Abstract
Background: The relationship between the shape of the first
metatarsal head and hallux valgus deformity remains controversial. The purpose
of the present study was to retrospectively analyze differences in the
radiographic appearance of the shape of the lateral edge of the first
metatarsal head between women with normal feet and those with hallux valgus
and to clarify the relationship between the shape of the lateral edge and the
postoperative recurrence of hallux valgus deformity.
Methods: Dorsoplantar weight-bearing radiographs of sixty normal
feet in women (the control group) and sixty feet in women with hallux valgus
(the hallux valgus group) were reviewed. The feet in the hallux valgus group
were treated with a proximal metatarsal osteotomy, and the radiographs of
those feet were assessed preoperatively, at the time of early follow-up (mean,
3.4 months), and at the time of the most recent follow-up (mean, forty-eight
months). The shape of the lateral edge, which was defined as consisting of the
articular and lateral surfaces of the first metatarsal head, was examined. The
shape of the lateral edge was classified as one of three types: round (type
R), angular (type A), and intermediate (type I). We defined the round sign as
being positive when the shape of the lateral edge was classified as type
R.
Results: Prior to surgery, the prevalence of the type-R shape was
significantly greater in the hallux valgus group than it was in the control
group (78.3% compared with 1.7%; p < 0.0001) and the prevalence of type-A
shape was significantly lower in the hallux valgus group than in the control
group (3.3% compared with 81.7%; p < 0.0001). In the hallux valgus group,
the prevalence of the type-R shape at the time of the early follow-up after
surgery was significantly lower than that before surgery (p < 0.0001). Feet
with a positive round sign at the time of the early follow-up had a greater
risk of having recurrence of the hallux valgus deformity at the time of the
most recent follow-up than did those without a round sign at the time of the
early follow-up (odds ratio, 12.71; 95% confidence interval, 3.21 to
50.36).
Conclusions: There is a significant relationship between a
round-shaped lateral edge of the first metatarsal head and hallux valgus, and
a positive round sign after a proximal first metatarsal osteotomy can be a
risk factor for the recurrence of hallux valgus.
Level of Evidence: Prognostic Level III. See Instructions
to Authors for a complete description of levels of evidence.
Variations in the shape of the first metatarsal head have been described in
the literature and have been classified into three types: round, square, and
chevron (square with a central
ridge)1,2.
A round metatarsal head is believed to predispose to hallux valgus deformity,
whereas a square metatarsal head is thought to resist deforming forces.
Several studies have analyzed the relationship between the shape of the first
metatarsal head on radiographs and the development of hallux
valgus3-6.
None of those studies succeeded in demonstrating a strong correlation between
the two factors. Therefore, it is unknown whether a round-shaped metatarsal
head predisposes to the development of hallux valgus.
Postoperative recurrence is one of the common complications of hallux
valgus
surgery7-11.
We are not aware of any previous study that has investigated the relationship
between the postoperative shape of the first metatarsal head and the
recurrence of hallux valgus.
The purposes of the present study of women were to retrospectively examine
differences in the shape of the lateral edge of the first metatarsal head
between normal feet and feet with hallux valgus and to investigate the
relationship between the postoperative radiographic appearance of the shape of
the lateral edge of the first metatarsal head and the recurrence of hallux
valgus.
The present study was approved by our institutional review board. Between
July 1994 and November 2002, fifty-one consecutive adult female patients
(seventy-six feet) with an age of twenty years or more who had symptomatic
moderate to severe hallux valgus deformities (a hallux valgus angle of
>25° or an intermetatarsal angle of >12°) were managed with a
distal soft-tissue procedure combined with a proximal crescentic osteotomy of
the first metatarsal at our institution. All procedures were performed by two
of us (R.O., M.K.). Conservative treatment, including modification of shoe
wear, nonsteroidal antiinflammatory medications, or arch supports, had failed
in all patients. Male patients were excluded from the study because of the
extremely high prevalence of hallux valgus among
women12,13
and as a way to decrease the number of variables. Patients were excluded from
the study if they had had previous foot surgery or if they had rheumatoid
arthritis or hallux rigidus.
