Anatomy and Biomechanical Properties of the Plantar Aponeurosis: A Cadaveric Study

Abstract

To explore the anatomy of the plantar aponeurosis (PA) and its biomechanical effects on the first metatarsophalangeal (MTP) joint and foot arch.
Anatomic parameters (length, width and thickness of each central PA bundle and the main body of the central part) were measured in 8 cadaveric specimens. The ratios of the length and width of each bundle to the length and width of the central part were used to describe these bundles. Six cadaveric specimens were used to measure the range of motion of the first MTP joint before and after releasing the first bundle of the PA. Another 6 specimens were used to evaluate simulated static weight-bearing. Changes in foot arch height and plantar pressure were measured before and after dividing the first bundle.
The average width and thickness of the origin of the central part at the calcaneal tubercle were 15.45 mm and 2.79 mm respectively. The ratio of the length of each bundle to the length of the central part was (from medial to lateral) 0.29, 0.30, 0.28, 0.25, and 0.27, respectively. Similarly, the ratio of the widths was 0.26, 0.25, 0.23, 0.19 and 0.17. The thickness of each bundle at the bifurcation of the PA into bundles was (from medial to lateral) 1.26 mm, 1.04 mm, 0.91 mm, 0.84 mm and 0.72 mm. The average dorsiflexion of the first MTP joint increased 10.16° after the first bundle was divided. Marked acute changes in the foot arch height and the plantar pressure were not observed after division.
The first PA bundle was not the longest, widest, or the thickest bundle. Releasing the first bundle increased the range of motion of the first MTP joint, but did not acutely change foot arch height or plantar pressure during static load testing.

Full text

Anatomy and Biomechanical Properties of the Plantar
Aponeurosis: A Cadaveric Study
Da-wei Chen, Bing Li, Ashwin Aubeeluck, Yun-feng Yang, Yi-gang Huang, Jia-qian Zhou, Guang-rong Yu*
Department of Orthopaedics, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
Abstract
Objectives:
To explore the anatomy of the plantar aponeurosis (PA) and its biomechanical effects on the first
metatarsophalangeal (MTP) joint and foot arch.
Methods:
Anatomic parameters (length, width and thickness of each central PA bundle and the main body of the central
part) were measured in 8 cadaveric specimens. The ratios of the length and width of each bundle to the length and width of
the central part were used to describe these bundles. Six cadaveric specimens were used to measure the range of motion of
the first MTP joint before and after releasing the first bundle of the PA. Another 6 specimens were used to evaluate
simulated static weight-bearing. Changes in foot arch height and plantar pressure were measured before and after dividing
the first bundle.
Results:
The average width and thickness of the origin of the central part at the calcaneal tubercle were 15.45 mm and
2.79 mm respectively. The ratio of the length of each bundle to the length of the central part was (from medial to lateral)
0.29, 0.30, 0.28, 0.25, and 0.27, respectively. Similarly, the ratio of the widths was 0.26, 0.25, 0.23, 0.19 and 0.17. The thickness
of each bundle at the bifurcation of the PA into bundles was (from medial to lateral) 1.26 mm, 1.04 mm, 0.91 mm, 0.84 mm
and 0.72 mm. The average dorsiflexion of the first MTP joint increased 10.16uafter the first bundle was divided. Marked
acute changes in the foot arch height and the plantar pressure were not observed after division.
Conclusions:
The first PA bundle was not the longest, widest, or the thickest bundle. Releasing the first bundle increased
the range of motion of the first MTP joint, but did not acutely change foot arch height or plantar pressure during static load
testing.
