Crouched gait in myelomeningocele: a comparison between the degree of knee flexion contracture in the clinical examination and during gait.

Abstract

The purpose of this study was to quantitatively evaluate, in patients with low lumbar and sacral level myelomeningocele who have knee flexion contractures, whether there are significant differences between the degree of knee flexion contracture measured clinically and the degree of actual knee flexion during gait, measured by computerized gait analysis. Patients were divided into two groups, those who walked with ankle-foot orthoses (AFOs) alone and those who walked with AFOs and crutches. In both groups, the patient's knee flexion contractures were measured clinically, and the degree of knee flexion was measured dynamically at two representative points in the gait cycle. In both groups and at both points of the gait cycle, the degree of knee flexion during gait was significantly greater than the degree of clinical knee flexion contracture. This should be taken into account when evaluating the crouch gait of children with myelomeningocele and planning the proper treatment.

Full text

Page 1

ORIGINAL ARTICLE
Crouched Gait in Myelomeningocele
A Comparison Between the Degree of Knee Flexion Contracture in the
Clinical Examination and During Gait
Todd Moen, BA,*† Nicholas Gryfakis, MS,† Luciano Dias, MD,†§ and Laura Lemke, MD‡
Abstract: The purpose of this study was to quantitatively evaluate,
in patients with low lumbar and sacral level myelomeningocele who
have knee flexion contractures, whether there are significant differ-
ences between the degree of knee flexion contracture measured
clinically and the degree of actual knee flexion during gait, measured
by computerized gait analysis. Patients were divided into two groups,
those who walked with ankle–foot orthoses (AFOs) alone and those
who walked with AFOs and crutches. In both groups, the patient’s
knee flexion contractures were measured clinically, and the degree
of knee flexion was measured dynamically at two representative
points in the gait cycle. In both groups and at both points of the gait
cycle, the degree of knee flexion during gait was significantly greater
than the degree of clinical knee flexion contracture. This should be
taken into account when evaluating the crouch gait of children with
myelomeningocele and planning the proper treatment.
Key Words: myelomeningocele, crouch gait, knee flexion contrac-
ture, gait analysis
(J Pediatr Orthop 2005;25:657–660)
A
a crouch gait.1–3The crouched gait caused by knee flexion
contractures increases oxygen consumption and oxygen cost,
and the amount of increased oxygen cost is directly related
to the degree of knee flexion contracture. Rueter and Pierre
showed that progressive increases in fixed knee flexion during
gait caused progressive increases in oxygen cost, with
a contracture of 15 degrees increasing oxygen cost by 13%,
a contracture of 30 degrees increasing oxygen cost by 19%,
and a contracture of 45 degrees increasing oxygen cost by
38%.4Although Duffy et al5argued that in patients with
common problem in patients with myelomeningocele is
the development of knee flexion contractures, leading to
myelomeningocele and knee flexion contractures, the in-
creased energy cost is not due solely to the increased knee
flexion but rather a combination of multiple other factors, the
consensus in the literature is in agreement with the findings of
Rueter and Pierre.4,6–8Thus, to improve the efficiency of
ambulation, the surgical treatment of knee flexion contractures
is indicated when the contractures are greater than 15 to 20
degrees.3
Many patients with myelomeningocele at our clinic
undergogait analysis as part of their evaluation; it has been our
observation that a patient’s degree of knee flexion is often
significantly more severe during ambulation compared with
the knee flexion contracture measured in the clinical exam-
ination.Althoughthere are a few studies in the literature focusing
on knee flexion contractures in patients with myelomeningo-
cele,2,9,13–18to our knowledge there has never been a study
comparing knee flexion contractures and the actual degrees of
knee flexion during gait using dynamic gait analysis. The
purpose of this study was to quantitatively test the validity of
our clinical observations, and to see whether there is a sig-
nificant difference between the degree of knee flexion mea-
sured clinically and that measured through computerized gait
analysis.
METHODS
This was an Institutional Review Board-approved
retrospective study of all children who had high sacral or
low lumbar level myelomeningocele and who also underwent
clinical gait analysis. Children who walked with ankle–foot
orthoses (AFOs) and an assistive device were classified with
a low lumbar lesion at the L4-L5 level. Children who walked
with AFOs independently were classified with a high sacral
lesion at the L5-S1 level. In addition, to be eligible for this
study all children needed to show a clinically measured knee
flexion contracture at the time of their gait analysis. The child
first underwent complete clinical evaluation and manual
muscle testing, performed by the same physical therapist. The
degree of knee flexion contracture was measured according
to the methods described by Norkin and White10with the
patient in the supine position, the knee in maximum extension,
and the hip at neutral. Following the physical therapist’s
clinical examination, the patient underwent a gait analysis
performed with a Vicon 370 motion capture system (Vicon
Motion Systems Inc, Lake Forest, CA). After application of
retroreflective markers according to Kadaba et al,11the patient
From *Northwestern University Feinberg School of Medicine, Chicago, IL;
†Children’s Memorial Hospital, Motion Analysis Center, Chicago, IL;
‡Fox Valley Orthopaedics, Geneva, IL; and §Northwestern University
Feinberg School of Medicine, Department of Orthopaedic Surgery,
Chicago, IL.
Study conducted at Children’s Memorial Hospital, Motion Analysis Center,
Chicago, IL.
None of the authors received financial support for this study.
Reprints: Nicholas Gryfakis, MS, Children’s Memorial Hospital, Motion
Analysis Center, 2300 Children’s Plaza, #92, Chicago, IL 60614 (e-mail:
ngryfakis@childrensmemorial.org).
Copyright ? 2005 by Lippincott Williams & Wilkins
J Pediatr Orthop?Volume 25, Number 5, September/October 2005
657