Of the fifty-one adult female patients (seventy-six feet) who were
identified, forty patients (sixty feet) with a mean age of fifty-three years
(range, twenty to seventy-eight years) met the criteria for inclusion in the
study group (the hallux valgus group). The inclusion criteria were defined as
(1) a minimum duration of follow-up of fourteen months; (2) the availability
of dorsoplantar weight-bearing radiographs of the feet that were made
preoperatively, at the time of early follow-up (mean, 3.4 months; range, two
to six months), and at the time of the most recent follow-up (mean,
forty-eight months; range, fourteen to 125 months); and (3) a minimum interval
of twelve months (mean, forty-five months; range, twelve to 118 months)
between the early follow-up radiograph and the most recent follow-up
radiograph. We also examined sixty normal feet in sixty adult female subjects,
which served as the control group. The mean age of the control subjects was
fifty-one years (range, twenty-three to eighty-three years). The individuals
in the control group had sought treatment for a disorder of the contralateral
foot, and a dorsoplantar weight-bearing radiograph of the unaffected foot,
which had no history of trauma and disease, was made to compare with that of
the affected foot. We obtained this historical information regarding the
unaffected foot with use of a questionnaire. Subjects were excluded from the
control group if they had a hallux valgus deformity (a hallux valgus angle of
=20°). The sixty subjects in the control group were matched with
patients in the hallux valgus group on the basis of gender and age.
Surgical Technique
The surgical technique consisted of release of the distal soft tissues,
excision of the medial eminence, plication of the medial capsule, and a
proximal crescentic osteotomy of the first
metatarsal14. The
medial eminence was excised minimally in order to preserve the distal
articular surface of the first metatarsal head. The adductor hallucis tendon
was then dissected from its insertion. The transverse intermetatarsal ligament
was released. The crescentic osteotomy was performed 1.5 cm distal to the
metatarsocuneiform joint. The osteotomy was curvilinear, and the concavity of
the cut was directed distally. The distal fragment was moved laterally, and
the proximal fragment was moved medially. Two crossed 1.5-mm Kirschner wires
were used to fix the osteotomy site. The medial capsule and the abductor
hallucis tendon were plicated.
In eleven patients (fifteen feet) with painful plantar callosities, a
proximal shortening osteotomy of the second and third
metatarsals15 was
performed at the time of hallux valgus surgery. In five patients (seven feet)
with a painful bunionette, a proximal dome-shaped osteotomy of the fifth
metatarsal16 was
performed at the time of hallux valgus surgery.
Radiographic Technique
Dorsoplantar weight-bearing radiographs were made while the subject was
standing on both legs with the knees in full extension. The x-ray beam was
inclined 20° from the vertical in the sagittal plane at a distance of 100
cm. The direction of the x-ray beam was vertical to the cassette in the
coronal plane and was centered on the middle of the third metatarsal. Lateral
weight-bearing radiographs were made while the subject was standing on both
legs with the knees in full extension. The cassette was positioned vertical to
the floor. The medial surface of the foot was placed on the cassette. The
direction of the x-ray beam was vertical to the cassette at a distance of 100
cm, and it was centered on the base of the fifth metatarsal.
Radiographic Examination
The hallux valgus angle and the intermetatarsal angle were measured on the
dorsoplantar weight-bearing radiograph. The hallux valgus angle was subtended
by lines bisecting the longitudinal axis of the first metatarsal and the
proximal phalanx. The intermetatarsal angle was subtended by lines bisecting
the longitudinal axis of the first and second metatarsals. The longitudinal
axis of the first metatarsal was defined as the line connecting the center of
the articular surface of the metatarsal head with the center of the proximal
articulation. The longitudinal axis of the proximal phalanx was defined as the
line connecting the center of the proximal end of the diaphysis with the
center of the distal end of the diaphysis. The longitudinal axis of the second
metatarsal was defined as a line connecting the center of the proximal end of
the diaphysis with the center of the distal end of the diaphysis. In the
hallux valgus group, the inclination angle of the first metatarsal was
measured on the lateral weight-bearing radiographs that were made
preoperatively and at the time of the most recent follow-up. The inclination
angle was the angle between the longitudinal axis of the first metatarsal and
the floor. The longitudinal axis of the first metatarsal was defined as a line
connecting the center of the proximal articular surface with the center of the
distal end of the diaphysis.
The shape of the lateral edge of the first metatarsal head consisted of the
articular surface and the lateral cortical surface of the metatarsal head. The
shapes of the lateral edge were classified into three types according to the
following method (Fig. 1). A
geometric device (a Mose sphere) was used to determine the best-fit circle
(circle Q) that applied to the metatarsal head, and then the center (C) and
the radius (r) of circle Q were found. Circle Q is defined as a circle that
has three points of contact with the metatarsal head, including the medial
edge, the top, and the lateral edge. The geometric device that we used
consists of concentric circles separated by 2-mm increments and radial
measurements separated by 1-mm increments. The farthest point (A) from the
circle Q is found on the curve of the lateral cortical surface of the
metatarsal head. The distance D (in millimeters) is defined as r —
CA.