Citation: Chen D-w, Li B, Aubeeluck A, Yang Y-f, Huang Y-g, et al. (2014) Anatomy and Biomechanical Properties of the Plantar Aponeurosis: A Cadaveric
Study. PLoS ONE 9(1): e84347. doi:10.1371/journal.pone.0084347
Editor: Steve Milanese, University of South Australia, Australia
Received June 24, 2013; Accepted November 14, 2013; Published January 2, 2014
Copyright: ß2014 Chen et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This study was supported by the National Natural Science Foundation of China No. 10-81071471 (http://www.nsfc.gov.cn). The funders had no role in
study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.
* E-mail: yuguangrong2012@gmail.com
Introduction
The plantar aponeurosis (PA) originates from the calcaneal
tubercle and extends to the forefoot. The aponeurosis consists of a
medial, central and lateral part. The medial and lateral parts
attach to the abductor hallucis and the musculus abductor digiti
quinti pedis, respectively. These parts are usually categorized as
‘‘fascia’’. The central part is thicker and is considered an
‘‘aponeurosis’’ [1]. As the central aponeurosis extends towards
the forefoot, it divides into five separate bundles. These bundles
radiate towards and attach through the plantar plates to the
proximal phalanges [1–3]. Most anatomic studies of the PA have
focused on its attachment to the calcaneus. Detailed descriptions of
each central PA bundle are rare.
There is dorsiflexion of the metatarsophalangeal (MTP) joints
during walking. The PA tightens via a windlass mechanism first
described by Hicks [3]. All five bundles contribute to raising the
foot arch. It is not known whether dysfunction of only one central
bundle could affect this mechanism.
The PA and osseous longitudinal arch of the foot form a
triangular truss. When the foot is weight bearing, the PA prevents
the foot arch from separating and collapsing. Resection of the PA
removes this supportive effect. However, proximal plantar
fasciotomy is widely used to treat recalcitrant plantar fasciitis
[4,5]. The biomechanical function of the main body of the PA has
been well described, but the function of the central PA bundles has
not [6–8]. The biomechanical effect of releasing one central PA
bundle is not clear.
We performed anatomic and biomechanical measurements to
determine if releasing the first central PA bundle would increase
dorsiflexion of the first MTP joint, lower the longitudinal arch of
the foot, and change forefoot pressures.
Materials and Methods
Ethics Statement
This work complied with the Helsinki Declaration related to
research carried out on human subjects. Ethical approval was
obtained from the Human Research Ethics Committee, Tongji
University School of Medicine, Shanghai, China. Written
informed consent from the donor or the next of kin was obtained
for research use of the patient limbs.
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Anatomic Measurement
Eight fresh-frozen cadaveric foot specimens were examined.
Obvious preexisting foot abnormalities were excluded by visual
inspection and review of the medical history. Radiographs were
performed to exclude osteoarthritis, previous fractures, tumors,
osteonecrosis, and foot deformities. The mean age of the donors at
death was 43.6 years (range: 32–65). The specimens were dissected
through a longitudinal incision from the heel to the forefoot. The
insertion of the PA to the calcaneal tubercle was exposed. The skin
and soft-tissue were removed along the PA. The PA formed a
complex network just distal to the metatarsal heads with superficial
fibers inserting into the dermis. Only the width and thickness of
the origin of each central bundle, which is at the bifurcation of the
PA into bundles, were measured. The plantar plate is a
fibrocartilaginous structure at the plantar aspect of the MTP
joint. It is regarded as the most distal insertion of the plantar
aponeurosis. The length of each central bundle was defined as the
distance between the plantar plate and the origin of the bundle.
Because of the different sizes of the specimens, the ratios of the
length and width of each central bundle to the length and width of
the central part of the PA were used to describe these bundles
(Figure 1, Figure 2). The distance between the plantar plate of the
second MTP joint and the origin of the central part attaching to
the calcaneal tubercle was defined as the length of the central part
of the PA. The maximum width of the main body of the central
part, proximal to the origin of the bundles, was taken as the width
of the central part. The width and thickness of the central part at
its origin on the calcaneal tubercle was also measured. Each
measurement was performed by three different persons using the
same vernier caliper. A one-way analysis of variance (ANOVA)
was used to test for differences of length of the five bundles. A
Kruskal-Wallis test was used to test for differences of width and
thickness of the five bundles because of inequality of variances.
