Distal Clavicular Osteolysis

Introduction Distal clavicular osteolysis (DCO) is an atypical injury occurring most often in athletes and weight lifters, specifically those who perform repetitive overhead movements. Distal clavicular osteolysis results from repetitive excess load to the AC joint, typically through horizontal adduction, adduction, internal rotation, and forward/lateral flexion of the shoulder, such as bench pressing or overhead lifting and causes pain at the acromial clavicle (AC) joint. ( ref Evans DC, Schroeder JD. Distal Clavicular Osteolysis. InStatPearls [Internet] 2022 May 25. StatPearls Publishing.) Distal clavicular osteolysis should be on the differential for any patient presenting for evaluation of AC joint or superior shoulder pain Anatomy The proximal clavicle interfaces with the sternum at the sternoclavicular (SC) joint, and the distal clavicle adjoins the acromion process to make the acromioclavicular (AC) joint. The AC joint receives its static stability from the AC joint capsule (AC ligaments) and the coracoclavicular ligaments; its dynamic stability from the deltoid and trapezius muscles. (Evans DC, Schroeder JD. Distal Clavicular Osteolysis. InStatPearls [Internet] 2022 May 25. StatPearls Publishing.) Causes The most common cause of DCO is aggravating activities such as bench pressing, overhead lifting, and overhead athletic movements such as volleyball, basketball, tennis, and swimming.

These movements cause frequent traction and compression loading of the AC joint, which leads to the repetitive microtrauma pattern implicated in DCO. This repetitive loading causes micro-trauma to the subchondral bone of the distal clavicular head, resulting in subchondral cystic changes, disruption of the articular cartilage, and metaplastic bone formation with increased osteoclastic activity. Epidemiology Distal clavicular osteolysis is almost exclusively a diagnosis of young athletes and weight lifters, particularly those engaging in repetitive pressing or overhead activities. However, there is no limit to the age at which DCO can occur physiologically. Historically, DCO was exclusively a disease of young male weightlifters and athletes, but it is now known to appear in females engaged in similar provoking activities. Signs and symptoms Pain over the lateral clavicle- Patients with DCO complain of gradual onset of dull aching pain, which may be unilateral or bilateral over the distal clavicle and AC joint. Localized tenderness and swelling of the lateral clavicle. Clinical findings There is pain with palpation over the area of the AC joint. Strength is often preserved but may have some pain inhibition during testing. Range of motion is also typically complete and pain-free outside of the extremes of shoulder abduction and internal rotation. Loading of the AC joint through Hawkins and Scarf tests elicits pain. Including a cervical spine and neurologic exam helps rule out referred pain. Differential diagnosis Musculoskeletal • AC joint arthritis • subacromial bursitis • superior labral (SLAP) tears Non-musculoskeletal • Hyperparathyroidism • Gout • Scleroderma • Rheumatoid arthritis • Multiple myeloma • Infection • Gorham disease • Referred pain from cervical region Investigations X-ray- Plain film X-ray of the AC joint is typically sufficient to evaluate for distal clavicular osteolysis. Imaging of DCO often demonstrates microcysts, loss of subchondral bone detail, and osteolysis of the distal clavicle. Early, mild, or unclear radiograph findings warrant consideration of other imaging modalities such as MRI, bone scan, or ultrasound. Diagnostic musculoskeletal ultrasound is an emerging option for diagnosing DCO. Ultrasound may be performed during evaluation by a trained clinician and is significantly less expensive than MRI and bone scan. It may also be more sensitive than plain film X-ray. Management The management of DCO include Physiotherapy, modification of activity, oral analgesia Excision of the AC joint. Patient education: As with other overuse injuries, limitation of provocative maneuvers such as repetitive loading and traction of the AC joint can prevent worsening of DCO. Shared decision-making: This allows for counseling these specific patients and identifying their goals and treatment options. Conservative management: Activity modification and nonsteroidal anti-inflammatory medication use are the first line management for DCO. Activity modification of bench press motion modification is widely recommended. Physiotherapy: Although no studies or position statements to date advocate a specific physical therapy regimen for DCO, restoring flexibility and rotator cuff strength are standard recommendations for those with additional shoulder pathology Surgical: Surgical management can be highly effective for those who fail nonoperative management or athletes unable to modify specific athletic tasks and activities. The mainstay of surgical intervention is resectioning the distal clavicle with no more than 8 mm of excision to avoid iatrogenic AC joint instability. This is performed through an open or arthroscopic technique. The open procedure offers the surgeon direct visualization and the ability to adjust the resection margin with a broader frame of reference. Additionally, many patients have a large superior osteophyte, which is more easily resected through an open approach. Recovery time for the open approach ranges from 5 to 12 weeks. The argument against the open technique is that it disrupts the deltotrapezial fascia superiorly. The two arthroscopic approaches are direct and indirect. Advantages of these techniques are less tissue dissection and potentially an earlier return to sport and recovery. The direct approach utilizes two portals, one located 1 cm posterior to the AC joint and the other 1 cm anterior. The indirect method requires three portals (anterior, posterior, and lateral), utilizing the subacromial space to visualize the inferior AC joint capsule. Both procedures involve a cutting burr to remove no more than 8 mm of the distal end of the clavicle to preserve the anterior and posterior AC ligaments.