| History: A thorough history will help establish the mechanism of injury and rule out other processes. In older individuals, it is important to distinguish AC separation from rotator cuff injuries, impingement syndrome (adhesive capsulitis), and glenohumeral arthritis. Individuals usually report a direct blow to the lateral shoulder area, either from a fall (e.g., landing on the side of the shoulder in a football tackle), or from a push or stumble (e.g., being checked into a wall when playing hockey). Individuals complain of pain, tenderness, swelling on the top of the shoulder, and decreased shoulder range-of-motion. Pain may be worse at night, particularly when rolling onto the injured shoulder. Athletes who do weight training may report difficulty with a specific exercise. Physical exam: Observation may reveal asymmetry of the two shoulders with a noticeable deformity on the affected side. Deformity is most obvious with a Grade III injury or with a clavicle fracture. Loss of the normal shoulder contour and prominence of the clavicle can be accentuated in Grade I and II injuries by having the individual hold a 10 to 15 pound weight in the hand of the affected side. There may be an abrasion on the shoulder as well as swelling and bruising (ecchymosis) at the site of the injury. The individual may hold the arm across the chest and apply upward pressure to the elbow.
Gentle examination of the AC joint with the fingers (palpation) may reveal tenderness. There is limited active range of motion and painful assisted (passive) range of motion of the shoulder. The cross-body (or crossover) adduction test is the most reliable physical exam technique for AC joint pathology. In grade III injuries, the high riding end of the clavicle may be rocked front to back (anterior-posterior) if examined shortly after the injury. Pain can be elicited over the coracoclavicular space. In grades IV through VI, the end of the clavicle may be depressed, aimed behind (posterior), above (superior), or below (inferior) the normal position. Comparison to the opposite shoulder is important when determining position. The nerves to the arm and circulation to the extremity should be examined by testing reflexes, sensation, pulses, and capillary filling time. Tests: X-rays of the AC joint help confirm the diagnosis. Stress radiographs may be used to assess degree of instability and distinguish Grade III separations. The individual holds a weight in the hand on the affected side to show the joint separation more clearly on x-ray (stress radiograph). In rare situations, a CT or MRI may be needed to evaluate injury to soft tissues surrounding the shoulder. A nerve conduction study (NCV) and electromyogram (EMG) study may be used to assess nerve damage. |
Source: Medical Disability Advisor