Distal Biceps Tendon Repair With Interlinked Knotless All-Suture Anchors Provides Greater Footprint Optimization and Higher Fixation Security Over Intramedullary Cortical Button Repair: A Biomechanical Study.

Abstract

Recent biomechanical investigations of distal biceps tendon repair (DBTR) constructs have typically evaluated time-zero fixation security, while tendon-bone repair footprint characterization has been limited. Consequently, interactions between repair construct design, fixation security, and repair footprint parameters remain minimally assessed. The purpose was to compare time-zero fixation security and repair footprint parameters between a new DBTR construct with 2 interlinked knotless all-suture anchors and an established DBTR construct with an intramedullary cortical button. It was hypothesized that the new interlinked twin-anchor repair technique would demonstrate greater time-zero fixation security and footprint optimization. Controlled laboratory study. A total of 20 cadaveric elbows in 2 matched groups underwent DBTR with either (1) twin interlinked knotless all-suture anchors or (2) a single intramedullary cortical button. Anatomic and repair footprints were digitally captured with a 3-dimensional coordinate-measuring machine. The repair constructs underwent cyclic loading and then were loaded to failure. Anatomic and repair footprint areas and their overlap, tendon-bone interface and total construct displacement, ultimate failure load, and failure mode were recorded. Anatomic footprint restoration and repair footprint accuracy were calculated. The interlinked knotless twin-anchor repair construct demonstrated a larger repair footprint area (55.1 ± 14.9 vs 35.2 ± 19.8 mm², respectively; <i>P</i> = .032), greater anatomic footprint restoration (42.7% ± 12.9% vs 20.2% ± 9.4%, respectively; <i>P</i> = .003), lower tendon-bone interface displacement (3.2 ± 1.2 vs 12.4 ± 6.6 mm, respectively; <i>P</i> = .003), lower total construct displacement (5.5 ± 1.7 vs 13.9 ± 8.1 mm, respectively; <i>P</i> = .015), and higher ultimate failure load (468.3 ± 124.2 vs 313.2 ± 103.4 N, respectively; <i>P</i> = .001) compared with the single-button repair construct. The most common failure mode was knot slippage/suture breakage (60%) in the single-button group and suture-tendon interface failure (50%) in the twin-anchor group. While this cadaveric study did not account for the effects of tendon-bone healing, the novel interlinked twin-anchor DBTR construct demonstrated greater time-zero fixation security, a larger repair footprint, and greater anatomic footprint restoration over the established single-button repair construct. A DBTR construct with twin interlinked knotless all-suture anchors offers multiple features, including time-zero fixation security and footprint optimization, that may potentially improve clinical outcomes.