Effect of donor age on bone mineral density in irradiated bone-patellar tendon-bone allografts of the anterior cruciate ligament.

BACKGROUND Allograft tissue remains a valuable alternative for anterior cruciate ligament reconstruction. No study to date has correlated the effect of donor age to bone mineral density (BMD) in a large series of irradiated bone-patellar tendon-bone (BPTB) allograft tissue. Hypothesis/ PURPOSE The authors attempted to correlate donor age with BMD in a large group of BPTB allograft specimens treated with low-dose gamma irradiation (1.0-1.3 Mrad) collected over a 4-year period. They hypothesized there would be no effect of donor age on the BMD of irradiated BPTB allografts. STUDY DESIGN Descriptive laboratory study. METHODS A total of 110 BPTB allograft specimens from 44 male and 66 female donors with a mean age of 46 years (range, 21-58 years) were analyzed. Bone mineral density data were obtained from both the patellar and tibial bone plugs of the BPTB complex. Statistical analyses were conducted using linear regression for correlations and 2-tailed Student t tests for comparisons between groups. RESULTS The mean BMD of the patellar bone plug (0.471 g/cm(2)) was significantly greater than the mean BMD of the tibial bone plug (0.328 g/cm(2)) (P < .001). No correlation was identified between donor age and BMD for either the patella or tibial bone plugs (R(2) = .014 and .011, respectively). Both patellar and tibial BMD was significantly greater for the male grafts than the female ones. CONCLUSION No correlation was found between donor age and BMD for irradiated BPTB allograft tissue. The patellar bone plugs were noted to have a greater BMD than the tibial bone plugs. Allograft tissue from male donors had higher BMD values than that harvested from female donors.