Classification System for the Shape of the Lateral Edge of the First
Metatarsal Head
The shape of the lateral edge was classified as one of three types: angular
(type A), round (type R), or intermediate (type I). The shape was classified
as type A if the curve of the lateral cortical surface of the metatarsal head
was not apparently located on circle Q and if distance D measured =2 mm
(Fig. 2-A), as type R if the
curve of the lateral cortical surface of the metatarsal head was located on
circle Q and if distance D measured =0 mm and <1 mm
(Fig. 2-B), and as type I if
the curve of the lateral cortical surface of the metatarsal head was not
located on circle Q and if distance D measured =1 mm and <2 mm
(Fig. 2-C).
We defined the "round sign" as being positive when the shape of
the lateral edge of the first metatarsal head was classified as type R, and we
defined it as being negative when the shape of the lateral edge was classified
as either type I or type A.
Reliabilities of Measurements and Our Classification System
We calculated the interobserver and intraobserver reliability for the
measurements of the hallux valgus and intermetatarsal angles with use of
twenty preoperative and twenty postoperative dorsoplantar weight-bearing
radiographs of patients in the present study. The identification labels of all
of the radiographs were removed. Two foot and ankle surgeons (R.O., H.S.)
assessed the radiographs. After at least one week, these radiographs were
reassessed, and the correlation coefficients were used to analyze the
interobserver and intraobserver reliability. Reliability was classified as
little if any (correlation coefficient, =0.25), low (0.26 to 0.49),
moderate (0.50 to 0.69), high (0.70 to 0.89), or very high
(=0.90)17.
We assessed the interobserver and intraobserver reliability of our
classification system for the shape of the lateral edge of the first
metatarsal head with use of ten preoperative and ten postoperative
dorsoplantar weight-bearing radiographs of the feet of ten patients with
hallux valgus and ten dorsoplantar weight-bearing radiographs of the feet of
ten control subjects. The identification labels of all of the radiographs were
removed. Two foot and ankle surgeons (R.O., H.S.) classified the thirty
radiographs for ten patients with hallux valgus and ten control subjects.
After at least one week, they reclassified these radiographs. Kappa statistics
were used to analyze the interobserver and intraobserver reliability.
According to the system of Landis and
Koch18, agreement
was graded as slight (K = 0.0 to 0.20), fair (K = 0.21 to 0.40), moderate (K =
0.41 to 0.60), substantial (K = 0.61 to 0.80), and almost perfect (K = 0.81 to
1.00).
Statistical Analysis
The differences in the measured variables between the two groups were
analyzed with the Mann-Whitney U test or the Wilcoxon signed-rank test. The
chi-square test was used to compare the dichotomous data. The level of
significance was set at p < 0.05.
The average hallux valgus angle in the control group was 11.4°. The
average hallux valgus angle in the hallux valgus group was 39.2°
preoperatively, 11.9° at the time of the early follow-up, and 14.2° at
the time of the most recent follow-up. The average intermetatarsal angle in
the control group was 9.6°. The average intermetatarsal angle in the
hallux valgus group was 18.1° preoperatively, 7.2° at the time of the
early follow-up, and 8.4° at the time of the most recent follow-up
(Table I). The average
preoperative intermetatarsal angle in the hallux valgus group was greater than
the average intermetatarsal angle in the control group (p < 0.0001). The
average hallux valgus and intermetatarsal angles at the time of the most
recent follow-up were significantly greater than those at the time of the
early follow-up (p = 0.0074, and p = 0.0085, respectively).
The intraobserver correlation coefficients for the measurements of the
hallux valgus and intermetatarsal angles for the first observer were 0.99 (95%
confidence interval, 0.99 to 1.00) and 0.95 (95% confidence interval, 0.91 to
0.97), respectively. The intraobserver correlation coefficients for the
measurements of the hallux valgus and intermetatarsal angles for the second
observer were 0.99 (95% confidence interval, 0.97 to 0.99) and 0.95 (95%
confidence interval, 0.90 to 0.97), respectively. These values corresponded
with very high reliability. The interobserver correlation coefficients for the
measurement of the hallux valgus angle were 0.98 (95% confidence interval,
0.96 to 0.99) for the first reading and 0.98 (95% confidence interval, 0.97 to
0.99) for the second reading. The interobserver correlation coefficients for
the measurement of the intermetatarsal angle were 0.95 (95% confidence
interval, 0.90 to 0.97) for the first reading and 0.92 (95% confidence
interval, 0.86 to 0.96) for the second reading. These values corresponded with
very high reliability.
