A meta-analysis of stability of autografts compared to allografts after anterior cruciate ligament reconstruction

Abstract

Allografts have recently become increasingly popular for anterior cruciate ligament reconstruction (ACLR) in the United States even though many studies have shown high allograft failure rates (Gorschewsky et al. in Am J Sports Med 33:1202, 2005; Pritchard et al. in Am J Sports Med 23:593, 2005; Roberts et al. in Am J Sports Med 19:35, 2006) and no meta-analysis or systematic review of allograft clinical stability rates in comparison to autog rafts has previously been performed. We hypothesized that allografts would demonstrate overall lower objective stability rates compared to autografts. To test this hypothesis we performed a meta-analysis of autograft and allograft stability data. A pubmed literature search of all allograft series in humans published in English was performed. Articles were then bibliographically cross-referenced to identify additional studies. Series inclusion criteria were arthrometric follow-up data using at least 30 lb or maximum manual force, stratified presentation of stability data and minimum two-year follow-up. Twenty allograft series were thus selected and compared to a previously published data set of all BPTB and Hamstring (HS) autograft ACLR series using the same study inclusion criteria and analytic and statistical methodology. IKDC standards of 0-2 mm (normal) and >5 mm (abnormal) side-to-side differences were adopted to compare studies. Normal stability for all autografts was 72 versus 59% for all allografts (P < 0.01). Abnormal stability was 5% for all autografts versus 14% for all allografts (P < 0.01). Bone-patellar-tendon-bone (BPTB) autograft normal stability was 66% versus 57% for BPTB allografts (P < 0.01). Abnormal BPTB autograft stability was 6 versus 16% for BPTB allograft. Hamstring autograft normal or abnormal stability rates were 77% and 4% and were compared to soft tissue allografts as a group which were 64% and 12% (P < 0.01). This is the first meta-analysis comparing autograft to allograft stability in ACLR. Allografts had significantly lower normal stability rates than autografts. The allograft abnormal stability rate, which usually represents graft failure, was significantly higher than that of autografts: nearly three times greater. It would therefore appear that autografts are the graft of choice for routine ACLR with allografts better reserved for multiple ligament-injured knees where extra tissue may be required.

Allograft versus autograft for anterior cruciate ligament reconstruction: an up-to-date meta-analysis of prospective studies

“…The first meta-analysis conducted by Prodromos et al reported better stability with autograft reconstruction [13]. However, the findings of this study were compromised by the selection bias and questionable statistical methods.…”

“…However, there is still considerable controversy regarding the use of allografts versus autografts in ACL reconstruction, because most of the publications are low-quality studies or different graft procurement and secondary sterilization techniques have been used in those studies. Until now, five previous studies systematically reviewed the clinical outcomes of allograft versus autograft for ACL reconstruction [13][14][15][16][17]. However, all the five systematic reviews were conducted over three years ago and the findings of those studies were compromised by the limited availability of high-quality trials.…”

ACL reconstruction with BPTB autograft and irradiated fresh frozen allograft

“…The difference was statistically significant. Similarly, a meta-analysis (Prodromos et al, 2007) of the stability showed that irradiated grafts had an abnormal stability rate of 31% versus 12% for non-irradiated grafts, which was not to advocate the use of the irradiated allograft either, another reason against the use of irradiated allograft.…”

Soft tissue allograft for primary anterior cruciate ligament reconstruction

“…12 The results of our study with allografts are compared to certain other previous studies and tabulated (Table 4). We also compared our results with other studies where autografts were used and our results are similar to them (Table 5).…”

“…Although Gamma irradiation is known for its bactericidal and virucidal properties, a meta-analysis has shown that even a small dose of about 2 Mrad can cause about 31% abnormal laxity in ligaments reconstructed with irradiated allografts, because of alteraltion in biomechanical properties which is significantly high when compared to non-irradiated grafts which is around 12%. 12,13 Hence, all the grafts we used were maintained as fresh frozen but not irradiated. This procedure helps reduce antigenicity and disease transmission without affecting the graft strength.…”