الفهرس 
Acromio-Clavicular Joint Architecture
BiomechanicsOnly 14 pages are availabe for public view
Abstract
Distal clavicle fractures account for 21% of all clavicle
fractures and are most common among middle-aged men. The
majority of the injuries are caused by traffic accidents and
accidental falls.
Acromio-clavicular joint dislocations encompass 9% to 12%
of traumatic shoulder lesions and are more prevalent among
young and active individuals, particularly athletes involved in
contact sports. These dislocations are more common among
patients in their third and fourth decades and in males.
Stability of the lateral clavicle is provided mostly by the
acromioclavicular and coracoclavicular ligaments. These
ligaments have statistically been proven to enhance stability,
especially the superior acromioclavicular ligament, which is
responsible for the vertical stability (suspensory mechanism) of
the shoulder girdle.
Neer’s classification is widely used to classify the distal
clavicle fractures according to their relations to the
coracoclavicular ligaments. The Neer type II fractures have received a clinical concern because of the high nonunion rate in
nonsurgical treatment that have been observed (>30%).
Rockwood classified ACJ dislocations into 6 grades
according to the direction of the dislocation and the integrity of
the acromioclavicular and coracoclavicular ligaments.
Radiography is usually the first-line imaging modality used
to evaluate patients with uncomplicated clavicular and acromio -
clavicular joint injury. Computed tomography (CT) is not
routinely used for the evaluation of simple, non-displaced clavicle
fractures. MRI is extremely helpful to delineate concomitant
ligamentous injury with distal clavicular fractures and aid in
further subtyping these injuries.
Non-union of displaced clavicular fractures can result in
orthopaedic, neurovascular, and cosmetic complications. Recent
studies demonstrate lower rates of non -union with surgery
compared to non -operative treatment. Furthermore, patients
nowadays expect improved cosmetic outcomes and earlier
resumption of preoperative activity levels, leading surgeons to
focus on primary surgical repair of displaced clavicular fractures.
Treatment of distal clavicle fractures ranges from nonoperative
to operative approaches. Various surgical procedures
have been described in the literature [coraco-clavicular stabilization, hook plate, intramedullary fixation, interfragmentary
fixation, K-wire plus tension band wiring (TBW) and arthroscopic
fixation] , each with potential complications. For fractures treated
operatively, the goal was to maximize stability and functionality
with early mobilization and low morbidity.
Complications of surgical treatment of distal clavicular
fractures are similar to those of midshaft clavicle fractures,
including hardware-related complications, loosening and
infection, delayed union and nonunion. Unique complications
with the hook plate include hook migration, loosening, and
osteolysis around the hook, warranting hardware removal.
Just like any other joint in the body, once the acromioclavicular
joint has been injured, it has tendency for arthritis and
pain, with pain in the joint is the most common problem after
these injuries.