2021 ISAKOS Biennial Congress ePoster
The epidemiology of acute acromioclavicular dislocations in an urban population. A prospective cohort study investigating the capital region of Denmark
Kristine Bramsen Haugaard, MD, Aarhus DENMARK
Klaus Bak, MD, Copenhagen Oe, Copenhagen DENMARK
Per Hölmich, DMSc, Prof., Copenhagen DENMARK
Kristoffer Michael Seem, MD, Copenhagen DENMARK
Kristoffer W. Barfod, MD, PhD, Virum DENMARK
Sports Orthopedic Research Center - Copenhagen, University Hospital Hvidovre , Hvidovre, Copenhagen, DENMARK
FDA Status Not Applicable
Summary
A prospective registration of all acromioclavicular joint dislocations in a catchment area of 549,225 residents in Copenhagen revealed an incidence of 19.3 per 100,000 person years at risk with Rockwood type III being the most common type of injury constituting 55,7% of the injuries.
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Abstract
Purpose
To investigate the incidence of acute acromioclavicular joint dislocations in the capital region of Denmark
Methods
All patients with acute AC joint dislocation admitted to the Emergency Departments at three University Hospitals serving a population of 549,225 residents in the Capital region of Denmark were prospectively registered from 1 January to 31 December 2019. Patients with trauma to the shoulder, pain from the AC joint and increased coracoclavicular distance on radiographs were included and classified according to Rockwood’s classification. Type I injuries were excluded as they represent a sprain to the joint rather than a true dislocation. Data on age, sex, affected side and mechanism of injury were registered.
Results
106 patients, male:female ratio 8.6:1, were included. The overall incidence of AC joint dislocations was 19.3 per 100,000 person years at risk (PYRS); 34.9 per 100,000 PYRS for men and 4.0 per 100,000 PYRS for women. The age distribution was bimodal peaking at the ages of 20-24 (39.8 per 100,000 PYRS) and 55-59 (43.6 per 100,000 PYRS). Rockwood type III was the most common type of AC joint dislocation accounting for 55.7% of the injuries. Type II and V accounted for 40.6% and 3.8% respectively. There were no type IV or VI dislocations. The most common mechanism of injury was sports accounting for 80/106 (75.5%) with cycling accounting for almost half of all injuries with 51/106 (48.1%).
Conclusions
The incidence of AC joint dislocations was 19.3 per 100,000 PYRS, which is in concordance with results from previous similar studies reporting incidences in the range 8-45:100,000. Rockwood type III was the most common type of AC joint dislocation accounting for 55.7% of the injuries. Young and middle-aged men were at highest risk. Seventy-five % of the injuries occurred during sports, most frequently within cycling.