Post-hoc multiple comparisons were done with a non-parametric
Mann-Whitney-U rank sum test when a Kruskal-Wallis test was
significant. A Bonferroni-corrected value of P,0.005 was consid-
ered statistically significant. Ten comparisons were made for each
anatomic parameter. Data was analyzed using SPSS software
(version 14.0, Chicago, IL, USA).
Biomechanical Range-of-motion Testing
Six specimens were collected for measuring the range of motion
of the first MTP joint. The mean donor age was 38.7 years (range:
24–50). The rigid-body kinematics theorem was used in the
measurement [9–10]. The first metatarsal and the proximal hallux
were marked with three pins, as reported by Panchbhavi et al.
[11]. The coordinate system was constructed after the specimen
was fixed to the homemade braces. The y axis was the vertical
projection of the long axis of the first metatarsal in the horizontal
plane with the direction from proximal to distal. The x axis was
perpendicular to the y axis in the coronal plane, with the direction
from medial to lateral. The z axis was perpendicular to the
horizontal plane with the direction determined by the right
Figure 1. Axial view of the plantar aponeurosis. LP, lateral part;
CP, central part; MP, medial part; L, length; W, width.
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Figure 2. Five central part plantar aponeurosis bundles. B,
bundle.
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(upward) or left (downward) foot. The initial position for the
measurement was the neutral position. The first MTP joint was
dorsiflexed with a 10 N pull force on the distal hallux, before and
after releasing the first central PA bundle. The coordinate figures
of the mark points were measured using a Microscribe 3D digitizer
(G2X, Immersion Corp., San Jose, CA, USA). All specimens were
measured three times by the same person using the same
instrument. Motion was analyzed using the Euler-Cardan
approach programmed using MATLAB software (version 7.11,
MathWorks, Natick, MA, USA) [12]. A paired t-test was used to
compare dorsiflexion before and after the first central PA bundle
was divided. A value of P,0.05 was considered statistically
significant.
Biomechanical Foot Arch and Plantar Pressure Testing
Another six specimens were used for the next biomechanical
testing. The mean donor age was 40.2 years (range: 28–63). Each
specimen was dissected to remove the dorsal skin and muscles
while the ligaments were kept intact. Custom-made black-beaded
pins were inserted into the navicular, cuboid, three cuneiforms and
five metatarsals as identification points. Two digital cameras
positioned laterally and in front of the specimen, 90uto each other,
were used to capture the motion of the specimen (Figure 3). The
specimen was subjected to an axial load of 600 N, equivalent to
the body weight of a 60-kg subject. The axial load was applied by a
universal testing machine (CSS-44010; CRIMS Co., Ltd.,
Changchun, China). Displacement of the identification points on
the photographs was measured using an image analyzing software
(Image J, version 1.46, NIH, USA) [13]. A scale on the loading
platform was used to calculate actual displacement. Displacements
of the navicular, medial cuneiform and first metatarsal in the
inferior-superior direction, and displacements of the heads of the
five metatarsals in the medial-lateral direction were measured. An
F-scan plantar pressure analysis system (Tekscan Inc., Boston,
MA, USA) was used to measure plantar pressure during loading.
An insole sensor film containing 960 independent sensing regions
was placed between the plantar foot and the loading platform. The
data collection period was scheduled for 8 s, with a collection
frequency of 50 frames/s [14]. Five boxes added to the plantar
Figure 3. Experiment setup. LS, loading system; F, F-scan film; C, camera; S, scale.
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Figure 4. Plantar pressure distribution areas. Zone 1, hallux; Zone
2, first metatarsal head; Zone 3, second metatarsal head; Zone 4, third
to fourth metatarsal head; Zone 5, fifth metatarsal head.
