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Acromioclavicular
Separations:
Etiology & Treatment
By Jennifer R. Farrell
A Senior Project
April 11, 2001
Introduction
• Acromioclavicular (AC) separation:
– Acromion pulls apart from clavicle
– Scapula falls away
– Common in athletics
– Classification varies
Anatomy of the AC Joint
• Diarthrodial joint.
– Freely moveable.
• Formed by the distal
clavicle and acromion.
• Coracoclavicular (CC),
Acromioclavicular (AC)
and Coracoacromial
(CA) ligaments maintain
joint reduction and
stability.
(Rockwood et al., 1998)
Function of the AC Joint
• Suspend upper extremity
• Transmit forces to the axial skeleton.
• Responsible for allowing arm to swing
clear of the trunk (Hauser, 1996).
• AC joint must have a strong ligament
complex for support.
Ligaments Involved
• Acromioclavicular
capsule
– Four AC ligaments
• Coracoclavicular ligament
– Trapezoid and Conoid.
• Coracoacromial ligament
(Klassen, Morey & An, 1997)
Motion of the AC joint
• Elevate and abduct the arm.
• The clavicle is capable of 30° to 40° of upward
rotation (Field & Warren, 1996 and Hauser, 1996).
• Motion occurs in a triaxial pattern (Klassen et al.,
1997).
• 90% of restraint to posterior displacement and
resistance to horizontal translation by AC ligament
(Field & Warren, 1996).
• Coracoclavicular ligaments are the prime stabilizers
and prevent superior dislocation (Klassen et al.,
1997).
Classification of Injury
• AC joint injuries are classified based on
the severity of injury sustained to the
ligaments and supporting musculature
(Rockwood, Williams & Young, 1998).
• Traditionally only three types.
• The most widely used 3-grade
classification system is the Tossy system.
Tossy System
• Type I injury:
– Basic sprain or contusion of the AC ligaments.
– No tear or visible deformity, except slight swelling.
• Type II injury:
– Partial tear of the CC ligaments.
– Superior clavicle, obvious swelling and difficulty lifting
objects.
• Type III injury:
– Completely ruptured CC ligaments.
– Severe pain, disability, swelling and marked deformity
(Tossy, Mead & Sigmond, 1963).
Classification of Injury
• Since Tossy et al’s (1963) study, many
studies have proposed expanding the
classification system.
• In addition, the Tossy system has been
modified.
Modifications to the Original
Tossy System
• Types I, II and III injuries modified in a
study by Zlotsky, 1976.
• Field and Warren (1996) divided types II
and III into IIA & IIB, and IIIA & IIIB.
Additions to the Tossy System
• In a study by Gazielly (1995) types IV and
V were proposed, while keeping the
original Tossy classifications the same.
• Hauser (1996) argued for six classes of AC
separations while using the modified Tossy
system proposed by Zlotsky (1976).
Classification Overview
• Most commonly used
classification system
presently (Rockwood et al.,
1998).
• Types I, II and III depict the
modified Tossy system
proposed by Zlotsky (1976).
• Types IV, V and VI illustrate
the classes proposed by
Hauser (1996) and Gazielly
(1995).
(Rockwood et al., 1998)
Mechanism of Injury
 Direct Mechanism*
• * (Rockwood et al., 1998)
 Indirect Mechanism*
Mechanics of Injury
• With both direct and
• There have been cases
indirect trauma, the
reported in which the
clavicle usually detaches
clavicle is lodged under
from the acromion process
the acromion, displaced
superiorly.
anterior, posterior or
simply resting on top of
• The clavicle will appear as
the acromion.*
a prominent protrusion on
– *(Schwartz & Kuderna, 1988,
the superior aspect of the
Shildhaus & Meyers, 1987, &
shoulder.*
Leonard & Capen, 1983).
– *(Irvin et al., 1998).
Diagnosis of Injury
• Weighted x-rays
– bilateral
• Basic anteroposterior and
axillary views
Treatment
• Two types of treatments can be utilized to
treat AC separations.
– Conservative
• Usually used for types I-III.
– Surgical
• Most often used for types III-VI.
• Treatment options are controversial and
highly debated.
Conservative Treatment
• Conservative treatment has been proven
effective in grades I-III.
– Gazielly (1995) found that surgery can be
postponed for 2 to 3 months.
• Conservative methods include:
–
–
–
–
Taping/Strapping
Ice/NSAIDs
Modalities: E-Stim & Ultrasound
Muscle strengthening
Conservative Treatment
• Basic strapping technique
using a modified sling.
• When taping, the same
principle applies.
• Generally it is best to
support the arm as shown
to limit stress placed on
the AC joint.*
* (Rockwood et al., 1998)
Surgical Procedures
• Four basic types of procedures used:
–
–
–
–
Primary Acromioclavicular Joint Fixation
Primary Coracoclavicular Ligament Fixation
Excision of the Distal Clavicle
Dynamic Muscle Transfer
• With each of these procedures it is often
necessary to remove devices used for reduction.
Primary Acromioclavicular Joint
Fixation
• Most popular procedures used today
(Rockwood et al., 1998).
• Maintain reduction of the AC joint while
the injured ligaments heal.
• It is a common practice to repair damaged
ligaments after joint fixation has occurred.
Primary Acromioclavicular Joint
Fixation
• Pins, screws, suture wires and metal plates are
used to bring the clavicle and acromion
together.
– Steinmann pins (Rockwood et al., 1998).
– Wolter & Balser metal “crook” plates (Habernak,
Weinstabl, Schmid & Fialka, 1993).
Primary Coracoclavicular
Ligament Fixation
• Screws, ligament transfers, and synthetic &
metal loops
– Fix CC ligament
– Suspend the clavicle from the coracoid process.
• Examples include:
– Bosworth screw (Bosworth, 1941).
– GORE-TEX loop (Morrison & Lemos, 1995).
– PDS bands (Hessman, Gotzen, Gehling & Ricter,
1995).
Surgical Procedures
• Examples of various
surgical techniques
(Rockwood et al., 1998).
– A. Pins or screws across
the joint.
– B. Loops between the
clavicle and coracoid.
– C. A coracoclavicular
lag screw.
Excision of the Distal Clavicle
• Origin unknown (Rockwood et al., 1998).
• Usually done in conjunction with ligament
transfer and fixation.
– Weaver and Dunn (1972)
• Treatment for chronic pain (Morrison &
Lemos, 1995).
Dynamic Muscle Transfer
• Severely chronic cases.
• Transfer of the trapezius and deltoid
muscles.
• Rarely used.
• The actual procedure is not clear, and the
findings vary (Rockwood et al., 1998)
Complications
• Conservative:
– Calcification
– Arthritis
– Loss of strength
– Removal of the
device
– Skin irritation
• Surgical:
– Wound infection
– Migration of pins,
screws, etc.
– Scarring
– Additional fractures
– Excision due to
wires
– Removal of devices
Rehabilitation Following
Surgery
• Limited motion
• Sling for 1 to 2 weeks
• Patients are to refrain
from heavy lifting after
removal of sling.
• Muscle strengthening,
and stretching at 6
weeks.
• Modalities
– E-Stim
– Ultrasound
• Rehabilitation can be
more difficult and longer
if devices must be
removed (Habernek et
al., 1993).
Conclusion
• Considerable disagreement in the literature
regarding classification and treatment.
• Type III remains the most controversial.
• Various methods of treatment are available
and administered with no standard.
• Types IV, V and VI are rare.
• Necessary to revert back to the initial
Tossy system.
Questions?