Lacertus Fibrosus Good Autograft Option for Biceps Tendon Rupture

The lacertus fibrosus is a safe and effective autograft option for augmenting chronic distal biceps tendon ruptures, according to a new study.

In the study, “Augmentation of Distal Biceps Tendon Ruptures with the Lacertus Fibrosus: A Biomechanical Study in a Tendon-Deficient Model,” published online on January 5, 2022 in the American Journal of Sports Medicine, the researchers compared the biomechanical strength of distal biceps tendon repairs with and without lacertus fibrosus augmentation using a tendon-deficient cadaveric model.

The researchers randomized 16 fresh-frozen matched cadaveric pairs of elbows to either a standard distal biceps tendon repair group or to a tendon-deficient with lacertus fibrosus augmentation group.

They performed all repairs with an oval bone trough and two double-loaded No. 2 braided nonabsorbable sutures in a locked Krackow fashion tied over a lateral bone bridge.

For the tendons of the lacertus fibrosus augmentation group, the researchers wrapped the lacertus around the tendon and incorporated it into the Krackow suture to restore to native size. They then put all the cadavers under cyclic loading and then measured for displacement, stiffness, load to failure and mode of failure.

Overall, both groups had similar displacements on cyclic loading. The standard repair group: 1.66 ± 0.62 mm. The lacertus augmentation group: 1.66 ± 0.62 mm. However, the stiffness was greater for the standard repair group (21.3 ± 2.5 vs 18.5 ± 3.5 N/mm; p = .044).

While mean peak load to failure strengths were good in both groups, the standard repair group did have greater strength (462.4 ± 140.5 vs 377.3 ± 101.1 N; p = .022).

For the standard repair group, the primary mode of failure was fracture at the bone bridge. For the lacertus augmentation group, it was the suture pullout.

“Lacertus fibrosus augmentation of a tendon-deficient biceps repair was less stiff and had lower mean load to failure compared with repair of the native tendon in this cadaveric model, but these values remained biomechanically acceptable above critical thresholds. Consequently, lacertus fibrosus augmentation is a viable option for chronic distal biceps tendon ruptures with tendon attrition,” the researchers wrote.

“Chronic distal biceps tendon ruptures may require autograft or allograft reconstruction secondary to tendon scarring, shortening, attrition, and degeneration. The lacertus fibrosus is a cost-effective and low-morbidity local autograft that can be used to augment repairs.”

Study authors included Matthew R. LeVasseur, M.D., Antonio Cusano, M.D., Michael R. Mancini, Colin L. Uveki, Matthew J. Pina, M.D., Elifho Obopilwe, Andrew E. Caputo, M.D., and Augustus D. Mazzocca, M.D., all from the University of Connecticut.