In vivo analysis of tibial rotation after anatomical versus trans-tibial anterior cruciate ligament reconstruction surgery

The knee accounts for 40% of all injuries acquired through sports. (Majewski M,
2006) Ligament instability is a commonly seen result of these injuries. One of
these ligaments is the anterior cruciate ligament (ACL). ACL-ruptures mostly
result from abrupt deceleration, hyperextension or pivoting on a fixed foot.
(Boden BP, 2000) (Noyes FR M. D., 1983)
Sometimes they result from contact injuries, typically a blow to the lateral
side of the knee when the foot is planted. These injuries are often associated
with medial instability and patients sometimes report feeling or hearing a
*pop*. Patients are mostly unable to continue their current activity, and often
develop acute effusion. (Cummings JR, 2005)
With chronic ACL insufficiency patients frequently perceive their knee as
unstable and often complain about activity related swelling, difficulty walking
downhill and problems with acutely stopping. (Losee, 1985) (Noyes FR M. D.,
1983)

The anterior cruciate ligaments primary function is to prevent excessive
anterior tibial translation in relation to the femur. Abnormal anterior tibial
translation is tested through clinical tests like the Lachman and anterior
drawer tests or through mechanic testing using the KT-1000 or KT-2000
arthrometer. Cadaveric studies have shown that the ACL is the primary restraint
to anterior tibial translation and the ligaments greatest contribution to this
restraint was at 30° flexion. (Butler DL, 1980) Sectioning of the medial
collateral ligament increased anterior translation at 90° flexion but not at
30°, thereby giving the Lachmans* test a specificity advantage over the
anterior drawers test. (Beynnon BD, 1992)

An important secondary function of the ACL is the prevention of rotational
instability through preventing excessive internal rotation of the tibia. Most
often ACL-rupture results in a specific form of rotational instability called
Anterolateral Rotational Instability (ALRI), which typically results from acute
internal rotation and varus-stress on a weight bearing knee such as losing
balance after landing off a jump. (Hughston JC, 1976) Several tests can be used
to assess the presence and degree of ALRI, like the pivot-shift test, the
flexion-rotation drawer test, the Losee test and the Jerk test of Hughston.
(Hughston JC, 1976) (Losee RE, 1978) (Noyes FR B. R., 1980)
However, most of these tests have either low sensitivity or specificity. The
sensitivity of the Pivot-shift test varies between 0.18 and 0.48 and a
specificity varying between 0.97 and 0.99 (Scholten, 2003)
Flexion-rotation drawer for partial or complete ruptures reported sensitivity
of respectively 0.62 and 0.89 while under anesthesia, but only 8% and 38% while
not anaesthetized. (Noyes FR B. R., 1980)

After tearing of the ACL, initial treatment is conservative. In case of
persistent instability after conservative treatment, surgical reconstruction of
the ACL is advisable. Currently a few ACL-reconstruction techniques are used.
The most commonly used is the transtibial reconstruction. In this technique the
orientation of the femoral tunnel depends on the orientation of the tibial
tunnel, because the femoral tunnel is created through the tibial tunnel. In
this way a non-anatomical reconstruction of the ACL can be made, because the
ACL is not exactly oriented as is the native ACL. (E.F.P.A. Fievez, 2011) The
anatomical reconstruction aims to better restore this rotational stability by
placing an extra anteromedial arthroscopy portal through which the femoral
tunnel can be reamed more laterally and more diagonally oriented, hereby
placing the graft in a more anatomical orientation similar to the native ACL.
In 30° of flexion both anatomical and transtibial reconstruction techniques
cannot prevent tibial anterotranslation as is in a normal knee, but both
significantly improve stability compared to ACL deficient knees. In full
extension the anterior stability is also improved through both techniques, but
only the anatomical reconstruction seems capable of restoring ACL stability
back to the original native ACL state. (Sim, 2011 )
Theoretically, the anatomical ACL reconstruction might be superior to the
non-anatomical reconstruction in respect to stability and patient*s
satisfaction. Clinical results are however comparable with high satisfaction
rates in both anatomical or transtibial surgery techniques and no significant
differences exist between patient satisfaction rates or functionality
(Alentorn-Geli, 2010)

Experiments dealing with the rotational stability after an ACL reconstruction
have not been performed in vivo or were performed under static conditions.
Although static rotational stability testing is currently the standard, many
studies have shown that static stability tests are often incapable of
correlating with functional outcome following anterior cruciate
ligament-reconstruction-surgery. (Tashman S, 2008) (Barber SD, 1990) Through in
vivo testing in dynamic weight bearing knees we expect to get a better view of
the actual rotational pivoting forces in the knee.

Theoretically the anatomical reconstruction technique should give better
results in rotational stability due to a more anatomical placement of the
ACL-graft. Though it is difficult to test this correlating to functional
outcome, because in current literature there seems to be no significant
difference between both surgical techniques and because statically performed
anterolateral rotational instability tests do not reproduce the forces loaded
onto an in vivo anterior cruciate ligament (Noyes, 1980)
Through in vivo kinematic 3D- gait analysis, we aim to measure statistically
and clinically significant differences in tibial rotational excursion when
patients perform several motor tasks

Prospective non randomized pilot study

All possible, participating subjects will have three times contact.

The first time they will be informed by telephone about the study. The
information will be sent by post. (+ / - 15 minutes)
The second time the possible participant will be asked to participate and
informed consent will be signed (+ / - 15 minutes)
The third time, all measurements including physical examination by a physician
will be done. Also the questionnaires will be obtained. (+ / - 60 minutes)

total time 90 minutes