DR ZUBAIR RINGSHAWL POST GRADUATE SCHOLAR

1. ACROMIOCLAVICULAR
JOINT ARTHRITIS

2. DEFINITION
Acromioclavicular joint arthritis (AC joint arthritis) is a progressively
degenerative disease in which there is degeneration of joint cartilage and the
underlying bone which causes pain and stiffness.

3. ETIOLOGY
 The combination of three factors underlies the frequency of problems of
the AC joint.
 First, because it is a diarthrodial joint, it is
vulnerable to the same processes affecting
other joints in the body, such as
degenerative osteoarthritis, infections and
inflammatory and crystalline arthritis.

4.  Second, its superficial location and its
relationship to the shoulder girdle predispose
it to traumatic injury.
 Third, the biomechanics of the shoulder
girdle require the AC joint to transmit
large loads across a very small surface area,
which can result in failure with repetitive
activity or overuse.

5. RISK FACTORS
 1.Age (>45 yrs)
 2.History of previous injury to AC joint (specially previous trauma and
sports injury)
 3.Weight lifting activities particularly those transmitting huge loads across
shoulder joint like bench press and military press.

6. CAUSES
 There are three common causes of acromioclavicular joint arthritis:
 1. Primary Osteoarthritis.
 2. Post Traumatic Osteoarthritis.
 3. Distal Clavicle Osteolysis.

7.  Primary Osteoarthritis
 In comparison to the rate of occurrence in the knee and hip, primary
osteoarthritis in the shoulder is relatively rare.
 However, primary involvement of the AC joint is much more common
primary involvement of the glenohumeral joint and is, in fact, the most
common cause of pain in the AC joint.
 Degenerative changes by the fourth decade in the majority of AC joint.

8.  In one study, 54% to 57%of elderly patients demonstrated radiographic
evidence of degenerative arthritis.
 In another study, magnetic resonance (MR) imaging demonstrated
evidence of arthritic changes in 48% of the AC joints in over 300 older
asymptomatic patients.
 Despite its seeming prevalence by radiologic criteria, symptomatic primary
osteoarthritis is a relatively uncommon clinical entity.

9.  Posttraumatic Arthritis
 Acromioclavicular arthritis following trauma is even more common than
primary osteoarthritis, due to the frequency of injury to this vulnerable
joint.
 The incidence of posttraumatic arthritis symptoms after injury or surgery
highly variable and depends on the degree of injury and the type of
operative procedure.

10.  Arthritis also occurs, although less commonly, after distal clavicle fractures,
particularly those with intra-articular extension.
 Operative procedures for AC joint dislocations in which the AC joint is
preserved or transfixed have been associated with a higher incidence of
arthritis than those in which the joint is sacrificed(i.e., Weaver-Dunn
procedure).

11.  Distal Clavicle Osteolysis
 An increasingly recognized but still infrequent entity that causes AC joint
symptoms is distal clavicle osteolysis.
 Osteolysis related to repetitive microtrauma has recently been receiving
more attention, particularly among weight-lifting athletes.
 This condition is thought to be growing in frequency due to the
of weight-training and its incorporation into fitness programs and training
regimens for other sports.

12.  The proposed mechanism of this form of osteolysis is that repetitive
stresses to the subchondral bone of the distal clavicle lead to fatigue
failure, which initiates resorption.

13. GRADING OF OSTEOARTHRITIS

14. Evaluation and Diagnosis
 Presentation
 Isolated AC joint arthritis presents with discomfort or aching over the
anterior and/or superior aspect of the shoulder.
 Pain is often brought on by activities of daily living, such as washing the
opposite axilla, reaching back to retrieve a wallet.
 Symptoms are often exacerbated by more demanding activities, such as
pushing or overhead work in the case of laborers and weight lifting,
golfing, swimming, or throwing in athletes.

15.  Patients may note pain at night, with nocturnal awakening when rolling
onto the affected shoulder.
 There may be associated symptoms of popping, catching, or grinding.

16.  Physical Examination
 Careful examination of the entire shoulder girdle combined with cervical
spine examination is essential to rule out any contribution from cervical
lesions.
 Inspection of the affected extremity may reveal swelling, deformity, joint
prominence or asymmetry which may indicate AC joint instability.
 Palpation over the AC joint may elicit tenderness, which is anecdotally
sensitive but non specific.

17.  Dynamic stability of the AC joint can be assessed by placing the patient
supine and affected extremity in 90 degrees of flexion.
 With one hand on the affected joint , examiner assesses for the movement
of the clavicle with respect to acromion while applying a downward force
on the patient’s flexed arm.

18. SPECIFIC TESTS
 1. Provocative maneuvers, such as reaching across to touch the opposite
shoulder or placing the hand behind the back, may elicit discomfort.
 Provocative tests include:
 a) Cross body adduction test
 The most reliable provocative physical examination is the cross body
adduction test, in which the arm on the affected side is elevated 90
degrees of forward flexion and the examiner then grasps the elbow and
adducts the arm across the body.

19.  Reproduction of pain over the AC joint is
suggestive of an AC joint lesion.
 This test may also be positive in patients
with subacromial impingement and may cause
discomfort posteriorly in patients with
posterior capsular tightness.
 Sensitivity is 77% and specificity is 79%.

20.  b) AC resisted extension test :
 The patient is seated with the examiner standing
behind him/her.
 The patient's shoulder is positioned into 90
flexion and internal rotation, with the elbow
placed into 90 flexion.
 The examiner places his/her hand on the
patient's elbow and asks him/her to
horizontally abduct the arm against
isometric resistance
 A positive test is pain at the AC joint.
 Sensitivity is 72% and specificity is 85%.

