160.
Agreement between two strength devices used in the newly modified
Constant score.
Morten Tange Kristensen, Signe Hjerrild, Pernille Lund Skov Larsen, Maria
Aagesen, Bente Hovmand, Ilija Ban
Department of Physiotherapy and Orthopaedic Surgery Hvidovre University
Hospital; , Metropolitan University College Copenhagen; , Metropolitan
University College Copenhagen; , Metropolitan University College
Copenhagen; , Metropolitan University College Copenhagen; Department of
Orthopaedic Surgery, Hvidovre University Hospital
Background:
The strength testing (part D) of the Constant score (CS) has
been a major source of error, but a new and standardized CS, translated into
Danish following international guidelines, provide new methodology. Still
different devices are used for objective strength testing, which gives up to 25
out of the total 100 possible CS points.
Purpose / Aim of Study:
To examine the agreement of the IsoForceControl
(
ISO) and the IDO isometer (IDO) for the evaluation of maximal shoulder
abduction muscle strength in the modified CS.
Materials and Methods:
Sixty healthy subjects,age 18-70+ years (range 19-
83), 5
men and 5 women in each of six-decade groups, were included. The
IDO and ISO were used in randomized order with an 8-minute rest between
devices. Subjects performed three trials with strong verbal encouragement,
with a 1-minute rest between trials The best performance < 25 pounds was
used in analysis.The same person supervised all strength testing, and was
blinded to all results until end of study.
Findings / Results:
The total Constant score reached an average (SD) of 92.7
(6.1)
points, and was negatively associated with age (r = -0.419, P=0.001).
Men presented higher (P<0.001) total Constant (96.4 versus 88.9) and strength
(22.4
versus 14.2 pounds) scores as compared to women. Paired t-test showed
that the IDO produced an average of -0.58 (95%CI, -0.94 - -0.23) lower
strength scores than the ISO (P=0.002). The ICC2.1 was 0.97 (95%CI, 0.94-
0.98),
while the Standard Error of Measurement was calculated to 1 pound.
Conclusions:
The agreement between ISO and IDO is acceptable at group
level, but it is recommended that an individual should be tested with the same
device at re-testing. Data from this study can be used as a preliminary Danish
reference material, confirming the need for age and gender stratification when
using Constant score in clinical trials.
