AAOS Now

Published 9/1/2010
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Peter Pollack

Allograft or autograft for ACL reconstruction?

Outcomes similar, but autografts may be better for the most active patients

Patellar tendon allograft and autograft offer similar clinical outcome potential for reconstruction of the anterior cruciate ligament (ACL), although autografts may be a better option for patients who wish to return to the most strenuous levels of activity, said Randy Mascarenhas, MD, who presented a paper on the topic at the 2010 annual meeting of the Arthroscopy Association of North America.

“The literature has shown that patellar tendon autograft reconstruction is the gold standard in high-demand patients, but allograft reconstruction is gaining popularity due to decreased donor site morbidity and easier rehabilitation,” he explained. “Autograft reconstruction offers the advantages of being clinically proven and having a faster incorporation time. Allograft reconstruction avoids the donor site morbidity associated with autograft, but poses a risk of disease transmission, the cost is higher, and incorporation takes longer.”

No statistical difference
To compare outcomes using the two techniques, Dr. Mascarenhas and his colleagues conducted a matched pair study of 38 patients who had had a bone-patellar tendon-bone ACL repair using either an allograft or an autograft. The patients met inclusion criteria if they had more than 2 years of follow-up and participated in strenuous athletics at least four times per week prior to surgery. Patients were excluded from the study for the following reasons:

  • previous surgery on the contralateral knee
  • previous unrelated surgery on the affected knee
  • posterolateral corner injury on the affected knee
  • grade III collateral ligament injury on the affected knee
  • articular cartilage changes greater than Outerbridge grade I

The research team matched the patients by gender (36.8 percent female), age, and length of follow-up.

“Our operative technique involved a single-incision, single-bundle ACL reconstruction with either an autograft or an allograft,” said Dr. Mascarenhas. “The grafts were secured on the femur and tibia with interference screws, and all surgeries were performed either by Freddie H. Fu, MD, or Christopher D. Harner, MD.

Overall, 14 of the patients in the autograft group reported that they were able to perform very strenuous activity without a sense of instability, compared with 7 in the allograft group. Dr. Mascarenhas pointed out, however, that those results only approached statistical significance (p < 0.07).

“No significant differences were noted in patient-reported outcome scores between groups,” said Dr. Mascarenhas. “In terms of return-to-sport, we found that about 80 percent of patients in each group stated that they returned to very strenuous sports four to seven times per week, though only about 60 percent of these stated that this was at the same level or better than prior to injury. We did find that more autograft patients were participating in strenuous or very strenuous activities at final follow-up, but this finding did not reach statistical significance (Table 1).”

Divergence from other studies
Researchers found no significant differences between the groups for the KT-1000 (pivot-shift) tests or knee range-of-motion. In addition, radiographic analysis revealed no significant differences between the allograft or autograft groups at the final postoperative follow-up.

“We concluded that autograft and allograft patellar tendon ACL reconstructions have no statistically significant differences in clinical outcomes,” he said. “That differs from some of the other results found in the current literature.”

According to Dr. Mascarenhas, the strengths of the study were the matched pairs design, which was based on specific matching criteria, and the fact that all surgeries were performed by two experienced knee surgeons. The weaknesses involved its retrospective nature and low patient numbers.

Dr. Mascarenhas’ co-authors included Dr. Fu; Dr. Harner; Michael Tranovich, BA; John Karpie, MD, and James J. Irrgang, PT, PhD, ATC, FAPTA.

Disclosure information: Dr. Fu—Arthrocare; Stryker; Smith & Nephew; Saunders/Mosby-Elsevier; Orthopaedic Research and Education Foundation; American Orthopaedic Society for Sports Medicine; International Society of Arthroscopy; Dr. Harner—Smith & Nephew; Breg; Drs. Mascarenhas, Karpie, and Irrgang, and Mr. Tranovich—no conflicts.

Peter Pollack is a staff writer for AAOS Now. He can be reached at ppollack@aaos.org

Bottom line

  • This matched pair study compared the use of patellar tendon autograft and patellar tendon allograft in ACL reconstruction and found no significant differences in patient-reported outcome scores between groups.
  • More autograft patients were participating in strenuous or very strenuous activities at final follow-up, but the difference was not statistically significant.