Purpose: Shoulder instability is a common problem affecting patients in their most active years resulting in an impact on their quality of life. The WOSI is a validated, disease-specific (shoulder instability) evaluative quality of life measure. It has not been tested for its ability to discriminate between those who require surgical care and those who do not. The purpose of this study is to determine if the WOSI can discriminate between surgical and non-surgical patients and between patients with different types of shoulder instability.

Method: Sixty patients with a confirmed diagnosis of shoulder instability were included as cases. Twenty had documented multidirectional instability requiring surgery: Group 1 Surgical MDI – 20 patients had documented recurrent traumatic anterior dislocations requiring surgery: Group 2 Surgical Anterior – 20 patients were first time anterior dislocators who were followed for a minimum one year who had no further recurrences and did not require surgery: Group 3 Non-Surgical First Time Anterior – The cases were compared to 60 age and gender matched control patients with no history of shoulder problems: Group 4 Control – WOSI scores were analyzed using a one-way ANOVA.

Results: The WOSI scores were as follows: Group 1 Surgical MDI- mean 30.5 (95% CI 23.1–37.8); Group 2 Surgical Anterior- mean 39.8 (95% CI 33.1–46.5); Group 3 Non-Surgical First time Anterior- mean 76.2 (95% CI 66.4–86.0) and Group 4 Control- mean 96.6 (95% CI 95.8–97.4). Based on the 95% Confidence Intervals, there were statistically significant differences between the two surgical groups (Group 1 Surgical MDI and Group 2 Surgical Anterior) compared to the non-surgical patients (Group 3 Non Surgical First Time Anterior) and the controls (P=0.000). There is a trend to discriminate between the two surgical groups (P=0.079).

Conclusion: The WOSI Index clearly discriminates between surgical and non-surgical patients with shoulder instability, and the control population with normal shoulders. There is a trend to discriminate between MDI and recurrent anterior traumatic dislocators.