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

Abstract and Introduction

Objective: This prospective investigation is designed to determine the prognostic factors associated with the response to conservative therapy of subacromial impingement syndrome. Materials and Methods: We treated 102 patients with subacromial impingement syndrome, diagnosed by physical examination and a subacromial lidocaine injection test, with a standardized conservative protocol. We followed the patients for a period of 12 months. Outcome was evaluated with Constant score and effects of 8 variables: Age, sex, pretreatment symptom duration, dominant shoulder, initial Constant score, active range of motion, acromion morphology, and acromial spur on patient outcomes were evaluated with univariate and multivariate analyses. Results: Among 89 patients (44 men; mean age, 56.4 years) who finished the study, the mean difference between initial and final scores was 15.9 (95% confidence interval [CI]: 13.9-17.8). Three variables, the initial Constant score ( b = .52, 95% CI: .28-.76), the duration of disease before treatment ( b = -4.4, 95% CI: from -7.2 to -1.6), and acromial morphology ( b = -5.3, 95% CI: from -9.8 to -.8) were found to be independent predictors of outcome (model R 2 = .68). Conclusion: Patients with more severe disease, a long duration of symptoms, and type II or III acromion may require more invasive therapeutic options as the first intervention.

Subacromial impingement and rotator cuff tears are common causes of shoulder disability. For the first time, Neer[1] popularized the concept of this syndrome, and described it as impingement of the rotator cuff tendon below the anteroinferior part of the acromion. This impingement caused tendonitis and eventual tendon tear. He described a clinical sign in which pain was aggravated when the affected shoulder was placed in forward-flexed and internally rotated position. He also introduced an impingement test that evaluated pain relief in response to subacromial injection of local anesthetics.

Three current accepted approaches to treatment of impingement syndrome include conservative management, arthroscopic surgery, and open surgical interventions. All of these therapeutic modalities have been found to be effective, even though there is controversy in the medical literature[2,3,4,5,6] about their success rates. Based on the effectiveness of noninvasive therapies, many investigators recommend a period of conservative management for at least 6-12 months.[6,7,8,9,10] Nevertheless, with the advent of arthroscopic surgical techniques, which are remarkably less invasive and require shorter rehabilitation periods than open surgical procedures, some surgeons suggest earlier arthroscopic intervention in rotator cuff disorders.[11]

A significant amount of our knowledge about the prognostic factors associated with the response to conservative therapy is from retrospective studies. The aim of our study is to determine these prognostic factors on the basis of a prospective investigation.


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