Acromioclavicular Joint
- Discussion:
- AC joint is situated between the clavicle and acromion;
- acromion has two ossification centers which fuse at age 22 yrs;
- it permits motion in three planes:
- AP gliding of
acromion during protraction & retraction of scapula;
- tilting of acromion
during abduction & adduction of arm;
- rotation of the
clavicle;
- rotation occurs
during abduction & adduction of shoulder.
- Anatomy:
- innervation: provided by the suprascapular and lateral pectoral
nerves
- joint is reinforced by two sets of ligaments:
- AC ligament
- directed horizontally, and functionally the AC joints control horizontal
stability;
- palpable shallow depression between end of clavicle & acromion;
- superior AC lig is most important ligament in stabilizing AC joint for normal
daily activities;
- coracoclavicular ligaments:
- stronger, vertically directed contains conoid and trapezoid ligaments help to control vertical stability;
- coracoclavicular lig are suspensory ligaments of upper limb;
- conoid:
- is the most important ligament for support of the joint against significant
injuries and superior displacement;
- cone shaped which extends between the conoid tubercle on the posterior
clavicle and the base of the coracoid;
- trapezoid:
- resists AC joint compression;
- begins anteriorly and laterally to the conoid ligament on the clavicle and
inserts on the coracoid process;
- references: Biomechanical study
of the ligamentous system of the acromioclavicular joint.
- Sternoclavicular joint:
- see S.C. joint injury in
the adolescent;
- inherently more stable than AC
joint; because of this stability & its more protected medial location;
- it is injured less frequently than the acromioclavicular joint.
- Management of Specific Injuries:
- AC joint arthrosis / distal clavicle excision
- The influence of
distal clavicle resection and rotator cuff repair on the effectiveness of anterior acromioplasty.
- AC joint septic arthritis:
- Septic arthritis of
the acromioclavicular joint - a report of four cases
- Septic arthritis of
the acromioclavicular joint.
- Sonographic detection, evaluation
and aspiration of infected acromioclavicular joints.
- Primary septic
arthritis of the acromio-clavicular joint: case report and review of literature
- AC Joint Separation:
- Exam:
- palpate the AC joint during flexion and extension of shoulder;
- distract the arm as it is placed in adduction
- significant prominence of the distal clavicle
indicates unstable AC injury;
- BvR test for DJD: resisted shoulder upward flexion with arm
hyperadducted;
- ref: Clinical evaluation
of acromioclavicular joint pathology: Sensitivity
of a new test
- Radiology:
- classification of AC
separation:
- acromioclavicular
joint stresses views
- grade I injuries
remain nondisplaced;
- type I and type II
injuries can be differentiated on stress radiographs;
- w/ pt standing, 10 lb
weight is secured to affected upper limb;
- w/ grade II injury,
suspended wt displaces AC joint articulation, which increases distance between
clavicle & acromion;
- zanca view
- scapular outlet view
- references: Radiological
evaluation of the acromioclavicular joint.
- AC
Joint Separation:
- non operative treatment:
- in
the report by TF Schlegel MD et al, the authors prospectively studied natural
history of untreated acute grade III
AC separations;
- 25
patients were treated nonoperatively with a sling for comfort through
progressive early range of motion
as tolerated;
- 10
additional uninjured subjects underwent strength testing to evaluate difference
between dominant and
nondominant sides;
- one patient underwent a surgical procedure at 2 weeks after
injury because of cosmetic concerns;
- 20
of the 25 patients completed the 1-year evaluation and strength-testing
protocol;
- 4
of the 20 patients (20%) thought that their long-term outcome was suboptimal,
although for 3 of them it was not
enough to warrant surgery;
- testing of the 20 patients revealed no limitation of shoulder motion
in injured extremity and no diff between
sides in rotational shoulder muscle
strength;
-
bench press was the only strength test that showed a significant short-term
difference, with the injured extremity
being an average of 17% weaker;
-
ref: A Prospective Evaluation of Untreated Acute Grade III AC Separations. TF
Schlegel MD. Am Jour of Sports
Med 29:699-703 (2001)
- operative treatment:
- surgical
precautions:
- attempt to keep fixation over the anterior third of the clavicle (avoid more
anterior translation);
- coracoclavicular cerclage techniques may provoke malreduction of the joint due
to anterior subluxation;
- consider some technique to defray pressure over the clavicle (endo button,
plate ect) to avoid cut through;
- CA
ligament reconstruction:
- ligament is identified as it passes from the tip of coracoid process and inserts along undersurface
of
anterior aspect of acromion;
- small piece of bone was taken with the ligament from the acromion to allow
bone-to-bone healing;
- references:
- Surgery about the
coracoid: neurovascular structures at risk.
- The cortical ring
sign: A reliable radiographic landmark for percutaneous coracoclavicular
fixation
- Clinical results of
coracoacromial ligament transfer in acromioclavicular dislocations: A review of
published literature
- Method of
Subcoracoid Graft Passage in Acromioclavicular Joint Reconstruction
- reconstruction w/o tendon graft:
- consider direct verticle suture limb(s) and a second suture limb running more
lateral to engage lateral
edge of clavicle (to reproduce trapezoid ligament);
- Technique of
Reconstruction for Complete Acromioclavicular Dislocation. A Prospective Study.
- Stability of
acromioclavicular joint reconstruction: biomechanical testing of various
surgical
techniques in a cadaveric model.
- A cadaveric study
examining acromioclavicular joint congruity after different methods of
coracoclavicular
loop repair.
- Consistency of
long-term outcome of acute Rockwood grade III acromioclavicular joint
separations
after K-wire transfixation.
- Mid-term outcome
comparing temporary K-wire fixation versus PDS augmentation of Rockwood grade
III AC joint separations.
- Treatment of Tossy
III acromioclavicular joint injuries using hook plates and ligament suture.
- Failure of
Coracoclavicular Artificial Graft Reconstructions From Repetitive Rotation
- Surgical Treatment
of Acute Acromioclavicular Joint Injuries Using a Modified Weaver-Dunn
Procedure
and Clavicular Hook Plate
-
reconstruction with tendon graft: (palmaris longus, gracilis, semitendinosis)
- AC joint dislocation: a comparative
biomechanical study of the palmaris tendon graft
reconstruction w/ other methods
in cadaveric models
- Reconstruction of
the Coracoclavicular Ligaments with Tendon Grafts. A Comparative
Biomechanical
Study.
- Anatomical
acromioclavicular ligament reconstruction: a biomechanical comparison of
reconstructive techniques of the AC joint.
- Clinical outcomes of
coracoclavicular ligament reconstructions using tendon grafts.
- Acromioclavicular
joint reconstruction using peroneus brevis tendon allograft.
- Clavicular Fractures
Following Coracoclavicular Ligament Reconstruction with Tendon Graft
- modified weaver dunn
procedure: (for chronic injuries)
