Published 9/1/2008
Annie Hayashi

Young athletes have high failure rate with allograft ACL

“With 300,000 anterior cruciate ligament (ACL) reconstructions performed in the United States every year, this procedure has become routine with favorable results. Graft selection, however, continues to be controversial,” said Gene R. Barrett, MD, senior author of “Allograft anterior cruciate ligament reconstruction in the young, active patient.”

“In a previous study of fresh-frozen bone-tendon-bone allograft ACL reconstructions performed at our institution, we found a failure rate of 2.6 per­cent in individuals older than 40 years of age who were less active and had lower Tegner scores,” said Dr. Barrett.

“To the best of our knowledge, there have been no studies examining the results of fresh-frozen bone-tendon-bone allograft ACL reconstructions among younger, more active patients who have higher Tegner scores,” he said.

This led Dr. Barrett and his colleagues to conduct a 12-year retrospective review of 64 patients younger than age 40, who underwent primary ACL reconstruction using fresh-frozen bone-patella tendon-bone (BPTB) allografts. In this patient group, however, the failure rate was nearly one in four.

The results were presented by Kurre T. Luber, MD, at the annual meeting of the American Orthopaedic Society of Sports Medicine.

Who was selected?
“We wanted to analyze the outcomes of fresh-frozen BPTB allograft ACL reconstruction in those younger than age 40 with regard to their activity level or Tegner score,” said Dr. Luber.

All patients had the same surgeon and a minimum of 2 years of follow-up. The 64 patients who met the inclusion criteria had a mean age of 28 years and a mean follow up of 57 months.

According to Dr. Luber, results of each patient’s initial exam, surgical findings, and follow-up examinations were prospectively entered into a computerized relational database.

How were patients evaluated?
Using both objective and subjective criteria, all patients were evaluated pre- and postoperatively by the same surgeon who performed the surgery.

Objective evaluation methods included Tegner scores, Lysholm scores, Lachman testing, KT-1000 arthrometer testing, thigh circumference difference, range of motion differences, and the presence or absence of an effusion.

Fifteen visual analog scale (VAS) scores from 0 to 10 comprised the subjective evaluation.

“Clinical failure was defined as a documented graft failure with repeat ACL revision surgery, or a combination of a 2+ Lachman, 1+ or greater pivot shift test, 5 mm or greater side-to-side difference in KT-1000 arthrometer testing,” said Dr. Barrett.

High failure rate reported
Of the 64 patients, 15 (23.4 per­cent) met the failure criteria. “The allograft failure rate in this young active population is exceedingly high when compared to the 2.6 per­cent failure rate in our previous study of patients older than 40 years of age,” said Dr. Barrett.

Though no real differences were seen in VAS scores, some variations in swelling and jumping were found when researchers compared patients whose allografts failed to those whose allografts did not fail.

Dr. Barrett and his colleagues were surprised to find no statistically significant differences in Lysholm scores, thigh circumference, and extension and flexion between the failure and nonfailure groups.

When the researchers evaluated the Tegner scores, they found that the failure group (the more active population) had a statistically higher pre-injury Tegner score (mean 6.47) than the nonfailure group (mean 5.59) (p = 0.04).

“We also noted that our failure group returned to a statistically higher Tegner activity level,” said Dr. Luber. “Although they did not return to their original pre-injury level, they did have a mean postoperative Tegner score of 5.93, while the nonfailure group had a mean postoperative score of 4.86 (p = 0.018).”

What is the next step?
Numerous reports have raised concerns about delayed graft incorporation with allografts. “Although we did not study this factor in our analysis,” said Dr. Barrett, “we think that delayed healing may play a role in allograft failure among patients who return to a higher level of activity.”

In addition, higher Tegner activity levels may increase the risk of BPTB allograft failure—making this type of graft less desirable for the young, active athlete.

“The pre-injury and postop­erative Tegner scores for the failure group with ACL-dependent sports such as tennis, basketball, soccer, and downhill skiing were consistently 6 and 7,” he said.

“In con­trast, the scores for the nonfailure group were close to 5 for activities such as cycling and jogging.

“Although using allografts has obvious benefits—such as avoiding a second surgical site on the patient, enabling a quicker return to work, and less postop­erative pain—it may not be the right choice for a young, active patient,” said Dr. Barrett.

Neither author reported any conflicts of interest related to this study.

Annie Hayashi is the senior science writer for AAOS Now. She can be reached at hayashi@aaos.org