Download A Reliable Method for Intraoperative Evaluation of

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Transcript
ORIGINAL ARTICLE
A Reliable Method for Intraoperative Evaluation of
Syndesmotic Reduction
Hobie D. Summers, MD, Micah K. Sinclair, MD, and Michael D. Stover, MD
Objectives: To determine the accuracy of a technique for intraoperative assessment of syndesmotic reduction in ankle fractures.
Design: Prospective, case series.
Setting: University hospital.
Patients/Participants: Eighteen consecutive patients with suspected syndesmotic injuries were enrolled between 2007 and 2009.
The diagnosis of syndesmotic injury was based on static ankle
radiographs. The study group consisted of 12 male and 6 female
patients with an average age of 32 years (range 19–56 years).
Intervention: All patients had mortise and talar dome lateral
fluoroscopic images obtained of the uninjured ankle in the operating
room. The injured ankle underwent operative reduction and provisional fixation using the uninjured ankle radiographs as a template
for comparison. An intraoperative computed tomography (CT) scan
was obtained to verify the syndesmotic reduction before syndesmotic
fixation. If the reduction was not anatomic, the reduction was revised
using fluoroscopy and the CT repeated.
Main Outcome Measurements: Accuracy of syndesmotic
reduction performed using fluoroscopy and confirmed by intraoperative CT scan.
Results: Using the technique described, intraoperative CT
confirmed anatomic reduction initially in 17 of the 18 fractures.
The 1 case where CT did change the course of treatment, revision of
fibular fracture reduction resulted in an anatomic reduction of the
syndesmosis on repeat CT.
Conclusions: Accurate evaluation of the syndesmotic reduction
can be determined intraoperatively using comparison mortise and
talar dome lateral fluoroscopic images. Direct visualization of the
syndesmosis or CT may not be necessary to achieve an accurate
reduction in these injuries.
Key Words: ankle fracture, syndesmosis
(J Orthop Trauma 2013;27:196–200)
Accepted for publication July 11, 2012.
From the Loyola University Medical Center, Department of Orthopaedic
Surgery and Rehabilitation, Maywood, IL.
No funds were received in support of this work.
No benefits in any form have been or will be received from a commercial
party related directly or indirectly to the subject of this article.
The authors have no conflicts of interest to declare.
Reprints: Hobie Summers, MD, Department of Orthopedic Surgery and
Rehabilitation, Loyola University Medical Center, 2160 South First
Avenue, Maywood, IL 60153 (e-mail: [email protected]).
Copyright © 2013 by Lippincott Williams & Wilkins
196
| www.jorthotrauma.com
INTRODUCTION
Unstable ankle fractures are common injuries, frequently treated operatively to restore a stable, anatomic
tibiotalar relationship. The goal of anatomic restoration of
the ankle mortise is preventing posttraumatic arthritis and
allowing for the best possible prognosis and functional
outcome.1 Syndesmotic disruption requires an accurate reduction for improved functional outcome.2–6
Evaluation of a syndesmotic injury has traditionally
been described using static and/or stress anteroposterior (AP)
and mortise radiographs.4–8 Because AP and mortise radiographic parameters alone have been shown to be diagnostically unreliable9,10 and tibiofibular diastasis is known to often
occur in the sagittal plane,5 evaluation of this relationship
should include a reproducible lateral view.13 In addition to
plain radiography, computed tomography (CT) and magnetic
resonance imaging have proven to be more sensitive tools for
evaluation of syndesmotic injury based on displacement of
the fibula within the tibial incisura.10–12 CT was found to
detect syndesmotic widening at 2 mm of diastasis, whereas
plain radiography only reliably predicted widening at .4 mm
of diastasis.10 Magnetic resonance imaging findings of ligamentous injury do not seem to correlate with accepted radiographic measurements used to evaluate syndesmotic injury,
with the exception of tibiofibular overlap on the mortise view
correlating to interosseous membrane injury.12
Outcome studies evaluating the quality of syndesmotic
reduction most commonly use postoperative AP and mortise
radiographs alone. Postoperative AP and mortise radiographs
have been shown to be inaccurate for determining the
accuracy of reduction as confirmed by postoperative CT
scan. In a recent series assessing the accuracy of syndesmotic
reduction, half of the cases reviewed were found to be
malreduced on CT evaluation, and half of these malreductions
were unrecognized using plain postoperative radiographs.14 In
addition, direct visualization of the syndesmosis has been
proposed to improve the accuracy of syndesmotic reduction.