The average inclination angle of the first metatarsal in the hallux valgus
group was 15.0° ± 3.5° preoperatively and 14.3° ±
4.2° at the time of the most recent follow-up. There was no significant
difference in the average inclination angle between the preoperative and most
recent follow-up measurements (p = 0.1000). Fifty-seven feet (95%) had no
change or minimal change (=4°) in the inclination angle between the
preoperative and most recent follow-up measurements. In the remaining three
feet, the inclination angle decreased by >4° (range, 6° to
9°).
The distributions of the shape of the lateral edge of the first metatarsal
head in the control group and the hallux valgus group are shown in
Table II. The prevalence of the
type-R shape in the hallux valgus group before surgery was significantly
higher than that in the control group (p < 0.0001). The prevalence of the
type-A shape in the hallux valgus group before surgery was significantly lower
than that in the control group (p < 0.0001). In the hallux valgus group,
the prevalence of the type-A shape at the time of the early follow-up was
significantly greater than that before surgery (p < 0.0001). In the hallux
valgus group, the prevalence of the type-R shape at the time of the early
follow-up was significantly less than that before surgery (p < 0.0001). In
the group of fifteen feet that had a proximal shortening osteotomy of the
second and third metatarsals at the time of hallux valgus surgery, thirteen
(87%) had the type-R shape, one had type-I shape, and one had the type-A shape
preoperatively. At the time of the most recent follow-up, nine of those feet
had the type-R shape, four had the type-I shape, and two had the type-A
shape.
In twenty-eight (60%) of the forty-seven feet in which the lateral edge of
the metatarsal head had the type-R shape before surgery, the radiographic
appearance of the shape of the lateral edge changed to type A or I at the time
of the early follow-up (Figs.
3-A,
3-B, and
3-C). None of the thirteen feet
in which the lateral edge had a type-A or type-I shape before surgery had a
change to the type-R shape at the time of the early follow-up. In fifty-seven
feet (95%), there was no change in the appearance of the shape of the lateral
edge between the early and most recent follow-up radiographs. In the remaining
three feet, the shape of the lateral edge had changed from the early to the
most recent follow-up radiographs.
The round sign was positive for nineteen feet (31.7%) on the early
follow-up radiographs. In those feet, the average hallux valgus and
intermetatarsal angles at the time of the most recent follow-up were
significantly greater than they had been at the time of the early follow-up (p
= 0.0022 and p = 0.0067, respectively)
(Table III). However, in the
feet that had a negative round sign at the time of the early follow-up, there
were no significant differences in the average hallux valgus and
intermetatarsal angles between the early and most recent follow-up
radiographs, with the numbers available (p = 0.414 and p = 0.239,
respectively) (Table IV).
Of the twenty-two feet that had a proximal shortening osteotomy of the
second and third metatarsals or a proximal dome-shaped osteotomy of the fifth
metatarsal at the time of hallux valgus surgery, eleven had a positive round
sign at the time of early follow-up. For those eleven feet, the average hallux
valgus angle was 42.3° preoperatively, 15.0° at the time of the early
follow-up, and 19.3° at the time of the most recent follow-up. For the
remaining eleven feet, which had a negative round sign at the time of early
follow-up, the average hallux valgus angle was 42.0° preoperatively,
11.6° at the time of the early follow-up, and 15.0° at the time of the
most recent follow-up. In the feet that had a positive round sign at the early
follow-up, the average hallux valgus angle at the time of the final follow-up
was significantly greater than that at the time of the early follow-up (p =
0.019). However, in the feet that had a negative round sign at the time of the
early follow-up, there was no significant difference in the average hallux
valgus angle between the early follow-up and the most recent follow-up, with
the numbers available (p = 0.14).
