The acromioclavicular (AC) joint is located at the top of the shoulder, where the collarbone (clavicle) meets the highest point of the shoulder blade (acromion). This joint facilitates movements and allows the scapula to rotate, positioning the arm for various activities. Injuries to the AC joint are frequently encountered, particularly among active individuals and athletes, often resulting from a direct fall onto the shoulder or a forceful impact.
Understanding AC Joint Injuries
An AC joint injury occurs when the ligaments supporting this joint are stretched or torn, leading to varying degrees of separation between the clavicle and acromion. These injuries are classified into grades based on the extent of ligament damage and joint displacement. The Rockwood classification system is used, categorizing injuries from Grade I to Grade VI.
A Grade I injury represents a mild sprain where the AC ligament is stretched or partially torn, with no visible deformity or significant joint displacement. In a Grade II injury, the AC ligament is completely torn, and the AC joint may show some instability, though the coracoclavicular (CC) ligaments remain intact or are partially torn. Grade III injuries involve a complete tear of both the AC and CC ligaments, resulting in noticeable upward displacement of the clavicle, creating a visible bump on the shoulder. More severe but less common injuries (Grades IV-VI) involve greater clavicle displacement, often requiring specialized assessment due to complex tears.
Factors Influencing Healing
The healing duration for an AC joint injury can vary among individuals, influenced by several factors beyond the injury grade. An individual’s overall health plays a role, as good general physical condition can support faster tissue repair. Age is another contributing factor, with younger individuals demonstrating quicker healing responses compared to older adults.
Adherence to prescribed rehabilitation protocols is an important determinant of recovery speed and completeness. Following physical therapy exercises and activity modifications diligently helps recovery and prevent re-injury. Good nutrition and the absence of other underlying medical conditions also affect how efficiently the body recovers from an AC joint injury.
Typical Healing Timelines by Injury Grade
Healing timelines for AC joint injuries largely depend on their severity, categorized by grade. For a Grade I AC joint injury, initial pain and swelling subside within a few days to two weeks. Individuals can return to light activities quickly, with full recovery expected within one to two weeks, though symptoms can persist for up to three months.
Grade II injuries, involving a complete tear of the AC ligament, require a longer recovery period. Pain reduction and the ability to perform light activities occur within three to six weeks. Full recovery for a Grade II injury takes between three to six weeks, although symptoms may linger for up to three months.
A Grade III AC joint injury requires a more extended healing process. While initial pain may decrease and light activities can be resumed within six to twelve weeks, full recovery spans two to three months without surgery. For some, symptoms can continue for three to six months, highlighting the individual variability in healing.
Treatment and Rehabilitation Approaches
Treatment for AC joint injuries is guided by the injury’s severity. Conservative management is the initial approach for most Grade I, II, and many Grade III injuries. This involves rest, applying ice to reduce swelling and pain, and using a sling for comfort and support, often for one to three weeks. Over-the-counter pain medications, such as anti-inflammatory drugs, are also used to manage discomfort.
Physical therapy plays an important role in rehabilitation, beginning once initial pain and swelling subside. Rehabilitation aims to restore range of motion, strength, and stability to the shoulder through a progressive exercise program. This includes gentle pendulum exercises, active range-of-motion movements, and later, strengthening exercises targeting the muscles around the shoulder blade and rotator cuff. While most AC joint injuries heal with conservative treatment, surgical intervention may be considered for severe cases (Grades IV-VI) or for Grade III injuries in specific situations, such as in younger, highly active individuals, or when conservative treatment does not yield satisfactory outcomes. Surgical recovery involves several months of rehabilitation, potentially taking four to six months for a full return to function.
Safe Return to Activities
Returning to daily activities, work, and sports after an AC joint injury requires a gradual approach. It is important to avoid rushing the return to strenuous activities, as this can lead to re-injury or chronic issues. Individuals should progress through activities based on pain levels and functional improvements, rather than strict timelines.
Listening to the body and respecting any discomfort is an important aspect of safe recovery. Clearance from a healthcare professional (e.g., physical therapist or orthopedic specialist) is recommended before resuming demanding physical tasks or sports. They can assess joint stability, range of motion, and strength to ensure the shoulder is adequately prepared for increased loads, sometimes recommending protective padding for contact sports.