This has also proven to be insufficient in achieving an accurate reduction in 16% of cases.17 To date, there is limited
information describing the intraoperative evaluation of syndesmotic reduction. The standard of care for accurate reduction of the syndesmosis is unknown.
Considering the reported inaccuracy of syndesmotic
reduction by plain radiography and direct visualization, and
the importance of accurate reduction on patient outcome, the
aim of this prospective study was to evaluate a reliable
method for intraoperative assessment of syndesmotic reduction and the possible role of intraoperative CT. Unlike
J Orthop Trauma Volume 27, Number 4, April 2013
J Orthop Trauma Volume 27, Number 4, April 2013
previous studies, intraoperative fluoroscopic mortise and talar
dome lateral views of the uninjured ankle were used as
a template to guide the reduction of the injured syndesmosis.
We hypothesized that by performing syndesmotic reduction
using the normal side as a template, we would improve the
accuracy of syndesmotic congruence using plain radiography.
As CT is proven to be more reliable in the evaluation of
syndesmotic reduction and is currently available intraoperatively, its use would allow for immediate evaluation of
reduction and provide feedback regarding use of the contralateral images.
PATIENTS AND METHODS
Eighteen consecutive patients with suspected syndesmotic injuries were enrolled between 2007 and 2009 after
Institutional Review Board approval. The preliminary diagnosis was based on the fracture pattern and static ankle
radiographs showing widening of the anterior tibiofibular
clear space (Figs. 1A, B). The study group consisted of
12 male patients and 6 female patients with an average age
of 32 years (range 19–56). There were 1 43C1.2, 3 C1.3,
3 C2.1, 1 C2.2, 4 C2.3, 4 C3.1, and 2 C3.3 fractures as classified by the Arbeitsgemeinschaft für Osteosynthesefragen/
Orthopaedic Trauma Association classification.
In the operating room, before sterile preparation and
draping of the operative leg, mortise and talar dome lateral
images of the contralateral, uninjured ankle were obtained
(Figs. 2A,B). The talar dome lateral images were centered on
the talus to produce a perfect, lateral image of the talar body
as this is reliably reproducible. The mortise image was taken
to clearly demonstrate the medial, superior, and lateral joint
spaces as symmetrically as possible, and the distal fibula’s
relationship to the talus (Shenton line). The patient subsequently underwent operative fixation of their ankle fracture,
fibula, and tibia (if present), by 1 of 2 fellowship-trained
Syndesmotic Reduction
orthopedic trauma surgeons, employing standard techniques.
For those patients with high fibula fractures where direct
reduction is difficult, the fibula was brought out to length
distally (indirectly) and reduced in the incisura.
After fixation of the ankle fracture, the syndesmotic
injury was confirmed by intraoperative stress testing under
fluoroscopic guidance, using a cotton test and/or external
rotation distraction test.5,15 If disrupted, syndesmotic reduction
was performed and subsequently confirmed using the relationship of the fibula to the tibia on both mortise and talar dome
lateral fluoroscopic views as compared with the contralateral,
uninjured ankle. The mortise view was used to evaluate fibular
length and rotation. The talar dome lateral view was used to
assess the AP relationship of the fibula to the tibia. This was
determined by the distance from the point at which the posterior border of the fibula crosses the posterior tibial articular
surface to the tip of the posterior malleolus. Alternatively,
the same distance can be determined from the point at which
the anterior border of the fibula crosses the tibial articular
surface to the anterior tibial cortex (Fig. 2B-1). This is particularly helpful in cases of a small, displaced posterior malleolus,
or in cases where fixation prohibits accurate measurement posteriorly. We use a periarticular clamp (or collinear clamp) to
reduce the syndesmosis by placing the clamp on the medial
tibia (through a small stab incision) to the lateral fibula at the
level of the tibiofibular articulation. Care must be taken to
ensure the orientation of the clamp is accurate to afford the
correct translation in the sagittal plane. The syndesmosis is then
provisionally stabilized with K-wires to prevent displacement.
