Back Pain Doctor
AC Joint Injury
Written by Dr Joshua Hatch, Musculoskeletal GP, RACGP Fellow, Diploma in Musculoskeletal Medicine (FSEM UK).
The AC joint sits where the collarbone meets the highest point of the shoulder blade. A direct blow to the point of the shoulder can sprain the acromioclavicular and coracoclavicular ligaments, producing anything from a painful but stable joint to a more obvious separation.
Assessment checks the exact site of pain, deformity, collarbone and shoulder movement, strength, and whether there may also be a fracture, glenohumeral injury or rotator-cuff problem. A visibly displaced joint after trauma should be assessed promptly so the injury can be graded and the treatment options discussed accurately.
Most AC joint injuries start without surgery
Early treatment usually uses a sling briefly for comfort, pain control and progressive return of shoulder movement, followed by strengthening of the shoulder blade and rotator cuff. Contact, heavy pressing and overhead work are reintroduced according to function and the demands of the sport or job.
Lower-grade injuries are generally managed non-surgically. Higher-grade and persistent unstable injuries need an individual decision because radiographic alignment, symptoms and function do not always point in the same direction. The current review of AC joint injury management describes both non-operative and operative pathways; an early shoulder-surgeon opinion is arranged when the injury pattern or functional demands warrant it.
A residual bump can remain after non-surgical care. That does not mean treatment has failed. What matters is a comfortable, stable shoulder that can handle the required work and sport.
An AC joint injury is not the same as a dislocation of the main shoulder joint, where the ball comes out of the socket. That has its own guide: shoulder dislocation and instability.
Common symptoms
- Pain and tenderness directly on top of the shoulder
- Pain bringing the arm across the body or lifting overhead
- Swelling, bruising or a visible step at the AC joint
- Pain lying on the injured side or carrying a bag
Commonly seen in
Evidence for twelve treatment options in ac joint injury
This is not a fixed ladder or a package of treatments. Every option is assessed independently against this diagnosis, including treatments with limited direct research that may still be reasonable for a clearly defined tissue target. The evidence level, likely benefit, risks, cost and alternatives are weighed at consultation.
Foundation: diagnosis, education and rehabilitation
The part of care with the broadest relevance. For many people it is enough on its own; other options are judged against it, not automatically added after it.
Diagnosis, education and progressive rehabilitation Working out what is driving the pain, explaining what your imaging does and does not mean, and building a graded loading plan you can actually follow. Core care
What it involves
Assessment to identify the likely pain source, an explanation of what the diagnosis means, adjustment of the loads that aggravate it, and a progressive strength and conditioning plan, with weight management where that is clinically relevant.
What the evidence shows
Move it, within reason, rather than rest it. Pooling 22 studies, functional treatment beat immobilisation on return to sport, return to work, swelling, range of motion and patient satisfaction (Kerkhoffs, Arch Orthop Trauma Surg 2001). An overview of 46 systematic reviews found strong evidence for early mobilisation and moderate evidence for exercise (Doherty, Br J Sports Med 2016), and the international guideline prefers supervised exercise over passive modalities, reserving surgery for those who do not respond (Vuurberg, Br J Sports Med 2018). Exercise-based rehabilitation roughly halves the odds of doing it again within twelve months (Wagemans, PLoS One 2022). One caveat: in 503 patients with simple grade 1 to 2 ankle sprains, adding supervised physiotherapy to good advice produced no clinically important benefit (Brison, BMJ 2016).
Pairing reviewed 2026-09-02.
Where it fits
For a straightforward sprain or strain, clear advice and a graded return are usually enough, and you do not need to buy a course of anything. Supervised rehabilitation earns its place where the injury is more severe, where it keeps recurring, or where the demands you are returning to are high.
Muscle and symptom-modifying options
Useful only when the examination identifies the tissue they target or when short-term pain control creates a useful rehabilitation window.
Wet needling and trigger point injection (trigger point injection) A fine needle into a tender band of muscle, with a small volume of dilute glucose solution injected through it. Only if relevant
What it involves
The needle is placed into the tender muscle band and a small volume of 5% glucose with a very dilute local anaesthetic (0.02-0.08%) is injected. Often done in the same visit as your assessment, and usable where the tender area sits deeper. Dry needling (the same technique with nothing injected) is not offered here.
