Epidemiology

Anterior shoulder dislocations account for more than 95% of shoulder dislocations and are the most common major joint dislocation. [3] Posterior shoulder dislocations occur in 2% to 4% of cases, and inferior (i.e., luxatio erecta) dislocations in approximately 5% of cases. The incidence of shoulder dislocations has bi-modal peaks, the first in men aged 21 to 30 years, and the second in women aged 61 to 80 years. [4] Studies from the US and Denmark found that the incidence rates are higher in males than in females, with an overall incidence of 11 to 17 per 100,000 population. [4] [5] One study in Scotland found the incidence of posterior fracture-dislocations of the shoulder to be 0.6 per 100,000. [6]

In the US, fractures and fracture dislocations of the hand account for 2% to 28% of all emergency department visits. They are more likely to occur in males aged 10 to 40 years, and only two-thirds of patients present within 24 hours of the time of injury. [7]

In a study of young military personnel in Germany, the incidence of acute traumatic primary dislocation of the patella was estimated to be 77 per 100,000 people per year. [8] In adolescent populations, patellar dislocations are often associated with sports-related activities. [9] In the non-athletic population, women aged 10 to 17 years are more likely to have patellar dislocations. Women are also more likely to have a prior history of patellar instability and recurrent dislocation. [10] In addition, patients with a history of patellar instability and recurrent dislocation are more likely to have contralateral injuries. [11]

Studies from the US, Sweden, and Germany have shown that the annual incidence of elbow dislocations is 6 to 8 per 100,000 population. [12] [13] [14] Approximately 50% are associated with sports-related activities and 20% to 50% are associated with fractures. The incidence in males and females is equal. Most elbow dislocations (80% to 90%) are posterior or posterolateral. [15]