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pressure distribution areas were used to collect the peak plantar
pressure of the hallux, first metatarsal head, second metatarsal
head, third to fourth metatarsal heads, and fifth metatarsal head
(Figure 4). Testing consisted of four sequential procedures: (1)
Without load. The arch height of the foot was measured with the
MTP joints passively dorsiflexed by 45uusing a wedge shaped
block with an angle of 45uplaced under the toes. (2) Axial load of
600 N. The displacement and plantar pressure were measured. (3)
The first procedure was repeated with the first central bundle
divided. (4) The second procedure was repeated with the first
central bundle divided. A paired t-test was used to compare the
results before and after releasing the first bundle. Statistical
significance was defined as P,0.05.
Results
Anatomic measurements were performed in eight specimens.
The width and thickness of the origin of the central part of the PA
at the calcaneal tubercle were 15.4560.72 mm and
2.7960.14 mm, respectively. The length of the central part was
146.4569.54 mm and the width was 26.8563.05 mm. The first
bundle was not the longest, widest, or thickest of the five central
bundles (Table 1). The widths (H = 22.341, P = 1.71E-4) and
thicknesses (H = 26.377, P = 2.66E-5) of the five central bundles
were significantly different. The lengths (F = 1.870, P = 0.138)
were not significantly different. The first central bundle was wider
than the fourth (Mann-Whitney U = 4, P = 0.003) and fifth (Mann-
Whitney U = 2, P = 0.002) bundles, but not the second (Mann-
Whitney U = 31, P = 0.916) or third bundle (Mann-Whitney
U = 24, P = 0.401). The first central bundle was thicker than the
third (Mann-Whitney U = 5, P = 4.57E-3), fourth (Mann-Whitney
U = 0, P = 0.001), and fifth (Mann-Whitney U = 0, P = 0.001)
bundles, but not the second bundle (Mann-Whitney U = 14,
P = 0.059).
Dorsiflexion of the first MTP joint increased by 10.1662.10u
after releasing the first PA bundle (Table 2). The increase was
statistically significant (paired t-test, t = 11.83, P = 7.59E-5).
The vertical displacement of the medial cuneiform decreased
significantly after the first PA bundle was released with the MTP
joints dorsiflexed by 45u. The navicular and first metatarsal base
had no change in vertical displacement (Table 3). No change in
arch height (Table 4) or width of the forefoot (Table 5) was seen
when an axial load of 600 N was placed on specimens that had the
first bundle divided. The peak plantar pressure of each metatarsal
heads also did not change significantly after the first bundle was
divided (Table 6).
Table 1. Central aponeurosis bundle measurements (Mean 6
SD, n = 8).
Bundle L (mm) W (mm) T (mm) LB/LC WB/WC
1 42.1265.99 7.1262.14 1.2660.24 0.2960.04 0.2660.05
2 44.4368.41 6.6861.39 1.0460.22 0.3060.05 0.2560.03
3 41.4366.95 6.1760.77 0.9160.10 0.2860.04 0.2360.03
4 36.4864.42 4.9360.21 0.8460.07 0.2560.02 0.1960.02
5 40.0963.10 4.5560.47 0.7260.07 0.2760.03 0.1760.02
NOTE: SD = standard deviation, L = length, W = width, T = thickness, LB/LC= ratio
of the length of the bundle to the length of the central part, WB/WC = ratio of
the width of the bundle to the width of the central part.
doi:10.1371/journal.pone.0084347.t001
Table 2. Dorsiflexion of the first MTP joint.
Cadaver
Intact
(degrees)
Release FB
(degrees)
Increase
(degrees)
1 70.57 77.85 7.28
2 78.31 87.74 9.43
3 75.52 86.11 10.59
4 69.59 81.10 11.51
5 77.45 90.72 13.27
6 82.60 91.49 8.89
Mean 75.67 85.84 10.16
SD 4.92 5.40 2.10
NOTE: MTP= metatarsophalangeal, FB = first bundle, SD = standard deviation.
