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Techniques in Shoulder & Elbow Surgery 8(4):213–221, 2007
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R E V I E W
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Acromioclavicular Joint Reduction,
Repair and Reconstruction Using Metallic
ButtonsVEarly Results and Complications
Yeow Wai Lim, MBBS, MMed (Surg), FRCSEd (Ortho)
Changi General Hospital
Singapore, Singapore
and Modbury Public Hospital
Adelaide, Australia
Aman Sood, MBBS
University of Adelaide
and Royal Adelaide Hospital
Adelaide, Australia
Roger P. van Riet, MD, PhD, and Gregory I. Bain, MBBS, FRACS, FA (OrthA)
Modbury Public Hospital
University of Adelaide
and Royal Adelaide Hospital
Adelaide, Australia
| ABSTRACT
Acromioclavicular joint (ACJ) dislocation is a common
injury often affecting young adults. Its sequalae range
from an asymptomatic shoulder to one that is painful
with significant loss of strength in the affected upper
limb. The management of ACJ dislocation has revolved
around expert neglect for asymptomatic low-grade dislocation to complex surgical reconstruction.
The authors describe their early experience with a
new technique to reduce and maintain reduction of the
coracoclavicular interval using a low-profile doublemetallic button technique (Tightrope; Arthrex Inc, Naples,
Fla). The fixation device comprises of a no. 5 Fibrewire
suture that is tensioned and secured at both ends by metallic buttons against the cortices of the clavicle and the
coracoid. The proposed advantages include a non rigid
fixation of the AC joint that maintains reduction yet
allowing for normal movement at the joint. The Bsnow
shoe[ hold on cortical bone means that the implant should
withstand cyclic loading without cutting out from the
bone. With these reasons, and because it is relatively low
profile, there is no need for removal of implant.
Reprints: Gregory I. Bain, MBBS, FRACS, FA (OrthA) 196 Melbourne
St, North Adelaide, South Australia 5006, Australia (e-mail: greg@
gregbain.com.au).
The authors have used this fixation technique on
8 patients. All the patients had strong intraoperative fixation. Immediate and 2-week postoperative radiographs
demonstrated excellent reduction of the coracoclavicular
interval and the AC joint. However, there were 4 patients
with loss of reduction between 2 and 6 weeks postoperatively without additional injury. The mode of fixation failure is unclear at present. While the concept of
metallic button fixation may have promise, the authors
recommend further biomechanical assessment to evaluate potential weak link of the implant before its clinical use.
Keywords: acromioclavicular, new technique, metallic
buttons, Tightrope, joint fixation
| HISTORICAL PERSPECTIVE
Acromioclavicular joint (ACJ) dislocation is a common
injury often affecting young adults. Its sequalae range
from an asymptomatic shoulder to one that is painful,
with significant loss of strength in the affected upper limb.
Acromioclavicular dislocation was recognized as
early as 400 BC by Hippocrates. He suggested a compressive bandage in an attempt to hold the lateral end of
the clavicle in a reduced position. Galen (129 AD), almost
600 years later, documented his own AC dislocation that
he sustained while wrestling. In the modern era, this injury is better recognized, but its treatment remains a source
of great controversy.
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Lim et al
The management of ACJ dislocation has revolved
around expert neglect for asymptomatic low-grade dislocation to complex surgical reconstruction.
