Full thickness quadriceps tendon grafts with bone had similar material properties to bone-patellar tendon-bone and a four-strand semitendinosus grafts: a biomechanical study

Abstract

Purpose Despite increasing interest in utilizing quadriceps tendon (QT) grafts in anterior cruciate ligament reconstruction (ACLR), data on the optimal quadriceps graft thickness are limited. The purpose of this study was to characterize the mechanical properties for the quadriceps tendon, comparing full-thickness (FT) QT grafts with and without bone to a partialthickness (PT) QT graft, and comparing the three QT grafts to four-stranded semitendinosus (4-SST) and bone-patellar tendon-bone (BTB) grafts and one experimental graft, the two-stranded rectus femoris (RF). Methods Forty-eight (n = 48) young cadaveric grafts (mean age 32 ± 6 years) were utilized for testing with N = 8 specimens in each of the following groups; (1) FT QT with bone, (2) FT QT without bone, (3) PT QT without bone, (4) BTB, (5) RF, and (6) 4-SST. Each specimen was harvested and rigidly fixed in custom clamps to a dynamic tensile testing machine for biomechanical evaluation. Graft ultimate load and stiffness were recorded. Independent groups one-factor ANOVAs and Tukey's pairwise comparisons were performed for statistical analyses. Results FT QT with bone and 4-SST grafts demonstrated similar ultimate loads to BTB grafts (both n.s), whereas PT QT demonstrate statistically significantly lower ultimate loads to BTB grafts (n.s) and 4-SST grafts (n.s). Furthermore, no statistically significant differences were observed between the ultimate loads of FT QT vs. PT QT grafts without bone (n.s) or between FT QT with vs. without bone (n.s). FT QT grafts with bone did not demonstrate statistically significantly greater ultimate loads than PT QT grafts without bone (n.s). The RF graft demonstrated statistically significantly lower ultimate loads to BTB grafts (p < 0.005) and 4-SST grafts (p < 0.014). Conclusions Full thickness QT grafts with bone had similar material properties to BTB and a 4-SST grafts, while Partial thickness QT graft without bone had significantly lower material properties than BTB and 4-SST, in a biomechanical setting.

Current trends in graft choice for anterior cruciate ligament reconstruction – part I: anatomy, biomechanics, graft incorporation and fixation

“…The ultimate load to failure of BPTB autograft ranges from 319 to 4389 N, with the highest load reported in 15 mm-wide grafts [ 75 ]. In clinical practice, 10 mm-wide grafts with ultimate loads to failure of 1880 to 2664 N are typically used [ 26 , 50 , 111 ].…”

“…Similarly, the ultimate load to failure for a 10 to 12 mm-wide QT autograft ranges from 249 to 2186 N [ 50 , 75 , 111 ]. QT autograft with bone block, as well as full-thickness grafts appear to have higher ultimate loads to failure compared to all-soft tissue or partial thickness grafts [ 111 ].…”

“…For HT autograft, graft configuration (including total number of strands) correlates with graft size, which is in turn positively correlated with tensile strength [ 14 ]. Depending on graft configuration, graft diameters ranging from 6 mm to over 10 mm can be obtained with ultimate loads to failure ranging from 225 to 4590 N [ 50 , 75 , 111 ]. While a graft should have a minimum thickness of 8 mm, increased graft CSA is associated with an increased complication risk due to notch and PCL impingement [ 49 , 74 , 76 , 89 ].…”

“…For BPTB grafts, stiffness is reported to range from 158 to 685.2 N/mm, with values between 324 and 543 N/mm for grafts of 10 mm width [ 3 , 75 , 111 ]. For QT, stiffness is reported to be between 17.0 and 809.0 N/mm, with the smallest values seen by Noyes et al when testing a quadriceps tendon-patellar retinaculum-patellar tendon graft construct [ 83 ].…”

Technique of ACL Reconstruction With Autologous Quadriceps Tendon Bone Graft and Femoral Press Fit Fixation

“…A biomechanical study has shown equivalent material properties to the hamstrings and patellar tendons, regarding strength and volume. 9 Second, the graft is predictable in length and diameter, which is not the case with patellar tendon and hamstrings. 5 Third, there is less postoperative weakness in ACL agonists than after harvesting of hamstring tendons, with low donor side morbidity.…”