Primary dislocation of the shoulder. Factors affecting the two-year prognosis.

: Two hundred fifty-five patients with 257 primary dislocations of the shoulder were followed up for two years +/- 15 days in a multicenter study in Sweden. In patients 22 years of age or younger, there was a 47% recurrence rate. The corresponding figures for patients 23-29 and 30-40 years of age were 28% and 13%, respectively. The greatest risk for recurrence was in patients 17-19 years of age, 53% of whom had at least one recurrence. Such factors as sex, type of trauma, or physical activities did not enter into the prognosis. Spontaneously appearing dislocations were found most often in patients 22 years of age or younger--14% as compared with 1% in patients 30-40 years of age. The incidence of bilateral dislocations was greatest in patients 23-29 years of age.