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Table 3. Vertical displacement with the MTP joints
dorsiflexed by 45u(n = 6).
Bone Intact (mm) Release (mm) t value P value
Na 23.2960.53 23.2160.57 1.52 0.19
Cu 22.4960.48 22.2460.37 2.96 0.03
MT 21.6260.22 21.5760.16 1.44 0.21
NOTE: MTP= metatarsophalangeal, Na = navicular, Cu= medial cuneiform,
MT = metatarsal, ‘‘2’’ means upward.
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Table 4. Vertical displacement with an axial load of 600 N
(n = 6).
Bone Intact (mm) Release (mm) t value P value
Na 4.1060.27 4.1460.25 0.86 0.43
Cu 3.4660.24 3.4960.17 0.73 0.50
MT 2.4860.20 2.5360.21 1.37 0.23
NOTE: Na= navicular, Cu = medial cuneiform , MT = metatarsal.
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Table 5. Transverse displacement of the metatarsal head
with an axial load of 600 N (n = 6).
Bone Intact (mm) Release (mm) t value P value
MT 1 21.4860.11 21.5060.13 1.17 0.30
MT 2 1.2460.10 1.2560.10 0.67 0.53
MT 3 1.5460.12 1.5560.17 0.36 0.74
MT 4 1.8760.18 1.9160.20 1.03 0.35
MT 5 2.0460.16 2.0360.14 0.25 0.81
NOTE: MT= metatarsal head, ‘‘2’’ means medial.
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Discussion
The anatomy of the PA has been well described in the literature,
but most descriptions focused on the attachment of the PA to the
calcaneus. This is the first study to give a detailed measurement of
all five central PA bundles. Since the number of specimens was
limited, it cannot be proved that the first bundle was the strongest
bundle. The first bundle was not the longest, widest, or thickest of
the five central bundles. Further biomechanical testing of the
failure load of each bundle is needed [15]. The thickness and
width of the origin of the central part of the PA we measured were
similar to previous reports [16,17]. The PA is often thickened
greater than 4 mm in plantar fasciitis [18]. Our measurements
reflected the normal anatomy of the PA. The lateral part of the PA
we evaluated was much thicker than the medial part. The medial
part was very thin and could not be easily measured. The color of
the lateral part was white, similar to the central part. But the
medial part was almost transparent. Some avulsion fractures
occurring at the proximal end of the fifth metatarsal are caused by
forces directed through the lateral part, which indicates that the
lateral part is very strong [19]. Based on these findings, we think it
is more appropriate to categorize the lateral part as an
‘‘aponeurosis’’ and the medial part as a ‘‘fascia’’, an opinion
which differs from that of Aquino et al. [1].
One function of the PA is to support the foot arch. The effect of
dividing the PA on the foot arch has been extensively investigated.
Murphy et al. [7] used cadaveric specimens to evaluate changes in
the medial and lateral longitudinal arches after sequential division
of the PA. Complete release of the PA resulted in greater loss of
arch height than release of the medial third part. There was 62%
less medial arch and 100% less lateral arch. A biomechanical
model constructed by Arangio et al. [6],using a load of 683 N
applied to a foot with the PA divided, demonstrated a 17%
increase in vertical displacement and 15% increase in horizontal
elongation. Thordarson et al. [8] also found a consistent decrease
in arch support with sequential division of the PA in eight
cadaveric specimens. Almost all related studies used a technique
where the main body of the central part of the PA was released.
The biomechanical effect of releasing only one PA bundle has not
been reported. We found that releasing the first bundle did not
acutely lower the foot arch when an axial load of 600 N was
applied. This indicates that the arch support was not weakened by
resection of the first bundle.