After provisional reduction and fixation of the syndesmosis, verification of reduction was confirmed by performance of an intraoperative CT scan of the injured ankle
(Siemens Arcadis Orbic 3D-CT model numbers 08081403
and 08081080). This was used to confirm the AP position and
rotational placement of the fibula within the tibial incisura
(Figs. 3A,B). We used the same criteria used in the literature
FIGURE 1. A, B, AP and lateral of
a 36-year-old male with a C1.2 ankle
injury sustained jumping over
a fence.
Ó 2013 Lippincott Williams & Wilkins
www.jorthotrauma.com |
197
Summers et al
J Orthop Trauma Volume 27, Number 4, April 2013
FIGURE 2. A, B, Mortise and talar dome lateral images of the uninjured side demonstrating reproducible images as a template for
the injured ankle. B-1, Talar dome lateral with arrows demonstrating measurement technique.
previously to determine malreduction.14 We measured the
distance between the fibula and the anterior and posterior
facets of the incisura approximately 1 cm proximal to the joint
line. A discrepancy of $2 mm was considered a malreduction.
Revision of syndesmotic reduction and repeat provisional fixation was performed if the initial CT scan exhibited poor positioning of the fibula, with subsequent verification using repeat
CT scan of the injured ankle. No costs were incurred to any
patient for intraoperative CT evaluation, as this technology is
immediately available in our operating room.
Once confirmation of an adequate reduction was
achieved by static fluoroscopic images and confirmed with
intraoperative CT scan, definitive syndesmotic fixation was
completed. It is our preference to use two 4.0-mm fully
threaded cortical screws after drilling four cortices across the
syndesmosis through a fibular plate with the foot in a dorsiflexed position. The provisional fixation was then removed, and
repeat fluoroscopic images were obtained to confirm reduction
with the final fixation in place (Figs. 4A,B). Postoperatively,
mortise and lateral radiographic images were obtained, followed by application of a well-padded, short leg, plaster splint.
RESULTS
All 18 patients were suspected by preoperative
radiography to have syndesmotic instability, which was
confirmed with intraoperative stress testing under fluoroscopic guidance. After preliminary syndesmotic reduction
and provisional fixation, guided by mortise and talar dome
lateral fluoroscopic images of the contralateral, uninjured
side, all the patients underwent CT evaluation of the
accuracy of syndesmotic reduction. Seventeen of 18
patients were found to have an accurate reduction and
syndesmotic screws were placed without a change in
reduction. One patient was determined to have a malreduction on the intraoperative CT evaluation and underwent
revision of the fibula and syndesmotic reduction. This
patient had a malreduction of the fibula fracture, thereby
making an accurate reduction of the syndesmosis unlikely.
The fibular fixation was removed and the fibular fracture
malreduction was corrected. The syndesmosis was again
reduced according to our method confirming accurate
reduction. Definitive fixation of the syndesmosis then
proceeded per protocol.
FIGURE 3. A, B, Intraoperative axial
cuts demonstrating accurate reduction of the tibiofibular relationship in
the sagittal plane. Coronal and sagittal cuts were also obtained and
examined.
198
| www.jorthotrauma.com
Ó 2013 Lippincott Williams & Wilkins
J Orthop Trauma Volume 27, Number 4, April 2013
Syndesmotic Reduction
FIGURE 4. A, B, Final fluoroscopic
mortise and talar dome lateral views
obtained to compare with the preoperative, uninjured side.
DISCUSSION
With the knowledge that accurate reduction of syndesmotic injuries remains a problem and patient outcomes are
optimized by anatomic restoration of the syndesmosis,2,3,4,16
we sought to describe a method for reliable intraoperative
confirmation of syndesmotic reduction, which has been used
at our institution for .10 years. Addition of new technology
during this time (intraoperative CT) has allowed for intraoperative validation of our technique.
