Joints and pain
Shoulder Impingement and Rotator Cuff Problems
In short
Shoulder impingement (subacromial pain syndrome) is pain arising from the rotator cuff tendons and the bursa above them, typically felt when lifting the arm, and it is closely linked to rotator cuff tendinitis and tears. Most people improve within a few months with activity changes, pain relief and a structured exercise programme, sometimes with a steroid injection. Current evidence does not support subacromial decompression surgery for impingement alone, while repair may be considered for some rotator cuff tears.
What is shoulder impingement?
The rotator cuff is a group of four muscles and tendons that wrap around the head of the upper arm bone. It lifts and rotates the arm and keeps the ball of the joint centred in its socket [2].
This type of shoulder pain can come from three related problems: inflammation of the tendons (tendinitis), inflammation of the lubricating sac above them (bursitis), or impingement. In impingement, the gap between the bony tip of the shoulder (the acromion) and the tendons narrows when the arm is raised, and the tendons become irritated [1]. Recent guidelines also call this condition subacromial pain syndrome or rotator cuff disease [4].
Over time the tendons can wear, and partial or full-thickness tears may develop. A tear can happen suddenly after a fall or a heavy lift, but more often it develops slowly through age-related wear [2].
What are the symptoms?
A sudden tear after an injury usually causes intense pain and immediate weakness in the arm. A wear-related tear, by contrast, can be fairly painless at first and develops slowly, which is why long-lasting shoulder pain and weakness deserve assessment [2].
Symptoms usually start mildly and may build up over time [1][2]:
- Pain at the front and outer side of the shoulder, sometimes spreading down the side of the arm
- Pain when lifting the arm above shoulder height or reaching
- Night pain, especially when lying on the affected shoulder
- Weakness and difficulty with dressing, washing hair or reaching behind the back
- A crackling feeling in the shoulder with certain movements
Causes and risk factors
Impingement and rotator cuff problems usually develop from a combination of repeated strain and age-related changes. They may follow a minor injury or start without an obvious cause [1][2]. The main risk factors are:
- Overhead sports such as swimming, volleyball, tennis and baseball [1][2]
- Jobs involving overhead work or repeated lifting, such as construction, painting and carpentry [1][2]
- Age over 40, as the blood supply to the tendons decreases with age [2]
- The dominant arm, where these problems are more common [2]
How is it diagnosed?
The doctor examines the range of movement and the strength of the shoulder; which movements bring on the pain helps guide the diagnosis [1].
An X-ray can show a bone spur under the acromion and helps rule out other causes. MRI or ultrasound shows the condition of the tendons and whether there is a tear, where it is and how large it is [1][2].
Treatment
Non-surgical treatment is the foundation. Rather than keeping the painful shoulder completely still, it is advised to keep using it gently while cutting back on the movements that make it worse [1][3]. The main options are:
- Rest and activity changes, especially reducing overhead movements for a while [1]
- Anti-inflammatory painkillers [1][2]
- Physiotherapy and exercise: stretching and strengthening exercises are central to treatment, and continuing them for 6 to 8 weeks helps stop the pain coming back [1][3]
- A steroid injection into the bursa when other measures have not given enough relief [1]
Is surgery needed?
In the past, impingement that did not respond to non-surgical care was often treated with subacromial decompression, a keyhole operation that removes the bone spur and the inflamed bursa [1]. However, a Cochrane review including trials against placebo (sham) surgery found that this operation gives no clinically important extra benefit for pain, function or quality of life [5]. Based on this evidence, an international guideline makes a strong recommendation against decompression surgery for subacromial pain lasting more than 3 months [4].
Rotator cuff tears are a different matter. Repair of the tear may be considered when pain lasts 6 to 12 months despite proper treatment, for large tears, for a recent tear after an injury with marked weakness, or in active people who rely on overhead use of the arm [2].
Recovery
With impingement and tendinitis, full pain relief usually takes 2 to 4 months, but in some people it can take up to a year [1]. Shoulder pain may take six months or longer to settle, and it is important to keep moving the shoulder gently and continue the exercises during this time [3].
When the exercise programme is kept up, the shoulder muscles become stronger and daily activities get easier. A return to demanding work or sport should be gradual and guided by pain and strength [1][3].
When to see a doctor urgently
See a doctor if the pain does not improve within two weeks, keeps getting worse, or makes it very hard to move the shoulder. Urgent assessment is needed in the following situations [3]:
- Sudden or very severe shoulder pain
- Being unable to move the arm
- A change in the shape of the shoulder or marked swelling
- Pins and needles or numbness in the arm, or the arm feeling hot or cold
- Pain or inability to lift the arm after a fall or injury
- Pain in both shoulders at once, or shoulder pain with a fever
Frequently asked questions
+What is the difference between shoulder impingement and a rotator cuff tear?
In impingement the tendons and the sac above them are irritated, but the tendon is intact. In a tear, part or all of the tendon has come apart, either suddenly after an injury or gradually through wear [1][2].
+Can shoulder impingement heal without surgery?
In most people, yes. With activity changes, pain relief and regular exercise, the pain usually eases within a few months. Research shows that decompression surgery for impingement alone gives no meaningful extra benefit compared with placebo surgery [1][4][5].
+Why does my shoulder hurt more at night?
Night pain is a typical sign of rotator cuff problems and is often worse when lying on the painful shoulder [1][2].
+Is a steroid injection used for shoulder impingement?
If rest, medicines and physiotherapy have not given enough relief, a steroid injection into the bursa may be offered. It is meant to support the exercise programme, not replace it [1].
+Does every rotator cuff tear need surgery?
No. Many tears can be managed without surgery. Surgery is considered for long-lasting pain, large tears or marked weakness after an injury [2].
Sources
- [1]Shoulder Impingement/Rotator Cuff Tendinitis — American Academy of Orthopaedic Surgeons (OrthoInfo), 2024.
- [2]Rotator Cuff Tears — American Academy of Orthopaedic Surgeons (OrthoInfo).
- [3]Shoulder pain — NHS (nhs.uk), 2023.
- [4]Subacromial decompression surgery for adults with shoulder pain: a clinical practice guideline — BMJ (Vandvik PO, et al.), 2019.
- [5]Subacromial decompression surgery for rotator cuff disease — Cochrane Database of Systematic Reviews (Karjalainen TV, et al.), 2019.
This article is general information and does not replace an examination or personal medical advice. In an emergency, go to the nearest emergency department.