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The use of the modified Broström ligament reconstruction
has been clinically successful.7,10 Anatomical lateral ankle
reconstruction techniques are currently in favor in the
adult population because the procedures restore normal
anatomy and joint mechanics, preserve subtalar motion,
have no donor site morbidity, and do not change gait
mechanics.3Further advancement of the technique has
been obtained by the use of suture anchor systems to sim-
plify reattachment of the ligaments to the fibula in their
anatomical positions. Messer et al, Hess et al, and Paden
et al have reported good results in adults with the use of
the modified Broström reconstruction using suture anchor
fixation.6,10,11 Anatomical repairs may be more attractive
in the pediatric or adolescent patient because they avoid
the possible long-term restriction of subtalar motion pro-
duced by nonanatomical reconstruction.
Symptomatic ankle ligament instability in pediatric
patients is uncommon, and the growth plate region is often
the site of failure in traumatic events.8However, intrasub-
stance lateral ankle ligament disruption and instability
does occur in adolescents and is seen in specialty foot and
ankle and sports medicine centers.9,13,14 Three studies on
lateral ligament reconstruction in the adolescent age
group have been performed.1,3,9 The modified Broström
ankle ligament repair in adult patients using suture
anchors is successful; however, the use of suture anchors
in adolescents has the potential danger of damage to the
distal fibular physis. The purpose of this study was to com-
pare adult and pediatric ankle radiographs to determine if
A Radiographic Investigation
to Determine the Safety of Suture
Anchor Systems for Pediatric Modified
Broström Ankle Ligament Reconstruction
Kaushik Hazratwala,* MBBS, BSc(Med), Alistair Best,†FRCS Ed (Tr&Orth),
Matthew Kopplin,†MD, Eric Giza,†MD, and Martin Sullivan,†‡ FRACS
From *St. Vincent’s Hospital, Sydney, Australia, the †Foot and Ankle Clinic, St. Vincent’s Clinic
and North Shore Private Hospital, Sydney, Australia
Background: The modified Broström ligament reconstruction using anchor sutures has been performed in adults with clinical
success; however, the safety parameters for the use of suture anchors in adolescent lateral ankle ligament reconstruction have
not been established.
Purpose: To perform a radiographic analysis comparing the depth of penetration of suture anchors in adult ankle ligament
reconstruction with the average distance of the physis from the tip of the fibula in adolescents.
Study Design: Cross-sectional study, Level of evidence, 4.
Methods: Forty postoperative ankle radiographs of adult patients who had a modified Broström procedure were compared with
40 normal adolescent ankle radiographs. In the adult group, the distance of the suture anchor penetration from the distal tip of
the fibula was measured; in the adolescent group, the distance of the physis from the distal tip of the fibula was measured.
Results: The mean depth of the suture anchors was 17 mm (range, 14-21 mm) from the tip of the fibula in the adult group, and
the mean distance of the growth plate was 23 mm (range, 18-29 mm) in the adolescent group. Eight radiographs from the ado-
lescent group (20%) had a physis measurement of <22 mm on the anteroposterior or mortise view.
Conclusions: Using careful preoperative planning and intraoperative technique, it is possible to safely perform lateral ankle lig-
ament repair in the skeletally immature patient using suture anchors.
Keywords: pediatric ankle instability; modified Broström procedure; suture anchor; ankle ligament reconstruction
435
‡Address correspondence to Martin Sullivan, FRACS, St. Vincent’s
Clinic, Suite 901E, Victoria Street, Darlinghurst, NSW 2010, Australia (e-
mail: bunion@bigpond.net.au).
No potential conflict of interest declared.
The American Journal of Sports Medicine, Vol. 33, No. 3
DOI: 10.1177/0363546504268136
© 2005 American Orthopaedic Society for Sports Medicine
436 Hazratwala et al The American Journal of Sports Medicine
lateral ankle suture anchors can be safely used in skele-
tally immature patients.