The recurrence of a hallux valgus deformity, defined as a hallux valgus
angle of =20°, was observed in fifteen feet (25%) at the time of the
most recent follow-up. Of the fifteen feet with recurrence of hallux valgus,
eleven had had a positive round sign at the time of the early follow-up. Nine
feet had a hallux valgus angle of 20° to 25°, three feet had a hallux
valgus angle of 26° to 30°, and the remaining three feet had a hallux
valgus angle of 31° to 33°. Of the thirty-eight feet that had had a
proximal crescentic osteotomy of the first metatarsal combined with a distal
soft-tissue procedure, eight (21%) had a recurrence of hallux valgus at the
time of the most recent follow-up. Of these, six had had a positive round sign
at the time of the early follow-up. Seven of the twenty-two feet that had had
a proximal shortening osteotomy of the second and third metatarsals or a
proximal dome-shaped osteotomy of the fifth metatarsal at the time of hallux
valgus surgery had recurrence of hallux valgus at the time of the most recent
follow-up. Of these seven feet with recurrence of hallux valgus, five had had
a positive round sign at the time of the early follow-up. Feet that had had a
positive round sign at the time of the early follow-up had a greater risk of
having recurrence of the hallux valgus deformity than did those that had had a
negative round sign at the time of the early follow-up (odds ratio, 12.71; 95%
confidence interval, 3.21 to 50.36) (Figs.
4-A,
4-B, and
4-C).
The kappa value for interobserver reliability of our classification system
was 0.61 for the first reading and 0.65 for the second reading. These values
corresponded to a "substantial" level of agreement. The kappa
values for intraobserver reliability for the two observers were 0.64 and 0.65.
These values corresponded to a "substantial" level of
agreement.
Although there is no clear definition of the shape of the first metatarsal
head, three variations of the first metatarsal head shape have been
recognized, including round, square, and chevron-type metatarsal
heads1,2.
A rounded metatarsal head has been considered to be a predisposing factor in
hallux
valgus1,2,19.
Several authors have reported a relationship between a round-shaped metatarsal
head and hallux valgus but have not detected a strong correlation between
them3-6.
Therefore, it is unknown whether a round-shaped metatarsal head predisposes to
the development of hallux valgus. In the present study, the shape of the
lateral edge of the first metatarsal head was assessed radiographically and
was classified into three types. We found that the prevalence of the type-R
shape in feet with hallux valgus was significantly higher than that in normal
feet, whereas the prevalence of the type-A shape in feet with hallux valgus
was significantly lower than that in normal feet. These results indicated that
there is a strong relationship between a round shape of the lateral edge of
the first metatarsal head and hallux valgus.
In the present study, the average preoperative intermetatarsal angle in the
hallux valgus group was significantly greater than the average intermetatarsal
angle in the control group, and the most frequent shape of the lateral edge of
the metatarsal head in the hallux valgus group was type R, which was uncommon
in the control group. Eustace et
al.20, in a study
of first metatarsal rotation and the role of pronation in hallux valgus, found
that the amount of first metatarsal rotation increases as the intermetatarsal
angle increases. They concluded that pronation and varus deviation of the
first metatarsal are intimately related and appear to contribute to the
development of hallux valgus. From an anatomical point of view, the first
metatarsal head presents a convex articular surface in the sagittal and
coronal planes that extends farther proximally on the plantar aspect than on
the dorsal aspect, and its sides are flattened. The lateral surface of the
metatarsal head appears on the dorsoplantar radiograph when the pronation of
the first metatarsal increases. Consequently, the lateral edge of the first
metatarsal head presents a round shape on the dorsoplantar radiograph. The
pronation of the first metatarsal in feet with hallux valgus may cause the
shape of the lateral edge to appear round on this radiograph. Forty-seven feet
(78.3%) in the hallux valgus group had the type-R shape of the lateral edge of
the first metatarsal head before surgery. After surgery, twenty-eight feet
(60%) demonstrated a change from type R to type A or I. In these feet,
supination of the distal fragment of the first metatarsal may have occurred
when the distal fragment was moved laterally at the osteotomy site. We believe
that a postoperative round sign may be positive when the pronation of the
first metatarsal presents or recurs after surgery. There is a possibility that
the round sign is secondary to deformity of the metatarsal head. However, we
found that, in twenty-eight of forty-seven feet, the apparent shape of the
lateral edge changed from type R (the round type) preoperatively to type A
(the angular type) or I (the intermediate type) at an average of 3.5 months
after surgery. This result suggests that the apparent change of a round-shaped
lateral edge was caused by the rotation of the metatarsal head rather than
deformity of the metatarsal head. Robinson et
al.21 reported on
variation of the distal metatarsal articular angle with axial rotation and
inclination of the first metatarsal and found that it varied significantly in
a linear pattern with axial rotation of the first metatarsal (p < 0.0001)
and that inclination of the first metatarsal affected the magnitude of the
angle. Therefore, there is a possibility that a change in the shape of the
lateral edge of the metatarsal head is secondary to a change in inclination of
the metatarsal head. In the present study, the inclination angle of the first
metatarsal was measured in patients with hallux valgus. We found that there
was no significant difference in the average inclination angle between the
preoperative and most recent follow-up measurements and that most patients had
no change or minimal change in the inclination angle. These results suggest
that inclination of the first metatarsal did not affect the radiographic
results in the present study.
