Donor age has no relevant role in biomechanical properties of allografts used in anterior cruciate ligament (ACL) reconstruction: A systematic review.

PURPOSE: Surgeons generally consider the donor age as a factor that negatively influences the quality of allograft used in anterior cruciate ligament (ACL) reconstruction, however, the available evidence does not clearly support this statement. The purpose of the study was to investigate if donor age influences the biomechanical properties of allografts used in ACL reconstruction.

METHODS: A comprehensive literature search was conducted for all relevant articles using MEDLINE (PubMed), Scopus, and Cochrane Collaboration Library, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. Studies including the analysis of the correlation between biomechanical properties of the allografts and donor age were selected. The role of donor age was labelled as 'none' if absent, 'higher' or 'lower' if the properties were higher or lower in older specimens with respect to younger. The correlation was defined as 'weak' or 'strong' according to each study definition.

RESULTS: No conflicting role of donor age was reported for modulus of elasticity, load to failure, strain, stiffness and displacement. The only parameters where the significant results were consistent were the tensile strength and the stress (low or moderate correlations). When considering the tested samples with a donor's age <65 years, a significant role of age was reported in only four out of 13 groups of graft tested (patellar tendon, fascia lata, anterior tibialis tendon and posterior tibialis tendon).

CONCLUSION: The current literature did not allow to state that the donor age negatively influences the biomechanical properties of allografts, making it impossible to identify a clear age cut-off value to exclude them from ACL reconstruction procedures.

LEVEL OF EVIDENCE: Level IV, systematic review.