BEAR in Mind: There’s a New ACL Repair Technique on the Block



Bridge-Enhanced Anterior Cruciate Ligament Repair: Two-year results of a first-in-human study

Murray MM, Kalish LA, Fleming BC, Proffen BL, Ecklund K, Kramer DE, Yen YM, & Micheli LJ.  Ortho J Sports Med. 2019; 7(3).  DOI: 10.1177/2325967118824356  
Take Home Message: Bridge-enhanced anterior cruciate ligament repair is producing similar outcomes to hamstring autograft reconstruction up to 2 years post-surgery.

Anterior cruciate ligament (ACL) surgical reconstruction techniques are evolving to improve short- and long-term outcomes for patients after surgery.  A newer approach that is getting a lot of attention is the bridge-enhanced anterior cruciate ligament repair (BEAR). To perform a BEAR, a surgeon repairs the ACL with sutures and a scaffold to promote optimal alignment and healing.  Before large clinical trials can be performed with this new procedure it is critical to have initial results to ensure it is safe and potentially beneficial. Hence, the authors conducted an observational cohort study of 10 participants who received a BEAR and 10 who received a hamstring autograft ACL reconstruction to assess physical exam findings, patient-reported outcomes, and adverse events at one and two years after surgery. The researchers evaluated the 20 participants pre-operatively and then at 6-, 12-, and 24-months post-surgery.  To be included, participants must have been between 18 to 35 years old and had at least 50% ACL tibial remnant length left.  The post-operative rehabilitation was standardized and identical recommendations were made for both groups.  Patients completed patient-reported outcomes (IKDC subjective & KOOS), IKDC physical examination, and functional outcomes measures (hop testing, strength), and knee laxity (KT-1000), and magnetic resonance imaging.  The authors reported that the outcomes were comparable between the BEAR technique and the more traditional ACL reconstruction.  All patient-reported outcomes, clinical evaluation, and most functional measures improved and were similar between groups.  However, isometric hamstring strength was typically better in the BEAR group at all time points than the ACL reconstructed group. 

This is the first time researchers have examined the outcomes over 2 years of the BEAR technique to manage ACL tears.  The BEAR technique seems to be safe and comparable to a traditional ACL reconstruction up to 2 years post-surgery.  This builds on the preliminary report from this cohort that found a BEAR led to no increased risk for adverse events in the first few months after surgery. It would be very interesting to continue to follow these participants longer to determine the long-term effects and how they may compare to ACL reconstructions using more traditional methods.  However, the surgery was performed within a wide variety of individuals, and it would be interesting to see the outcomes of this technique if used in an athletic population.  The researchers noted that there was higher water content seen in the magnetic resonance images around midsubstance of the graft in about half of the participants.  Following this group longer would be critical to see how the grafts responded to increasing loads and physical activities as these individuals continue to participate in their normal activities.  The BEAR technique requires arthrotomy over arthroscopy, which may create some long-term issues due to the trauma of the surgery.  It will be interesting to see if the surgical technique could improve over time to become less invasive as surgeons become more familiar with it.  This reminds me of the novelty of the double-bundle technique, which showed some really positive outcomes, yet has not caught on as much as people expected.  However, early results from the BEAR procedure seem comparable to a more traditional ACL reconstruction, but the applicability to athletes and long-term knee health still needs to be determined. In the meantime, clinicians should stay up-to-date on the latest news on BEAR and other novel surgical strategies for an ACL tear because patients may ask about them.
Questions for Discussion:  What are your thoughts on any potential benefits or major concerns to the BEAR technique?  Are there any other newer ACL surgical techniques that you think may catch-on?
Reviewed by: Jeffrey Driban
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