ACL Graft Options: Allograft or Autograft?

Does the Graft Source Really Matter in Outcomes After ACL Reconstruction?  That seems to be a popular topic of late, with two new research articles in the last several months addressing this topic (one from AJSM and another from Sports Health ).  These two particular articles performed systematic reviews of allograft versus autograft tissue during anterior cruciate ligament reconstruction. 

The first article, from AJSM, performed a systematic review of over 400 articles.  In the end 31 met all the criteria for analysis.  One word of caution with the results of this study, due to the nature of ACL surgical techniques, the group of autograft reconstructions included 2184 patients versus 137 in the allograft group, a pretty big discrepancy.  Results revealed:

• Positive pivot shifts were found in 6.2% of allograft patients and 2.1% of autograft patients, but this was not statistically significant.
• KT arthrometer testing 81% of allograft and 78% of autograft patients had less than 3mm side-to-side differences in laxity.  This was also not significantly different.  3% of allograft patients and 3.3% of autograft patients had laxity greater than 5mm.  3mm is the gold standard for side-to-side laxity difference, anything greater than 3mm is considered significant, anything greater than 5mm is considered a failure.
• No significant differences were found in Lysholm and IKDC scores, as well as postoperative complications.
• Failure rate was 4.5% in autograft and 8.3 in allograft reconstructions

The second article, from Sports Health, had a larger pool of studies reviewed.  The authors reviewed 576 studies and utilized 56 for analysis.  In all, there were 3887 autograft patients and 113 allograft patients, representing and even larger discrepancy than the AJSM article.  Results of the study revealed:

• 1% of autograft patients had a positive Lachman test and 0.5% had a positive pivot shit test.  94% of autograft patients had good to excellent IKDC scores.  15% of autograft patients had a KT test of greater than 3mm.
• 4.6% of allograft patients had a positive Lachman test and 2.2% had a positive pivot shit test.  90% of allograft patients had good to excellent IKDC scores.  30% of allograft patients had a KT test of greater than 3mm.
• The only statistically significant difference between autograft and allograft patients was the percentage of KT tests greater than 3mm, with a greater incidence in allograft patients.

Clinical Implications

So what can we take from these two studies?  Here are my thoughts:

1. Two similarly performed systematic reviews revealed similar, yet different results.  The take home here is that there are multiple ways to perform systematic reviews – don’t just assume that because it is a meta-analysis, that the results are perfect!  Also, realize that the large discrepancy between groups makes these studies less than ideal.
2. It appears that allograft versus autograft sources for anterior cruciate ligament reconstruction yield pretty similar results.
3. My past experience tends to lean towards the Sports Health study.  Outcomes in my experience between the graft sources have been similar, but allograft patients tend to have more laxity after surgery.  This is shown in both studies.
4. This may be fine depending on your patient.  The large piece of info we are missing here involves the types of patients involved in these studies.  The athletic patient may want to assure that they do not have residual laxity and prefer the autograft, while the sedentary patient may prefer the allograft tissue and less postoperative pain.  I think this is really the main issue when choosing a graft for ACL reconstruction – what activities do you want to go back to?

What have you observed in your past experiences?