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OJHAS Vol. 10, Issue 2:
(Apr-Jun 2011) |
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| Comparison of Ankle Proprioception
Between Pregnant and Non Pregnant Women. |
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Preetha R, Lecturer,
John Solomon M, Associate Professor,
Department of Physiotherapy, MCOAHS, Manipal University, Manipal, India |
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Address for Correspondence |
Lecturer,
Department of Physiotherapy,
MCOAHS, Manipal University
Manipal, India.
E-mail:
preetha.r@manipal.edu |
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Preetha R, John SM. Comparison of Ankle Proprioception
Between Pregnant and Non Pregnant Women. Online J Health Allied Scs.
2011;10(2):9 |
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Submitted: Apr 25,
2011; Accepted: Jul 14, 2011; Published: Jul 30, 2011 |
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| Abstract: |
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Pregnant women report falls especially
during their third trimester. Physiological changes along with ligament
laxity can affect the joint proprioception in this population. This study was
conducted to compare the ankle proprioception
between pregnant and non pregnant women. Thirty pregnant and 30 non pregnant women
were included in the study and the position of ankles were recorded by a digital
camera placed 60 cms away from the feet of the subject. UTHSCSA Image tool
software version 3.0. was used to measure the difference between the initial and
the final angle. The median repositioning error in the
pregnant group was 11.6 (7.6, 12.4) degrees and the median repositioning error in the non-pregnant
group was 4.2 (2.1, 6.3) degrees. There was a statistically significant difference in
ankle joint proprioception between pregnant and non pregnant
women.
Key Words:
Pregnancy; Ankle proprioception;
Falls; Repositioning error
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Pregnancy triggers a wide range of
changes in a woman’s body which includes weight gain, postural changes,
hormonal variations, joint laxity and musculotendinous strength.1
One of the less investigated but commonly reported change is related
to the foot of a pregnant woman. The structural changes could be due
to the accumulation of fluid or fat or both or changes in the ligaments
caused by the extra weight gain that is carried during pregnancy or
by hormonally induced alterations of the connective tissue in the ligaments.2
Human postural control during quiet
standing involves integration of sensory information from mechanoreceptors
on the foot soles3 and precise modulation in ankle torque
through fine adjustment in the length of the plantar flexors.4,5 This may also get affected due to increased muscle work of the
plantar flexors during pregnancy as studies have suggested increased
postural sway in women in third trimester compared to women in first
trimester.6
Physiological changes that occur throughout
pregnancy can alter both balance and postural control in a pregnant
woman. The lower trunk has significantly greater rates of change in
weight than all other body segments during the second and third trimesters
of pregnancy. The changing shape and inertia of the lower trunk requires
postural adjustments such as elevation of the head, hyperextension of
the lumbar spine and extension of knee and ankle joints.7
Stabilogram diffusion analysis results
suggested differences in postural control mechanisms between pregnant
and non pregnant women as increased sway was predominantly directed
along the sagittal plane that is in the antero -posterior direction
than the medio -lateral direction in the static stance phase.8
Studies have also indicated that there is an increased reliance on the
visual cues to maintain balance during pregnancy which suggests that
there could be a proprioceptive loss that leads to postural instability
which in turn leads to increased rate of falls in pregnant women when
compared to non pregnant women.7
A fall rate of 27% was reported during
pregnancy especially during third trimester due to a decline in the
balancing ability, which persists even after six to eight weeks after
delivery.9 These falls can lead to maternal and fetal complications
including 3-7% of fetal deaths.10,11. The leading causes
of falls at work for pregnant women includes slippery floors, moving
at a fast pace and carrying an object or a child.11
Even though the balance issues and
the visual reliance have been recorded in the pregnant women, the loss
of proprioception in them was not studied. Hence we aimed at comparing
the ankle joint proprioception sense between the pregnant and non pregnant
women.
We selected a random
sample of 30 pregnant women, primiparae within age group between 18-35
years in their third trimester. Women with any ankle deformities or
contractures, history of arthritis, recurrent ankle sprain, severe pedal
edema that restricts the range of motion at ankle and diabetic neuropathies
were excluded from the study. We also included 30 age matched non-pregnant
women with regular menstrual cycle and the following procedure was followed.
An informed consent
was obtained from all the subjects. The subjects were asked to sit in
the high sitting position on a high plinth with their feet hanging.
The markers were placed at a) lateral aspect of base of fifth metatarsal,
b) tip of lateral malleolus and c) 5 cm above lateral malleolus on the
shaft of fibula. The subject was blind folded. The tester moved the
ankle into dorsiflexion and plantar flexion for 10 times and placed
the ankle in a particular position. This was considered to be the target
angle. The subjects were asked to feel the position for fifteen seconds
and remember it. A Sony cybershot 5 megapixel digital camera was placed
60 cm away from the subject’s feet on a foot stool perpendicular to
the ankle. The target angle was photographed. The subjects were then
asked to move the ankle 10 times actively and then position the ankle
in the target angle. This position was again photographed and the images
were transferred to a computer. The images were then analysed using UTHSCSA
Image tool software version 3.0 to measure the difference between the
initial and the final angle. The difference in the initial and final
angle (reposition error) was noted and taken for analysis.
Data
Analysis: Data were analysed
using SPSS package version 16.0 and the statistical differences between
pregnant and control subjects were determined using Mann- Whitney U
test as there was no normal distribution of the data.