21.  c) O’Brien active compression test:
 In this test, the affected arm is brought
into 90 degrees of forward flexion and 10
degrees of adduction.
 The patient then performs resisted
shoulder flexion with the arm in maximum
internal rotaion and then in maximum
supination.
 Pain with the former maneuver is
consistent with a SLAP lesion and pain
with the latter maneuver indicates
AC joint abnormality.

22.  Sensitivity is 41% and specificity is 95%.
 The overall accuracy of these provocative tests in diagnosing AC joint
arthritis is 93%.

23.  2. Painful arc sign:
 In this test, the affected shoulder is
abducted and if the patient
experiences pain during the last 30
degrees of abduction, it is consistent
with AC joint arthritis.
 Sensitivity is 50% and specificity is 47%.

24.  3. Paxinos Sign:
 With the patient sitting and the symptomatic arm by
the side, the examiner's thumb is placed under the
posterolateral aspect of the acromion and the
index and middle fingers of the same (or
contralateral) hand are placed superior to the mid-
clavicle.
 If we are examining left shoulder right hand is to
be used for eliciting this sign and vice versa.
 The examiner provides pressure to the acromion in
an anterosuperior direction with the thumb, while also
applying pressure an inferior direction to the mid-clavicle with the index
and middle fingers

25.  If pain is elicited or increased in the region of the acromioclavicular joint,
the test is considered positive

26. RADIOLOGICAL EVALAUATION
 X - RAYS
 1. Shoulder AP view:
 The AP projection is usually obtained with the patient in the upright or
supine position and with the coronal plane of the body parallel to the
cassette.
 The beam is directed in a true AP direction relative to the body.This results
in slight overlap of the glenoid rim and the humeral head as the
glenohumeral joint is tilted anteriorly approximately 40°.

27. The beam is oriented in true AP view to the patient with the arm positioned in
either neutral, internal, or
external rotation. The beam is centered on the coracoid process with
the blade of the scapula
parallel to the film.

29.  2. Zanca View:
 Zanca described a modified technique that provides a clear, unobstructed
view of the distal clavicle and AC joint. This projection is obtained by
angling the x-ray beam 10 to 15 degrees superiorly and
decreasing the kilovoltage to about 50% of that used for a standard
glenohumeral exposure.

31. AP view of the shoulder demonstrates
the glenohumeral joint anatomy but is
overpenetrated and fails to
demonstrate the AC joint well.
Zanca view better depicts the soft-tissue
and joint detail of the AC joint; however,
the glenohumeral joint is no longer well
visualized

32.  Findings: Patients with primary or posttraumatic degenerative arthritis
will have findings of arthritic changes which include
 sclerosis,
 osteophyte formation,
 subchondral cysts, and
 joint space narrowing.

33. 3. SUPRASPINATUS OUTLET VIEW
 The supraspinatus outlet view is useful for evaluating the acromion process
and subacromial abnormalities such as osteophytes that may cause
impingement.
 It is similar to the Y-view but with caudal tube angulation.
 This view is taken with the patient turned as for the Y projection and the
cassette perpendicular to the body of the scapula and parallel to glenoid
fossa.
 The X-ray is taken from a mediolateral projection along the axis of the
scapular spine, with X-ray beam angled 10–15° craniocaudally and centred
on the acromioclavicular joint.

34. This view is taken with the patient turned as for the Y
projection and the cassette perpendicular to the
body of the scapula and parallel to glenoid fossa, with X-
ray beam angled 10–15° craniocaudally and centred on
the acromioclavicular joint.

35. The subacromial space (arrows) and contour of the acromion (A) are
well seen. The water density of the supraspinatus muscle is shown (S).

36. ULTRASONOGRAPHY
 Ultrasonography can be used to assess joint space detect osteophytes or
other bony erosions, although the usefulness of this technique is
dependent on the skill of the technician and is limited to superficial soft
tissue.

37. MRI
 Magnetic resonance imaging is very sensitive in identifying abnormalities
of the AC joint, but these changes often do not correlate with physical
findings.
 In one study of asymptomatic volunteers, findings indicative of AC joint
arthritis were present in 75% of shoulders.
 The nonspecificity of MR imaging precludes it from being useful in the
evaluation of patients with AC joint symptoms.
 But MRI can be helpful in ruling out other causes of shoulder joint pain
which can be concomitantly present with AC joint arthritis.

38. JOINT INJECTION:
 Joint injection can be used both diagnostically and therapeutically.
 A combination of local anaesthetic and corticosteroid is used.
 Technique:
 Palpate the bony landmarks and mark the site of injection.
 Prepare the skin using sterile technique.
 A 23-gauge needle is directed into the joint from a superior approach. The
needle is then slowly advanced perpendicular to the articulation while
palpating for a tactile pop through the capsule.
 The mixture can then be easily injected and noted to flow freely into the
joint

39. Direct injection into the AC joint
through a superior approach.

40. The joint can be injected under sonographic guidance
using this view

41.  Despite the subcutaneous nature of the joint, intraarticular injections can
sometimes be difficult where the accuracy can be improved with the use of
ultrasound guidance.
 Elimination of pain within a few minutes of the injection confirms the AC
joint as the source of the patients symptoms and is considered by many
authors to be the most valuable diagnostic tool.
 Relief after an injection is also considered the most accurate prognostic
indicator of success with distal clavicle resection.

42. THANK YOU