What the evidence shows
Trigger-point injection reviews address confirmed myofascial pain and find heterogeneous, generally low-certainty results; they do not establish the technique as treatment for the underlying diagnosis. Condition reviewed: AC joint injury.
Evidence source: Debrosse et al., trigger-point injection systematic review (2022)
Pairing reviewed 2026-08-30.
Where it fits
For AC joint injury, this may be considered only when examination finds a separate tender muscle band reproducing part of the pain. It does not treat the primary pathology and is used to help movement or rehabilitation.
Ultrasound-guided injections Guidance means the needle can be seen reaching the target. What goes into the needle depends on the diagnosis. Good support
What it involves
The injection is performed under ultrasound so the needle can be watched into the target structure. What is injected is decided by the diagnosis, and corticosteroid is used sparingly, for the reasons set out below.
What the evidence shows
Ultrasound raised accuracy of acromioclavicular joint injection from 68.2% to 93.6% (Aly, Br J Sports Med 2014). The joint is small and the landmarks are unreliable.
Pairing reviewed 2026-08-30.
Where it fits
Where an injection is indicated for a painful AC joint, guidance is worth the extra step.
V-ACTOR vibration therapy (vibration therapy) Low-frequency vibration applied over tender muscle. Not a shockwave, despite sharing the machine. Plausible: no studies
What it involves
A vibration handpiece is moved over the tender muscle and fascia for a few minutes. It runs from the same STORZ MASTERPULS icon console as radial shockwave but is a separate handpiece delivering a different, gentler form of energy. No needles, no anaesthetic, no downtime.
What the evidence shows
No published clinical trial of this device in this condition. It is a vibration handpiece delivered from the same console as radial shockwave, and the rationale is myofascial rather than tendon- or bone-directed.
Pairing reviewed 2026-08-30.
Where it fits
A comfort measure used within a session where muscular tightness is limiting movement. Never the reason for the appointment, and not a substitute for the treatments that do have evidence.
Energy-based treatment options
Radial pressure wave, focused shockwave and EMTT have different targets and different evidence. They are assessed separately rather than treated as one category.
Radial or focused shockwave? Read the overviewRadial shockwave (radial pressure wave) Broad treatment across tender muscle and fascia, close to the surface. Only if relevant
What it involves
A handpiece is moved over the tender tissue while ballistic pressure pulses are delivered, using a transmitter head chosen for the tissue, including heads shaped for fascia and for the muscle either side of the spine. The pulse is strongest at the skin and weakens with depth, so this is mainly a myofascial treatment, though it can reach deeper in some areas. No anaesthetic, no downtime, usually a course of sessions about a week apart.
What the evidence shows
No study has tested shockwave, radial or focused, in an acromioclavicular (AC) joint injury. A PubMed search for shockwave with acromioclavicular and other ligament terms (15 records, all read) returned only reviews of shoulder pain that mention the AC joint, and a second search pairing acromioclavicular with shockwave or extracorporeal (11 records) found no treatment study.
Pairing reviewed 2026-10-23.
Where it fits
Not part of early management. Considered only once pain persists well beyond the expected healing time, and then for the tender muscle and fascia around the shoulder rather than the injured joint.
Focused shockwave (ESWT) A true shock wave converging at depth: for tendon, joint, ligament and bone. Only if relevant
What it involves
A focused system generates an acoustic shock wave that converges at a focal point set at a defined depth, concentrating the energy where the target is. This is the form used for tendon, joint, ligament and bone. Typically four to six sessions about a week apart, no anaesthetic and no formal downtime.
What the evidence shows
No study has tested shockwave in an acromioclavicular (AC) joint injury. A PubMed search for shockwave with acromioclavicular and other ligament terms (15 records, all read) returned only reviews of shoulder pain that mention the AC joint, and a second search pairing acromioclavicular with shockwave or extracorporeal (11 records) found no treatment study. A trial and systematic-review pass over shockwave in ligament injuries (17 records) found none at this joint.
Pairing reviewed 2026-10-23.
Where it fits
Not part of early management, which is a sling for comfort, then movement and strengthening. It may become a question only for persistent pain in the surrounding muscle, and then without evidence in this injury.
