Abstract
The aim of this article is to compare tibial fixation strength of suspensory fixation
for a quadrupled semitendinosus continuous loop all-inside anterior cruciate ligament
(ACL) construct versus a doubled semitendinosus and gracilis graft fixated with an
interference screw. Biomechanical testing was conducted using human hamstring allografts
and porcine tibias. Constructs were cycled from 50 to 250 N for 500 cycles followed
by a pull to failure. The average load to failure of tibial suspensory fixation of
the all-inside continuous loop construct (1,012 N) was statistically different compared
with the tibial interference screw group (612 N) (p < 0.001). The cyclic displacement of the continuous loop construct (2.5 mm) was not
statistically different from the interference screw construct (1.9 mm). For both the
groups, approximately half the overall cyclic displacement occurred with the first
cycle. Tibial side suspensory fixation of a novel all-inside continuous loop hamstring
graft provided suitable strength for tibial fixation for ACL reconstruction. The continuous
loop construct had a significantly higher load to failure compared with the use of
an interference screw, and cyclic loading was comparable. Use of hamstring soft tissue
grafts is very common for ACL reconstruction. An all-inside ACL reconstruction is
based on a continuous loop construct utilizing a single semitendinosus graft that
is quadrupled employing suspensory fixation on both the femoral and tibial side. Suspensory
fixation on the femoral side been previously reported, but this is the first report
of strength of this method of suspensory fixation on the tibia.
Keywords
suspensory fixation - tibial side - all-inside ACL - continuous loop graft
