KEYSTONE, COLO. — The time has come to revisit anterior cruciate ligament repair as an alternative to reconstruction for certain patients, said speakers at the annual meeting of the American Orthopaedic Society for Sports Medicine.
“Primary repair has potential advantages over reconstruction in that we can preserve the anatomy better,” said Martha M. Murray, M.D., of the department of orthopedic surgery at Children's Hospital of Boston.
“We can also preserve the physiology and proprioceptive nerves,” she said.
Primary anterior cruciate ligament (ACL) repair went out of favor in the 1990s because reconstruction techniques produced such good results.
However, a classic paper from a pioneer of repair, John A. Feagin Jr., M.D., showed that his early repairs done in West Point cadets mostly failed (a 70% failure rate), said Mark E. Sherman, M.D., an orthopedist who practices in Staten Island, N.Y.
A few surgeons have persisted with trying repairs, however, and technology has improved as well, he said. For example, endoscopy is possible, instrumentation has improved, and MRI is used routinely.
In the pioneering days, Dr. Feagin used a single, absorbable suture in his repairs, Dr. Sherman noted. Today, Dr. Sherman routinely uses two or three sutures.
While there is no definitive evidence supporting primary repair, experience has shown us successes, which in turn suggest one could identify good candidates, he said.
In his experience, the best candidates for ACL repair are skiers with a type I or type IIproximal tear caused by valgus stress, perhaps the most common skiing-related ACL tear, Dr. Sherman said. About 90% of these tears will have a proximal stump of the ligament long enough for the surgeon to use to reattach the ligament, Dr. Sherman said.
In a series of about 150 repair cases, Dr. Sherman said he has a 54% subjective and objective success rate, with various lengths of follow-up. But the series includes patients with football injuries and patients under age 22 years, both of which he has now found do not do well, he noted.
Addressing the conference audience after Dr. Sherman's presentation, Stephen Abelow, M.D., of South Lake Tahoe, Calif., said he has had very good results with just the type of patient Dr. Sherman identified.
He has experience with almost 200 repairs, performed since the early 1980s. In an analysis of those cases, less than 10% went on to reconstruction. Moreover, among the patients who were over age 40 and followed for at least 2 years, less than 5% went on to reconstruction.
“Skiers tend to tear their ACLs very proximally, and those can be repaired,” he said.
Overall, around 60% of ACL tear patients will have a proximal tear with a ligament-bundle stump adequate for the repair procedure, Dr. Murray said.
Dr. Murray said the reason the ACL does not heal itself naturally is probably because of the abundance of plasmin in joint synovial fluid. The plasmin keeps the joint mobile when there is an injury by interfering with clotting and fibrin formation. But fibrin formation is also the first step in tissue repair.
In tendon injuries, for example, fibrin forms a bridge in the gap between the ends of a rupture, a bridge that migrating cells follow to bring the ends back together.
She is attempting to develop a collagen-rich scaffolding that can be placed into a repair as an artificial bridge to stimulate ligament regeneration, and in the laboratory it works well.
This technique could dramatically improve repair results, she said.