EMTT (magnetotransduction therapy) High-energy magnetic pulses applied over the area. Usually painless, no contact. Plausible: no studies
What it involves
You sit with the applicator positioned over the area for a short session. It is usually painless and needs no gel or skin contact. It is usually given as a course, commonly alongside shockwave.
What the evidence shows
There are no published randomised trials of EMTT in this condition, or in any musculoskeletal condition, that could be identified. The supporting work is laboratory work: EMTT increased tenocyte proliferation, migration and collagen expression in cultured human tendon cells (Mancini, Int J Mol Sci 2025). The nearest human evidence for a related electromagnetic therapy is negative. A randomised trial of pulsed electromagnetic field therapy added to eccentric exercise for Achilles tendinopathy found no improvement in outcome scores or tendon neovascularity over eccentric exercise alone (Ko, Orthop J Sports Med 2024).
Pairing reviewed 2026-08-30.
Where it fits
Offered only as an adjunct alongside treatment that does have evidence, never as the plan itself, and only after that gap is explained. Much of the EMTT literature is manufacturer-affiliated, which is part of why it is described this way.
Biologic and joint injection options
Each injection is assessed independently for the named diagnosis. Cost, uncertainty, likely benefit, risks and alternatives are part of the decision.
Platelet-rich plasma (PRP) Your own blood, concentrated and injected under ultrasound guidance. Plausible: no studies
What it involves
Blood is taken from your arm, spun to concentrate the platelets, and injected into the target under ultrasound guidance in the same appointment.
What the evidence shows
A PubMed search for platelet-rich plasma in the acromioclavicular joint returns eight records and no controlled trial in AC joint injury. The nearest published human report is a single case of refractory distal clavicular osteolysis settled with an ultrasound-guided PRP injection, whose authors note that no efficacy studies exist for that indication either (Kim, Clin J Sport Med 2024). Where AC joint arthrosis has been measured as a variable rather than a target, it predicted a worse response to PRP elsewhere in the shoulder (Berna-Mestre, AJR Am J Roentgenol 2020).
Pairing reviewed 2026-09-02.
Where it fits
Rarely relevant. Most AC joint sprains settle with load management and a graded return, and the position on PRP here is that nobody has tested it.
Prolotherapy (dextrose) A course of dextrose injections into and around the structure and its attachments. Only if relevant
What it involves
Hypertonic dextrose is injected at the tender ligament and tendon attachments, and into the joint where relevant, usually as a series of treatments a few weeks apart.
What the evidence shows
No study has tested prolotherapy in an acute AC joint sprain or separation. The one prospective study injected 15% dextrose around the acromial enthesis and AC joint capsule in 31 people with chronic AC joint arthropathy and acromial enthesopathy, and reported substantial pain reduction in 20 of them with no adverse effects, but it had no control group and a mean follow-up of only 62 days (Hsieh, J Ultrasound Med 2018).
Pairing reviewed 2026-09-05.
Where it fits
Not used for the acute injury, where the joint needs time and graded loading. Considered only for AC joint pain that is still there months later, and offered as an option with weak uncontrolled evidence behind it.
Viscosupplementation (hyaluronic acid) A gel-like injection into an arthritic joint. Widely used, and genuinely contested. Not used here
What it involves
One or a short series of hyaluronic acid injections into the joint under ultrasound guidance.
What the evidence shows
A search for hyaluronic acid trials in the acromioclavicular joint returned no randomised trial in either acute injury or arthritis of that joint, only reviews listing the injection as a technique. The one prospective study that reported on it, 80 shoulders given five weekly subacromial injections, found the subgroup with acromioclavicular arthritis got worse on every scale measured while other diagnoses improved (Jimenez, Acta Ortop Mex 2018).
Pairing reviewed 2026-09-07.
Where it fits
Not offered for this problem. An acute AC joint injury is managed with a sling and relative rest, then a return to loading.
Nerve-targeted options
Relevant when examination identifies a superficial neuropathic pattern or a compressed peripheral nerve, not simply because pain is present.
