The acromioclavicular (AC) joint connects the collarbone (clavicle) to the shoulder blade (acromion). This joint allows the arm to move through various ranges of motion, especially overhead, and transmits forces from the arm to the rest of the skeleton. Injuries to this joint, often referred to as shoulder separations, are common, especially from direct impacts to the shoulder or falls onto an outstretched hand. These injuries can range from mild sprains to complete dislocations, and treatment depends on the injury’s severity.
Understanding AC Joint Injuries
AC joint injuries are classified into six grades, known as the Rockwood classification, which helps determine the extent of ligament damage and clavicle displacement. Grade I injuries involve a mild AC ligament sprain, causing tenderness without significant displacement. Grade II injuries indicate a complete AC ligament tear and partial coracoclavicular ligament tear, leading to more pain and a noticeable bump. In these lower grades, the joint may still maintain some alignment.
Grade III injuries involve a complete rupture of both the AC and coracoclavicular ligaments, causing significant clavicle displacement and a prominent bump. Higher grades (IV, V, and VI) represent increasingly severe displacements. For example, Grade IV involves backward clavicle displacement, Grade V includes extreme downward displacement, and Grade VI sees the clavicle lodged beneath the coracoid process. Diagnosis involves a physical examination and imaging like X-rays to assess the injury’s grade.
Non-Surgical Treatments
Conservative management is the initial approach for AC joint injuries, particularly for lower-grade separations (Grade I and II), and sometimes for Grade III injuries. This approach aims to alleviate pain and restore function. Rest is a primary component, often involving immobilizing the shoulder in a sling for a few days to several weeks. Applying ice to the injured area helps reduce pain and swelling, with recommendations for 15-30 minute applications multiple times a day.
Over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen are commonly used to manage pain and inflammation. As pain subsides, physical therapy becomes an important aspect of recovery. Physical therapy focuses on regaining the shoulder’s range of motion, improving strength in surrounding muscles, and restoring overall function. Exercises may start with gentle movements and progress to more active strengthening to stabilize the shoulder. Activity modification, which involves avoiding movements that worsen pain or strain the joint, is also important throughout the recovery process.
When Surgery is Considered
Surgery for AC joint injuries is considered under specific circumstances, such as when the injury is severe or non-surgical treatments fail. High-grade separations, particularly Rockwood Grades IV, V, and VI, warrant surgical intervention due to significant displacement and instability. These severe injuries can cause substantial dysfunction if left untreated.
For Grade III injuries, the decision for surgery is individualized and sometimes debated. However, surgery may be recommended if there is persistent pain, ongoing instability, or a significant cosmetic deformity despite conservative treatment. Individuals with high physical demands, such as athletes or those whose occupations require frequent overhead arm use, may also be candidates for surgery, as they often require a higher level of functional recovery. The decision involves discussing benefits and risks with a surgeon.
What AC Joint Surgery Involves
AC joint surgery aims to stabilize the joint and restore proper alignment between the collarbone and shoulder blade. Various surgical techniques are employed, chosen based on injury severity and surgeon preference. One common approach involves directly repairing torn ligaments. In cases where ligaments are severely damaged or in chronic injuries, reconstruction may be necessary. This often involves using a tissue graft (synthetic, donor, or from the patient’s own body). These grafts recreate the coracoclavicular ligaments, providing vertical stability.
To hold the bones in their corrected position while healing occurs, surgeons may use various types of hardware, including screws, plates, wires, or buttons. For instance, a common technique involves passing sutures through drilled holes in the collarbone and shoulder blade, securing them with buttons to pull the clavicle back into place. Some procedures can be performed arthroscopically, using small incisions and a camera, offering advantages like smaller incisions and potentially shorter recovery times.
Recovery and Outcomes After Surgery
Recovery after AC joint surgery involves a structured rehabilitation program to regain strength, flexibility, and stability. Immediately after surgery, the arm is immobilized in a sling for several weeks (e.g., four to six weeks) to protect healing tissues. Gentle exercises for the hand, wrist, and elbow maintain mobility.
Physical therapy progresses gradually, beginning with passive range-of-motion exercises where the therapist moves the arm without the patient’s muscle activation. Active range-of-motion exercises start around six to eight weeks post-surgery, followed by strengthening exercises targeting shoulder muscles. Full recovery can take four to six months or longer, depending on healing capacity, injury severity, and surgical technique. Potential complications include infection, stiffness, re-injury, or issues with implanted hardware. Many individuals experience improved function and pain relief, often returning to sports or daily activities. Some studies suggest outcomes might be similar to non-surgical treatment for certain injury types.