The windlass mechanism of the PA was examined. The MTP
joints were dorsiflexed 45uto test the elevating effect on the foot
arch. Releasing the first bundle did not acutely weaken the
elevating effect. The upward displacement of the navicular and
first metatarsal base did not decrease significantly after dividing
the first bundle. This indicates that the arch-raising effect was
preserved by the remaining four bundles. During dissection, we
noticed that some plantar muscles (flexor digitorum brevis) were
firmly attached to the PA. We suspect these muscles might also
contribute to elevating the foot arch when the PA is tightened by
extending the toes. As a result, the arch-raising effect was
maintained after dividing the first bundle.
The transverse displacements of the metatarsal heads were
measured to identify the effect of releasing the PA on the forefoot.
With the axial load applied, the width of the forefoot increased,
allowing medial movement of the first metatarsal head and lateral
movement of other four metatarsal heads. Releasing the first PA
bundle did not cause the width of the forefoot to change
significantly, similar to the findings of Waldecker et al. [20]. With
the specimens axially loaded to 900 N, they found that the overall
effect of PA release on the structure of the forefoot was not
significant. However, they performed a proximal plantar fasciot-
omy, while we only divided the first bundle. Dividing the PA may
not affect forefoot width if the integrity of the intermetatarsal
ligaments is maintained.
The effect of releasing the first central bundle on forefoot
plantar pressure was also evaluated. The plantar pressure of the
forefoot did not change significantly after the first bundle was
divided when an axial load of 600 N was applied to the foot. These
results were different from other studies where the PA was released
next to the calcaneus. Sharkey et al. [21] found an increase of
plantar pressure under the metatarsal heads after releasing the
medial half of the central part. Complete release resulted in a
pressure shift from the toes to the metatarsal heads. Another study
by Erdemir and coworkers [22] reported similar results. The site at
which the release was performed might play a role in these
different findings. Near the calcaneus, the central part bears
relatively higher loads than in any one central bundle. Releasing
the whole central part can also lead to a deformation of the foot
arch. Consequently, dividing the PA near the calcaneus would
change the load distribution of the forefoot. Differences in loading
environments could also have contributed to the difference in
findings. The test would be more meaningful if the late stance
phase (when the heel is off the ground) was simulated.
Unfortunately, during our preliminary tests, the foot position
could not be consistently maintained with the heel off the loading
platform. As a result, foot loading in the neutral position was
chosen as our definitive test. A review of the literature found no
study reporting how force was transmitted through each bundle or
the whole central PA during gait. Although the ideal testing
method has not been identified, we speculate that testing the
tension forces in each bundle and the whole central part might
reveal the true function of the PA and help define the role of the
first bundle in foot function.
Six specimens were used to measure the change in dorsiflexion
of the first MTP joint after releasing the first central bundle.
Dorsiflexion increased by 10.16u, comparable to the results
reported by Harton et al. [23]. They performed a proximal
plantar fasciotomy in eighteen patients with recalcitrant plantar
fasciitis in the absence of first MTP joint pathology. This resulted
in an average increase of dorsiflexion in the first MTP joint of 9.8u.
A load of 10 N was applied to the distal hallux to produce
dorsiflexion of the first MTP joint in our testing. Although the load
chosen was different from that found during walking, we think it
had two advantages. First, it could be easily reproduced when
different specimens were measured. Second, this load was relative
small, avoiding injury to the joint. These factors served to increase
the reproducibility of the testing.
Hallux rigidus is the second most common disorder of the first
MTP joint next to hallux valgus [24]. Some studies suggest that a
Table 6. Peak forefoot plantar pressure with a 600-N load
(n = 6).
Bone Intact (KPa) Release (KPa) t value P value
P1 13.8363.76 12.5063.08 1.06 0.34
MT1 33.1766.97 32.3366.95 0.47 0.66
MT2 67.1766.43 69.5065.09 0.94 0.39
MT3–4 58.1766.31 59.5065.54 0.69 0.52
MT5 21.6765.13 20.5063.94 0.67 0.53
NOTE: P= phalange, MT = metatarsal head.
