Shoulder impingement

Your shoulder is made of three bones; these are your: 

• Collarbone (clavicle)
• Shoulder blade (scapula)
• Upper arm bone (humerus)

A band of muscle and tendon called your rotator cuff holds your arm securely in your shoulder socket. It covers the head of your humerus and attaches it to your scapula. There are fluid-filled sacs (bursae) that provide a cushion between your rotator cuff and the top part of your scapula (the acromion). The bursae allow your rotator cuff to move smoothly when you move your arm.

Shoulder impingement occurs when the space between your acromion and rotator cuff narrows. The acromion then rubs against (impinges on) the tendon of your rotator cuff and the bursae. It is a common cause of shoulder pain and it gets worse when you lift your arm or shoulder.

It can also be described as:

• Impingement syndrome
• Painful arc syndrome
• Rotator cuff tendonitis
• Subacromial impingement
• Swimmer’s shoulder

It’s common in young athletes as well as middle-aged people who use their arms overhead or are involved in repetitive lifting and suffer a rotator cuff injury.

Shoulder impingement can happen without warning or begin gradually.

If you have shoulder impingement you may feel:

• Pain at the top and on the outside of your shoulder
• Pain or aching at night
• Pain or weakness when throwing a ball or placing your arm behind your back
• Sudden pain when your arm is raised, especially above your head
• Swelling and tenderness at the front of your shoulder

Symptoms can develop gradually and be mild to start, including: 

• Minor pain with activity and at rest
• Pain radiating from the front of your shoulder to the side of your arm
• Sudden pain when lifting and reaching — if you play sports eg tennis you may feel pain when throwing or serving a tennis ball

As shoulder impingement worsens, your symptoms will too. You may experience: 

• Difficulty performing activities that involve moving your arm behind your back eg buttoning or zipping up
• Loss of strength and range of movement
• Pain at night

Severe tenderness of your shoulder can cause sudden pain. Eventually, all of your shoulder movements may become painful and restricted

However, if your shoulder is stiff you're more likely to have a different condition known as frozen shoulder.

Make an appointment to see your doctor or a physiotherapist if your shoulder pain lasts more than a few weeks or is affecting your everyday life.

It usually takes three to six months for a full recovery. However, in more severe cases, it can take up to a year. In most cases, you can begin returning to your everyday activities after two to four weeks.

Your doctor may ask you lots of questions about the nature of your pain eg:

• The impact the pain is having on your everyday activities
• When it started
• Where the pain is
• Whether you’ve injured yourself

They will carry out a thorough physical examination and may also ask you to carry out certain movements with your arms, hands and shoulders. This will help them determine what kind of shoulder impingement you have based on criteria including:

• The location of your shoulder impingement ie on the joint side of the rotator cuff (articular sided impingement) or on the outer side of the rotator cuff (bursal impingement)
• The structures involved — this refers to different areas of your shoulder joint eg coracoacromial arch, internal, subacromial or subcoracoid
• The underlying cause ie primary (due to narrowing of the space between your acromion and rotator cuff) or secondary (due to other causes eg muscles imbalances or poor posture)

In some cases, your doctor may suggest further tests including:

• • An X-ray
  • Blood tests — if the doctor has a concern that there are signs of another health concern such as a fever, other joint pains, recent respiratory problems or weight loss 
  • MRI scan
  • Ultrasound scan

Causes of shoulder impingement include:

• Age-related wear and tear 
• An irregular or misshapen acromion — this can reduce the space needed by the rotator cuff tendon, causing pinching or trapping of the tendon when your arm is raised
• Bony growths (spurs) on the acromion — these can develop as you get older
• Bursitis — the bursae between the rotator cuff tendon and the acromion become irritated and inflamed because of an injury or through overuse of your shoulder
• Injury eg falling onto your hand or elbow
• Overuse eg repetitive use of the arms overhead

Treatments for shoulder impingement will vary depending on how serious it is.

Treatments for less serious shoulder impingement

Home care 

Avoid things that cause your pain for a few days or weeks eg anything that involves repeatedly lifting your arms above your head, such as swimming or tennis. This is called activity modification. 

Before you resume these particular activities, get advice from your GP or physiotherapist. However, do not stop moving your arm altogether and avoid wearing a sling. Try to complete your usual daily activities as much as you can to prevent your shoulder from becoming stiff and weak.

You can also try applying ice packs (or a bag of frozen peas wrapped in a tea towel) for up to 20 minutes several times a day. This will help reduce your pain and any swelling. 

Anti-inflammatory painkillers

A common over-the-counter anti-inflammatory painkiller you can try is ibuprofen. If needed, your doctor can prescribe stronger anti-inflammatories.

Steroid injections 

If rest and exercises don't help on their own, your doctor may also recommend steroid injections. However, the effects only last a few weeks; if you stop your exercises after this time, your pain can come back. 

You can only have two rounds of steroid injections. More steroid injections can damage the tendon in your shoulder and cause other side effects eg permanent dimpling or lightening of your skin. 

Physiotherapy 

A physiotherapist can advise you about simple shoulder exercises for shoulder impingement. These exercises will: 

• Improve your pain 
• Improve your range of movement
• Improve your shoulder posture 
• Strengthen your shoulder muscles

You may need to practice these exercises with a physiotherapist first before you do them at home. You will need to do these exercises regularly to see an improvement in your shoulder impingement. Your physiotherapist will usually suggest you do them for around six weeks.

If these exercises worsen your pain or your pain doesn't improve after a few weeks, see your GP or physiotherapist.

Treatments for more serious shoulder impingement

You will usually need surgery. There are two main types of surgery:

Shoulder arthroscopy

This keyhole surgery is used to widen the space around the rotator cuff tendon by removing some of the bony growth (spur) rubbing against it.

It is carried out under general anaesthetic. You don't usually need to stay in hospital and can go home on the same day of your surgery. 

In most cases, the recovery time from surgery is usually three to six months but your consultant can give you more specific guidance about getting back to normal.

Subacromial decompression surgery

This keyhole surgery is usually only considered if other treatments haven't worked as it isn't clear how much it helps. It involves widening the space around the rotator cuff tendon to help stop it from catching or rubbing against anything.

As with shoulder arthroscopy, it is also carried out under general anaesthetic and you can usually go home on the same day.