AJSM - 2026-06-01 - Journal Article; Comparative Study
Lateral Extra-articular Tenodesis Restores Knee Rotational and Translational Stability Regardless of Fixation Type: A Matched-Pair Cadaveric Study.
Ihn H, Quintana D, Puzzitiello R, Sakelaris P, Rawson H, Barber N, Ernat JJ, Aoki SK, Maak TG
Topics
Key Takeaway
All three LET fixation methods (suture anchor, interference screw, metallic staple) restored internal rotational stability to near-native levels after 2000 cycles of 5 N·m loading, though suture anchors showed significantly greater rotational change under cyclic loading versus screws (7.2% ± 2.3% vs -1.3% ± 2.6%, P=.011).
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Summary
This matched-pair cadaveric study compared suture anchor, interference screw, and metallic staple fixation for modified Lemaire LET across four sequential states: intact, anterolateral lesion, post-LET, and post-cyclic loading (2000 cycles, 5 N·m internal rotation). All three constructs restored anterior translation and internal rotational stability to near-native levels after cyclic loading with no significant between-group differences in absolute rotation values. Suture anchors demonstrated significantly greater percent change in internal rotation from pre- to post-cyclic loading compared to interference screws (7.2% vs -1.3%, P=.011), but this difference did not reach significance versus staples (14.3% vs 5.3%, P=.338).
Key Limitation
Cyclic loading was limited to 2000 cycles of isolated internal rotation torque, which does not replicate the multiplanar, variable-magnitude loading of in vivo rehabilitation or sport, potentially underestimating or misrepresenting real-world fixation fatigue behavior.
Original Abstract
BACKGROUND
Lateral extra-articular tenodesis (LET) is used as an adjunct to anterior cruciate ligament reconstruction (ACLR) to enhance stability. However, understanding of the optimal fixation method is limited.
PURPOSE/HYPOTHESIS
The purpose was to compare biomechanical knee stability using 3 femoral LET fixation methods before and after cyclic loading. It was hypothesized that the fixation achieved with a suture anchor or an interference screw would demonstrate greater stability than that achieved with a metallic staple.
STUDY DESIGN
Controlled laboratory study.
METHODS
Ten matched pairs of cadaveric knees (mean age 64 years) underwent modified Lemaire LET. Each pair received suture anchor fixation on 1 knee and either interference screw (arm A) or metallic staple (arm B) fixation on the contralateral knee. Specimens were tested in 4 states: intact (native), anterolateral knee lesion, modified Lemaire (LET) procedure, and modified Lemaire (LET) procedure after cyclic loading. Cyclic loading consisted of 2000 cycles of 5 N·m internal rotation at 1 Hz. Anterior translation was applied at 90 N of force using visual marker motion capture. Internal rotation was measured using a 5 N·m moment and a digital inclinometer.
RESULTS
No significant differences in anterior translation were observed between the different states (anterolateral lesion, LET, and post-cyclic loading) for all constructs. The mean increase in internal rotation among the subgroups after undergoing anterolateral lesion ranged from 2.1° to 4.0°. No significant difference was found in mean internal rotation after samples underwent cyclic loading in both arms of the study (arm A [suture anchor vs screw], P = .262; arm B [suture anchor vs staple], P = .450). Specimen undergoing suture anchor fixation demonstrated significantly greater change in internal rotation from pre- to post-cyclic loading than those using screw fixation (arm A, 7.2% ± 2.3% vs -1.3% ± 2.6%, respectively; P = .011) but not staple fixation (arm B, 14.3% ± 16.7% vs 5.3% ± 3.1%; P = .338). Internal rotatory stability was restored by all LET methods even after undergoing cyclic loading.
CONCLUSION
All fixation methods restored rotational stability to near-native levels even after loading. Suture anchor fixation appeared more vulnerable to cyclic loading than the other 2 methods.
CLINICAL RELEVANCE
Suture anchors appeared most vulnerable to cyclic loading. No significant difference was found in absolute mean internal rotation values between suture anchors and screws or staples. Clinically, all 3 methods remain viable options for LET fixation. Staples and screw may better resist cyclic physiologic stress when compared with suture in controlled settings; however, this may not be clinically significant.