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tight or short first central PA bundle may contribute to hallux
rigidus [25,26]. Davies-Colley [27] treated patients with hallux
rigidus by dividing the first PA bundle and part short muscles in
the sole of the foot. At present, release of the distal insertion of the
first central bundle is still, but not universally, used to treat early-
stage hallux rigidus [28]. The first central bundle was divided in
our testing, causing increased dorsiflexion of the first MTP joint.
However, the specimens had no hallux rigidus. Further studies are
needed to determine whether releasing the first central bundle
would benefit hallux rigidus.
There were some limitations to our study. Loading the foot in
the neutral position was not consistent with normal walking.
Unfortunately, simulating the late stance phase with the heel off
the ground could not be reproduced by our equipment. Also,
dynamic loading to simulate pressures obtained during walking
could not be performed. A load of 600 N was chosen for the
biomechanical testing. A much heavier load or repeated loading
might produce different results. Normal specimens were used to
measure the dorsiflexion of the first MTP joint. The results of our
testing may not be applicable for those with hallux rigidus.
In conclusion, the first PA bundle was not the longest, widest or
the thickest of the five central bundles. Releasing the first bundle
increased the range of motion of the first MTP joint, but did not
acutely change the arch height or plantar pressure in static tests.
Further studies are needed to determine whether releasing the first
central bundle would benefit hallux rigidus.
Author Contributions
Conceived and designed the experiments: DC BL. Performed the
experiments: DC BL AA. Analyzed the data: DC YY YH. Contributed
reagents/materials/analysis tools: JZ GY. Wrote the paper: DC BL GY.
References
1. Aquino A, Payne C (1999) Function of the plantar fascia. The Foot 9: 73–78.
2. May TJ, Judy TA, Conti M, Cowan JE (2002) Current treatment of plantar
fasciitis. Curr Sports Med Rep 1: 278–284.
3. Hicks JH (1954) The mechanics of the foot. II. The plantar aponeurosis and the
arch. J Anat 88: 25–30.
4. Sinnaeve F, Vandeputte G (2008) Clinical outcome of surgical intervention for
recalcitrant infero-medial heel pain. Acta Orthop Belg 74: 483–488.
5. Tweed JL, Barnes MR, Allen MJ (2009) An evaluation of the long-term effects of
total plantar fasciotomy–a preliminary study. The Foot 19: 75–79.
6. Arangio GA, Chen C, Kim W (1997) Effect of cutting the plantar fascia on
mechanical properties of the foot. Clin Orthop Relat Res 339: 227–231.
7. Murphy GA, Pneumaticos SG, Kamaric E, Noble PC, Trevino SG, et al. (1998)
Biomechanical consequences of plantar fascia release. Foot Ankle Int 19: 149–
152.
8. Thordarson DB, Kumar PJ, Hedman TP, Ebramzadeh E (1997) Effect of partial
versus complete plantar fasciotomy on the windlass mechanism. Foot Ankle Int
18: 16–20.
9. Nester C, Jones RK, Liu A, Howard D, Lundberg A, et al. (2007) Foot
kinematics during walking measured using bone and surface mounted markers.
J Biomech 40: 3412–3423.
10. Maletsky LP, Sun J, Morton NA (2007) Accuracy of an optical active-marker
system to track the relative motion of rigid bodies. J Biomech 40: 682–685.
11. Panchbhavi VK, Vallurupalli S, Yang J, Andersen CR (2009) Screw fixation
compared with suture-button fixation of isolated Lisfranc ligament injuries.
J Bone Joint Surg Am 91: 1143–1148.
12. Cattrysse E, Baeyens JP, Van Roy P, Van de Wiele O, Roosens T, et al. (2005)
Intra-articular kinematics of the upper limb joints: a six degrees of freedom study
of coupled motions. Ergonomics 48: 1657–1671.