Currently, there are 4 main surgical treatment options
for the dislocated ACJ: (1) primary ACJ fixation (with
pins, screws, suture wires, plates, hook plates) with
or without ligament repair or reconstruction1; (2) primary coracoclavicular interval fixation (with Bosworth
screw, wire, fascia, conjoint tendon, or synthetic sutures)
with or without incorporation of AC ligament repair/
reconstruction2,3; (3) excision of the distal clavicle with
or without coracoclavicular ligament repair with fascia
or suture, or coracoacromial ligament transfer4Y6; (4)
dynamic muscle transfers with or without excision of the
distal clavicle.7
The multitude of techniques described illustrates the
fact that the ideal technique to treat a symptomatic
ACJ dislocation remains to be found. The use of metal
implants can be complicated by migration of these
implants.8Y10 Muscle transfers are technically demanding
and serve to dynamically pull the clavicle downward
through the action of the coracobrachialis and the biceps
muscles. However, in dislocation of the ACJ, the problem is one of a Bsagging[ upper limb and not a highriding clavicle. Hence, the pathologic finding is not
addressed by muscle transfer procedures. Furthermore, these procedures carry significant chance of injury
to the musculocutaneous nerve, failure of the coracoid
to heal to the clavicle or loss of screw fixation or screw
breakage.
We describe a technique to reduce and maintain reduction of the ACJ with the use a low-profile doublebutton technique (Tightrope) composed of a no. 5
Fibrewire suture that is tensioned and secured at both
ends by metallic buttons against the cortices of the clavicle and the coracoid (Fig. 1). The proximal end com-
prises a round metallic button with 4 holes, and the distal
end has an oval metallic button with 2 larger holes. The
proposed advantages include a nonrigid fixation of the
ACJ that maintains reduction, yet allowing for normal
movement at the joint. The snow shoe hold on cortical
bone means that the implant should withstand cyclic
loading without cutting out from the bone. With these
reasons, and because it is relatively low profile, there is
no need for removal of implant. This implant was originally designed for the repair of the syndesmotic joint
in the ankle, but subsequently has also been suggested
for closing the coracoclavicular interval in patients with
ACJ dislocation.
The Tightrope uses the principle of the Endobutton
system (Acuflex; Microsurgical Inc, Mansfield, Mass),
which has been widely used for anterior cruciate ligament reconstruction. The senior author (G.I.B.) has
used the Endobutton technique for surgical repair of
distal biceps rupture.11 The Endobutton technique has
also been used for repair of chronic biceps tendon ruptures
with supplemental hamstring graft. 12 Biomechanical
studies have demonstrated that it is superior to other fixation techniques for the anterior cruciate ligament and
the distal biceps tendon.13
| INDICATIONS/CONTRAINDICATIONS
Most articles in the literature have supported conservative management for Rockwood grade 1 and 2 injuries,14
whereas there is a general consensus that grade 4, 5 and
6 injuries15 are best treated with surgery16 (Table 1). The
management of grade 3 injuries, however, remains controversial, with proponents for and against surgical
treatment.1,17Y19
The authors have used this technique for acute ACJ
dislocations (G4 weeks), lateral clavicle fractures with
increased coracoclavicular interval, and as an adjunct
fixation for chronic ACJ dislocations, in addition to ligamentous reconstruction using hamstrings autograft. In
lateral clavicle fractures, a plate bridges the fracture,
and the device is then used through the plate to stabilize
the coracoclavicular interval. The contraindications for
the use of this technique include coracoid fractures,
lack of soft tissue coverage, and ongoing infections.
Both metallic buttons need an intact cortex to be able
to provide stable fixation.
| PREOPERATIVE PLANNING
FIGURE 1. Tightrope implant. Used with permission of
Arthrex Inc, Naples, Fla.
