August 02, 2019
1 min read

Bridge-enhanced ACL repair may restore tissue quality, quantity

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At 2-year follow-up, bridge-enhanced ACL repair yielded a cross-sectional area, signal intensity and sagittal orientation similar to the contralateral native ACL, according to published results.

Ata M. Kiapour , PhD, MMSc , and colleagues analyzed the MRIs of patients with a complete midsubstance ACL tear treated with either bridge-enhanced ACL repair (BEAR; n=10) or ACL reconstruction with hamstring autograft (n=10) at 3, 6, 12 and 24 months after surgery to determine the average cross-sectional area and signal intensity of the ACL or graft. Researchers also assessed ACL orientation, stump length and bony anatomy.

At all time points, results showed the ACL reconstruction group had a 48% to 98% larger mean cross-sectional area compared with the contralateral intact ACLs. Although BEAR ACLs had a 23% to 28% greater cross-sectional area vs. the contralateral intact ACLs at 3 and 6 months, researchers found these were similar at 12 and 24 months. The BEAR ACLs and contralateral ACLs had similar sagittal orientation compared with the grafts in the ACL reconstruction group, which were 6.5° more vertical.

Researchers noted a correlation between a bigger notch and a bigger cross-sectional area, while high signal intensity was associated with shorter ACL femoral stump, steeper lateral tibial slope and shallower medial tibial depth for BEAR ACLs. Results showed an increased ACL cross-sectional area after the BEAR procedure resulted from performance of notchplasty. ACL graft size or signal intensity were not correlated with any anatomic features.

Kiapour and colleagues noted use of BEAR may lead to a significant impact on the clinical care of patients with ACL injuries.

“These results suggest that BEAR procedure can offer a subject-specific treatment to ACL injury, which is a major breakthrough considering the biological variations in ACL tissue quality and anatomy between different subjects,” Kiapour told “The observed 2-year changes in the repaired ACL, as well as the associations between knee anatomy and repaired ACL properties, are very informative and justify the need for future studies to further improve the outcomes of the BEAR procedure.” – by Casey Tingle

Disclosures: Kiapour reports he received research grants from the NIH and the National Football League Players Association through the Harvard Catalyst’s Football Players Health Study. Please see the full study for a list of all other authors’ relevant financial disclosures.