Role of clinical and radiological parameters for recurrence after primary anterior shoulder dislocation

Recurrent shoulder dislocation risk is influenced by modifiable (sports participation, immobilization after first anterior dislocation of shoulder (FADS), timing of athletic activity resumption) and nonmodifiable factors like age, sex, hypermobility, and the initial mechanism of injury. These factors, individually or in combination, contribute to an increased risk of recurrent shoulder dislocation. This study aims to ascertain the factors contributing to recurrent anterior shoulder dislocation, explore their interplay, and assess their impact on the overall frequency of dislocations.

Clinical data regarding patient demographics, mechanism of injury, number of dislocations, night dislocations, and sports participation were retrospectively collected for 206 subjects. Radiological data, including glenoid bone loss and glenoid track, were also collected and analyzed.

Out of 206, 195 patients were men (94.7%). The mean age ± standard deviation at which men and women experienced their FADS was 25.3 ± 8.25 and 33.7 ± 9.43 years, respectively. Although FADS was common in overhead sports vs. other sports (83% vs. 17%), there was no difference in further recurrences between the two groups (P = .98). The second or further dislocations were more frequent in nonimmobilized shoulders than immobilized for 2-3 weeks (P = .006). The mean time gap between the first and second dislocation for self-reduced and doctor-reduced cases was 36.33 ± 1 08.48 and 53.43 ± 112.07 weeks (P = .022), respectively. Those with recurrent dislocation during sleep had 22.2 total dislocations compared to 8.3 who did not (P = .002). The mean glenoid bone loss in patients with dislocations during sleep-present and the sleep-absent groups was 15.34% and 10.12% (P = .028), respectively. The mean number of dislocations within the 0-10%, 10-20%, and 20-30% bone loss groups was 5.1, 9.9, and 29.9, respectively (P = .001), demonstrating a linear relationship with increasing bone loss. Furthermore, patients with off-track Hill Sachs lesions had a higher propensity for dislocation (P = .011).

Recurrence is more common in men and occurs at a younger age than in women. It is common in overhead sports. People who self-reduce their initial dislocation than doctor reduced, or nonimmobilized ones have a greater recurrence rate. Frequent dislocations during sleep have a strong association with higher glenoid bone loss. Increasing glenoid bone loss and off-track Hill Sachs lesion are also strongly associated with increased recurrent dislocations.