Longer immobilization extends the "symptom-free" period following primary shoulder dislocation in young rugby players

The purpose of this study was to evaluate the effect of longer immobilization following primary shoulder dislocation in young rugby players for the prevention of recurrence. We sent a questionnaire regarding shoulder dislocation to all senior high school and college rugby teams in the southwest region of Japan. We received replies from 5476 players in 196 teams (i.e., answers were received from 76% of the teams). Based on the answers from the 79 rugby players who had undergone shoulder dislocations and who were eligible for the study, we divided them into two groups; group I: immobilization for 0-3 weeks at the time of the initial dislocation (n = 61), and group II: immobilization for 4-7 weeks (n = 18). We compared the time-course from primary dislocation to recurrence between the two groups, using the Kaplan-Meier method. The age range at the time of the primary dislocation was 14-23 years (average, 16.7 years). The probability of recurrence in groups I and II, respectively, was 78% and 44% after 1 year; and 85% and 69% after 2 years. The median period from return to rugby to recurrence was 4 months in group I and 14 months in group II. The symptom-free period was extended when immobilization was carried out for 4 weeks or more, in comparison with the symptom-free period in those who had immobilization for 3 weeks or less.