Role of pain in measuring shoulder strength abduction and flexion with the Constant-Murley score.

OBJECTIVES: The Constant-Murley score (CS) has been used for more than 25 years to assess shoulder function. Strength by itself accounts for 25% of the total score. The measurement at 90° abduction seems to be sometimes limited by pain, particularly with tendinopathy or subacromial impingement. We compared the assessment of isometric strength in anterior forward flexion and abduction and its effect on pain and total CS.

METHODS: Strength was assessed by CS at both 90° forward flexion and abduction in the scapular plane by using an Isobex dynamometer, the first position tested being randomized. Pain was assessed on a 100-mm visual analog scale (VAS) and total CS was assessed.

RESULTS: We included 54 patients with unilateral shoulder problems; 50% had rotator cuff injury. Mean strength on the affected side was 4.7±2.5kg in forward flexion and 4.6±2.8kg in abduction. Induced pain and total CS did not differ between the 2 positions tested.

CONCLUSIONS: Strength can be measured by the CS in forward flexion or abduction, because the measurement does not affect strength, pain intensity or total score. The choice of direction for measurement should be based on the underlying pathology, related contraindications and patient preference.