MATERIALS AND METHODS
Patients
The study design consisted of a radiographic comparison of
2 groups, each containing 40 patients. Permission for radi-
ograph file review was obtained from the hospital execu-
tive office and record review committee. Patient confiden-
tiality was maintained at all times. Group A, the adoles-
cent control group, established the distance from the distal
tip of the fibula to the inferior margin of the physis in
skeletally immature patients. Group B, the adult group,
established the maximum depth of penetration of the
suture anchors in adult patients who had undergone the
modified Broström procedure. The senior author per-
formed all the modified Broström procedures in group B
using Mitek GII suture anchors (Mitek, Johnson &
Johnson, Norwood, Mass).
Measurements
A search of the hospital film library identified 40 normal
adolescent ankle radiographs. In group A, measurements
were made from the distal tip of the fibula to the inferior
margin of the physis on both the AP and mortise views.
Lateral views in group A were excluded because of obscur-
ing of the physis by superimposition of the tibia. In group
B, 40 patients who had a modified Broström ankle recon-
struction had ankle radiographs taken 2 weeks after sur-
gery. Measurements were made from the tip of the fibula
to the most proximal end of the anchor on AP, mortise, and
lateral ankle radiographs. Measurements were made inde-
pendently by 2 of the authors using standard radiographs
and rulers.
Statistical Analysis
Power analysis was performed by assuming that the dis-
tance measurements had a 20% coefficient of variation;
therefore, 40 patients per group were needed to provide a
90% probability of establishing a 10% difference in meas-
urements at the 5% level of significance. Statistical analy-
sis of the measurements was performed by an independent
statistician using the S-Plus statistics package (Mathsoft
Engineering & Education Inc, Cambridge, Mass) employ-
ing a linear model that included group as a factor and age
as a covariate.Analysis of variance was used to summarize
the results of the linear model.
RESULTS
In group A, there were 24 male and 16 female patients;the
mean age at the time of radiograph was 13.8 years (range,
11-16 years). The mean distance between the physis and
the tip of the fibula was 23 mm (range, 18-29 mm) on the
AP view and 23 mm (range, 18-29 mm) on the mortise
view. Eight radiographs from group A (20%) had a physis
measurement of <22 mm on the AP or mortise view.
In group B, there were 22 male and 18 female patients
(all with closed physes), and the mean depth of maximal
suture anchor penetration was 17 mm (range, 14-21 mm)
on the AP view, 17 mm (range, 14-20 mm) on the mortise
view, and 16 mm on the lateral view (range, 12-20 mm)
(Figure 1). In 3 patients, there was a discrepancy in the
depth of penetration between the AP or mortise views, and
in each patient the difference was 1 mm or less. The prob-
ability that the difference between the 2 mean values
could have arisen by chance was 0.
DISCUSSION
Previous reports of the lateral ankle ligament reconstruc-
tion in skeletally immature patients have concentrated on
the direct repair of torn ligament ends or reconstruction
using the peroneus brevis as a graft.13,14 Reconstruction
techniques involve suturing of the ligaments to the perios-
teum or drilling of holes to gain purchase into bone.5,8,9
Abulencia et al reported on 48 ankle ligament reconstruc-
tions in patients with an average age of 14.5 years and
4.5-year follow-up using the Chrisman-Snook technique.1
They found 96% good subjective results, but there was no
Figure 1. Postoperative AP radiograph in a skeletally mature
patient demonstrating placement of suture anchors in the
fibula.
Vol. 33, No. 3, 2005 Safety of Suture Anchor Systems in Adolescent Ankle Reconstruction 437
mention of subtalar joint restriction. Complications includ-
ed 1 postoperative distal fibular fracture. Barnum et al
investigated the outcome of an Evans-type reconstruction
in 20 adolescents with an average age of 15.4 years and
reported an 85% satisfactory outcome.3Follow-up aver-
aged 12 years, 60% of patients had limitation of inversion
on examination, and 1 patient had a complaint of stiffness
with activity. Letts et al treated 12 adolescent girls with an
average age of 14 years with a variety of reconstruction
procedures including 1 anatomical repair without the use
of suture anchors.9They reported that 92% of their
patients were stable but that only 50% returned to sports.
