Sports Medicine Research: In the Lab & In the Field: ACL Question Remains: Allo- or Auto-? (Sports Med Res)
Wednesday, May 29, 2013

ACL Question Remains: Allo- or Auto-?

Bone-Patellar Tendon-Bone Autograft Versus Allograft in Outcomes of Anterior Cruciate Ligament Reconstruction: A Meta-Analysis of 5182 Patients

Kraeutler MJ, Bravman JT, & McCarty EC.  American Journal of Sports Medicine. 2013, E-pub ahead of print. DOI: 10.1177/0363546513484127

Take Home Message: There is still no clear answer as to whether to use an autograft or allograft bone-patellar tendon-bone ACL reconstruction.

Patients and clinicians often need to consider what surgical options they prefer when undergoing anterior cruciate ligament (ACL) reconstruction.  Many physicians and researchers have investigated the benefits of either an auto- or allo- bone-patellar tendon-bone graft, however, conclusive evidence as to which is the best option has yet to be determined.  The purpose of this meta-analysis was to compare outcomes between these two specific surgical options in efforts to better answer this debate.  A literature search yielded 76 studies published between 1998 and 2012 that included 5182 patients (young and physically active) who had ACL reconstruction utilizing either an auto- or allo-graft reconstruction.  The studies did not have to directly compare the two types of grafts. Outcomes of interest were passive knee stability (pivot-shift), anterior knee laxity (KT-1000), single-legged hop, anterior knee pain, return to preinjury activity level, and overall International Knee Documentation Committee (IKDC) scores.  The authors found that patients with allografts had better return to preinjury level, passive knee stability, overall IKDC scores, and anterior knee pain.  However, patients with autografts had better graft rupture rate, subjective IKDC scores, Lysholm scores, anterior knee laxity, and single-legged hop test performance. 

The debate continues as to whether or not an allograft or an autograft may be better when utilizing a bone-patellar tendon-bone ACL reconstruction.  The results of this study, as well as a previous meta-analysis, appear to be marginally in favor of the autograft.  However, readers should interpret these results with caution.  In efforts to gather a higher number of scientific studies for this analysis, this study merely looked at outcomes based studies, and did not exclusively include studies that directly compared the two techniques.  This results in a possibility for variability in between study methodology results, ultimately potentially affecting the outcomes. For example, there may be patient characteristics that influenced the decision of whether to have an allograft or autograft (e.g., history of anterior knee pain, age).  What is interesting is that this study, along with an earlier 2008 meta-analysis, found higher graft rupture rates in allograft patients.  There are different theories as to why this may be occurring, but there is consistent evidence that autografts have a lower risk of graft rupture.  The authors highlight patient satisfaction as the most important factor in deciding outcomes post ACL reconstruction and indicate that indirect assessments of patient satisfaction (i.e., Lysholm, subjective IKDC) favor autograft as the best selection.  Anterior knee pain was significantly less in an allograft patient (as expected), but it is interesting that this is not considered to be a measure of patient satisfaction based on the authors’ interpretation. It would be interesting to see a meta-analysis conducted on randomized comparative studies of these two grafts that followed patients out to various time points and included imaging to assess joint degeneration as well as the traditional patient-reported and functional outcomes. 

Questions for Discussion: What are your thoughts on what measures constitute a successful ACL reconstruction?  What recommendations are you currently making to patients regarding graft type?

Written by: Nicole Cattano
Reviewed by: Jeffrey Driban

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Kraeutler, M., Bravman, J., & McCarty, E. (2013). Bone-Patellar Tendon-Bone Autograft Versus Allograft in Outcomes of Anterior Cruciate Ligament Reconstruction: A Meta-analysis of 5182 Patients The American Journal of Sports Medicine DOI: 10.1177/0363546513484127

2 comments:

John Kelly said...

This article still eludes the question of whether non irradiated grafts are as effective as autografts. When all the meta analysis literatur is considered, non irradiated allografts compare equally to autografts. The presence of small amounts of gamma irradiation (terminal sterilization) immediately renders allograft tissue mechanically inferior to autograft.

Nicole Cattano said...

John, you are absolutely right. These articles didn't address whether or not the grafts were irradiated or not. But that being said, it still seems that the option is up to the patient and the surgeon as both result in relatively similar outcomes. Are you personally in favor of one over the other? Any thoughts as to when you would pick either?

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