Page 2

walked along a walkway in the laboratory at a self-selected
speed. Three-dimensional joint kinematics were obtained for
the hip, knee, and ankle joints. The kinematic data were
determined according to the model described by Kadaba et al.11
A minimum of three trials were captured for each patient and a
representative trialwas chosen to address intra-subject variability.
Overall, 34 patients were eligible and enrolled. Of the
34 patients, 23 had bilateral contractures and 11 had unilateral
contractures, for a total of 57 total limbs studied. The patients
were divided into two groups: group 1, those who walked
withAFOs independently, and group 2, thosewhowalked with
AFOs and an assistive device. Data were collected from each
knee that had a flexion contracture. Group 1 (high sacral level)
comprised 14 patients, 12 with bilateral knee flexion con-
tractures (n = 26 limbs). All 14 patients walked with solid
AFOs. The mean age of the patients in group 1 was 11.2 6 4.3
years. Group 2 (low lumbar level) comprised 20 patients,
11withbilateralkneeflexioncontractures(n=31limbs).Seven-
teen patients walked with solid AFOs and crutches, and three
patients walked with solid AFOs and a walker. The mean age
of the patients in group 2 was 11.0 6 3.7 years.
To determine whether the value of knee flexion in gait was
significantly different than the value of knee flexion contracture
measured clinically, the value of knee flexion contracture was
compared with the value of knee flexion calculated during gait at
two points: initial contact (IC) and minimum knee flexion in
single limb stance (SLSMF) (Fig. 1). The difference between
the value of knee flexion contracture and knee flexion at IC and
the difference between knee flexion contracture and knee flexion
at SLSMF were calculated. In addition, the percentage difference
from knee flexion contracture was calculated for knee flexion at
IC and at SLSMF. For example, if a patient with a knee flexion
contracture of 10 degrees measured clinically had 20 degrees
of knee flexion at IC, the percentage change would be 100%.
Due to the non-normal distribution of data, a nonparametric
Wilcoxon paired signed rank sum test12was used to determine
the statistical significance of the differences, and the Mann-
Whitney test was used to determine statistical difference between
the groups.
RESULTS
Group 1
In group 1 (Table 1), the median knee flexion contracture
measuredduringtheclinicalexaminationwas15.0degrees.The
median knee flexion at IC was 22.2 degrees. The median
difference between these two points was 5.8 degrees (25th–
75th percentile: 23.1 to 16.7 degrees), and the median
percentage differencewas 44.5% (25th–75th percentile: 219.7%
to114.6%).ThemediankneeflexionatSLSMFwas30.8degrees.
The median difference between the initial flexion contracture
and this point was 13.6 degrees (25th–75th percentile: 4.9–
24.4 degrees), and the median percentage difference was
81.5% (25th–75th percentile: 47.1–188.3%). All differences
described were statistically significant to P , 0.05.
Group 2
In group 2 (see Table 1), the median knee flexion con-
tracturemeasuredduringtheclinicalexaminationwas10.0degrees.
The median knee flexion at IC was 20.9 degrees. The median
difference between these two pointswas 7.1 degrees (25th–75th
percentile:22.1to17.4degrees),andthemedianpercentagedif-
ference was 62.4% (25th–75th percentile: 25.6% to 173.9%).
The median knee flexion at SLSMF was 20.6 degrees. The
median difference between the initial flexion contracture and
this point was 9.5 degrees (25th–75th percentile: 21.2 to
21.6 degrees), and the median percentage difference was
97.8% (25th–75th percentile: 215.8% to 190.9%). All
differences described were statistically significant to P , 0.05.
Patients With Unilateral Knee
Flexion Contractures
In patients with unilateral knee flexion contractures, the
median knee flexion contracture measured during the clinical
examination was 8.0 degrees. The median degree of knee
flexion at IC was 10.2 degrees. The median difference between
these two points was 1.5 degrees (25th–75th percentile: 24.5
to 3.3 degrees), and the median percentage difference was
29.8% (25th–75th percentile: 236.9% to 52.8%). The median
degree of knee flexion at SLSMF was 26.4 degrees. The me-
dian difference between the initial flexion contracture and this
point was 11.4 degrees (25th–75th percentile: 23.2 to 20.0
degrees), and the median percentage difference was 171%
(25th–75th percentile: 39.9–228.1%). The differences at
SLSMF were statistically significant to P , 0.05.
Patients With Bilateral Knee
Flexion Contractures
In patients with bilateral knee flexion contractures, the
median knee flexion contracture measured during the clinical
examination was 15.0 degrees. The median degree of knee
flexion at IC was 24.5 degrees. The median difference between
these two points was 11.3 degrees (25th–75th percentile: 20.1
to 17.8 degrees), and the median percentage difference was
65.3% (25th–75th percentile: 0.1–165.1%). The median degree
of knee flexion at SLSMF was 28.8 degrees. The median
difference between the initial flexion contracture and this point
was 9.8 degrees (25th–75th percentile: 2.2–25.6 degrees), and
the median percentage difference was 81.5% (25th–75th
percentile: 13.0–181.2%). All differences described were
statistically significant to P , 0.05.
DISCUSSION
These results show a statistically significant difference
between the degree of knee flexion contracture on clinical
examination and the actual degree of knee flexion during gait.
These findings suggest some noteworthy conclusions. First,
our study brings to light the importance of computerized gait
analysis in the evaluation of patients with myelomeningocele.
Our study shows that in patients with myelomeningocele and
knee flexion contractures, their actual functional status is often
significantly different than what their static clinical examina-
tion suggests. By displaying how a patient’s true functional
status is often much different than what would be expected
from clinical examination, our study shows that gait analysis
should play a prominent role in the complete and thorough
658
q 2005 Lippincott Williams & Wilkins
Moen et al
J Pediatr Orthop?Volume 25, Number 5, September/October 2005

