The document discusses the anatomy and function of the acromioclavicular (AC) joint, highlighting its role in shoulder mechanics and susceptibility to injury. It categorizes AC joint injuries into traumatic and overuse types, explaining their causes, symptoms, classifications, diagnosis, and treatment options including physiotherapy. Treatment aims to relieve pain, restore joint range of motion, and strengthen the shoulder's supporting muscles.

1. DR. NIRAJ KUMAR , PT
BPT, MPT MHA & Ph. D (PHYSIOTHERAPY)
ORTHOPEDICS.
ASSOCIATE PROFESSOR PHYSIOTHERAPY
DEPT.
Shri Guru Rai Institute Of Paramedical Sciences
, Dehradun
ACROMIO-CLAVICULAR JOINT INJURY

2. ANATOMY-The Acromioclavicular Joint, or AC Joint, is one of
four joints that compose the Shoulder Complex.
The AC Joint is formed by the junction of the lateral clavicle
and the acromion process of the scapula, and is a gliding, or
plane style synovial joint.
The AC Joint attaches the scapula to the clavicle and serves as
the main articulation that suspends the upper extremity from the
trunk.
ACROMIO-CLAVICULAR JOINT INJURY

4. The primary function of the AC Joint is:
To allow the scapula additional range of rotation on the thorax
Allow for adjustments of the scapula (tipping and internal/external rotation) outside
the initial plane of the scapula in order to follow the changing shape of the thorax as
arm movement occurs.
In addition, the joint allows transmission of forces from the upper extremity to the
clavicle
 The acromioclavicular (AC) joint is stabilized by two sets of ligaments: 1) the
acromioclavicular (AC) ligaments connect the end of the collarbone to the end of
the shoulder blade;
 2) the coracoclavicular (CC) ligaments, connect a bony projection of the shoulder
blade, known as the coracoid process, to the collarbone.

5. The ligaments that hold the joints
together are the
1. Acromio-clavicular liga.
2. Coracoacromial liga.
3. Coracoclavicular (trapezoid and conoid) ligaments.

6.  Acromioclavicular (AC) joint injury is a term used to describe an
injury to the top of the shoulder, where the front of the shoulder
blade (acromion) attaches to the collarbone (clavicle).
 It can be caused by a traumatic event, such as a fall directly on
the outside of the shoulder, or by repetitive overuse.

7. INCIDENCE
 AC joint injuries are most common in individuals younger than 35 years
of age, with males sustaining 5 times more traumatic AC joint injuries
than females.
 Because younger athletes are most likely to participate in high-risk and
collision activities, such as football, biking, snow sports, hockey, and
rugby traumatic AC joint injuries occur most often in this population.

8. What Are Acromioclavicular (AC) Joint Injuries?
• There are 4 ligaments holding the 2 bones of the AC joint
(the acromion and the clavicle) together.
• When an AC joint injury occurs, these ligaments are
stressed, resulting in some degree of joint separation.
• There are 2 types of injuries that can occur at the AC joint:
traumatic and overuse injuries.

9. • A traumatic AC joint injury occurs when there is a disruption of the joint
due to damaged ligaments holding the 2 bones of the joint together.
• This injury is called a shoulder separation (in contrast to a shoulder
dislocation, it involves the ball-and-socket joint of the shoulder).
Traumatic AC joint injuries are most common in individuals who
sustain a fall and land on the outside of the shoulder or onto a
hand (eg, a football player who is tackled, a bicyclist who
crashes, or a manual laborer who falls off a ladder.

10.  Traumatic AC joint injuries are graded from mild to severe based on
the amount of separation of the joint.
Treatment of mild cases likely will be provided by a physical therapist;
more severe cases may require surgery followed by physical therapy.
• An overuse AC joint injury occurs over time as repeated, excessive stress is placed
on the joint. Cartilage at the ends of the acromion and clavicle bones protects the
joint from daily wear and tear.
Over time, the demand placed on this cartilage may be more than it is capable of
enduring, resulting in an overuse injury.

11. Overuse AC joint injury is most common in individuals who
perform tasks, such as heavy weight lifting (bench and
military presses), or jobs that require physical labor with
the arms stretched over the head.

