Reliability and Validity of the Duncan-Ely Test for

Reliability and Validity of the Duncan-Ely Test for

Reliability and Validity of the Duncan-Ely Test for Assessing Rectus Femoris Spasticity
in Patients with Cerebral Palsy
Gye Wang Lee, MD1; Seung Yeol Lee, MD2; Chin Youb Chung, MD1; Ki Jeong Kim, MD3; Ju Seok Ryu, MD4; Kyoung Min Lee, MD1;
Soon Sun Kwon, PhD5; Ki Hyuk Sung, MD6; Myoung Ki Chung, MD1; Byung Chae Cho, MD1; Moon Seok Park, MD1
1
Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Gyeonggi, Korea.
2 Department of Orthopaedic Surgery, Ewha Womans University Mokdong Hospital, Seoul, Korea
3 Department of Neurosurgery, Seoul National University Bundang Hospital, Gyeonggi, Korea
4 Department of Rehabilitation Medicine, Seoul National University Bundang Hospital, Gyeonggi, Korea.
5 Department of Mathematics, College of Natural Science, Ajou University, Gyeonggi, Korea
6 Department of Orthopaedic Surgery, Myungji Hospital, Gyeonggi, Korea.
OBJECTIVES
Table 2. Cutoff values of the Duncan-Ely test
RESULTS
Velocity
To clarify the method of the Duncan-Ely test and to estimate its
interobserver reliability and validity by comparing it with 3dimensional(3D) gait analysis.
The intraclass correlation coefficient(ICC) measuring interobserver
reliability of the Duncan-Ely test showed the highest ICC value during
fast velocity(0.819)(Table 1).
V1
(slow)
This study included 36 consecutive ambulatory patients with cerebral
palsy(CP) who underwent preoperative 3D gait analysis.
The sensitivity and specificity of the test during fast velocity for knee
range of motion total were 66.7% and 100%, respectively, with a cutoff
value of 65°(Table 2).
The Duncan-Ely test was performed during 3 different velocities(slow,
gravity, and fast) (Figure 1).
The interobserver reliability was assessed by 3 examiners.
The results of the Duncan-Ely test were compared with kinematic
variables derived from the 3D gait analysis to assess the sensitivity and
specificity of the test.
Area under the
ROC curve
95% CI
p value
Pk flexion in swing
phase
55.6 ± 7.1°
0.663
0.469–0.825
0.104
Knee ROM total
51.6 ± 5.1°
0.753
0.562–0.891
0.066
72 ± 7%
0.562
0.370–0.743
0.582
Pk flexion in swing
phase
55.6 ± 7.1°
0.644
0.449–0.809
0.350
Knee ROM total
51.6 ± 5.1°
0.790
0.603–0.916
0.017
72 ± 7%
0.598
0.404–0.772
0.376
Pk flexion in swing
phase
55.6 ± 7.1°
0.562
0.370–0.742
0.718
Knee ROM total
51.6 ± 5.1°
0.846
0.667–0.951
<0.001
72 ± 7%
0.589
0.395–0.764
0.436
Timing of pk flexion in
swing
The sensitivity and specificity of the test during gravity velocity for knee
range of motion total were 63.0% and 100%, respectively, with a cutoff
value of 78.3°.
METHODS
Reference value
of 3D gait analysis
Gait parameter
V2
(gravity)
Timing of pk flexion in
swing
V3
(fast)
Timing of pk flexion in
swing
CONCLUSIONS
Cutoff
value
≤78.3°
≤65°
The Duncan-Ely test showed excellent reliability in fast knee flexion
velocity and good sensitivity and specificity compared with the 3D gait
analysis during physical examination as a preoperative assessment of
rectus femoris spasticity in CP patients.
The cutoff value was determined at the point of trade-off between the
highest sensitivity and specificity.
Figure 1. The estimated knee flexion
angle during the Duncan-Ely test.
(A) With the patient in the prone position, the
lower leg is brought into flexion (B).
Table 1. Interobserver reliability of the Duncan-Ely test
Measurements
V1 (slow)
87.5 ± 22.1
(range, 40–150)
V2 (gravity)
75.7 ± 19.9
(range, 35–153)
V3 (fast)
65.7 ± 22.3
(range, 28–152)
(C) The knee flexion angle (i.e., the point at
which the hip rises or resistance is felt by the
Knee flexion angle (°)
(mean ± SD)
Interobserver reliability
Measurement
ICC
95% CI
Single
0.721
0.537 – 0.854
Average
0.865
0.795 – 0.915
Single
0.626
0.455 – 0.768
Average
0.848
0.766 – 0.904
Single
0.819
0.636 – 0.952
(A) 65° during fast velocity for peak knee flexion in the swing phase
Average
0.914
0.869 – 0.946
(B) 78.3° during gravity velocity
examiner) is measured.
Figure 2. Receiver operating characteristic curves of the Duncan-Ely test for
normal and abnormal knee motion in three-dimensional gait analysis. These
curves define the cutoff values of the preoperative Duncan-Ely test as follows:
(C) 65° during fast velocity for knee range of motion in the swing phase
This study has been published in Developmental Medicine & Child Neurology