Page 3

evaluation of patients with myelomeningocele, particularly
when considering surgical treatment.
Second, for patients in whom gait analysis is not avail-
able, our study offers additional information to the orthopaedic
surgeon evaluating and caring for them. Namely, our study
shows that in patients with knee flexion contractures, their
functional status is not only different from that which would
be expected based on clinical examination, but also worse.
Increased knee flexion during gait causes increased oxygen
cost and a less efficient gait, and our study shows that there
would be a greater oxygen cost in patients with knee flexion
contractures than that expected from the clinical examina-
tion. This should be kept in mind when evaluating patients
for possible surgical treatment, particularly patients with
borderline-level contractures. A patient may appear to have
a mild contracture deformity on clinical examination and not
be immediately considered for surgical treatment; in actuality,
this same patient may have significantly impaired function and
would greatly benefit from surgery.
Trends in cumulative data can also be found when com-
paring patients with bilateral contractures versus those with a
unilateral contracture. For this analysis, data from groups 1 and
FIGURE 1. Graph of points during the gait cycle from which data were collected. Also, representative knee flexion pattern of
a patient in group 1 with 25-degree and 35-degree knee flexion contractures on the left and right sides, respectively. Note the
significant difference in knee flexion at IC compared with SLSMF. Solid line, left knee; dashed line, right knee.
TABLE 1. Knee Flexion Constructive Data
KFC
15?
15?
10?
10?
8?
8?
15?
15?
Median Knee Flexion
22.2?
30.8?
20.9?
20.6?
10.2?
26.4?
24.5?
28.8?
Median Difference
5.8?
13.6?
7.1?
9.5?
1.5?
11.4?
11.3?
9.8?
Median % Difference
Group 1
IC
SLSMF
IC
SLSMF
IC
SLSMF
IC
SLSMF
44.5%
81.5%
62.4%
97.8%
29.8%
171.1%
65.3%
81.5%
Group 2
Unilateral
Bilateral
KFC, knee flexion contracture measured on clinical exam; IC, initial contact point during the gait cycle; SLSMF, minimum knee
flexion in single limb stance of the gait cycle.
q 2005 Lippincott Williams & Wilkins
659
J Pediatr Orthop?Volume 25, Number 5, September/October 2005Crouched Gait in Myelomeningocele