Nonanatomical repairs can be technically demanding,
with possible donor site morbidity due to sacrifice of the
peroneal tendons or damage to the sural nerve.10
Anatomical repair has the advantage of most closely
restoring normal ankle and subtalar motion while avoid-
ing donor site morbidity. Modified Broström repair also
involves tightening of the calcaneofibular ligament, a sta-
bilizer of the subtalar joint, hence addressing hindfoot
instability. A biomechanical cadaveric study in adults
using buckle transducers found that both the nonanatom-
ical Watson-Jones reconstruction and the modified
Broström procedure significantly reduced the increase in
ankle joint laxity after sectioning of the anterior inferior
talofibular ligament and the calcaneofibular ligament.2
However, they also found that ankle joint motion after the
Watson-Jones procedure was restricted.
Suture anchor systems were originally designed for the
surgical repair of soft tissues around the shoulder, includ-
ing the rotator cuff.12 In the foot and ankle, they have been
successfully used for ankle ligament repair, ankle liga-
ment reconstruction, split tibialis anterior tendon transfer,
the Kidner procedure, and the reattachment of the
Achilles tendon.12,15 Their advantages include elimination
of soft tissue irritation, tenodesis and ligament repair with
minimal soft tissue dissection, and greater accuracy in
reattachment of the ligament to their normal anatomical
position. The simplicity of application potentially decreases
operating time and potential fracture of the fibula second-
ary to multiple drill holes.10
A concern in the skeletally immature patient is the
potential for the suture anchors to damage the growth
plate, causing subsequent growth arrest and angular
deformity. Caterini et al investigated the effect of displaced
distal fibula and tibia fractures with an average 27-year
follow-up.4All 15 patients with a Salter-Harris type I fibula
fracture had a good outcome with no residual deformity.
The dimensions for the Mitek GII system (Mitek,
Johnson & Johnson) used in our unit were as follows: drill
diameter = 2.4 mm and drill depth = 14.2 mm.15 The
results of this study showed that the average drill pene-
tration was 17 mm, the maximal depth of penetration of
the Mitek anchor system was 21 mm from the tip of the
fibula, the mean distance of the growth plate was 23 mm,
and the minimum physial distance was 18 mm. Twenty
percent of patients from group A had a physis measure-
ment of <22 mm on the AP or mortise view. Therefore,
based on our radiographic comparison, physial breach
with the use of Mitek suture anchors with the modified
Broström ankle ligament reconstruction is possible, but
not highly probable, if care is taken to not disrupt the
physis (Figure 2).
The difference between the reported Mitek drill dis-
tance15 and the penetration depth found in group B could
be caused by magnification of the radiographs. In standard
ankle radiographs, magnification should be minimal; how-
ever, any magnification that may have occurred would
have been present in both groups. Nonetheless, the sur-
geon should be cognizant of this fact when using the
anchors during surgery.
Because 20% of radiographs from the adolescent group
had a physis measurement of <22 mm on the AP or mor-
tise view, we recommend measurement on preoperative
radiographs or CT scan or the use of intraoperative fluo-
roscopy to determine if the growth plate is at risk. Another
option is the mini-Mitek anchor system, which has the fol-
lowing dimensions: drill diameter = 2.1 mm and drill
depth = 9.7 mm. If other suture anchor systems are
employed, the surgeon must have precise knowledge of the
depth of penetration of these systems to ensure that there
will be no damage to the physis.
CONCLUSION
Based on radiographic comparison of normal adolescent
and postoperative modified Broström ankle radiographs,
the use of suture anchors is theoretically safe in skeletally
immature patients. A long-range follow-up on a clinical
series of pediatric patients is warranted to establish the
safety of anchor use.
Figure 2. Postoperative AP and mortise ankle radiographs of
a 7-year-old female patient with chronic instability. The
patient underwent a modified Broström procedure with
repair of the anterior talofibular and calcaneofibular liga-
ments with reinforcement of the inferior extensor retinacu-
lum. Note that the mini-Mitek (Mitek, Johnson & Johnson,
Norwood, Mass) anchors are placed into the fibular epiph-
ysis without penetration into the physis.
438 Hazratwala et al The American Journal of Sports Medicine
ACKNOWLEDGMENT
The authors thank Dr George Pitsis for his assistance in
the preparation of the article.
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