(For affiliations, see bottom of article.)
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- PMID: 41281456
- PMCID: PMC12638636
- DOI: 10.1177/23259671251385225
Abstract
Background: Avulsions of the biceps femoris and fibular collateral ligament (FCL) from the fibula often present as a knee ligament injury for treatment. Recent advances in suture anchors allow for knotless tension and retension of repair constructs in contrast to using transosseous sutures alone. The tensionable suture anchors may eliminate creep and improve the biomechanical performance of repairs at time point zero.
Purpose/hypothesis: The aim of this study is to compare the biomechanics of 2 repair constructs for biceps femoris repair. It was hypothesized that both repair constructs would effectively restore knee stability in a distal biceps femoris/FCL injury pattern, and that the modern knotless suture anchor would produce a biceps femoris repair that would fail at a higher load and exhibit greater stiffness during tensile testing.
Study design: Controlled laboratory study.
Methods: Sixteen match-paired, fresh-frozen cadaveric knees (74 ± 7.5 years) were tested by external rotation (at 5 N·m) and varus (at 10 N·m) on a 6 degrees of freedom robotic system in 3 conditions: uninjured state, avulsed FCL and biceps femoris, and 1 of the 2 repair options, repair with knotless suture anchors or transosseous sutures alone. After robotic testing, repairs underwent tensile testing to failure on a uniaxial tensile testing machine to determine the failure load and stiffness of each repair construct. The mean degrees for external and varus rotation, failure load, and stiffness values were calculated for each group and compared using paired t tests between the 3 conditions and 2-sample independent t tests between the 2 repair groups.
Results: Robotic testing of both repairs showed significant reductions (P < .05) compared with the sectioned state in varus rotations at 0° and 30° and external rotations at 0° of knee flexion. The repair with suture anchors significantly reduced laxity in varus rotation at 60° of knee flexion (P = .02), whereas the suture alone repair did not (P = .09). Tensile testing revealed mean failure loads for the knotted suture repair of 317 N (range, 193-450 N) and for the knotted anchor repair of 447 N (range, 239-818 N), showing no statistically significant difference (P = .12). The mean stiffness for the knotted suture repair was 9.45 N/mm (range, 4.6-12.8 N/mm). The anchor repair was 9.16 N/mm (range, 3.6-15.3 N/mm), showing no statistically significant difference (P = .87). The sectioned state was significantly different from the intact state at all flexion angles for all conditions tested (P < .05).
Conclusion: Our study demonstrated that a transosseous biceps femoris repair with knotless suture anchors performed similarly to a transosseous biceps femoris repair with suture alone in robotic varus and external rotation testing. With tensile testing, a higher failure load was observed in each matched pair with suture anchor repair. However, no statistically significant differences were found between the restoration of knee kinematics, mean failure loads, and stiffness in these 2 repair constructs.
Clinical relevance: Understanding the biomechanical and tensile performance of the biceps femoris aids clinicians with pre- and intraoperative decisions.
Keywords: Kuka; avulsion; biceps femoris; failure load.
© The Author(s) 2025.
Conflict of interest statement
One or more of the authors has declared the following potential conflict of interest or source of funding: This study was supported by Arthrex and the State of Florida Appropriation Department of Health for Regenerative Medicine. B.D. has received research funding and a grant from Arthrex, support for education from Smith & Nephew, and food and beverage from Stryker. S.E.J. has received research funding, royalties or a license, and consulting and speaking fees from Arthrex; nonconsulting fees from CGG Medical. R.V.O. has received research funding and hospitality payments from Arthrex; and consulting fees from DePuy. J.T., D.P., and G.C. have received research funding from Arthrex. A.A. has received research funding from Smith & Nephew; research funding, consulting fees, and royalties from Arthrex; a grant from DJO; and support for education from CGG Medical. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto. Ethical approval was not sought for the present study.
Affiliations
- 1Andrews Research & Education Foundation, Gulf Breeze, Florida, USA.
- 2Texas Tech University Health Sciences Center School of Medicine, Lubbock, Texas, USA.
- 3Department of Mechatronics Engineering, Kent State University, Kent, Ohio, USA.
Figures
Figure 1.
Suture alone biceps femoris repair construct.
