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Nguyen et al. Plast Aesthet Res 2019;6:31 I http://dx.doi.org/10.20517/2347-9264.2019.42 Page 9 of 10

We choose to place the gracilis in the rectus femoris position for several reasons. The ability to stand
from a seated position is one of the most important measures of physical function and is essential for
independent living [4,13] . The biarticulated rectus femoris is critically important in the sit-to-stand transition,
as well as stepping and gait [14,15] . The rectus femoris is a two-joint muscle that acts both as a flexor of the
hip and an extensor of the knee and is active during two phases of the gait cycle; in other words, it has
bimodal activity [16-20] . The first burst of activity occurs during the loading response phase where it acts with
[21]
the vasti by acting at the knee during load bearing to stabilize it . The second burst occurs during the
pre- and initial-swing phase of the gait cycle where it acts as a hip flexor in propelling the limb forward
[21]
into swing . These unconscious complex sets of coordinated movements are the reason we chose to
reinnervate the gracilis with the motor nerve to rectus femoris rather than simply transfer it with its
obturator innervation intact and hope that retraining could occur. The three vasti muscles are important
[22]
for standing function and they extend the knee without flexing the thigh . Likely because of this, two
of our functional gracilis patients did have symptoms of fatigue if standing for longer periods of time.
The vastus lateralis and intermedius are the strongest vasti; however, the vastus medialis is important for
[22]
locking the knee in terminal extension and preventing patellar drift and lateral subluxation . Considering
this, our patients could all reach complete knee extension while seated on a bench but only one could
hold their knee in full extension for more than a brief period of time. Interestingly, we did not have any
problems with patellar subluxation or drift, and this may be attributed to the long distance distally that we
weaved the gracilis tendon into the quadriceps tendon complex as well as some stabilizing fibrosis from the
neo adjuvant radiotherapy that may have occurred.

In summary, the required amount of quadriceps strength necessary to maintain quality of life has not been
[4]
accurately established . It remains unclear which muscle or muscle transfers in the body are suitable to
replace enough quadriceps strength and function to achieve this endpoint. Although the gracilis muscle
is clearly not as strong as the quadriceps muscle complex, there are other clinical examples where a much
smaller and weaker muscle can replace the essential functions of a much larger muscle group. An example
would be the scenario of total biceps and brachialis resection or denervation in which a much smaller and
weaker brachioradialis can adequately compensate for elbow flexion such that no additional reconstruction
is usually required. Our experience suggests that with physiotherapy and training, and in the appropriate
patient, the gracilis has enough capacity to provide essential quadriceps function following complete
resection and/or denervation associated with limb salvage sarcoma surgery.

DECLARATIONS
Authors’ contributions
Concept study design, literature search, and manuscript writing: Hayakawa TEJ
Manuscript preparation, data acquisition: Nguyen CM, Ratanshi I
Manuscript review: Giuffre JL, Buchel EW

Availability of data and materials
IRB approved retrospective study based on University of Manitoba Health Sciences Centre hospital charted
data.

Financial support and sponsorship
None.

Conflicts of interest
All authors declared that there are no conflicts of interest.