AC Joint Sprain

A sudden pain on top of the shoulder after a fall or contact hit, often with tenderness right over the bony bump, usually points to an AC joint sprain. We grade the injury, settle it down, and walk it back to full overhead use at our Burlington clinic.

What the Small Joint on Top of Your Shoulder Does

The AC joint, short for acromioclavicular joint, is where the outer end of the collarbone meets the bony tip of the shoulder blade. You can usually find it as a small bump on top of the shoulder, an inch or two in from the edge. Ligaments hold the two bones together and link the collarbone down to a small piece of the shoulder blade below.

An AC joint sprain is a stretch or tear of those ligaments. It is also called a shoulder separation, which gets confused with a shoulder dislocation. Dislocation happens at the main ball-and-socket joint. Separation happens at this smaller joint on top.

Sprains are graded one to six. Grades one and two are most common and respond well to conservative care; higher grades sometimes need surgical consultation. The shoulder injuries we see day to day include AC joint sprains, particularly from hockey, mountain biking, snowboarding, and other falls onto the shoulder.

How the Joint Gets Pushed Past Its Ligaments

AC joint sprains are almost always a single-event injury, not an overuse problem. The mechanism is a force pushing the bony tip of the shoulder downward while the collarbone stays in place, which loads the ligaments past what they can handle.

A fall onto the point of the shoulder, common in hockey, rugby, and martial arts
A fall from a bike or motorbike landing on the shoulder
A snowboard or skiing fall with a hard landing on the shoulder
A hit from above during contact sport

A fall onto an outstretched arm that loads the AC joint through the collarbone
A direct blow to the top of the shoulder from a swung object or contact
A car accident with shoulder belt loading or shoulder-first impact
Repetitive heavy pressing or overhead loading that aggravates a previous injury

Grading the Sprain Through Story, Look, and Test

The assessment starts with the story: the mechanism, how long ago it happened, whether you heard or felt a pop, and what you have been able to do with the arm since. The classic AC sprain story is a fall onto the shoulder followed by pain on top, particularly with reaching across the body or lifting overhead.

The physical exam is straightforward. We look first, since higher-grade AC sprains often produce a visible step where the collarbone sits higher than the shoulder blade tip. We palpate directly over the joint for tenderness and test the painful arc between roughly 160 and 180 degrees of overhead lifting, plus the cross-body adduction test.

X-rays are usually the first imaging step for any AC injury with significant pain, deformity, or trauma, since grading depends on how far the collarbone has shifted. MRI is reserved for higher-grade injuries heading toward surgical consultation. We also rule out clavicle fractures, rotator cuff injuries, and chronic AC arthritis in patients without a fresh trauma.

Physiotherapist assessing AC joint sprain in Burlington sports therapy clinic

Settling the Joint, Then Restoring Overhead and Pulling

Why the Timeline Depends on the Grade

Grades one and two, which make up most of what we see in clinic, almost always respond well to conservative care. Higher grades need surgical consideration.

In the acute phase (first one to three weeks), we calm the joint and protect it from further loading. A sling for the first few days, ice in the first forty-eight hours, and gradual pain-free range of motion are the staples. Manual therapy works on the surrounding shoulder blade, neck, and upper back regions that tighten up to protect the injured joint. Laser therapy supports tissue healing during the irritable phase.

Once irritability settles, we load the surrounding musculature. Rotator cuff and shoulder blade strengthening takes pressure off the AC joint. Progressive resistance moves through isometrics, bands, dumbbells, and back to pre-injury loads. Overhead work and pressing patterns reintroduce gradually since the AC joint compresses through both. You can’t go wrong with strong, and rebuilding strength is the most reliable way to keep AC sprains from leaving lasting weakness.

Surgical consultation is reserved for higher-grade injuries with significant displacement, grade three sprains in high-demand overhead athletes, and grade four and above. Most grade three sprains can still be managed conservatively, with research showing comparable long-term outcomes. Grade one returns to full activity in four to six weeks, grade two in six to ten weeks, and grade three managed conservatively in three to six months.

