Shoulder Impingement Syndrome

The name is misleading. Modern terminology has moved toward subacromial pain syndrome or rotator cuff-related shoulder pain, because the older mechanical model of the acromion pinching the cuff does not match what the evidence shows. Imaging studies find so-called hooked acromions in plenty of pain-free shoulders, and the CSAW trial (Beard et al., Lancet 2018) found that shaving the underside of the acromion produced no meaningful benefit over placebo surgery. What I see clinically is a loading problem: cuff capacity does not match the demands being placed on it, often alongside scapular control issues and sensitisation. That reframing changes treatment from 'making more space' to 'building more capacity'.

Rarely. For uncomplicated subacromial shoulder pain without red flags or traumatic onset, MRI usually adds cost and anxiety without changing the plan. Imaging finds rotator cuff abnormalities in plenty of pain-free shoulders, especially past age 50, so a finding on the scan does not automatically explain your pain. I reserve imaging for shoulders not responding to 6 to 12 weeks of appropriate loading, suspected full-thickness traumatic tears, or when a specific clinical question would genuinely change management.

Most people notice meaningful change in 6 to 12 weeks of consistent loading, with further gains over 3 to 6 months. The biggest predictor of slower recovery I see is symptom duration before starting care, which matches Chester and colleagues (BJSM 2018, 1030 patients) who found longer symptom duration, higher baseline pain, and lower pain self-efficacy consistently predicted worse outcomes at 6 weeks and 6 months. Psychological factors were more strongly associated with outcome than any specific structural finding. Early structured loading beats waiting it out.

Lying on the affected side compresses the cuff and bursa, the shoulder loses the gravitational unloading it had during the day, and a sensitised tendon is more easily provoked by sustained positions. Most patients do better on the unaffected side with the sore arm supported forward on a pillow, or on their back with a small towel roll behind the scapula. Night pain usually settles meaningfully within a few weeks of appropriate loading, though it rarely disappears overnight.

It has a role, but a narrow one. The higher-quality evidence shows subacromial corticosteroid injection provides short-term pain relief over the first 6 to 8 weeks with no long-term advantage over exercise alone. I consider it when pain is so high that someone cannot engage with loading, or when sleep disturbance has pushed them into a flare-up cycle. It buys a window. It does not fix the underlying capacity problem, and repeated injections are not benign.

Surgery is not the next step after a slow month of rehab. The CSAW trial (Beard et al., Lancet 2018) randomised 313 patients with at least 3 months of subacromial pain who had already failed non-operative management including exercise and at least one steroid injection. Arthroscopic subacromial decompression produced no clinically important benefit over placebo surgery at 6 months. The 2022 JOSPT clinical practice guideline on rotator cuff disorders (Lafrance et al.) recommends against subacromial decompression for rotator cuff tendinopathy. My threshold for a surgical referral conversation is a shoulder that has genuinely plateaued on well-delivered loading over several months, not weeks.

Usually yes, with modifications. Complete rest tends to backfire. Early on I cut the movements that flare you (often overhead pressing, upright rows, behind-the-neck work) and keep loaded work below shoulder height with rotator cuff isometrics and scapular work layered in. As symptoms settle, overhead loading comes back in progressively. People who keep training modified almost always recover faster than those who stop everything for a month and try to jump back to their previous programme.

Less than most people assume, but not nothing. Cross-sectional studies have not shown a strong link between a specific resting posture and shoulder pain, so I do not spend much clinic time straightening people into an idealised upright position. What does matter is positional variety and cuff capacity: getting out of sustained end-range postures, moving regularly, and having enough strength to tolerate the positions your day requires.