Study shows a three times higher ACL reconstruction failure rate with allograft in young athletes

SEATTLE ─ In young athletic patients, ACL reconstruction performed with allograft has a higher failure rate than reconstruction with autograft, according to long-term study results presented here.

Perspective from Michael C. Meyers, PhD, FACSM

“ACL reconstruction at our institution using posterior tibialis allograft had a significantly higher failure rate than an autologous hamstring in exactly similar fixation and rehab protocol ─ three times higher as shown here. However, all [patients] with intact grafts had good clinical outcomes,” said Craig R. Bottoni, MD, at the American Orthopaedic Society for Sports Medicine Annual Meeting.

In the prospective study, Bottoni and colleagues randomized 99 patients, for a total of 100 symptomatic ACL deficient knees, to receive either hamstring autograft or tibialis posterior tendon allograft. The cohort included 87 men, and 95 patients were active duty military. Both groups had a mean age of 29 years and there was no difference in their concomitant pathology or demographics.

The researchers used fresh-frozen aseptically harvested, non-terminally irradiated allografts obtained from a single tissue bank. Graft fixation was identical for all knees and both groups followed the identical blinded postoperative rehabilitation protocol. The researchers performed preoperative and postoperative assessments of the patient’s knees by exam, telephone and Internet-based questionnaires. The primary outcome measures used were graft integrity, subjective knee stability and functional status. Minimum follow-up was 10 years.

For the 96 patients who were able to be contacted at follow-up, Bottoni and colleagues found failure rates of 26.5% for allograft and 8.5% for autograft. All other patients had intact grafts and there was no difference in clinical outcomes. – by Kristine Houck, MA, ELS

Reference:

Bottoni CR. Paper #21. Presented at: American Orthopaedic Society for Sports Medicine Annual Meeting; July 10-13, 2014; Seattle.

Disclosure: Bottoni is a consultant for Arthrex and receives research and institutional support from Musculoskeletal Transplant Foundation and Arthrex.

Perspective

Michael C. Meyers, PhD, FACSM

The issue of whether to perform ACL reconstruction with an autograph versus allograft has continued since the early 1990s when higher than expected failure rates were found after cruciate ligament allograft reconstructions. Dr. Bottoni and colleagues’ attention to detail in the study deserves merit, and reinforces the difficulty a surgeon has when deciding on a particular technique and the subsequent long-term outcomes. With the continual interest in minimally invasive techniques for ligament reconstruction in clinically unstable knees, the use of allografts and the research on allograft materials have increased.

Previous authors have reported the efficacy of allograft versus autograft reconstructions of the ACL, suggesting that graft viability, strength and functional stability were similar. Other authors have indicated allografts attain histologic stability at 6 months to 18 months after implantation. To prolong shelf life and to remove potentially infectious agents, ethylene oxide and freeze-drying sterilization have been used. Some studies have reported no deleterious effects on the strength, immunogenicity or reactivity of allografts following these techniques, while others have noted numerous complications.

Other factors have been reported that contribute to high allograft failure rates. These included graft type, size, and integrity, donor-host histocompatibility, inadequate biomechanical duplication after allograft implantation, shelf-life and age of the allograft at implantation, and surgical-rehabilitative techniques.

The final determination in choosing an allograft should be based on thorough knowledge of the allograft history from harvest to implantation, as well as monitoring the patient’s matriculation through rehabilitation and return-to-play. Obviously, further investigation is still warranted to delineate the causes of higher-than expected allograft failure rates.

Michael C. Meyers, PhD, FACSM

Associate professor, Department of Sports Science and Physical Education, Idaho State University

Pocatello, Idaho

Disclosures: Meyers has no relevant financial disclosures.