Outcome Predictors in Nonoperative Management of Newly Diagnosed Subacromial Impingement Syndrome: A Longitudinal Study

Afshin TaheriAzam, MD; Mohsen Sadatsafavi, MD; Alireza Moayyeri, MD

In This Article


Of the 102 participants who entered the study, 13 (12.7%) were excluded from the final analysis because of short follow-up (7 cases), discontinuation of drugs due to gastrointestinal adverse effects (2 cases), and noncompliance to the follow-up program (4 cases). Baseline characteristics of 89 participants who completed the follow-up program are shown in Table 1 .

Mean constant scores of the participants at the initial and last follow-up visits were 66.7 (SD = 11.1) and 82.6 (SD = 13.5), respectively. Participants had an average increase of 15.9 (95% confidence interval: 13.9-17.8) in their Constant scores. At the last follow-up, 69% (61 cases) of participants had an improvement of more than or equal to 10 points in their Constant scores; 27% (24 cases) had minor or no improvement (less than 10 points); and 4.5% (4 cases) experienced deterioration of the disease.

The association of 8 baseline variables to the final outcome was evaluated, in which 4 variables (pretreatment Constant score, pretreatment duration of symptoms, active range of motion, and acromial morphology) were found to be correlated to the final constant score ( Table 2 ).

In a multivariate linear model, 3 variables, including the pretreatment Constant score, the duration of involvement, and acromial morphology, were found to be independent predictors of the treatment outcome ( Table 2 ). Analysis of residuals revealed a normal distribution (1-sample Kolmogorov-Smirnov P value = .3). The 3-variable model had an R -square of .68 with a standard error of the estimate of 7.6. This model had a better fitness than each of the univariate models on the basis of 3 mentioned variables ( Table 3 ).


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