This document summarizes a study that aims to evaluate knee stability following injury and reconstruction of the anterolateral ligament (ALL). It introduces the pivot shift test, a common method used to examine ACL stability by inducing internal rotation and a valgus force on the extended knee. The study seeks to determine the importance of the deep fibers of the iliotibial band as they relate to combined anterior tibial translation and internal rotation during a pivot shift test. It also aims to clarify the roles of the deep iliotibial band fibers and ALL in relation to the ACL and their overall contribution to knee stability. The study method involves using metal clamps and instrumentation to reproduce the strain of a pivot shift test on

1. Evaluation of Knee Stability Following Injury
and Reconstruction of the Anterolateral Ligament
By: Dustin Johnson, Marcus Hurtado and Dr. Ferris Pfeiffer
Intorduction
One of the most common injuries in sports today
is that of the anterior cruciate ligament (ACL). It is
estimated that within the United States there are over
200,000 reconstructions preformed annually.1 These
injuries are acquired over a wide range of activates:
soccer, football, and basketball to name a few. With the
high popularity of activities such as these the majority of
the populace participating in said activities is in risk of a
possible ACL injury. Therefore there is a need for
improved methods to maximize the efficiency of the
repair.
Referances
1. Junkin DM, Johnson DL, Fu FH, et al. Knee ligament injuries. In: Kibler WB, ed. Orthopaedic
Knowledge Update: Sports Medicine 4. Rosemont, Illinois: American Academy of Orthopaedic
Surgeons; 2009:230-238.
2. Kocher MS, Saxon HS, Hovis WD, Hawkins RJ. Management and complications of anterior
cruciate ligament injuries in skeletally immature patients: survey of the Herodicus Society and
The ACL Study Group. J Pediatr Orthop. 2002;22(4):452-457.
Methods and Materials
Pivot Shift – The process being used to examine
the ACL stability is the pivot shift test. This simple test is
enacted by performing internal rotation alongside a
valgus force to the extended knee. If there is an ACL
tear, the tibia will sublux anterolaterally on the femur.
This will denote a positive test result indicating the lack
of stability in the knee. Although this test is subjective it
is a common practice among medical professionals for
examining knee stability.
Conclusion
Testing is ongoing and results will be reported
accordingly. Although results have not yet been
determined the proof of concept for inducing a pivot shift
test through instrumentation is promising.
Background
The current method of ACL reconstruction has
been called into question because of the potential
growth arrest (in still maturing patients) and the
damaged that is caused by drilling for tunnel formation.2
To attempt to avoid these complications multiple other
forms of procedures have arose. The three most
popular alternatives are all-epiphyseal (AE), transtibial
over-the-top (TT), and iliotibial band (ITB) ACL
reconstruction. The lack of clinical evidence advocating
a specific procedure makes it challenging to compare its
effectiveness to conventional transphyseal ACL
reconstruction. Therefore the goal of this study is to
investigate ITB function with relation to the anterolateral
ligament (ALL), a known key factor in ACL stability, to
determine how these tissues affect knee stability for
ACL reconstruction.
Objectives
The purpose of this study is to determine:
1. The importance of the deep tissue fibers of the ITB
as related to the combined motion of an anterior
translation and internal rotation of the tibia through
pivot shift.
2. The role of deep ITB fibers in relation to ALL
3. The relation between ITB, ALL, and ACL and their
overall contribution to knee stability
Method – To reproduce the strain exhibited by the
knee in a pivot shift test specifically designed metal
clamps were utilized in conjuction with Instron
instrumentation and Optotrak sensors. The restraints
limit the degrees of freedom to three degrees of motion.
This motion is motion within a horizontal plane and
internal rotation. The Instron hardware then applies a
valgus force to the extended knee. The knee is strained
to a predetermined strain and then relaxed. This method
has so far ben conducted on full intact knees giving a
base line value for
the study. From
here knees will
be tested in
progressively more
deteriorated states
in order to elicit the
overall relationship
between the ACL,
ALL, and ITB. After
degeneration is
examined, various
repair techniques
will be utilized to
determine their
individual effect
on knee stability.