Background: The autologous semitendinosus-gracilis graft is the
first choice of many orthopaedic surgeons when reconstructing the anterior
cruciate ligament. The effect that graft harvest has on muscle and tendon
morphology remains unclear. The purpose of this study was to describe these
effects more completely.
Methods: Magnetic resonance images were acquired from eight patients
before the anterior cruciate ligament reconstruction with
semitendinosus-gracilis autograft and then again postoperatively after they
had returned to sports. Muscle and tendon morphology was described by
determining the volume and peak cross-sectional area of each structure on
digitally reconstructed images. The effects that the procedure had on muscle
and tendon length were evaluated separately and then together as a
Results: Anterior cruciate ligament reconstruction with
semitendinosus-gracilis autograft resulted in a marked decrease in volume,
cross-sectional area, and length of the semitendinosus and gracilis muscles.
Tendon regeneration occurred in varying degrees in nearly all subjects. The
morphology of the biceps femoris and semimembranosus muscles suggested that
they had been compensating for the reduced semitendinosus and gracilis muscle
function. Although semitendinosus and gracilis muscle retraction occurred
following tendon stripping, nearly all of the subjects displayed evidence of
at least partial tendon regeneration.
Conclusions: Anterior cruciate ligament reconstruction with
semitendinosus-gracilis autograft had a marked impact on semitendinosus and
gracilis muscle morphology. However, this altered muscle morphology did not
appear to have a clinically important impact on short-term outcomes. The
biceps femoris and semimembranosus muscles appear to compensate for reduced
semitendinosus and gracilis function. Tendon regeneration is observed in most
people, but it is often incomplete at six months.