Basic Science
Minimal important changes in the Constant-Murley score in patients with subacromial pain

https://doi.org/10.1016/j.jse.2014.01.014Get rights and content

Objective

The purpose of this study was to determine the minimal important change (MIC) of improvement in the Constant-Murley score in patients with long-standing subacromial pain and in subgroups of patients with subacromial pain with and without rotator cuff ruptures.

Method

The MIC was estimated by the anchor-based MIC distribution method, which integrates an anchor- and distribution-based approach: the optimal cutoff point of the receiver operating characteristic curve (MICROC) and the 95% limit cutoff point (MIC95% limit). The study population consisted of 93 patients included in a randomized clinical trial evaluating the effect of a specific exercise strategy.

Results

The MICROC was found at a mean change of 17 points in the Constant-Murley score, which corresponds to a sensitivity of 91% and a specificity of 79%. The MIC95% limit was found at a mean change of 24 points. In the subgroup analysis, the MICROC was found at a mean change of 19 points and the MIC95% limit at 18 points in patients with an intact rotator cuff. In patients with rotator cuff ruptures, the MICROC was found at a mean change of 15 points and the MIC95% limit at 30 points.

Conclusion

The Constant-Murley score is able to detect the MIC in individual patients with long-standing subacromial pain when the rotator cuff is intact. The estimated MIC values could be used as an indication for relevant changes in the Constant-Murley score in clinical practice and guide the clinician in how to interpret the results of specific treatments.

Section snippets

Study population

The study population included patients in a randomized clinical trial evaluating the effect of a specific exercise strategy on long-standing subacromial pain.13 The inclusion criteria were as follows: age between 30 and 65 years, diagnosis of subacromial impingement syndrome, and on the waiting list for arthroscopic subacromial decompression. An orthopedic surgeon set the following criteria for surgery: a positive Neer impingement test result (injection of 1 mL of 20 mg/mL triamcinolone mixed

Results

Our analysis was based on 93 patients because 2 of the 97 patients included in the original RCT study13 lacked complete CM score change or PGIC data. Another 2 patients were excluded because of deterioration in the PGIC; this exclusion is in line with earlier studies.17, 18 Background data for the patients included in the analysis are presented in Table I. The mean changes in the CM score for each PGIC category are presented in Table II. Spearman ρ between the changes in the CM scores and the

Discussion

The CM score is often used in research and clinical practice to evaluate the effect of interventions for shoulder disorders. Therefore, it is important to identify the smallest change in the CM score that patients and clinicians should consider a clinically important change.

This study presents 2 MIC values for the CM score: the MICROC and the MIC95% limit cutoff points. In the current study, these values were quite different, with the MICROC at 17 points and the MIC95% limit at 24 points. The

Conclusion

Here we presented MIC values for the CM score for patients with long-standing subacromial pain. To our knowledge, this is the first time that MIC values in the CM score for patients conservatively treated with subacromial pain have been presented. The CM score is able to detect the MIC in individual patients with subacromial pain when the rotator cuff is intact. In all patients with subacromial pain, the MIC value was dependent on the subgroup being studied as well as on the choice of

Acknowledgment

We acknowledge the support and contribution of the Physiotherapy Orthopaedic Department of the University Hospital in Linköping, Sweden. We would also like to thank Henrik Magnusson for all statistical assistance.

Disclaimer

The authors, their immediate families, and any research foundation with which they are affiliated did not receive any financial payments or other benefits from any commercial entity related to the subject of this article.

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    Ethical approval: The study was approved by the ethics committee in Linköping (dnr: M124-07). All participants gave written informed consent.

    Data sharing: Physiotherapy protocols, statistical code, and data set are available from the corresponding author at [email protected].

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