Rehabbing an AC joint injury follows a phased approach that moves from protecting the joint while it heals to restoring full strength and mobility. The timeline depends heavily on severity: a mild sprain may need only 7 to 10 days of rest before starting rehab, while a surgical reconstruction can take 6 months or longer. Regardless of grade, the same core principles apply: control pain first, restore range of motion second, rebuild strength third, and return to full activity last.
Understanding Your Injury Grade
AC joint separations are classified on a scale from Type I to Type VI, and your grade determines whether you’ll rehab conservatively or recover from surgery. Type I is a sprain where the ligaments are stretched but intact. Type II involves a torn AC ligament with the deeper ligaments (called the coracoclavicular ligaments) still partially intact. Type III is a complete disruption of both sets of ligaments, causing the collarbone to visibly shift upward.
Types I and II are treated without surgery. Types IV through VI, where the collarbone displaces in more extreme directions, typically require surgical stabilization. Type III sits in a gray area that has been debated for decades. A meta-analysis of 244 patients found no significant difference in long-term functional outcomes between surgical and conservative treatment for Type III injuries. Surgery did provide better early pain relief, but it also carried a higher rate of complications including post-traumatic arthritis and hardware-related issues. Many orthopedic specialists now lean toward trying conservative rehab for Type III injuries first.
Why the AC Joint Matters
The AC joint sits at the top of your shoulder where the collarbone meets the shoulder blade. Two separate ligament systems hold it in place. The AC ligament resists about 50% of forward displacement and 90% of backward displacement. The coracoclavicular ligaments, a pair of deeper structures underneath, are responsible for keeping the collarbone from riding upward. When these ligaments are damaged, the shoulder blade loses its stable connection to the rest of the skeleton, which affects nearly every overhead and pushing movement.
This is why rehab focuses so heavily on strengthening the muscles around the shoulder blade. Even after the ligaments heal (or are surgically reconstructed), the surrounding muscles need to compensate and protect the joint from re-injury.
Phase 1: Protection and Pain Control
The first phase is about letting the damaged ligaments begin healing without additional stress. For a Type I injury, this means wearing a sling for about 7 to 10 days. For a Type II, sling use may last 4 to 6 weeks. After surgery, you’ll typically wear the sling most of the time for the first 2 weeks, including while sleeping, and remove it only for showering and exercises.
During this phase, avoid lifting anything, supporting your body weight with the injured arm, reaching behind your back, or reaching across your body. Ice as needed. The goal is simple: let pain and swelling settle so you can begin moving. For post-surgical patients, passive motion is kept below 90 degrees in any direction during the first 6 weeks.
Phase 2: Restoring Range of Motion
Rehab begins as soon as symptoms allow. For conservative cases, that could be within 1 to 2 weeks. For surgical cases, gentle motion starts during the first 6 weeks post-op but with strict limits.
Early exercises include pendulums, where you lean forward and let gravity gently swing the arm, and assisted range of motion where the uninjured arm helps guide the healing shoulder through its arc. Isometric exercises, where you press against a wall or doorframe without actually moving the joint, begin in this phase to keep the rotator cuff engaged without stressing the healing ligaments. These include pressing outward, inward, forward, backward, and sideways with the arm at your side.
The milestone for progressing past this phase is achieving about 90 degrees of forward flexion passively (someone else lifting your arm) and tolerating the isometric program without increased pain. For surgical patients, full progression criteria include reaching 140 degrees of passive flexion and being able to actively raise the arm against gravity to at least 100 degrees with good form.
Phase 3: Scapular and Rotator Cuff Strengthening
This is the most important phase for long-term AC joint health. The muscles that stabilize your shoulder blade, particularly the middle and lower trapezius and the serratus anterior, act as dynamic stabilizers that protect the AC joint during movement.
Key exercises in this phase include:
- Rowing with resistance tubing at various arm heights, focusing on squeezing the shoulder blades together rather than pulling with the arm
- Kinetic chain exercises like the “lawn mower” (mimicking the pull-start motion) and “disco” (a diagonal lifting pattern), which rebuild functional strength through coordinated full-body movement
- Shoulder shrugs with light resistance bands to re-engage the upper trapezius
- Prone T’s and Y’s, where you lie face down and raise your arms into a T or Y shape, recruiting high levels of middle and lower trapezius activity
T’s and Y’s are effective but place significant stress on the AC joint, so they’re generally reserved for later in this phase once the joint can tolerate load. Progressive resistance during this phase is typically capped at about 5 pounds. For surgical patients, overhead lifting with any weight is still off-limits, and objects heavier than 2 to 3 pounds should be avoided until around week 18.
Phase 4: Advanced Strengthening and Loading
Starting around week 13 for conservative cases and week 19 for surgical reconstructions, you transition from rehabilitation exercises to more traditional strength training. This means continuing the band and bodyweight exercises from Phase 3 while gradually adding free weights and machine work.
The progression should be gradual. Increase resistance in small increments and monitor how the joint responds over the following 24 to 48 hours. Soreness during exercise that resolves quickly is generally acceptable. Sharp pain at the AC joint, or aching that persists into the next day, means you’ve pushed too far.
Pay particular attention to pressing movements. The bench press is one of the most common aggravators of the AC joint. If you return to bench pressing, keep your hand placement narrower (less than 1.5 times the distance between your shoulders) and control the descent so the bar stops 4 to 6 inches above your chest rather than touching down. A rolled-up towel on the chest can serve as a spacer to enforce this range limit. These modifications substantially reduce stress on the distal end of the collarbone.
Return to Sport and Full Activity
There’s no single standardized test for clearing someone to return to contact sports or overhead athletics after an AC joint injury. A systematic review found that 95% of studies used time from surgery as the primary criterion, but only 6% used objective, conditional benchmarks. The most meaningful criteria to track are:
- Range of motion: full and pain-free in all directions, matching the uninjured side
- Strength: rotator cuff and scapular muscles testing at or near the level of the opposite shoulder
- Stability: no pain or excessive movement with direct pressure over the AC joint
- Functional tolerance: ability to perform sport-specific movements (throwing, tackling, handstands) without pain or apprehension
For most recreational athletes with a Type I or II injury, full return happens within 6 to 12 weeks. After surgical reconstruction, return to contact sports typically falls in the 5 to 7 month range, though this varies based on the specific procedure and individual healing.
Protecting the Joint Long-Term
Two complications can develop months or years after an AC joint injury, even one that healed well. The first is post-traumatic arthritis, where the cartilage in the joint gradually breaks down. The second is distal clavicle osteolysis, a condition where the end of the collarbone slowly resorbs due to repetitive stress. Both cause pain localized directly over the top of the shoulder, worsened by cross-body movements and pressing exercises.
If either develops, first-line treatment is activity modification, anti-inflammatory medication, and physical therapy focused on rotator cuff strength and flexibility. Modifying your bench press technique as described above is one of the most widely recommended adjustments. Corticosteroid injections into the AC joint can help both diagnostically (confirming the joint is the pain source) and therapeutically. Most people manage these conditions successfully without further surgery.