Ankle-Joint Laxity Using 2 Knee Positions and With Simulated Muscle Guarding

S, Caccese J, Knight CA, Swanik CB, & Kaminski TW.  J Athl
, 2016; 51(2): 111-117. doi:10.4085/1062-6050-51.3.06

Take Home Message: Knee flexion to 90 degrees limits ankle
laxity with the talar tilt test in comparison to a fully extended knee.  However, knee position has no effect on
anterior drawer laxity. Muscle guarding will limit our ability to accurately
assess ankle laxity with a talar tilt or anterior drawer test. 

accuracy and reliability of special tests, such as the anterior drawer and
talar tilt tests, can be affected by many factors, including muscle guarding,
patient positioning, and clinician experience. 
It is critical for clinicians to know how to properly perform these
tests at the ankle to optimize test performance. The authors of this study
compared ankle-joint laxity and muscle activity during these ligamentous ankle
special tests at different knee positions. They also investigated how muscle
guarding affects these tests.  The
authors measured ankle laxity and muscle activity of the medial gastrocnemius in
33 healthy college students with their knee in 2 positions (i.e., extension &
90° of flexion).  To simulate a guarding
condition, the authors asked participants to maintain a contraction of their
tibialis anterior at 30% of their maximum voluntary contraction. The two
special tests were standardized with an
ankle arthrometer, which can perform the
test with a standardized force and motion. The authors reported that knee
position did not affect muscle activity nor anterior translation, but that the
knee positioned in extension resulted in greater inversion/eversion motion than
a flexed knee.  The researchers reported
that there was a decrease in ankle motion during both tests and in both knee
positions when participants simulated muscle guarding.

findings of this study are interesting because the authors confirmed that a patient
needs to be relaxed and not guarding against the laxity tests to get the best
results.  It is important to try to find
ways to limit muscle guarding when performing an ankle evaluation.  They also reported that knee position may
affect the findings of the talar tilt, but not the anterior drawer test.  It would be interesting to see if the
findings of these ankle laxity tests were similar at other knee positions, such
as slight to moderate knee flexion. 
Clinically, this may mean that we could position the patient to allow us
to have an optimal line of pull for anterior translation without concern for
knee position, but that we should have the knee in extension to assess talar
tilt laxity.  It is surprising that there
is greater inversion/eversion motion with the knee in full extension, and it
would be interesting to see at what point of knee flexion does the motion start
to become limited.  However, as
clinicians we need to be cognizant of muscle guarding and knee position when we
assess ankle laxity – it will only benefit us. 

for Discussion:  How were you taught to
position the knee when assessing ankle laxity? 
What position works best for you when testing ankle laxity clinically?

Nicole Cattano
by: Jeffrey Driban


Diagnostic Accuracy of Clinical Tests for Ankle Syndesmosis Injury

Hanlon S, Caccese J, Knight CA, Swanik CB, & Kaminski TW (2016). Examining Ankle-Joint Laxity Using 2 Knee Positions and With Simulated Muscle Guarding. Journal of Athletic Training, 51 (2), 111-7 PMID: 26881870