13. Xia J, Zhang P, Yang YF, Zhou JQ, Li QM, et al. (2013) Biomechanical analysis
of the calcaneocuboid joint pressure after sequential lengthening of the lateral
column. Foot Ankle Int 34: 261–266.
14. Yu X, Yu GR, Chen YX, Liu XC (2011) The characteristics and clinical
significance of plantar pressure distribution in patients with diabetic toe
deformity: a dynamic plantar pressure analysis. J Int Med Res 39: 2352–2359.
15. Kitaoka HB, Luo ZP, Growney ES, Berglund LJ, An KN (1994) Materi al
properties of the plantar aponeurosis. Foot Ankle Int 15: 557–560.
16. Cardinal E, Chhem RK, Beauregard CG, Aubin B, Pelletier M (1996) Plantar
fasciitis: sonographic evaluation. Radiology 201: 257–259.
17. Tsai WC, Chiu MF, Wang CL, Tang FT, Wong MK (2000) Ultrasound
evaluation of plantar fasciitis. Scand J Rheumatol 29: 255–259.
18. McMillan AM, Landorf KB, Barrett JT, Menz HB, Bird AR (2009) Diagnostic
imaging for chronic plantar heel pain: a systematic review and meta-analysis.
J Foot Ankle Res 2: 32.
19. Theodorou DJ, Theodorou SJ, Kakitsubata Y, Botte MJ, Resnick D (2003)
Fractures of proximal portion of fifth metatarsal bone: anatomic and imaging
evidence of a pathogenesis of avulsion of the plantar aponeurosis and the short
peroneal muscle tendon. Radiology 226: 857–865.
20. Waldecker U, Roth E, Bodem F, Meurer A, Heine J (2005) Effec t of a sequential
plantar fasciotomy on the width of the forefoot. Foot Ankle Surg 11: 207–210.
21. Sharkey NA, Donahue SW, Ferris L (1999) Biomechanical consequences of
plantar fascial release or rupture during gait. Part II: alterations in forefoot
loading. Foot Ankle Int 20: 86–96.
22. Erdemir A, Piazza SJ (2004) Changes in foot loading following plantar
fasciotomy: a computer modeling study. J Biomech Eng 126: 237–243.
23. Harton FM, Weiskopf SA, Goecker RM (2002) Sectioning the plantar fascia.
Effect on first metatarsophalangeal joint motion. J Am Podiatr Med Assoc 92:
532–536.
24. Berlet GC, Hyer CF, Lee TH, Philbin TM, Hartman JF, et al. (2008)
Interpositional arthroplasty of the first MTP joint using a regenerative tissue
matrix for the treatment of advanced hallux rigidus. Foot Ankle Int 29: 10–21.
25. Flavin R, Halpin T, O’Sullivan R, FitzPatrick D, Ivankovic A, et al. (2008) A
finite-element analysis study of the metatarsophalangeal joint of the hallux
rigidus. J Bone Joint Surg Br 90: 1334–1340.
26. Fuller EA (2000) The windlass mechanism of the foot. A mechanical model to
explain pathology. J Am Podiatr Med Assoc 90: 35–46.
27. Davies-Colley (1887) Contraction of the metatarso-phalangeal joint of the grea t
toe. Br Med J 1: 728.
28. Giannini S, Faldini C, Grandi G, Leonetti D, Nanni M, et al. (2011) Guidelines
for Surgical Treatment of Hallux Rigidus. In: AAOS, editors. Proceedings of the
78th Annual Meeting of the American Academy of Orthopaedic Surgeons; 2011
Feb 15–19; San Diego, CA. Rosemont, IL: American Academy of Orthopaedic
Surgeons. 886.
A Cadaveric Study for the Plantar Aponeurosis
PLOS ONE | www.plosone.org 6 January 2014 | Volume 9 | Issue 1 | e84347