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Preoperative radiographic assessment of the patients included anteroposterior, Y-scapular, axillary views, and
a Zanca20 view of the ACJ. These views allow assessment of the severity of the dislocation and any associated
clavicle fracture. Weight-bearing views can assist in
identifying and differentiating between type 1 and 2 ACJ
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ACJ Reduction, Repair, and Reconstruction
TABLE 1. Rockwood Classification of ACJ Injuries
Type
1
2
3
4
5
6
Ligaments Involved
X-rays
AC ligament sprain
AC ligament disrupted
CC ligament sprain
AC and CC ligament disrupted
Deltoid and trapezius detached from distal
end of the clavicle
AC and CC ligament disrupted
Deltoid and trapezius detached from distal
end of the clavicle
Clavicle displaced posteriorly into or
through the trapezius
AC and CC ligament disrupted
Deltoid and trapezius detached from distal
half of the clavicle
AC and CC ligament disrupted
Deltoid and trapezius detached from distal
half of the clavicle
Clavicle displaced inferior to the
acromion or coracoid
Normal
Slight increase in the CC interspace (G25%
greater than the normal shoulder)
Increase in CC interspace of 25% to 100%
greater than the normal shoulder
Treatment Option
Conservative
Conservative
Distal end of the clavicle displaced posterior
to the acromion
Surgical
Increase in CC interspace of 100% to 300%
greater than the normal shoulder
Surgical
Distal end of the clavicle displaced inferior
to the acromion or coracoid process
Surgical
Conservative or
surgical
CC indicates coracoclavicular; AC, Acromioclavicular.
injuries. However, this differentiation is not important in
clinical practice and, in the authors’ view, are not useful
for the preoperative planning. Type 3 to 4 injuries are
easily diagnosed on plain radiographs.
| TECHNIQUE
4 cortices of the clavicle and the coracoid (Figs. 2 and
3A, B). A drill stop can be used, or a malleable retractor
is placed inferior to the coracoid process to ensure the
drill bit does not plunge too deep below the coracoid
process. It is important that the direction of the drill
is in the center of the superior surface of the coracoid
process to achieve an optimal fixation.
Acute Cases
The patient is given general anesthesia and placed in
a beach chair position. A saber-cut incision is made spanning from the clavicle to just inferior to the coracoid
process. The supraclavicular nerves are identified and
protected throughout the procedure. The trapeziusdeltoid fascia is opened transversely. The deltoid is dissected off the anterosuperior clavicle subperiosteally,
allowing visualization of the coracoid process and the
acromioclavicular joint. A deltoid split can be performed
in line with its fibers if additional exposure is needed.
Care should be taken not to damage the coracoacromial
ligament when dissecting the area between the clavicle
and the coracoid. The trapezoid component of the coracoclavicular ligament spans from the superior surface of the
posterior half of the coracoid process. The conoid component is attached to the Bcoracoid knuckle[ just posterior to
the trapezoid attachment and runs cranially in an inverse
cone shape to attach to the posterior margin of the clavicle
at the junction of the middle and lateral one thirds.
In acute cases, the ACJ is usually easily reduced.
This reduction is then maintained with direct pressure
or a clamp. The medial and lateral borders of the coracoid process are identified. A 3.65-mm drill bit (supplied
in kit) is positioned on the superior aspect of the clavicle
such that it can be drilled in a straight line through the
FIGURE 2. Dislocated ACJ showing torn coracoclavicular
ligaments.
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Lim et al
FIGURE 3. A, Drilling through the 4 cortices
of the clavicle and the coracoid process. B,
Drilling through the 4 cortices of the clavicle
and the coracoid process. Clamp is holding
coracoclavicular interval reduced.
The guide wire attached to the Tightrope is passed
through the clavicle and retrieved from the undersurface
of the clavicle (Figs. 4A, B). The passage of the leading
oval button through the coracoid process can be done in 1
of 2 ways. The lead suture can be passed through the coracoid and retrieved below the coracoid. With traction applied on this suture, it will deliver the button through the
coracoid process. However, the authors prefer to remove
the leading suture and position the leading button in the
coracoid hole. It can then be pushed through the hole
with a small instrument such as a Watson Cheyne periosteal elevator. The position of the button should be confirmed with an image intensifier. When in place, the
oval button should be perpendicular to the line of the suture and directly apposed to the undersurface of the coracoid process, whereas the round, superior button lies flat
on the superior surface of the clavicle (Figs. 5A, B). Once
the leading button is positioned, traction is placed on the
2 free ends of the sutures, which closes the interval
between the 2 buttons and reduces the clavicle onto the
coracoid process (Figs. 6A, B). Both ends of the suture
are then alternately tightened until the superior button
sits snugly on the clavicle. The author’s aim was to repro-
duce the normal coracoclavicular interval and achieve anatomical reduction of ACJ. This should allow normal rotation of the clavicle on the Fibrewire sutures. It should
therefore not be too tight. Once the position of the implant and reduction of ACJ are confirmed to be satisfactory on fluoroscopy, the sutures are tied. Tension on the
sutures should be aimed at achieving and maintaining adequate reduction while allowing physiological motion.
