting the conclusion that transosseous-equivalent fixation leads to an increase of the contact area and a better distribution of the pressure coverage.

Conclusion: The 3-dimensional finite element model approach allows multiple variables to be assessed singularly, weighing the specific influence. Moreover, the approach presented in this study could be a valid tool to predict and to reproduce different configurations, identifying how to reduce the stress over the tendon and when a repair could be effective or not.

Keywords: Shoulder; cuff repair; finite element model; transosseous.