Biomechanical Comparison of Full-Thickness Versus Partial-Thickness Quadriceps Tendon Grafts for ACL Reconstruction.

Abstract

Background: The quadriceps tendon (QT) autograft is increasingly becoming the graft of choice for reconstructing of the anterior cruciate ligament (ACL), likely because recent clinical studies demonstrate low harvest-site morbidity and failure rates. Both full-thickness QT (FQT) and partial-thickness QT (PQT) graft techniques have been described for ACL reconstruction, but there is currently limited research to guide surgeons on which thickness is optimal.

Purpose: To analyze and compare the material and mechanical properties of PQT and FQT grafts versus the standard patellar tendon (PT) graft.

Study design: Controlled laboratory study.

Methods: A total of 8 PQTs and 8 FQTs, each 10 mm wide, were harvested from the extensor mechanism from matched paired donors with a 10-mm PT graft. Specimens were loaded in tension to failure while load and displacement were continually recorded. Mechanical and material properties were calculated and compared using a 1-way analysis of variance.

Results: FQT grafts had a greater cross-sectional area and were stronger and stiffer compared with PQT and PT grafts (P < .05). There were no significant differences in strength and stiffness between the PQT and PT grafts when loaded to failure. Both quadriceps grafts recorded a lower ultimate strain at failure compared with the PT grafts (P < .05).

Conclusion: The biomechanical results from this study demonstrate that PQT grafts have similar biomechanical properties to the current gold standard PT grafts.

Clinical relevance: These results suggest PQT grafts are mechanically sufficient and may be preferred, as they do not carry concerns of residual postoperative weakness and knee pain that are associated with FQT and PT grafts, respectively.