Subsequently, the conoid and trapezoid ligaments, superior part of the AC ligament, and trapezius-deltoid fascia
are repaired.
Lateral Clavicle Fracture
This fixation technique can also be used in the presence
of lateral clavicle fracture with increased coracoclavicular
interval. Depending on the size of lateral fragment, it is
either excised, or open reduction and internal fixation is
performed using a plate. If the lateral fragment is excised,
the distal clavicle and coracoclavicular interval are reduced and stabilized using the technique as described
above. If the lateral fragment is of sufficient size to warrant fixation, then the fixation technique is slightly modified. After preparing the bony tunnels between clavicle
FIGURE 4. A, Passing the oval button
through the clavicle with the guide wire
provided. B, Passing the oval button through
the clavicle with the guide wire provided.
216
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ACJ Reduction, Repair, and Reconstruction
FIGURE 5. A, Pulling on the
sutures will approximate the 2
buttons and reduce the coracoclavicular interval. B, Image
intensifier picture confirms reduction of the AC parts and
correct position of the oval and
round buttons.
and coracoid, the oval metallic button is passed through
a hole in the plate before passing through the clavicle
and coracoid. Internal fixation of the fracture is then
performed, and adjunct fixation is achieved using the
Tightrope. In such cases, the superior metallic button is
positioned and secured over a hole in the clavicular plate.
Chronic Cases
In chronic cases, the authors recommend excision of the
distal end of the clavicle and a double-bundle autograft
reconstruction of the coracoclavicular ligament. The
authors prefer to use the hamstring tendon as a graft.
The role of adjunct fixation such as the Tightrope system
is to provide initial fixation to help reduce and maintain
reduction until the graft has ligamentized.
It is important to mark out all the drill holes before
excision of the clavicle. To achieve an anatomical reconstruction of both the trapezoid and conoid ligaments, the
lateral most drill hole for the passage of the hamstring
graft should be 23 mm (22 mm for women)21 from the
distal end of the clavicle. It should also be placed slightly
anterior to the center on the superior surface of the clavicle. The medial drill hole should be placed 42 mm
(37 mm for women)21 from the distal end of the clavicle.
The medial dill hole should be positioned posteriorly on
the superior surface of the clavicle. There should be adequate bone bridges surrounding the drill holes. The
3.65-mm drill bit used for the passage of the Tightrope
implant is positioned on the superior aspect of the clavicle such that it is between the 2 previously marked drill
holes. The placement of the Tightrope implant is then
carried out as alluded above.
Using a sagittal saw, 1 cm of the distal end of the
clavicle is then resected. The passage of the graft
through the clavicle and under the coracoid process is
aided by first passing an Ethibond no. 5 through the
clavicle and under the coracoid process. One end of
the suture is then tied to the hamstring graft by means
of a whipstitch. The other free end of the suture is tied
onto itself, thus creating a circular loop as shown in the
FIGURE 6. AYB, Pulling on the sutures
approximates the buttons and reduces the
coracoclavicular interval.