Page 4

2 were combined, as only 2 of the 14 patients in group 1 had
unilateral contractures, making intergroup comparisons statis-
tically weak. As shown in Table 1, patients with bilateral con-
tractures showed a greater absolute and percentage difference in
knee flexion at IC compared with patients with unilateral con-
tractures, while the opposite was true at SLSMF.
Knee flexion contractures are a significant problem for
patients with myelomeningocele. This study shows a signifi-
cant difference between the knee flexion contracture measured
clinically and the degree of knee flexion during gait. This
should be taken into account when evaluating the crouch gait
of children with myelomeningocele and planning the proper
treatment.
ACKNOWLEDGMENTS
The authors thank the Children’s Memorial Hospital
Motion Analysis Center Research & Education Fund and
Claudia Kelp-Lenane for their assistance in this project.
REFERENCES
1. Tachdijan MO. Myelomeningocele. In: Pediatric Orthopaedics. Phila-
delphia: WB Saunders, 1990:1773–1871.
2. Dias LS. Myelomeningocele. In: Canale ST, Beaty JH, eds. Operative
Pediatric Orthopaedics. St Louis: Mosby Year Book, 1991:683–715.
3. Dias LS. Surgical management of knee contractures in myelomeningo-
cele. J Pediatr Orthop. 1982;2:127–131.
4. Rueter K, Pierre M. Energy cost and gait characteristics of flexed knee
ambulation. In: Bunch WE, Keagy R, Knitter AE, et al, eds. Atlas of
Orthotics. St Louis: CV Mosby, 1985:154–155.
5. Duffy CM, Hill AE, Graham HK, et al. The influence of flexed-knee gait
on the energy cost of walking in children. Dev Med Child Neurol. 1997;
39:234–238.
6. Waters RL, Lunsford BR. Energy expenditure of normal and pathological
gait: application to orthotic prescription. In: Bunch WE, Keagy R, Knitter
AE, et al, eds. Atlas of Orthotics. St Louis: CV Mosby, 1985:151–
159.
7. Waters RL. Energetics. In: Perry J, ed. Gait Analysis. Thorofare, NJ:
Slack, 1992:443–489.
8. Winter D. Knee flexion during stance as a determinant of inefficient
walking. Phys Ther. 1983;63:331–333.
9. Wright J, Menelaus M, Broughton NS, et al. Natural history of knee
contractures in myelomeningocele. J Pediatr Orthop. 1991;11:725–730.
10. Norkin CC, White DJ. Measurement of Joint Motion: A Guide to
Goniometry, 2nd ed. Philadelphia: FA Davis, 1995.
11. Kadaba MP, Ramakrishnan HK, Wooten ME. Measurement of lower
extremity kinematics during level walking. J Orthop Res. 1990;8:383–
392.
12. Glantz SA. Primer of Biostatistics. New York: McGraw-Hill, 1981.
13. Bartonek A, Saraste H, Samuelsson L, et al. Ambulation in patients with
myelomeningocele: a 12-year follow-up. J Pediatr Orthop. 1999;19:
202–206.
14. Bunch WH. Myelomeningocele. In: Lovell WW, Winter RB, eds.
Pediatric Orthopaedics. Philadelphia: JB Lippincott, 1986:397–435.
15. Duffy CM, Hill AE, et al. Energy consumption in children with spina
bifida and cerebral palsy: a comparative study. Dev Med Child Neurol.
1996;38:238–243.
16. Ounpuu S, Thomson J, Davis RB, et al. An examination of the knee
function during gait in children with myelomeningocele. J Pediatr Orthop.
2000;20:629–635.
17. Perry J, Antonelli D, Ford W. Analysis of knee joint forces during flexed
knee stance. J Bone Joint Surg [Am]. 1975;57:961–967.
18. Samuelsson L, Skoog M. Ambulation in patients with myelomeningocele:
a multivariate statistical analysis. J Pediatr Orthop. 1988;8:569–575.
660
q 2005 Lippincott Williams & Wilkins
Moen et al
J Pediatr Orthop?Volume 25, Number 5, September/October 2005