How We Treat AC Joint Sprains in Burlington

Chiropractic Treatment

Our chiropractors work on the shoulder blade, upper back, and neck regions that tighten up to protect the injured AC joint. Active Release Technique addresses the surrounding muscle guarding that builds after a fall. Graston Technique helps with chronic tissue changes in patients whose AC injury has been around for many months or has flared repeatedly.

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Massage Therapy

Our massage therapists work on the muscle tension that builds across the shoulder blade, neck, and upper back during the weeks the AC joint is settling. Releasing that tension makes it easier to load the shoulder through full range as recovery progresses. Acupuncture is often a useful addition during the acute phase for pain control and sleep support, since AC sprains often disrupt sleeping positions for the first few weeks.

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Physiotherapy

Our physiotherapists build the strengthening program that takes the shoulder from the acute phase back to full overhead and pulling demand. Rotator cuff strengthening, shoulder blade control, progressive resistance loading, and return-to-sport testing form the core of the plan. Shockwave therapy is sometimes used for chronic AC joint pain, and laser therapy supports healing during the irritable early phase.

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What AC Joint Recovery Looks Like

The grade of the sprain sets the timeline, but the stages themselves look the same across grades.

Protecting the Joint

The first one to three weeks focus on settling pain, protecting the joint from further loading, and keeping the rest of the shoulder, neck, and upper back from stiffening up. Sling use, ice, and gentle pain-free movement keep the foundation in place.

Reclaiming Range

Once acute pain settles, we restore range of motion to the shoulder, particularly overhead and across the body. Manual therapy and soft tissue work address the surrounding regions that have guarded against the injury.

Rebuilding Strength

Rotator cuff strengthening, shoulder blade control, and progressive resistance work build the support system the joint needs for daily and athletic demand. Eccentric and end-range loading prepare the shoulder for full return.

Return to Demand

Sport, work, and overhead tasks return step by step. We test the shoulder under realistic loading before fully clearing the demands that produced the injury in the first place.

AC Joint Sprain: Questions We Hear From Patients

These answers reflect the patterns we see in practice. Every sprain has its own grade, story, and demand picture, and a proper hands-on assessment is the most reliable way to set the right plan.

Helping Burlington patients move better since 2005.

How do I tell an AC joint sprain from a regular shoulder injury?

A few features point at the AC joint. Pain right on top of the shoulder, tenderness directly over the bony bump where the collarbone meets the shoulder blade, pain with reaching across the body, and a recent fall onto the shoulder are the classic combination. Higher-grade sprains often produce a visible step on top of the shoulder. The diagnosis is usually clear from the exam, with X-rays confirming the grade when displacement is suspected.

Will I need surgery for my AC joint sprain?

Most do not. Grade one and two sprains are nearly always managed conservatively. Grade three sprains can be managed conservatively in many patients, with research showing comparable long-term outcomes to surgery for many cases, though high-demand overhead athletes sometimes opt for surgery. Grade four through six injuries usually warrant surgical consultation because of the degree of displacement.

How long until I can get back to sport or training?

Timelines depend on the grade. Grade one sprains usually return to full activity within four to six weeks. Grade two sprains usually take six to ten weeks. Grade three sprains managed conservatively often take three to six months for full return to athletic or high-demand work. The return-to-sport stage is paced by how the shoulder performs under realistic loading, not the calendar alone.

Will the bump on top of my shoulder go down?

For lower-grade sprains, often yes, as swelling settles. For grade three sprains where the ligaments have fully torn, the step on top of the shoulder usually stays visible long-term, though it does not typically affect function once strength has been rebuilt. The cosmetic step is one of the reasons some patients consider surgical consultation for higher-grade injuries.

Can I still train other things while my AC joint heals?

Usually yes. Lower body, core, and uninjured side training can almost always continue. For the injured side, the rule is to avoid loading patterns that aggravate the AC joint, which usually means overhead pressing, dips, bench at certain angles, and direct loading on the joint. We adjust the plan to your specific grade and timeline.

Will an AC joint sprain come back later?

A well-healed AC sprain rarely re-injures the same way unless the same mechanism repeats, particularly in contact sport, mountain biking, or snowboarding. Some patients with grade three sprains develop AC joint arthritis years later because the joint mechanics have changed permanently. The patients who do best long-term keep the surrounding strength up after they return to full activity.