Real-time screening tests for functional alignment of the trunk and lower extremities in adolescent – a systematic review

Introduction
The presence of neuromuscular imbalance (Hewett, 2010) or
functional malalignment may be part of the increased rate
of adolescent knee injuries, specifically the anterior cruciate
ligament (ACL). Abnormal lateral trunk and knee abduction
moment are possibly linked to the biomechanical mechanisms
resulting in ACL injuries (Hewett, 2010). Prevention may
therefore depend on identifying these potentially injury risk
factors. Screening tools must thus include patterns of typical
movements in sport and leisure time activities, consisting of
high-load and multi-directional tests, focusing on functional
alignment. In large epidemiological studies these tests must
only require a minimum of time and technical equipment.

Objective
The purpose of the study was to accomplish a systematic
review of screening tests for identification of adolescents at
increased risk of knee injuries, focusing on functional alignment
of the trunk and lower extremities.

Methods
An electronic database search was performed accessing Pub-
Med and Embase from 2000 to 2011. Eligible studies assessing
functional alignment screening of trunk and lower extremities
in children or adolescents (10-18 years old) were included.
Hand searching of all reference lists of the included studies
was performed. Laboratory settings were included as reference
tests, but studies with the primary test requiring force
plate, 3D analysis or other technical device were excluded.
The QUADAS score (Whiting, 2006) was used to evaluate
methodological quality.

Results
Of 1475 articles, 28 articles met all inclusion criteria. Only 3
studies assessing functional alignment were identified. The
Drop Jump Test showed moderate to excellent reliability (Kappa
.75-.85) of clinically assessed knee valgus motion in detection
of knee midline collapse in the frontal plane, (three raters,
n=40). However, the sensitivity was inadequate, ranging from
67-87% compared to 3D analysis. Concurrent validity during
Drop Jump showed a correlation between assessed knee valgus
motion and 3D measurements of r = .87 (n=20). Reliability of
The Single-limb mini squat test was fair to moderate (Kappa
.48- .57) corresponding to 76-79% agreement when evaluating
the medio-lateral knee position during dynamic movements
(two raters, n=33). No studies incorporated clinical assessment
of trunk alignment.

Conclusion
Since only 3 studies were identified including screening tests
of knee alignment, there is a further need to evaluate reliability
and validity of real-time functional alignment tests,
before the can be used as screening tools for prevention of
knee injuries among adolescents. Still the next step in this
systematic review is to evaluate the quality and feasibility
of the three identified tests.