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· DOS Abstracts
Strength testing following anterior cruciate
ligament reconstruction. A prospective cohort
study investigating redundancy of tests.
Kristoffer Weisskirchner Barfod
OrthoSport Victoria Research Unit, Deakin University and Epworth HealthCare,
Australia
Background:
Restoration of muscle strength after anterior cruciate ligament
(ACL) tear is considered important in order to safely return to sport, but com-
prehensive strength testing protocols are often very time-consuming.
Purpose / Aim of Study:
The purpose of the study was to improve the ef-
ficiency of a strength testing protocol by investigating if some tests are re-
dundant and could be omitted when evaluating outcomes at 6 and 12 month
following ACL reconstruction.
Materials and Methods:
The study was performed as a prospective cohort
study following the STROBE guidelines. The following 4 strength tests were per-
formed using a HUMAC NORM Dynamometer: 1. Isokinetic concentric strength
at 60°/s, 2. Isokinetic concentric strength at 180°/s, 3. Isometric strength,
and 4. Isokinetic eccentric strength at 60°/s. The redundancy of strength tests
was investigated by fitting a linear regression model to the data. An R-squared
value above 0.75 was chosen to indicate redundancy.
Findings / Results:
The cohort consisted of 123 patients (74 male, 49 fe-
male) who completed 6 and 12 months follow up after ACLR. The comparison
of concentric peak force at 60deg/s and 180deg/s showed redundancy at both
6 and 12 months when looking at the limbs separately (R2=0.775 to 0.861).
The comparison of isometric and isokinetic peak force and concentric and ec-
centric peak force often showed borderline redundancy (R2=0.574 to 0.806).
No analyses of limb symmetry index showed redundancy.
Conclusions:
At 6 and 12 month following ACL reconstruction little extra in-
formation was generated by testing concentric strength at both 60deg/s and
180deg/s, as the measurements showed considerable redundancy with one
explaining approximately 90% of the other. To achieve a more time-efficient
testing protocol only one concentric speed should be included.
No conflicts of interest reported
151.