FDA Approves Implant as Alternative to ACL Reconstruction

Marcia Frellick

December 21, 2020

The US Food and Drug Administration (FDA) granted marketing authorization for an anterior cruciate ligament (ACL) implant, intended as an alternative to surgical reconstruction after ACL tears.

According to the FDA, the implant is the only currently available alternative to reconstruction with allograft, autograft, or suture-only repair for treating ACL tears.

Dr Jay Lee

Jay Lee, MD, assistant professor of orthopedic surgery at Johns Hopkins School of Medicine, Baltimore, Maryland, told Medscape Medical News the implant offers two big benefits: "One, the native ACL is salvaged. Two, the morbidity of harvesting another tendon is avoided."

ACL injuries ― sprains and tears ― affect 250,000 people in the United States each year, according to the Centers for Disease Control and Prevention.

"Torn ACLs are among the most common knee injuries in the US, but for years, treatment has been limited to ACL reconstruction, which can be quite invasive and typically requires using tendon or a combination of tendon and bone from other parts of the body or obtained from a tissue bank to complete the reconstruction," Capt Raquel Peat, PhD, MPH, director of the Center for Devices and Radiological Health, Office of Orthopedic Devices, FDA, said in a statement.

The device, called the Bridge-Enhanced ACL Repair (BEAR) Implant, was approved under the de novo premarket review pathway for new low- to moderate-risk devices.

It is made from bovine collagen and is secured via suture to bridge the gap between the torn ends of a patient's ACL. It is absorbed by the body after about 8 weeks and is replaced by the body's own tissue.

According to the developer (Miach Orthopaedics, Inc), the implant holds "a small amount of the patient's blood in the wound site. The combination of the BEAR Implant and the patient's blood provides a scaffold that allows the torn ends of the ACL to heal back together."

Dr Martha Murray

The implant offers an alternative for suture-only repair, which fails "about 50% of the time," Martha Murray, MD, FAAOS, founder of Miach, told Medscape Medical News.

Murray is a professor of orthopedic surgery at Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts.

"Harnessing the biology of the body's own ligament-healing ability is possible with the BEAR Implant, where it is not with suture repair alone," said Murray, a member of the American Academy of Orthopaedic Surgeons' Committee on Devices, Biologics and Technology.

She said in the company's press release, "There are a number of advantages to repairing a ligament instead of replacing it. That is why, more than 30 years ago, we set out to find a way to help the ligament heal itself."

Implant Is for Complete Tears

The implant is meant for skeletally mature patients aged 14 years or older who experience a complete tear of the ACL, as confirmed by MRI. Use of the implant requires that an ACL stump be present on the tibia in order to facilitate the repair, the company says.

The FDA judged the safety and effectiveness of the implant on the basis of results of a randomized controlled trial involving 100 patients who had experienced complete ACL rupture.

In the trial, 65 patients received the BEAR Implant, and 35 members in the control group underwent ACL reconstruction with autograft. All patients received physical therapy and were followed for 2 years, at which point the investigators compared symptom scores on the International Knee Documentation Committee (IKDC) Questionnaire.

Patients who received the implant had an average score of 88.6, and control participants had an average score of 84.6. The questionnaire asks patients about pain and stiffness, sports activity, and knee function.

According to the FDA press release, laxity of the knee joint was assessed with arthrometry by comparing patients' healthy leg with the injured leg.

Readings <3 mm (the height of two stacked pennies) are considered normal. At 2 years, for patients who received the implant, average laxity was greater by 1.7 mm (about the thickness of a penny) in the treated knee than in the untreated knee. Laxity in the control group was almost the same, at >1.8 mm greater in the treated knee than in the untreated knee.

"Complications observed in the study consisted of graft or repair failure and the need for additional surgical procedures," the FDA reports.

Murray said ACL reconstruction is still a good option.

"Over 65% of patients can get back to their sports activities, and the vast majority will have a stable knee," she said. "For cutting and pivoting athletes, ACL reconstruction with autograft tendon is still the gold standard of surgical treatment."

Cost comparisons are unclear, Murray and Lee said.

Lee added, "The implant is unique, and so the developer likely will have some leeway in pricing."

Further research will highlight comparisons between the implants and surgical reconstruction.

"We will like our ACL treatments to last a lifetime; thus, it would be important to find out if these patients have comparable results at long term, 5, 10, and 20 years, in respect to function, ACL reinjury, and arthritis," Lee said.

Marcia Frellick is a freelance journalist based in Chicago. She has previously written for the Chicago Tribune, Science News and Nurse.com and was an editor at the Chicago Sun-Times, the Cincinnati Enquirer, and the St. Cloud (Minnesota) Times. Follow her on Twitter at @mfrellick

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