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Lim et al
FIGURE 7. A, The use of an ETHIBOND
loop suture to aid in ‘‘wheeling’’ the graft
through the clavicle and beneath the coracoid
process. B, Distal end of clavicle resected
and hamstring graft passed twice around the
coracoclavicular interval.
diagram (Figs. 7A, B). The Ethibond is then pulled from
1 end wheeling the graft through the passage. The graft
is passed transosseously twice through the clavicle. It is
first passed through the lateral drill hole on the clavicle
in an inferior-superior direction and then through
the medial drill hole from the superior-inferior direction
through the clavicle. It is looped under the coracoid process deep to the oval button. Subsequently, the graft is
brought through the clavicle in the same path as before
such that the graft spans the coracoclavicular interval
twice. (Fig. 7C) Once the graft is in a satisfactory position, the clavicle is reduced, and the Tightrope is then
tied securely. The 2 ends of the graft are sutured to
each other with no. 2 Fibrewire at the coracoclavicular
interval.
| RESULTS AND COMPLICATION
The senior author has used this fixation technique on 9
occasions in 8 patients. All patients were men with a
mean age of 35 years (range, 23Y50 years). Of these 9
procedures, 1 was performed in a revision setting after
failure of original fixation with Tightrope. This case is excluded from further analysis, which will focus on primary
cases.
In 8 cases, this fixation technique was used as a primary fixation. The dominant limb was involved in 6 of
8 cases. Indications of the procedure included a grade 5
ACJ dislocation (1 patient), grade 4 ACJ dislocation
(1 patient), grade 3 ACJ dislocation (2 patients), and a
lateral clavicle fracture with significantly increased coracoclavicular interval (4 patients). Of the 4 patients with
clavicular fractures, 2 underwent open reduction and
internal fixation using a plate in addition to Tightrope
fixation. In the other 2 cases, the lateral end of the clavicle was excised.
Of the 8 patients, 7 were operated upon within
4 weeks of their injury. In these acute cases, only Tightrope fixation was used to reduce the coracoclavicular interval. In the only chronic case, the patient had nonunion
of distal clavicle fracture with increased coracoclavicular
218
distance. He underwent distal clavicle excision, coracoclavicular ligament reconstruction using hamstring autograft, and Tightrope fixation.
Intraoperative satisfactory reduction and fixation
were confirmed clinically and with intraoperative fluoroscopy. Postoperatively, a sling was applied for
4 weeks with instructions of gentle range of motion up
to shoulder level. Light duties were allowed from 4 to
12 weeks, and full duties resumed from 3 months onward. Contact sports were discouraged for 6 months.
Clinical and radiological follow-up was at 2 weeks,
6 weeks, and 3 months. Minimum follow-up of 6 months
is available for all the patients.
Intraoperative and 2-week postoperative radiographs demonstrated excellent reduction of the coracoclavicular interval and the ACJ in all patients (Fig. 8).
However, 6-week postoperative x-rays of 4 patients
revealed a loss of reduction of the ACJ and an increased
coracoclavicular interval (Fig. 9). All 4 patients had
Tightrope fixation for acute injuries. Two of the patients
FIGURE 8. Intraoperative fluoroscopic image shows
anatomical reduction of ACJ and satisfactory placement
of fixation device.
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ACJ Reduction, Repair, and Reconstruction
FIGURE 11. This patient had Tightrope fixation for grade
3 ACJ dislocation. Three-month postoperative x-ray
shows anatomical ACJ reduction and calcification in
CCI. CCI indicates coracoclavicular interval.
FIGURE 9. Six-week follow-up x-ray shows loss of
reduction and increased coracoclavicular interval.
in which fixation failed underwent clavicle plating and
Tightrope fixation for a distal clavicle fracture with increased coracoclavicular interval. The other 2 patients
had a Rockwood grade 3 and 4 dislocation respectively.
All denied any further episodes of trauma. Of the 4
patients with fixation failure, 3 reported feeling a snap
followed by prominence of the lateral clavicle; the
fourth patient reported waking up in the morning with
recurrence of the dislocation. All the failures occurred between 2- and 6-week follow up visits. Figure 9 illustrates
an example of loss of reduction secondary to fixation failure (same patient as Fig. 8). Figure 10 demonstrates loss
of fixation in another patient where Tightrope fixation
was used with clavicle plating.
