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Risk Factors for Revision Following Primary Allograft ACLR

By: Maureen Leahy

Maureen Leahy

Data presented on Wednesday identified several factors associated with an increased risk of clinical failure and subsequent revision surgery after primary allograft anterior cruciate ligament reconstruction (ACLR).

“Allograft usage for ACLR is common in the United States, with surgeons citing decreased operative time, ease of graft preparation, no harvest morbidity, and improved cosmesis as primary advantages,” Sam G. Tejwani, MD, said. “Although multiple studies have demonstrated that autograft heals more favorably than allograft for ACLR, the explanation for this remains unclear. Is the higher allograft failure rate related to graft properties, to patient attributes, or to a combination of both?”

Retrospective cohort analysis
Dr. Tejwani and his colleagues sought to examine the association of graft processing techniques, patient characteristics, and graft type with risk of revision surgery after allograft ACLR. Using a large community-based ACLR registry, they identified 5,968 patients (61 percent male; median age = 34 years) who had undergone primary unilateral allograft ACLR between February 2005 and September 2012. Cases with incomplete vendor graft processing information were excluded.

Graft processing techniques included the following:

  • BioCleanse®, a proprietary technique developed by Regeneration Technologies (n = 367; 6.1 percent)
  • AlloSource’s AlloTrue™ or LifeNet Health’s AlloWash® (n = 2,278; 38.2 percent)
  • Irradiation using more than 1.8 Mrad (n = 1,146; 19.2 percent)
  • Irradiation using less than 1.8 Mrad (n = 3,637; 60.9 percent)
  • No irradiation at all (n = 1,185; 19.9 percent)

Among the 5,968 patients, 62.9 percent had undergone ACLR with soft tissue, 19.9 percent with Achilles tendon, and 17.2 percent with bone–patellar tendon–bone (BPTB) allograft. The median age of the allograft donors was 50 years. The mean time to follow-up after the initial surgery was 2.1 years.

The aseptic revision rate was 2.6 percent (n = 156). The researchers found statistically significant differences in the distribution of patient age (P < 0.001), allograft type (P = 0.021), and irradiation dosage (P = 0.041) among the cases, with and without revision. After adjusting for patient age, gender, and body mass index, they found that the BioCleanse technique—which sterilizes tissue through oscillating positive and negative pressure in the presence of detergents and sterilants—and irradiation with more than 1.8 Mrad were associated with a higher risk of revision after 1 year, compared to the other graft processing methods.

The study also revealed that BPTB allografts had a higher risk of revision compared to soft-tissue allografts. In addition, revision risk was notably higher in younger patients, particularly those younger than age 21; for every 5-year increase in age, the risk of revision dropped. Males also had a higher risk of revision, compared to females (Fig. 1).

Arthroscopic view of the final graft placement and fixation.
From ICL 58, page 346

“In addition to the graft processing technique (irradiation with more than 1.8 Mrad and BioCleanse processing), additional patient and graft factors were associated with a higher risk of revision after primary allograft ACLR,” Dr. Tejwani said. “By understanding that younger patients, males, and BPTB allograft are associated with higher risk of revision, surgeons can potentially tailor their patient choice for allograft and allograft selection accordingly to lessen the risk of clinical failure and need for revision. 

“I think the most valuable take-home message of this study is that not all primary ACLR patients are appropriate for allograft, and when allograft is used, processing techniques are not standardized among the numerous commercially available tissue vendors. Certain sterilization methods and patient demographics are associated with higher risk of revision than others,” Dr. Tejwani continued. “Essentially, not all allograft tissue performs the same in vivo. This will hopefully alert surgeons to learn more about the graft processing techniques used by their specific tissue vendor. I also hope it will stimulate additional research to better explain the results that were found.” 

Dr. Tejwani’s coauthors of “Revision Risk After Allograft Anterior Cruciate Ligament Reconstruction: Graft and Patient Associations” are Jason Chen, MA; Tadashi T. Funahashi, MD; Rebecca Love, BSN, RN; Maria C. Inacio, PhD; and Gregory B. Maletis, MD.

Details of the authors’ disclosure as submitted to the Orthopaedic Disclosure Program can be found in the Final Program; the most current disclosure information may be accessed electronically at www.aaos.org/disclosure

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