Outcome studies have historically used plain radiography
to evaluate the accuracy of syndesmotic reduction. However,
a recent study reported the incidence of syndesmotic malreduction to be 52% (13 of 25 patients) when evaluated by
postoperative CT scan.14 Only half of these malreductions were
diagnosed on plain postoperative radiographs alone. This reiterates the inaccuracy of postoperative AP and mortise radiographs alone to verify syndesmotic reduction and emphasizes
the need for an improved intraoperative evaluation before
definitive fixation. In addition, a recent study has shown that
direct visualization of the syndesmosis with an open reduction
still lead to a 16% rate of malreduction.17
Published radiographic parameters for evaluation of
syndesmotic disruption suffer from the lack of consensus on
accuracy and reproducibility,6–9,12 thereby limiting intraoperative usefulness for guiding syndesmotic reduction. Additionally, fibular translation in the sagittal plane often occurs in
rotational ankle fractures with associated syndesmotic disruption and can be overlooked if the ankle is not evaluated with
a lateral radiograph.5 Understanding the inaccuracy of syndesmotic evaluation on AP and mortise views alone, coupled
with the basic tenet of evaluating all injuries with orthogonal
radiographic views, it is our practice to evaluate syndesmotic
reduction with mortise and lateral radiographs. As a part of
our evaluation, we compare these to the same images
obtained preoperatively of the contralateral, uninjured side
as an anatomic comparison and template.
We found that by evaluation of our syndesmotic
reduction with mortise and talar dome lateral fluoroscopic
views, recreated to mirror the contralateral template, 17 of 18
syndesmotic reductions were accurately reduced as confirmed
by intraoperative CT imaging. The mortise view aided in
Ó 2013 Lippincott Williams & Wilkins
guidance of fibular length and rotation, whereas the talar
dome lateral view allowed for appropriate determination of
AP relationship of the fibula to the tibia. Thus, it seems that
biplanar comparison of the operative side to reproducible
contralateral images before fixation is a reliable method for
evaluating syndesmotic reduction as confirmed by intraoperative CT. We had a failure rate of approximately 6% with
1 syndesmotic malreduction in 18 cases. Although this is
higher than we would like to see with our technique, it is
significantly better than previously described methods of
assessing syndesmotic reduction. Postoperative plain radiographs have been shown to be unreliable in 52% of cases,14
whereas direct open visualization has been reported to be
inaccurate in 16% of cases.17
The use of intraoperative CT scan to evaluate and
confirm this as a reliable method of syndesmotic reduction
has also proven routine intraoperative CT may be unnecessary. After confirming our technique to be accurate with
quality fluoroscopic imaging, we no longer use intraoperative
CT to confirm our reduction. This does not imply, however,
that CT evaluation of syndesmotic reduction is contraindicated. It remains an important tool that is useful in instances
where the reduction of the fibula or syndesmosis is difficult,
or when the reduction is difficult to evaluate fluoroscopically.
Examples of this may include an unreduced small posterior
malleolar fragment, a severely comminuted fibula at the level
of the joint surface of the posterior tibia, or a previous or
concomitant injury to the contralateral ankle. In our study, we
had one syndesmotic malreduction noted on CT scan. This
was found to be secondary to an inaccurate reduction of the
fibula fracture prior to an attempt at syndesmotic reduction.
This emphasizes the importance of an accurate reconstruction
of the fibula, and is an example where postoperative CT may
be helpful in cases where fibular fracture reduction and
fixation are difficult.
We do recognize the lack of quantitative information in
this study, with regards to published parameters of acceptable
reduction of syndesmotic injury. We do not feel this is
a limitation, but rather a representation of true practice in the
operating suite. Because of the anatomic variation between
patients, we feel the most reliable method of evaluating
www.jorthotrauma.com |
199
J Orthop Trauma Volume 27, Number 4, April 2013
Summers et al
reduction is comparison to the contralateral side. In addition,
we did not obtain a CT of the normal ankle for comparison.
We made the assumption that if the fluoroscopic images of
the injured ankle were identical the uninjured ankle and the
CT showed ,2 mm of incongruency, then a CT on the normal side was unnecessary.
In conclusion, obtaining an accurate syndesmotic
reduction is critical to avoiding the significant morbidity that
can be associated with malreduction. Anatomic reduction of
the fibula and syndesmosis has been associated with improved
Short Musculoskeletal Function Assessment functional outcome scores,3 whereas malreduction leads to instability and
arthritis.2 We feel the results of this study provide a reproducible technique for reliably evaluating syndesmotic reduction.
