Ft. Blevins et al., THE EFFECTS OF DONOR AGE AND STRAIN-RATE ON THE BIOMECHANICAL PROPERTIES OF BONE-PATELLAR TENDON-BONE ALLOGRAFTS, American journal of sports medicine, 22(3), 1994, pp. 328-333
Over 50% of all knee injuries involve partial or complete tear of the
anterior cruciate ligament. Surgical reconstruction of this ligament u
sing an isometrically placed bone-patellar tendon-bone autograft is th
e current technique of choice; however, harvest of patellar tendon as
a free graft can lead to increased morbidity. To address this issue, a
llogenic patellar tendon grafts have been introduced as alternatives t
o autogenic graft material. The purpose of this study was to examine e
ffects of age and strain rate on tensile strength, modulus, and failur
e mode of bone-patellar tendon-bone allografts from a typical populati
on of tissue donors. Eighty-two, fresh-frozen, bone-patellar tendon-bo
ne allografts were harvested from 25 different donors, aged 17 to 54.
Paired grafts from individual patellar tendons were assigned randomly
to tensile testing at either 10% or 100% elongation per second. Tensil
e strength, modulus, and failure mode were not significantly different
for tests conducted at these 2 strain rates. Correlations between ten
sile strength and age were not significant for tests conducted at eith
er strain rate. Specimens tested at a strain rate of 100% per second e
xhibited weak but significant negative correlation between modulus and
age, with modulus decreasing 25% over the age range examined.