What is AC Arthritis? 


Shoulder pain has become the third most common cause with an estimated 25% of people getting affected due to it. It is a frequent problem in elderly people. 


Acromioclavicular (AC) joint arthritis is the damage to the joint that causes inflammation. The AC joint is joined to the shoulder blade(scapula) and the collarbone(clavicle) by ligaments and cartilage. The cartilage between the bones helps in guiding joint movement. 

As the cartilage wears out due to damage it becomes frayed and rough causing the protective space between the bones to decrease. This causes pain and swelling in the shoulder and also limits the shoulder’s ability to perform motions. 


What causes AC Arthritis


  • Gradual wear and tear of the cartilage. Over a period of time, the outer cartilage wears out causing the bones to rub against each other
  • Injury to the AC joint. A fracture or shoulder displacement leads to the bones not aligning correctly. This further leads to the bones scraping against each other
  • Constant overhead motions for an extended period 
  • Degeneration of the AC joint due to old age
  • Genetics may also influence the breaking down of the cartilage to a certain extent 
  • Minor damage to the cartilage can worsen over a period of time and can later lead to AC arthritis
  • Weak muscles that are unable to support the bones result in stress to the joint


There is no one particular cause that can be singled out which leads to AC arthritis however these are the plausible causes. 


Symptoms of AC Arthritis


The symptoms of arthritis develop slowly and worsen over time. Some common symptoms are:


  • Pain in the top of the shoulder spreads to the side of the neck.
  • Clicking sound when the shoulder is moved 
  • Pain during lifting heavy objects 
  • Limiting the range of motion 
  • Sleeping on the affected side may worsen the pain 
  • Compression of the joints, such as bringing the arm across the chest may aggravate pain
  • Friction between joints can lead to bone spurs. Bone spurs indicate that the bone is trying to grow new tissue and heal itself
  • Bone spurs may lead to deformity in the shoulder which can be physically seen
  • Swelling and soreness in the affected area


As the problem develops, any movement performed by the shoulder will cause pain. 

Many patients suffering from AC arthritis have also shown symptoms in other joints.


Diagnosis of AC Arthritis


To avoid persistent shoulder pain, an accurate diagnosis needs to be made. 

The doctor will inquire about past medical history and carry out a physical examination.


During the physical examination, the doctor will inspect for:


  • Weakness in the muscles near the AC joint
  • Tenderness and soreness in the top part of the shoulder
  • Range of motion in the shoulder
  • Injuries to the muscles, tendons, and cartilages around the joint 
  • Crepitus (scraping sensation inside the joint) with every movement 
  • Pain when pressure is put on the joint 

The doctor will also look for other joint problems in the body.


X-ray is the next step after physical examination to understand the severity of the problem. This will help in understanding the narrowing of the joint space, changes in the bone structure, and the formation of bone spurs if any.


MRIs help in providing a detailed look at the cartilages, ligaments, and tendons as well as the bone.

To confirm the diagnosis, the doctor may choose to inject a local anaesthetic into the joint. If the pain is relieved temporarily, AC arthritis is confirmed. 


Treatment for AC Arthritis 


The initial treatment after diagnosing AC arthritis is nonsurgical. This includes:


  • Ample rest is advised. Any activities that may aggravate the pain in the shoulder should be avoided
  • Applying an ice pack on the shoulder twice a day will help in minimizing the inflammation and ease pain
  • Nonsteroidal anti-inflammatory medications as prescribed by the doctor will help in reducing the inflammation and pain
  • Physical therapy based on the level of pain and functional limitations should be done. This helps in restoring strength and stability to the shoulder and will also restore ROM


If conservative methods fail in relieving the pain, surgical methods will be advised by the doctor.

 Distal clavicle excision (DCE) also known as the “Mumford” procedure aims at creating a gap between the clavicle and the acromion. This is achieved by resecting the bone from the distal end of the clavicle without compromising the joint stability. 


Any treatment plan should take into consideration the patient’s health circumstances and lifestyle