Of the 4 patients with fixation failure, 2 underwent
further surgery, 1 requiring removal of clavicle plate
and Tightrope and the other patient requiring revision
fixation with Tightrope in addition to autograft hamstring reconstruction of coracoclavicular ligament. The
remaining 2 patients were treated nonoperatively. One
of these patients has a very prominent lateral end of clav-
FIGURE 10. In this patient with distal clavicle fracture,
Tightrope was used with clavicular plate fixation. Threemonth postoperative x-ray shows loss of reduction.
icle, with painful clicking at ACJ on manual work and
extremes of abduction and flexion. However, he has refused further surgical intervention. The other patient is
completely asymptomatic.
At final follow-up, 4 of the 8 patients had uneventful
recovery with no pain and resumption of full duties. Anatomical reduction of the ACJ was maintained. Minor
calcification in coracoclavicular interval was seen on
plain radiograph (Fig. 11). There were no iatrogenic coracoid or clavicle fractures.
Overall, there was a 50% fixation failure rate when
Tightrope fixation was used in primary procedures (excluding revision surgery). Retrieved specimen revealed
multiple areas of abrasion on no. 5 Fibrewire suture
(Fig. 12). The mechanism of failure is postulated to be
secondary to suture abrasion. This could have resulted
from abrasion on metallic buttons, clavicle plate, or sharp
bony edges of coracoid or clavicle. Both patients who
underwent clavicle plating in addition to the Tightrope
fixation had failure of fixation. This accounted for 50%
of the failures in this series. The abrasion of the suture
can also potentially occur against the bone edges of the
FIGURE 12. Retrieved no. 5 Fibrewire suture.
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Lim et al
clavicle and/or coracoid process if the drill holes are not
in an exact straight line. Besides failure of fixation, there
were no neurovascular or other complications in this series. There is a potential for late development of symptomatic osteoarthritis of ACJ, which may necessitate a
delayed excision of distal clavicle.
| MAJOR CONCERNS
The high failure rate in our series is a major concern of using the Tightrope system. It may represent our
learning curve, but a structural flaw in the system cannot
be ruled out at this point. There are, however, many attractive potential advantages of using the Tightrope system.
The tensile strengths of the native coracoacromial
ligaments and a single no. 5 Fibrewire are highly comparable, with reported values of about 500 N22 and 483 N,23
respectively. The pullout strength of a metallic button has
been shown to be in excess of 1150 N.13 The use of 4
strands of no. 5 Fibrewire to hold 2 metallic buttons to
close the coracoclavicular interval is, at least theoretically, a much stronger repair than the native ligaments, coracoclavicular slings, suture anchors, or coracoacromial
ligament transfers.22 Furthermore, it provides a nonrigid
fixation of the ACJ, thus allowing normal rotation of the
clavicle. This is an attractive advantage of this technique.
In contrast, techniques using screws do not allow for this
rotation, and screws usually work loose due to repetitive
strains placed on the screw bone interval. The Tightrope
metallic buttons protect the sutures from cutting through
the clavicle, a failure mode often seen when using isolated sutures. The low profile of the implant may potentially
also eliminates the need for a second operation for removal of the implant.
The concept of this fixation technique is good and
provides very strong intraoperative fixation in addition
to other potential benefits as outlined above. Despite all
these theoretical advantages, there was a very high rate
of loss of reduction in our small series (4/8 patients).
To the best of our knowledge, there are no published
studies in the English literature on the efficacy of using
Tightrope fixation in ACJ dislocations. Our retrieved
specimen (Fig. 12) suggests that the mode of failure is
likely to be secondary to suture abrasion. This could
have resulted from abrasion on metallic buttons, clavicle
plate, or sharp bony edges of coracoid or clavicle. Other
potential causes such as knot slippage24 cannot be excluded in the 2 other patients that did not receive further
surgical treatment.
The metallic button fixation may have promise as an
alternative for stabilization of dislocated ACJ. However,
further biomechanical analysis of this fixation device is
required to evaluate and address the potential cause of
its in vivo failure.
220
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