12. CLINICAL FEATURES
 General shoulder pain and swelling
 Swelling and tenderness over the AC joint
 Loss of shoulder strength
 A visible bump above the shoulder
 Pain when lying on the involved side
 Loss of shoulder motion
 A popping sound or catching sensation with movement of the shoulder
 Discomfort with daily activities that stress the AC joint, like lifting objects
overhead, reaching across your body, or carrying heavy objects at your
side

13. AC Joint Classifications
1. AC joint dislocation: Tossy Classification
2. AC joint injury: Allman classification
3. AC joint injury: Rockwood classification
AC joint dislocation: Tossy Classification
Tossy et al, CORR, 28: 111-119, 1963
Grade 1: strain and contusions of AC joint; No deformity visible clinically or on x-ray
• Grade 2: localised pain, swelling and deformity; X-rays show one-half separation of the AC joint, ie
clavicle displaced cephalad by one-half the depth of the AC joint; Coraco-clavicular distance increased
as compared to normal side; Partial tear of Coraco-clavicular ligaments
Grade 3- complete AC joint seperation more than one-half the depth of the AC joint; clavicle under skin;
Coraco-clavicular distance significantly increased; complete tear of coraco-clavicular ligaments

14. AC joint injury: Allman classification
Allman F L, JBJS (am) 49:774-784, 1967
Grade 1:
Sprain of AC joint capsule and AC ligament
No deformity
Xrays normal
Grade 2:
Rupture of AC capsule and ligaments
Mild deformity
Xrays show upward displacement of clavicle
Coraco-clavicular (C-C) ligaments normal
Grade 3:
Complete AC joint dislocation
Complete rupture of AC and C-C ligament

15. AC joint injury: Rockwood classification
Type 1:
AC ligament sprain
AC joint intact, CC ligaments intact
Deltoid, Trapezius intact

16. Type 1:
AC ligament sprain
AC joint intact, CC ligaments intact
Deltoid, Trapezius intact
Type 2:
AC Joint disruption
Slight vertical separation of ACJ
CC ligament sprain, CC distance wide
Deltoid, Trapezius intact

17. Type 2:
AC Joint disruption
Slight vertical separation of ACJ
CC ligament sprain, CC distance wide
Deltoid, Trapezius intact
Type 3:
AC ligament disruption
AC joint dislocated
CC ligaments torn
CC distance 25 to 100 % > than normal side
Deltoid, Trapezius may be detached

18. Type 4:
AC ligament disruption
AC joint dislocated
Clavicle displaced posteriorly into Trapezius
CC ligaments completely torn
Deltoid, Trapezius detached from distal clavicle

19. Type 4:
AC ligament disruption
AC joint dislocated
Clavicle displaced posteriorly into Trapezius
CC ligaments completely torn
Deltoid, Trapezius detached from distal clavicle
Type 5:
AC ligament disruption
AC joint dislocated
CC ligaments completely torn
CC distance 100 to 300 % > than normal side
Deltoid, Trapezius detached from distal half clavicle

20. Type 6:
AC ligament disruption
AC joint dislocated
CC ligaments completely torn
Clavicle in subcoracoid position
Deltoid, Trapezius detached from distal half clavicle

21. DIAGNOSIS
Diagnosis of an AC joint injury starts with a thorough review of the patient’s medical
history, including specific questions regarding when the pain began, and what
aggravates and relieves the pain.
.
 physical therapist will examine PT shoulder and assess different measures, such
as sensation, motion, strength, flexibility, tenderness, and swelling.
While an AC joint injury can usually be identified through a shoulder examination,
diagnostic imaging, such as ultrasound, x-ray, or
MRI is often used to confirm the diagnosis and
determine the severity of the injury.

22. Physiotherapy Treatment
Most patients with acromioclavicular joint injury start to feel better within a few days or a
week of the injury. However, full ligament healing will take at least six weeks. During this
time it is important to protect your AC joint ligaments from overstretching the immature
scar tissue. It can be helpful to use a sling, taping or a shoulder brace that de-loads your
AC joint.
Goal of physiotherapist's treatment,
Reduce pain and inflammation.
Normalise joint range of motion.
Strengthen shoulder.
Improve your shoulder blade and shoulder alignment.
Normalise muscle lengths.
Improve upper limb proprioception.
Improve your technique and function eg lifting, overhead activities.

23. Pain Management.
1. Application of ice and heat to aid in pain management.
Manual Therapy. therapists are trained in manual (hands-on) therapy.
If needed, your physical therapist will gently move and mobilize your
shoulder joint and surrounding muscles as needed to improve their
motion, flexibility, and strength.

24. Range of Motion. An injury to the AC joint, whether traumatic or overuse, causes the joint
to be irritated, often resulting in swelling and stiffness, causing loss of normal motion.
Motions that are usually most difficult after an AC joint injury are reaching across your
body and lifting your arm directly overhead. While it is important to regain your normal
shoulder motion, it is also important to allow your injury to heal without placing excessive
stress on the healing joint. Your physical therapist will assess your motion and the
degree of your injury, and establish a plan that will balance joint protection and motion
restoration.
Strength Training. After an injury, the surrounding muscles demonstrate weakness. All of
the muscles near the shoulder and elbow as well as those of the upper back, work
together to allow for normal, coordinated upper-body motion. Therefore, balancing the
strength of all the upper-body muscles is crucial to making sure the shoulder joint is
protected and moves efficiently. Your physical therapist will design an individualized
exercise program to strengthen the muscles at and around the shoulder, so that each
muscle is able to properly perform its job.

25. THANKS