Comparable outcomes seen for bridge-enhanced ACL repair, autograft ACL reconstruction
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Patients who had a bridge-enhanced ACL repair technique showed similar patient-report outcomes with no infection or rejection compared with patients who had autograft ACL reconstruction, according to recently presented data.
“At 2 years, the [bridge-enhanced ACL repair] BEAR subjects had comparable patient-reported outcomes, comparable knee stability, improved muscle strength and a reinjury rate similar to that seen in ACL reconstruction for these young and active patients,” Martha M. Murray, MD, said.
Murray presented 2-year results of BEAR II, a prospective, randomized clinical trial of use of a bridge-enhanced ACL repair implant and technique compared with autograft ACL reconstruction, at the virtual American Orthopaedic Society for Sports Medicine Annual Meeting.
Murray, who is a professor of orthopedic surgery at Harvard Medical School and Boston Children’s Hospital, said the BEAR procedure is a suture repair of the ligament combined with an implant placed between the torn ends of the ligament and loaded with the patient’s blood to facilitate the biology of the ACL healing.
“The BEAR implant has low immunogenicity and is able to absorb and activate the biologic placed within it which in this case, is the autologous blood cells. It also encourages ACL ingrowth, so it has been specifically designed for this purpose,” she said.
The BEAR II trial enrolled 100 patients randomized to either BEAR or ACL reconstruction. There were 65 patients in BEAR group and 35 patients who had ACL reconstruction with autograft. The study was fully enrolled by May 2017.
Demographics were a young and active population, with both groups similar in age, gender and preoperative activity. Patient age ranged from 14 to 35 years, with a median age of 17 years in both groups. Median Marx activity was 16 in both groups. Researchers had 2-year follow-up on 99% of patients.
The BEAR II outcome measures were the patient-reported outcomes measured by the IKDC subjective score and AP laxity of the knee using KT-1000 testing. Secondary outcomes were hamstring strength and safety measures.
Patient-reported outcomes at 2 years for the IDKC subjective score showed the ACL reconstruction group had a mean at 85 points and the BEAR patients had a mean of 89 points. For KT-100 testing, the ACL reconstruction group had a mean side-to-side difference of 1.8 mm. The BEAR group had a mean of 1.6 mm. Murray said both were like other trials for ACL reconstruction, with differences reported between 1 mm to 3 mm.
“For this second primary outcome, BEAR was shown to be not inferior to ACL reconstruction,” she said.
The ACL reconstruction group, which was largely a hamstring cohort, had a persistent 60% hamstring strength deficit with the knee measured at 90 of flexion. Patients in the BEAR group did not have this deficit, she said.
Patients in the ACL reconstruction group had ACL retear rates of 6 %, with BEAR patients having a 14% retear rate. BEAR patients who converted to ACL reconstruction had outcomes like those patients who had an ACL reconstruction only, Murray said.
Murray reported no infections, significant immune response or allergic reactions in any patients.
“We feel now that the safety profile is acceptable. The efficacy is also reasonable. We feel there still is work to be done. We like to work to continue with this technique to see if we could use either modifications to the surgical technique or modifications to the rehabilitation protocol to further improve the outcomes for these patients. We feel that perhaps someday we will be able to repair and regenerate the torn ACL instead of replacing it,” she said.
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Murray MM, et al. Presentation 28. Presented at: American Orthopaedic Society for Sports Medicine Annual Meeting; July 8-9, 2020 (virtual meeting).
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