Several authors have reported that the prevalence of postoperative
recurrence of hallux valgus has ranged from 4% to 11% following a proximal
metatarsal osteotomy, although there were various definitions of recurrence
among the
articles7-11.
The recurrence of hallux valgus after a proximal metatarsal osteotomy may
occur for various reasons, including incomplete release of soft tissue,
insufficient imbrication of the medial capsule and the abductor hallucis
tendon, residual lateral displacement of the sesamoids, increased distal
metatarsal articular angle, and insufficient correction of the metatarsus
primus
varus14,18,22.
In the present study, the average hallux valgus and intermetatarsal angles at
the time of the most recent follow-up were significantly greater than those at
the time of the early follow-up in patients who had a positive round sign at
the time of the early follow-up. However, in patients who had a negative round
sign at the time of the early follow-up, there were no significant differences
in the average hallux valgus and intermetatarsal angles between the early and
most recent follow-ups. In addition, we found that patients who had a positive
round sign after surgery had a greater risk of having a recurrence of hallux
valgus than did patients who had a negative round sign. Thus, the results in
patients with a postoperative positive round sign might be expected to
deteriorate with time. Because of this concern, we believe that it is
desirable to confirm whether a round sign is positive or negative on an
intraoperative radiograph, although intraoperative weight-bearing radiographs
cannot be obtained. A positive round sign on an intraoperative radiograph may
suggest that pronation of the first metatarsal still remains and should be
corrected. In the future, we believe that the identification of a round sign
as a risk factor for recurrence of hallux valgus and/or uncorrected hallux
valgus may allow for the modification of surgical procedures and the
improvement of surgical results.
For any radiographic measurement or classification system, interobserver
reliability and intraobserver reliability are essential features. Several
methods have been described to define the longitudinal axis of the first
metatarsal for radiographic measurements of the hallux valgus and
intermetatarsal
angles23-26.
To assess patients undergoing a distal metatarsal osteotomy, the method in
which a line is drawn from the center of the first metatarsal head through the
center of the base of the first metatarsal has been recommended as the most
precise27. However,
we are not aware of any studies that have investigated the interobserver
reliability and intraobserver reliability of measurements of the hallux valgus
and intermetatarsal angles to assess patients undergoing a proximal metatarsal
osteotomy. In the present study, the longitudinal axis of the first metatarsal
was defined as the line connecting the center of the proximal articulation of
the metatarsal head with the center of the proximal articulation. We assessed
the measurement accuracy of this method and found that the correlation
coefficients for this method indicated very high reliability. Regarding the
reliability of the classification system for the shape of the lateral edge of
the first metatarsal head, we found that the kappa values for our
classification system indicated "substantial" agreement, and our
classification system was deemed to be reliable. Thus, in the present study,
we believe that the radiographic data were not affected by issues of
reliability and reproducibility.
The present study had some limitations. In some patients, we performed
additional procedures, including a shortening osteotomy of the second and
third metatarsals or a proximal dome-shaped osteotomy of the fifth metatarsal
at the time of hallux valgus surgery. These additional procedures may have
affected the radiographic results. Of the twenty-two feet that had an
additional procedure, seven (32%) had recurrence of hallux valgus at the time
of the most recent follow-up. Of these seven feet, five had had a positive
round sign at the time of the early follow-up. These rates were roughly equal
to those in patients without an additional procedure. In patients with a
positive round sign at the time of the early follow-up who had the additional
procedure, the average hallux valgus angle at the time of the most recent
follow-up was significantly greater than that at the early follow-up, just as
in patients without the additional procedure. Therefore, the additional
procedures seem unlikely to have affected the radiographic results in the
present study.
In conclusion, our radiographic results indicate that there is a
significant relationship between a round appearance of the lateral edge of the
first metatarsal head (a positive round sign) and hallux valgus and that a
positive round sign could be a risk factor for recurrence of hallux valgus
and/or uncorrected hallux valgus after a proximal metatarsal osteotomy. We
believe that a round sign is produced on the radiograph by rotation of the
first metatarsal head. The identification of a round sign intraoperatively may
allow for the modification of surgical procedures and improvement of the
clinical result. ?
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