As previous studies have evaluated syndesmotic reduction by
the use of AP or mortise imaging alone, we propose that the
additional use of the talar dome lateral image intraoperatively
will allow for reliable sagittal plane reduction of the fibula
relative to the tibia. When these biplanar images are used to
recreate the likeness of the contralateral uninjured side, intraoperative or postoperative CT scan will be necessary only in
those cases where an accurate restoration of these parameters
cannot be met.
REFERENCES
1. DeSouza LJ, Gustillo RB, Meyer TJ. Results of operative treatment of
displaced external rotation–abduction fractures of the ankle. J Bone Joint
Surg Am. 1985;67:1066.
2. Leeds HC, Ehrlich MG. Instability of the distal tibiofibular syndesmosis
after bimalleolar and trimalleolar ankle fractures. J Bone Joint Surg Am.
1984;66:490–503.
3. Weening B, Bhandari M. Predictors of functional outcome following
transsyndesmotic screw fixation of ankle fractures. J Orthop Trauma.
2005;19:102–108.
200
| www.jorthotrauma.com
4. Pettrone FA, Gail M, Pee D, et al. Quantitative criteria for prediction of
the results after displaced fracture of the ankle. J Bone Joint Surg Am.
1983;65:667–677.
5. Xenos JS, Hopkinson WJ, Mulligan ME, et al. The tibiofibular syndesmosis. Evaluation of the ligamentous structures, methods of fixation, and
radiographic assessment. J Bone Joint Surg Am. 1995;77:847–856.
6. Ostrum RF, De Meo P, Subramanian R. A critical analysis of the anteriorposterior radiographic anatomy of the ankle syndesmosis. Foot Ankle Int.
1995;16:128–131.
7. Harper MC, Keller TS. A radiographic evaluation of the tibiofibular
syndesmosis. Foot Ankle Int. 1989;10:156–160.
8. Pneumaticos SG, Noble PC, Chatziioannou SN, et al. The effects of
rotation on radiographic evaluation of the tibiofibular syndesmosis. Foot
Ankle Int. 2002;23:107–111.
9. Beumer A, Van Hemert WLW, Niesing R, et al. Radiographic measurement of the distal tibiofibular syndesmosis has limited use. Clin Orthop
Rel Res. 2004;423:227–234.
10. Ebraheim NA, Lu J, Yang H, et al. Radiographic and CT evaluation of
tibiofibular syndesmotic diastasis: a cadaver study. Foot Ankle Int. 1997;
18:693–698.
11. Ebraheim NA, Elgafy H, Padanilam T. Syndesmotic disruption in low
fibular fractures associated with deltoid ligament injury. Clin Orthop Rel
Res. 2003;409:260–267.
12. Nielson JH, Gardner MJ, Peterson MGE, et al. Radiographic measurements do not predict syndesmotic injury in ankle fractures. Clin Orthop
Rel Res. 2005;436:216–221.
13. Marsh JL, Saltzman CL. Ankle fractures. In: Robert W. Bucholz,
James D. Heckman, Charles Court-Brown, eds. Rockwood & Green’s
Fractures in Adults. 6th ed. Philadelphia, PA: Lippincott Williams &
Wilkins; 2006:2147–2247;chap 53.
14. Gardner MJ, Demetrakopoulos D, Briggs SM, et al. Malreduction of
the tibiofibular syndesmosis in ankle fractures. Foot Ankle Int. 2006;
27:788–792.
15. Jenkinson RJ, Sanders DW, Macleod MD, et al. Intraoperative diagnosis
of syndesmosis injuries in external rotation ankle fractures. J Orthop
Trauma. 2005;19:604–609.
16. Mont M, Sedlin E, Weiner L, et al. Postoperative radiographs as predictors of clinical outcome in unstable ankle fractures. J Orthop Trauma.
1992;6:352–357.
17. Miller A, Carroll E, Parker R, et al. Direct visualization for syndesmotic
stabilization of ankle fractures. Foot Ankle Int. 2009;30:419–426.
Ó 2013 Lippincott Williams & Wilkins