Single Assessment Numeric Evaluation for instability as an alternative to the Rowe score

Background: Several functional outcome scores have been proposed for the evaluation of shoulder instability. Most are multiple-item questionnaires, which can be time-consuming and difficult for patients to understand, as well as leading to lack of compliance. The Single Assessment Numeric Evaluation (SANE) score is a single question that has recently gained widespread acceptance based on its simplicity and correlation with more complex scoring systems. The purpose of this study was to assess the correlation of a new modified version of the SANE score, the SANE-instability score, with the Rowe score after treatment for shoulder instability.

Materials and methods: We prospectively evaluated a consecutive series of 253 patients (268 shoulders) treated surgically or nonoperatively for shoulder instability between November 2017 and November 2019, for whom the Rowe and SANE-instability scores were collected before treatment and/or after treatment. The SANE-instability score was assessed with the following question: "What is the overall percent value of your shoulder if a completely stable shoulder represents 100%?" Correlations were tested using the Pearson coefficient (r) and interpreted as very high (r = 0.90-1.00), high (r = 0.70-0.89), moderate (r = 0.50-0.69), low (r = 0.30-0.49), or negligible (r = 0.00-0.29). Subgroup analyses were also performed to observe correlation variations according to follow-up length (before treatment and at 6, 12, 26, 52, and 104 weeks after treatment), patient age (<20, 20-29, 30-39, or ≥40 years), and type of treatment (nonoperative or surgical).

Results: The overall correlation between the SANE-instability and Rowe scores was high (r = 0.85, P < .001). Subgroup analyses revealed that the correlation between the 2 scores was high before treatment (r = 0.74); moderate at 6 and 12 weeks after treatment (r = 0.66 and r = 0.57, respectively); and then high at 26, 52, and 104 weeks after treatment (r = 0.75, r = 0.75, and r = 0.78, respectively) (P < .001). The correlation was high across all types of treatment (r = 0.76-0.85), high for patients aged ≥ 20 years (r = 0.80-0.86), and very high for patients aged < 20 years (r = 0.93) (P < .001).

Conclusion: This study demonstrated a significant correlation between the SANE-instability and Rowe scores before and after treatment, as well as across all patient age groups and treatments. Owing to its high simplicity, the SANE-instability score could be used as an alternative to the Rowe score for patient follow-up at various time points.