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Figure 1: Photograph showing the placement of markers |
Results are shown in the Tables below:
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Table
1: Demographic characteristics of the subjects |
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Variable |
Pregnant (n=30) |
Non -pregnant (n=30) |
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Age (years) |
26±4.2
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24± 3.6
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Height
(cms) |
155± 8.7
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153± 6.2
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Weight
(Kgs) |
64.6 ± 8.4
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56.1 ± 4.2
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Foot length
(cms) |
23.38±0.95
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24.23±1.07
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Table 2:
Median proprioceptive error in degrees |
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Subjects |
n |
Mean proprioceptive error (in degrees) |
p |
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Pregnant |
30 |
11.6 (7.6,12.4) |
0.002
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Non pregnant |
30 |
4.2 (2.1,6.3) |
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Graph 1: Median
ankle proprioceptive error between pregnant and non-pregnant women |
Pregnant women included in this study
were in the age group between 18-35 years in their third trimester as
there is more postural instability caused due to various physical and
hormonal changes in this period.3
All the subjects were primiparae that warrants against the variations
that could occur due to the effect of hormones between the primi or
multiparae women.
Subjects whose sensations were already
affected due to diabetic neuropathies were excluded from the study to
avoid the influences of the already existing proprioceptive loss. Subjects
with ankle deformities, contractures or severe edema affecting the active
ankle range of motion were excluded from the study as otherwise their
ability to reposition the joint would have got affected. Subjects with
history of recurrent ankle sprain injuries were also excluded from the
study as the joint proprioception would have been already affected.
All the participants were made to
understand the procedure by demonstrating the subjects what they were
supposed to do and by showing them the photographs which were previously
taken. Two trials for familiarization were provided prior to the actual
test and the recordings were done. Due to inability to measure smaller
variations in the joint range of motion (ROM) using goniometer, we used
a photographic method and the angles were analysed using Image tool
software version 3.0 which is a reliable and a valid method
to analyse the ranges in uniaxial planes.12
The results of the study suggests
that when compared to the non pregnant control subjects there is a significant
increase in the proprioceptive error in pregnant women. This could be
due to the altered proprioceptive input obtained from the lax ligaments
around the ankle joint. It has been found that relaxin hormone levels
increases upto ten times more during pregnancy which predisposes for
ligament and joint laxity that may in turn affect the ability of the
receptors to sense the movement.13,14,15,16
The other factor that could alter the proprioceptive input could be
due to the mild oedema around the ankle which is more common during
the third trimester.
It has also been documented that there
is an increased postural instability during second and third trimesters
during pregnancy with increased reliance on visual cues, which indicates
reduction in proprioceptive input during this period.6 This
also predisposes them to increased risk of falls. Among the pregnant
subjects who participated in this study two of them had reported falls
in their 35th and 37th week. The reasons for the
falls were reported to be increased frequency of urination in the night
which led them to go to toilet and had a fall in the toilet.
This study warrants the necessity of
propriceptive training programs in pregnant women especially in their
third trimester to reduce the rate of falls due to postural instability.
Ankle proprioception is significantly
affected in pregnant women during their third trimester compared to
non- pregnant women.
- Foti T, Davids JR, Bagley AA. A
biomechanical analysis of gait during pregnancy. J Bone Joint Surg Am.
2002;82A:625–630.
- R Alvarez, IA Stokes, DE Asprinio,
S Trevino and T Braun. Dimensional changes of the feet in pregnancy.
J Bone Joint Surg Am. 1988;70-A:271-274.
- Morasso PG, Schieppati M. Can muscle
stiffness alone stabilize upright standing? J Neurophysiol. 1999;82:1622–1626.
- LoramID, Maganaris CM, Lakie M. Human
postural sway results fromfrequent,ballistic bias impulses by soleus
and gastrocnemius. J Physiol. 2006; 564:295–311.
- Oliveira LF, Vieira TMM, Macedo AR, Simpson DM, Nadal J. Postural sway changes during
pregnancy: A descriptive study using stabilometry. Eur J Obstet Gynecol
Reprod Biol. 2009;147:25–28.
- Butler EE, Colon I, Druzin
ML, Rose J. An investigation of gait and postural balance during pregnancy.
Gait & Posture 2006;S128-S129
- Butler EE, Colon I, Druzin
ML, Rose J. Postural equilibrium
during pregnancy: Decreased stability with an increased reliance on
visual cues. American Journal of Obstretics and Gynaecology
2006;95:1104-1108.
- Jang J, Hsiao KT, Hsiao-Wecksler
ET. Balance (perceived and actual) and preferred stance
width during pregnancy. Clinbiomech 2008;23:468-476.
- Dunning K, LeMasters G,
Bhattacharya A. A Major Public Health Issue: The High Incidence of falls
during Pregnancy. Matern Child Health J. 2010;14(5):720-725
- Connolly AM., Katz VL, Bash
KL, Mcmahon MJ, Hansen WF. Trauma and pregnancy. Am. J. Perinatol.
1997;14:331-336.
- Weiss HB, Songer TJ, Fabio
A, Fetal deaths related to maternal injury. JAMA. 2001;286:1863-1868
- Pausic J, Pedisic Z, Dizdar D. Reliability of a Photographic Method for Assessing Standing
Posture of Elementary School Students. J Manupulative Physiol Ther
2010;33(6):425-443.
- Zarrow M, Holmstrom EG, Salhanick
HA. The concentration of relaxin in the blood serum and other tissues
of women during pregnancy. J. Clin. Endocrinol.1955;15:22-27.
- Abramson D, Roberts SM,
Wilson. Relaxation of the pelvic joints in pregnancy. Surg Gynec. and
Obstet. 1934;58:595-613.
- Block RA, Hess LA, Timpano
EV, Serlo C. Physiologic changes in the foot during pregnancy. J.
Am. Podiat. Med. Assn.1985;75:297-299.
- Calguneri M, Bird HA, Wright
V. Changes in joint laxity occurring during pregnancy. Ann Rheumat.
Dis. 1982;41:126-128.
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