Primary ACL reconstruction with fresh-frozen patellar versus Achilles tendon allografts

In recent years, there has been an interest in the use of allografts as an alternative graft for anterior cruciate ligament (ACL) reconstruction to reduce potential donor-site morbidity resulting from the harvest of autogenous tissue. Nevertheless, in the literature, the use of allografts for primary ACL reconstruction is controversial due to a higher failure rate and the potential risk of disease transmission.

In this retrospective study, we evaluated the clinical outcome of 251 fresh-frozen patellar vs Achilles tendon allografts for primary ACL reconstruction. Patients (average age 39 years) were operated on between 1993 and 1998, and the mean follow-up was 37.7 months (range 24-74 months). We were able to follow up 225 patients (89.6%). According to the different types of allograft, we divided the patients into two groups: group P with patellar bone-tendon-bone allograft (BTB; n=183) and group A with Achilles bone-tendon allograft ( n=42). Clinical evaluation consisted of a history, an examination, IKDC Score, Cincinnati Knee Score (CKS), Cincinnati Sports Activity Scale (CSAS), KT-1000 testing, and standardized X-rays.

According to the IKDC, the outcome was normal or nearly normal in 75.3% in group P and 76.2% in group A. Overall rating according to the CKS was an average of 85 in group P and 82.9 in group A. CSAS was 79.6 in group P and 84.8 in group A. The objective stability measured with the KT-1000 showed an average side-to-side difference of 2.1 mm in group P and 2.0 mm in group A. 4.4% of group P and 2.5% of group A were considered a laxity failure, and 10.4% of group P and 4.8% of group A re-ruptured the reconstructed ACL. In summary, there was a significantly higher failure rate ( p<0.001) in group P compared with group A.

Satisfactory clinical results can be achieved with the use of allografts for primary ACL reconstruction. Comparing Achilles tendon and patellar BTB allografts, the Achilles tendon-bone allograft seems to be advantageous for ACL reconstruction as the failure rate was significantly lower. Nevertheless, the total failure rate appears to be much higher compared with autogenous ACL reconstruction, indicating that the use of an allograft for routine uncomplicated primary ACL reconstruction offers few advantages. Therefore, autograft tissue remains our graft of first choice for this procedure. We advise reserving allografts for revision procedures where suitable autogenous tissues have been previously compromised, where a contraindication for autogenous tissue harvest exists, or for multiple ligament surgery.