A break down of the distal clavicle, believed to be secondary to repetitive trauma resulting in microfractures of distal clavicle. It can result in subacromial impingement and subacromial bursitis. Occurs in body builders, weight lifters and athletes training with upper body resistance exercises. It affects male to females from 3:1 up to 9:1. 1,2
This injury is secondary to repetitive load on the acromioclavicular joint. This may include repetitive weight resistance exercises mainly bench press, shoulder press, power clean.3 It may also include repetitive trauma occupational or sport related – heavy bags/equipment on shoulder, use of oscillating equipment (jackhammer), or mixed martial arts/wrestling – repetitive shoulder impact into mats. One study of 227 participants with osteolysis of distal clavicle found 56% of athletes participated in a high intensity bench press program.
Acromioclavicular osteoarthritis, acromioclavicular separation, adhesive capsulitits, subacromial impingement, biceps tenosynovitis, referred pain from cervical spine, posterior labral tears, pectoralis tears/strain, subcoracoid bursitis,2 trapezius tear, rotator cuff pathology (calcific tendinitis, tendinitis, tears).
Xray: Subchondral cysts, widening of AC joint, irregular cortical appearance of distal end of clavicle See figures 1-4 for normal to abnormal findings.
Figure’s 1 and 2 – Normal Acromioclavicular joint on Right with normal appearance of distal clavicle – without weights and with weights (arrow)
Figure 3 and 4 – Left acromioclavicular joint
Ultrasound – may be used to screen for biceps, and rotator cuff pathologies.
MRI – The 2 findings in keeping with DCO on MRI are: 1) Bone marrow edema of distal clavicle and 2) Subchondral fracture. 1
MRI is also useful for ruling out associated rotator cuff, subcoracoid bursitis, biceps and labral pathology.
Patients are typically tender over the AC joint, it is important to palpate superiorly, anteriorly, posteriorly as well as well as dynamically by applying an anterior-posterior displacement of clavicle upon the acromion as simple superior palpation may not elicit the patient’s symptoms. With isolated DCO, patients will have full range of motion. They will typically have pain with compressive tests of the AC joint – cross chest adduction – passive and sometimes active, full abduction 150-180 degrees, scarf testing, and dynamic scarf testing – elevation of elbow against resistance with shoulder adducted (positive if patient points to AC as point of pain).
Examination of cervical spine, shoulder range of motion, rotator cuff, labrum and biceps as indicated.
Conservative: Modification of activity – for bench press – narrow grips, place towels on chest to limit amount of eccentric/descent phase of press.3 Avoid dips, shoulder press, bench press in painful ranges/high intensity, power clean – racking phase.
Many articles recommend non-steroidal antiinflammatories2,3 to reduce pain, however limited evidence to support improvement of condition as a result. Similarly, corticorsteroid injections into the AC joint may provide short term relief, however there is little evidence to support long term benefit. Some providers may recommend a cortisone injeciton in to subacromial space to treat a potential associated subacromial bursitis.
Prognosis with conservative treatment:
In younger patients (mean age 15.9) in a retrospective study 1, 93% reported improvement by 4.5 months with conservative therapy, whereas in an older cohort (mean age 28.7) 76% of patients responded to conservative treatment.2
Corticosteroid injection – often short acting – minimal evidence for any longterm relief. May be helpful diagnostically.
Surgical – several approaches have been described subacromial and direct – as well as open and arthroscopic. The main objective is to resect the distal clavicle by anywhere from 4mm-20mm have been described in the literature. 1,2, 3 The outcomes appear to be favourable for the patient to returning to prior level of activity with reduced pain. Failure is rare as are complications which include a case report of heterotrophic ossification of distal clavicle postoperatively. 3
Dr. Neil Dilworth (June 19, 2019 – PR )
1. Roedl JB1, Nevalainen M, Gonzalez FM, Dodson CC, Morrison WB, Zoga AC. Frequency, imaging findings, risk factors, and long-term sequelae of distal clavicular osteolysis in young patients. Skeletal Radiol. 2015 May;44(5):659-66. doi: 10.1007/s00256-014-2092-2. Epub 2015 Jan 7.
2. Nevalainen MT1, Ciccotti MG2, Morrison WB1, Zoga AC1, Roedl JB3. Distal clavicular osteolysis in adults: association with bench pressing intensity. Skeletal Radiol. 2016 Nov;45(11):1473-9. doi: 10.1007/s00256-016-2446-z. Epub 2016 Aug 22.
3. Schwarzkopf R1, Ishak C, Elman M, Gelber J, Strauss DN, Jazrawi LM. Distal clavicular osteolysis: a review of the literature. Bull NYU Hosp Jt Dis. 2008;66(2):94-101.