Lyftogt perineural therapy (perineural injection therapy) A series of small dilute dextrose injections just under the skin, over tender superficial nerves. Dextrose tested into the joint, not the nerve
What it involves
Small injections of low-concentration dextrose, usually 5%, placed just beneath the skin along tender superficial nerves. Given as a series of short sessions.
What the evidence shows
No study of perineural injection after an acromioclavicular joint injury. The dextrose evidence at this joint is an injection into the joint capsule and the acromial attachment of deltoid rather than around a nerve: 31 people with chronic moderate-to-severe shoulder pain had two sessions of ultrasound-guided 15% dextrose, average pain fell from 6.8 to 2.5 out of 10 and 20 of the 31 were substantially better with no adverse effects, in a single-arm study with no control group (Hsieh, J Ultrasound Med 2018). The supraclavicular nerves that supply the skin over this joint appear in the literature only as a target for anaesthetic blocks during surgery (Jiang, BMC Anesthesiol 2025).
Pairing reviewed 2026-09-16.
Where it fits
Not an acute-injury treatment. Occasionally relevant much later, if tender, hypersensitive skin persists over the joint after the injury itself has settled.
Ultrasound-guided nerve hydrodissection Fluid placed around a nerve to free it from the surrounding tissue. Only if relevant
What it involves
Under ultrasound, fluid is placed in the plane around the nerve to separate it from the tissue that is tethering or compressing it.
What the evidence shows
No study of hydrodissection at the acromioclavicular joint was found. Hydrodissection, hydrorelease, hydrodilatation and perineural injection searched against acromioclavicular and AC joint terms returned only general shoulder injection reviews (Mezian, Acta Chir Orthop Traumatol Cech 2025; Vargas-Figueroa, Cureus 2025), the second of which recommends brief sling use for acute low-grade AC joint injuries.
Pairing reviewed 2026-09-29.
Where it fits
Not a treatment for the injured joint. Considered only if a nerve becomes involved as the injury heals.
This is general information only and suitability is assessed individually. Treatments with limited or condition-dependent evidence may still be discussed, but only with clear explanation of the uncertainty, the expected benefit, risks, cost and alternatives. Red flags, progressive neurological symptoms or suspected serious pathology require a different pathway.
Every treatment above is described in full on the non-surgical treatments page, including what each one is used for and what the evidence supports. Ratings apply to the named diagnosis; an adjacent muscle, tendon, joint or nerve problem is assessed as a separate target. The method behind the ratings, and the treatments not offered, are set out on the evidence page.
Corticosteroid injection is reviewed separately for each diagnosis.
Cortisone reliably reduces pain in the short term, and that can be genuinely useful when pain is stopping you sleeping or moving enough to rehabilitate. Beyond that window the picture changes. A systematic review of 41 randomised trials and 2,672 participants found that corticosteroid injection reduced pain in the short term but that the effect reversed at intermediate and long term; in pooled analysis for lateral epicondylalgia the short-term effect was large (SMD 1.44, 95% CI 1.17 to 1.71) while no intervention was favoured at 26 weeks (-0.40, -0.67 to -0.14) and at 52 weeks (-0.31, -0.61 to -0.01) (Coombes, Lancet 2010). In a randomised trial in lateral epicondylalgia, 83 per cent of the corticosteroid group had completely recovered or much improved at one year against 96 per cent given a placebo injection, and recurrence ran at 54 per cent against 12 per cent; adding physiotherapy made no significant difference at one year (Coombes, JAMA 2013). In joints, repeated corticosteroid injections have been associated with cartilage loss. It does not repair anything.
So treatment plans are not built around it. Where an injection is the right call, the specific diagnosis and target are reviewed, what is being injected and why is discussed, the number is kept low, and it is paired with the loading work that changes the longer-term course.
When it might still be considered
- Pain severe enough to block rehabilitation
- A clear inflammatory or bursal target on imaging
- A specific short-term goal: a trip, a procedure, a return to work
- Diagnostic use, where the response shows where the pain is coming from
When a cortisone injection is worth doing, and when it is not
Other shoulder conditions
Pain in the same area can come from more than one source, and the label matters less than what the examination and history point to. These are the other guides for this region.
Frequently asked questions
Is an AC joint injury the same as a shoulder dislocation?
Does a visible bump mean I need surgery?
When is imaging needed?
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